Cartridge and method of testing one or more electronic devices

Abstract

A tester device is described. Various components, including an insertion and removal device, thermal posts, independent gimbaling, inclusion of a photodetector, combination of thermal control methods, detection circuit within a socket lead, through-posts with standoffs, and voltage retargeting, contribute to the functionality of the tester device.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] This application claims priority from U.S. provisional application No. 62 / 466,462 filed March 3, 2017 and U.S. provisional application No. 62 / 526,089 filed June 28, 2017, which are hereby incorporated by reference into this application.

[0003] The present invention relates to a tester device used to test microelectronic circuits. Background Technology

[0004] Microelectronic circuits are typically fabricated on and above semiconductor wafers. These wafers are subsequently "singulated" or "diced" into individual dies. These dies are typically mounted on a support substrate to provide rigidity and for the integration of the dies or electronic communication with the microelectronic circuits. Final packaging may involve the encapsulation of the dies, and the resulting package can then be shipped to the customer.

[0005] Dies or packages are required to be tested before being shipped to the customer. Ideally, dies should be tested at an early stage to identify defects that occur during early-stage manufacturing. Wafer-level testing may be achieved by providing contacts to handlers and contactors, and then using the handler to move the wafer so that the contacts on the wafer come into contact with the contactors. Power and electronic signals can then be provided through the contactors to and from the microelectronic circuits formed on the wafer.

[0006] According to various embodiments, the wafer comprises a substrate, such as a silicon substrate or a printed circuit board, and one or more devices fabricated within the substrate or mounted on the substrate.

[0007] Alternatively, the wafer may be placed within a portable cartridge having an electrical interface and a thermal chuck. Power and signals may be provided to and from the wafer through the electrical interface while the temperature of the wafer is thermally controlled by heating or cooling the thermal chuck.

[0008] After the wafer is singulated, individual dies may be required to be tested again, or the die may be required to be tested again after it is mounted on a support substrate. means of solving the problem

[0009] The present invention provides a testing device, the testing device comprising: a frame; a slot assembly on the frame; a slot assembly interface on the slot assembly; a holding structure for holding a cartridge that holds a plurality of microelectronic devices; a horizontal transport device operable to move the cartridge horizontally from a first position to a second position into the slot assembly; a vertical transport device operable to move the cartridge and the slot assembly in a first vertical direction relative to each other to engage the slot assembly interface with the cartridge interface on the cartridge; and a tester connected through the first slot assembly interface and the cartridge interface to provide at least power to each microelectronic device and to measure the performance of the microelectronic device, wherein the vertical transport device operable to move the cartridge and the slot assembly in a second vertical direction opposite to the first vertical direction relative to each other to disengage the slot assembly interface from the cartridge interface, and the horizontal transport device operable to move the cartridge horizontally from the second position to the first position out of the slot assembly.

[0010] The present invention also provides a method for testing electronic devices, the method comprising: holding a cartridge that holds a plurality of microelectronic devices at least partially at a first position outside a slot assembly on a frame; moving the cartridge horizontally from a first position to a second position into the slot assembly; moving the cartridge and the slot assembly in a first vertical direction relative to each other to engage a slot assembly interface on the slot assembly with a cartridge interface on the cartridge; testing the microelectronic devices through the first slot assembly interface and the cartridge interface by providing power to each microelectronic device and measuring the performance of the microelectronic device; moving the cartridge and the slot assembly in a second vertical direction opposite to the first vertical direction relative to each other to disengage the slot assembly interface from the cartridge interface; and moving the cartridge horizontally from a second position to a first position outside the slot assembly.

[0011] The present invention further provides a cartridge, the cartridge comprising: a socket made of insulating material and having an upper side and a lower side, wherein the upper side has a first formation for holding a first electronic device releaseably, and the socket has a first socket thermal opening formed from the lower side to the upper side through the socket; an interface connected to the socket for connecting the first device to an electrical tester; a chuck made of a thermally conductive material and a first thermal post attached to the chuck, wherein the first thermal post is inserted into the first socket thermal opening, and the end of the first thermal post is thermally connected to the first device, so that heat is transferred mainly through the first thermal post rather than through the socket of insulating material between the chuck and the first electronic device.

[0012] The present invention also provides a test piece, the test piece comprising: a socket made of insulating material and having an upper side and a lower side, wherein the upper side has a first forming for holding a first electronic device releaseably, the socket has a first socket column opening formed from the lower side to the upper side through the socket, and a first thermal conductive post insertable into the first socket column opening from the lower side, the socket comprising a first set of pins held in the socket and connecting the first device to a circuit board, wherein the first set of pins is elastically pressable, and a lead movable relative to the socket to press the first set of pins to bring the first electronic device into contact with the end of the first column post.

[0013] The present invention further provides a test piece, the test piece comprising a chuck of a thermally conductive material and a first column post attached to the chuck, wherein the first column post is insertable into a first socket column opening with the end of the first column post thermally connected to a first device, so that heat is transferred mainly through the first column post rather than through the socket of the insulating material between the chuck and the first electronic device.

[0014] The present invention also provides a method for testing one or more electronic devices, the method comprising: a step of releasingly holding a first device in a first formation on the upper side of a socket made of insulating material; a step of connecting the first device to an electrical tester through an interface connected to the socket; a step of inserting a first thermal post attached to a chuck of a thermally conductive material into a first socket thermal opening formed from the lower side to the upper side through the socket, wherein the end of the first thermal post is thermally connected to the first device; and a step of transferring heat between the chuck and the first electronic device, wherein the heat is transferred mainly through the first thermal post rather than through the socket of insulating material.

[0015] The present invention further provides a cartridge, the cartridge comprising: a socket of insulating material having an upper side and a lower side, a first formation on the upper side for holding a first electronic device, and a second formation on the upper side for holding a second electronic device; a lead; a first pusher plate rotatably mounted on the lead; a second pusher plate rotatably mounted on the lead, wherein the lead is positionable over the socket and movable toward the socket, and the rotatably mounted first pusher plate causes the first electronic device to rotate the first pusher plate relative to the lead, and the rotatably mounted second pusher plate causes the second electronic device to rotate the second pusher plate relative to the lead independently of the first pusher plate; a first set of contacts held in the socket for connecting to the first electronic device; a first set of terminals connected to the first set of contacts; a second set of contacts held in the socket for connecting to the second electronic device; and terminals connected to the second set of contacts. Includes a second set of terminals.

[0016] The present invention also provides a method for testing one or more electronic devices, the method comprising: a step of releasingly holding a first electronic device on a first formation on the upper side of a socket of insulating material; a step of releasingly holding a second electronic device on a second formation on the upper side of the socket; a step of positioning a lead on the socket, wherein the lead has a first pusher plate rotatably mounted on the lead and a second pusher plate rotatably mounted on the lead; a step of moving the lead toward the socket, wherein the rotatably mounted first pusher plate causes the first electronic device to rotate the first pusher plate relative to the lead and the rotatably mounted second pusher plate causes the second electronic device to rotate the second pusher plate relative to the lead independently of the first pusher plate; and a step of connecting the first and second electronic devices to an electrical tester through an interface connected to the socket.

[0017] The present invention further provides a cartridge, the cartridge comprising: an electronic device holder having a forming for removably holding an electronic device having an input contact and a light emitter; an input contact on the electronic device holder for connecting to an input contact on the electronic device to provide input power to an input contact on the electronic device through an input contact on the electronic device holder, wherein the input power causes a light emitter to transmit light; a light detector mounted on the electronic device holder and positioned to detect light and generate output power in response to the magnitude of the light; and an output contact connected to the light detector to measure the output power.

[0018] The present invention also provides a method for testing one or more electronic devices, the method comprising the steps of: inserting an electronic device having an input contact and a photoemitter into a device holder; connecting an input contact on the electronic device holder to an input contact on the electronic device; providing input power to an input contact on the electronic device through an input contact on the electronic device holder, wherein the input power causes a photoemitter to transmit light; detecting light; converting the detected light into output power; measuring output power through an output contact; and removing the electronic device from the electronic device holder.

[0019] The present invention further provides a testing device, the testing device comprising: a socket having a forming for removably holding an electronic device having an input terminal and an optical emitter; an input contact on the socket for connecting to an input terminal on the electronic device to provide input power to an input terminal on the electronic device through an input contact on the socket, wherein the input power causes the optical emitter to transmit light; a temperature changing device on a first side of the socket, wherein the temperature changing device changes the temperature to cause a temperature difference between the temperature changing device and the electronic device and a heat transfer between the temperature changing device and the electronic device to change the temperature of the electronic device when operated; a heat sink on the side of the socket opposite to the temperature changing device, wherein the heat sink has a surface for absorbing light, and the absorption of light generates heat in the heat sink; and a heat dissipation device thermally connected to the heat sink to remove heat from the heat sink.

[0020] The present invention also provides a method for testing one or more electronic devices, the method comprising: inserting an electronic device having an input contact and a light emitter into a socket; connecting the input contact on the socket to an input terminal on the electronic device; providing input power to the input terminal on the electronic device through the input contact on the socket, wherein the input power causes the light emitter to transmit light; changing the temperature of a temperature changing device on a first side of the socket to cause a temperature difference between the temperature changing device and the electronic device and a heat transfer between the temperature changing device and the electronic device to change the temperature of the electronic device; absorbing light onto the surface of a heat sink on the side of the socket opposite the temperature changing device, wherein the absorption of light generates heat in the heat sink; removing heat from the heat sink with a heat dissipation device thermally connected to the heat sink; and removing the electronic device from the socket.

[0021] The present invention further provides a cartridge, the cartridge comprising: a socket of insulating material having an upper side and a lower side and a formation on the upper side for holding an electronic device; a set of contacts held in the socket for connecting to the electronic device; a set of terminals connected to the set of contacts held by the socket; a circuit board, wherein the set of terminals connected to the set of contacts is connected to the set of contacts on the circuit board; a lead; a detector mounted on the lead, wherein the lead is movable so as to position the detector on the socket in a position for detecting a feature of the electronic device when and because power is supplied to the electronic device through at least one of the set of terminals held by the socket; and a measurement channel connecting the detector to an interface on the circuit board.

[0022] The present invention also provides a method for testing one or more electronic devices, the method comprising: a step of releasingly holding an electronic device in a socket of insulating material having an upper side and a lower side and a formation on the upper side for holding the electronic device; a step of connecting a set of contacts held in the socket to the electronic device; a step of connecting a set of terminals connected to the set of contacts to a set of contacts on a circuit board; a step of moving a lead on which a detector is mounted over the socket; a step of connecting the detector to an interface on the circuit board through a measurement channel; a step of supplying power to the electronic device through at least one of the contacts held by the socket; a step of detecting a feature of the electronic device when and because power is supplied to the electronic device through at least one of the contacts held by the socket; and a step of measuring a feature through the interface.

[0023] The present invention further provides a cartridge, the cartridge comprising: a backing structure on a first side of the support board having at least a support board through which a post opening passes; a contact for contacting a terminal on an electronic device positioned on a second side of the support board opposite the first side of the support board; a conductor having a portion maintained by the support board and a terminal connected to the contact on the circuit board; a spring; a force generating device on the side of the electronic device opposite the support board, wherein the force generating device and the support board are movable relative to each other to move the electronic device closer to the support board and deform the spring; a post comprising a stand-off having a surface on a plane spaced apart from the plane of the surface of the support board to prevent the electronic device from moving closer to the support board, a force transfer portion extending from the stand-off at least partially through the post opening; and a force delivery portion extending from the force transfer portion, wherein the force delivery portion is maintained by the backing structure.

[0024] The present invention also provides a cartridge, wherein the cartridge comprises positioning a backing structure having at least a circuit board having contacts on a first side of a support board; connecting a contact of a conductor to a terminal on an electronic device positioned on a second side of a support board opposite to the first side of the support board, wherein the conductor has a portion maintained by the support board and a terminal connected to a contact on the circuit board; positioning a force generating device on the side of the electronic device opposite the support board; moving the force generating device and the support board relative to each other to move the electronic device closer to the support board and deform a spring against its spring force; preventing the electronic device from moving closer to the support board by a post having a stand-off having a surface on a plane spaced apart from the plane of the surface of the support board; receiving a force from the electronic device by the stand-off of the post; and transferring the force from the stand-off at least partially through the opening to a force transfer portion of the post extending from the stand-off through a post opening formed at least partially through the support board. It includes receiving force to a force delivery portion of a post extending from a force transfer portion, wherein the force delivery portion is maintained by a backing structure, and delivering the force to the backing structure.

[0025] A tester device comprises a voltage targeting system, a holder for holding a plurality of electronic devices in at least first and second clusters, at least one voltage source connectable to electronic devices of a first cluster to provide a first test voltage to electronic devices of a first cluster in parallel and connectable to electronic devices of a second cluster to provide a first test voltage to electronic devices of a second cluster in parallel, and at least one current detector, wherein the at least one current detector is connectable to devices of a first cluster to measure a first test current from devices of a first cluster, wherein the first test current from devices of a first cluster measured by the current detector is the total current of devices of a first cluster in parallel, and is connectable to devices of a second cluster to measure a first test current from devices of a second cluster, wherein the first test current measured by the current detector from devices of a second cluster is the total current of devices of a second cluster in parallel. The voltage targeting system is connectable, and the voltage targeting system performs a first comparison by comparing a first test current from devices of a first cluster being measured with a target current, the at least one current detector, and a first voltage regulator that adjusts a first test voltage to a second test voltage for a first cluster in response to the first comparison so that the first test current from devices of the first cluster is adjusted to a second test current closer to the target current, wherein the voltage targeting system performs a second comparison by comparing a first test current from devices of a second cluster being measured with a target current, the first voltage regulator.and includes a second voltage regulator that adjusts the first test voltage to a second test voltage for the second cluster in response to a second comparison so that the first test current from the devices of the second cluster is adjusted closer to a second test current that is closer to the target current.

[0026] The present invention also provides a method for testing a plurality of electronic devices, the method comprising: maintaining a plurality of electronic devices in at least first and second clusters; connecting at least one voltage source to the electronic devices of the first cluster to provide a first test voltage to the electronic devices of the first cluster in parallel and connecting to the electronic devices of the second cluster in parallel to provide a first test voltage to the electronic devices of the second cluster in parallel; connecting at least one voltage source to the electronic devices of the second cluster in parallel to provide a first test voltage to the electronic devices of the second cluster in parallel; measuring a first test current from the devices of the second cluster with at least one current detector, wherein the first test current measured by the current detector from the devices of the second cluster is the total current of the devices of the second cluster in parallel; measuring a first test current from the devices of the second cluster with at least one current detector, wherein the first test current measured by the current detector from the devices of the second cluster is A step of measuring a first test current from the devices of the second cluster, which is the total current of the devices of the second cluster in parallel; a step of performing a first comparison with a voltage targeting system by comparing the measured first test current from the devices of the first cluster with a target current; a step of adjusting the first test voltage to a second test voltage for the first cluster in response to the first comparison with a first voltage regulator so that the first test current from the devices of the second cluster is adjusted to a second test current closer to the target current.The method includes the step of performing a second comparison with a voltage targeting system by comparing a first test current from devices of a second cluster being measured with a target current, and the step of adjusting a first test voltage to a second test voltage for the second cluster in response to the second comparison with a second voltage regulator so that the first test current from devices of the second cluster is adjusted to be closer to a second test current that is closer to the target current. Brief explanation of the drawing

[0027] The present invention is further described by examples with reference to the accompanying drawings. FIG. 1 is a side cross-sectional view of a tester device having slot assemblies according to one embodiment of the present invention. FIG. 2 is a side cross-sectional view of a tester device according to 2-2 of FIG. 1. FIG. 3 is a side cross-sectional view of a tester device according to 3-3 of FIG. 1. FIG. 4 is a side cross-sectional view of a tester device according to 4-4 of FIG. 2 and FIG. 3. FIGS. 5a, 5b, and 5c are perspective views of a tester device illustrating the insertion or removal of portable cartridges into or out of an oven defined by a frame. FIG. 6 is a time chart illustrating a method in which one cartridge can be inserted and used to test electronic devices on wafers and the subsequent insertion of another cartridge. FIG. 7 is a perspective view of a tester device illustrating the insertion or removal of a single slot assembly. FIGS. 8a and 8b are side cross-sectional views illustrating the use of a stand-off in the configuration of the cartridge described in FIGS. 1 to 7. FIGS. 9A, FIGS. 9B, and FIGS. 10 are side views illustrating a device used for inserting and removing portable cartridges into and out of an oven. FIG. 11 is a perspective view illustrating a cartridge according to another embodiment of the present invention. FIG. 12 is a side cross-sectional view of a portion of the cartridge of FIG. 11. FIG. 13 is a side cross-sectional view illustrating details of a part of FIG. 12. FIGS. 14a and FIGS. 14b are side cross-sectional views illustrating the use of a stand-off in the configuration of FIGS. 11 to 13. FIG. 15 illustrates the components of a tester device used to control voltages for individual electronic devices. FIG. 16 is a flowchart illustrating the operation of the components of FIG. 15. Figure 17 is a graph illustrating voltage retargeting following the process of Figure 16. FIG. 18 illustrates histograms to illustrate static filtering performed in FIG. 16. FIG. 19 illustrates histograms to illustrate outlier filtering performed in FIG. 16. FIG. 20 illustrates diagrams for illustrating sample size filtering performed in FIG. 16. Specific details for implementing the invention

[0028] FIG. 1 of the attached drawings illustrates a tester device (10) according to an embodiment of the present invention, the tester device (10) comprising a tester (12), a frame (14), a power bus (16), first and second slot assemblies (18A and 18B), a tester cable (20), a power cable (22), a cold liquid supply line (24A), a cold liquid recovery line (24B), a control liquid supply line (24C), a control liquid recovery line (24D), a vacuum line (24E), first and second cartridges (28A and 28B), and first and second wafers (30A and 30B).

[0029] The slot assembly (18A) includes a slot assembly body (32), a temperature changing device in the form of a thermal chuck (34), a temperature detector (36), and a heating resistor (38), a first slot assembly interface (40), and a plurality of second slot assembly interfaces including a control interface (44), a power interface (46) and a cold liquid supply interface (48A), a cold liquid recovery interface (48B), a control liquid supply interface (48C), a control liquid recovery interface (48D) and a vacuum interface (48E).

[0030] The first slot assembly interface (40) is located within the slot assembly body (32) and is mounted on the slot assembly body (32). Second interfaces in the form of a control interface (44), a power interface (46), and interfaces (48A to 48E) are mounted on the left wall of the slot assembly body (32).

[0031] The slot assembly (18A) can be inserted into the frame (14) from left to right and removed from the frame (14) from right to left. The tester cable (20), power cable (22), and lines (24A to 24E) are manually connected to the control interface (44), power interface (46), and interfaces (48A to 48E), respectively. Before removing the slot assembly (18A) from the frame (14), the tester cable (20), power cable (22), and lines (24A to 24E) are first manually disconnected from the control interface (44), power interface (46), and interfaces (48A to 48E), respectively.

[0032] The slot assembly (18A) includes a motherboard (60) having test electronics, a plurality of channel module boards (62) having test electronics, flexible connectors (64), and a connection board (66). A control interface (44) and a power interface (46) are connected to the motherboard (60), and a thermal controller (50) is mounted on the motherboard (60). The channel module boards (62) are electrically connected to the motherboard (60). The flexible connectors (64) connect the channel module boards (62) to the connection board (66). Control functionality is provided through electrical conductors connecting the control interface (44) to the motherboard (60). Power is provided to the motherboard (60) through the power interface (46). Both power and control are provided from the motherboard (60) to the channel module boards (62) through conductors. Flexible connectors (64) provide conductors that connect channel module boards (62) to a connection board (66). The connection board (66) includes a conductor that connects the flexible connectors (64) to a first slot assembly interface (40). This first slot assembly interface (40) is therefore connected to the control interface (44) and the power interface (46) through various connectors so that power and control can be provided to the first slot assembly interface (40) through the control interface (44) and the power interface (46).

[0033] The second slot assembly (18B) includes components similar to the first slot assembly (18A), and similar reference numbers indicate similar components. The second slot assembly (18B) is inserted into the frame (14), and the control interface (44), power interface (46), and interfaces (48A to 48E) of the second slot assembly (18B) are manually connected to a separate set of connection components, each including a separate tester cable (20), a separate power cable (22), and separate lines (24A to 24E).

[0034] The cartridge (28A) includes a cartridge body formed by a thin chuck (72) and a backing board (74). A plurality of microelectronic devices are formed in the wafer (30A). The wafer (30A) is inserted into the cartridge body between the thin chuck (72) and the backing board (74). Cartridge contacts (76) contact individual contacts (not shown) on the wafer (30A). The cartridge (28A) further includes a cartridge interface (78) on the backing board (74). Conductors within the backing board (74) connect the cartridge interface (78) to the cartridge contacts (76).

[0035] The cartridge (28A) has a seal (77) connected between the backing board (74) and the thin chuck (72). A vacuum is applied to the area defined by the seal (77), the backing board (74), and the thin chuck (72). The vacuum holds the cartridge (28A) together and ensures proper contact between the cartridge contacts (76) and the contacts on the wafer (30A).

[0036] The temperature detector (36) is located on the thermal chuck (34) and is therefore close enough to the wafer (30A) to detect the temperature of the wafer (30A) within 1 degree of 5 degrees Celsius, preferably 2 degrees Celsius.

[0037] The slot assembly (18A) further has a door (82) connected to the slot assembly body (32) by a hinge (84). When the door (82) is rotated to an open position, a cartridge (28A) can be inserted into the slot assembly body (32) through the door opening (86). The cartridge (28A) is then placed on the thermal chuck (34) and the door (82) is closed. The thermal chuck (34) is mounted on the slot assembly body (32). The thermal chuck (34) then essentially forms a holder having a testing station for the wafer.

[0038] The slot assembly (18A) further has a seal (88) positioned between the thermal chuck (34) and the thin chuck (72). Vacuum is applied to the area defined by the seal (88), the thermal chuck (34), and the thin chuck (72) through the vacuum interface (48E) and the vacuum line (90). Excellent thermal connection is thus provided between the thermal chuck (34) and the thin chuck (72). When heat is generated by the heating resistor (38), the heat is conducted through the thermal chuck (34) and the thin chuck (72) to reach the wafer (30A). When the thermal chuck (34) is at a lower temperature than the wafer (30A), the heat is conducted in the opposite direction.

[0039] The cartridge interface (78) engages with the first slot assembly interface (40). Power and signals are provided to the wafer (30A) through the first slot assembly interface (40), the cartridge interface (78), and the cartridge contacts (76). The performance of the devices within the wafer (30A) is measured through the cartridge contacts (76), the cartridge interface (78), and the first slot assembly interface (40).

[0040] The door (82) of the slot assembly (18B) is shown in a closed position. The front seal (100) is mounted on the upper surface of the slot assembly (18A) and seals together with the lower surface of the slot assembly (18B). The front seal (102) is mounted on the upper surface of the slot assembly (18B) and seals together with the lower surface of the frame (14). A continuous sealed front wall (104) is provided by the doors (82) of the slot assemblies (18A and 18B) and the front seals (100 and 102).

[0041] The slot assembly (18A) further includes a thermal controller (50). A temperature detector (36) is connected to the thermal controller (50) via a temperature feedback line (52). Power is supplied to the heating resistor (38) via a power interface (46) and a power line (54) so ​​that the heating resistor (38) heats up. The heating resistor (38) then heats the thermal chuck (34) and the wafer (30A) on the thermal chuck (34). The heating resistor (38) is controlled by the thermal controller (50) based on the temperature detected by the temperature detector (36).

[0042] In the thermal chuck (34), a thermal fluid passage (224) is formed therein. The thermal fluid passage (224) holds the thermal fluid. The thermal fluid is preferably a liquid rather than a gas because the liquid is not compressible and heat convects more quickly into or from the liquid. Different thermal fluids are used for different applications, and oil is used for applications where the temperature is highest.

[0043] Control liquid supply and return lines (226 and 228) connect opposite ends of the thermal fluid passage (224) to cold liquid supply and return interfaces (48C and 48D), respectively. A heating resistor (38) functions as a heater mounted at a location to heat the thermal chuck (34), which heats the thermal fluid. By recirculating the thermal fluid through the thermal fluid passage (224), a more uniform heat distribution is provided by the thermal chuck (222) to the thermal chuck (34) and ultimately to the wafer (30A). The temperature of the fluid can also be controlled to add heat to the thermal chuck (34) to cool the thermal chuck (34).

[0044] The tester device (10) further includes a cooling system (240), a temperature control system (242), and a vacuum pump (244). Two cold liquid supply lines (24A) connected to the first and second slot assemblies (18A and 18B) are also connected to the cooling system (240) via a manifold (not shown). Additional manifolds connect cold liquid recovery lines (24B) to the cooling system (240), control liquid supply lines (24C) to the temperature control system (242), control liquid recovery lines (24D) to the temperature control system (242), and vacuum lines (24E) to the vacuum pump (244). Each slot assembly (18A or 18B) has an individual cold plate (246) with an individual fluid passage (248). The cooling system (240) circulates fluid through the fluid passage (248) to cool the cooling plate (246). The cooling plate (246) then keeps the channel module boards (62) cold. The temperature control system (242) controls the temperature of the thermal chuck (34) and circulates fluid through the thermal fluid passage (224) to transfer heat from or to the wafers (30A and 30B). The vacuum pump (244) supplies air to the vacuum line (90) at a vacuum pressure.

[0045] The slot assembly (18A) includes a separator seal (108) mounted on the upper surface of the slot assembly body (32) above its inner wall (106). The separator seal (108) seals together with the lower surface of the slot assembly (18B). The slot assembly (18B) has a separator seal (110) mounted on the upper surface of its slot assembly body (32). The separator seal (110) seals together with the lower surface of the frame (14). A continuous sealed separator wall (112) is provided by the inner walls (106) of the slot assemblies (18A and 18B) and the separator seals (108 and 110).

[0046] FIG. 2 illustrates a tester device (10) according to 2-2 of FIG. 1. A frame (14) defines a first closed-loop air path (120). Air inlet and outlet openings (not shown) can be opened to change the first closed-loop air path (120) into an open air path, where air at room temperature passes through the frame (14) without being recirculated. A closed-loop path is particularly useful in a clean room environment because it allows less particulate matter to be released into the air.

[0047] The tester device (10) further includes a temperature changing device in the form of a first fan (122), a first fan motor (124), and a water cooler (126).

[0048] The first fan (122) and the first fan motor (124) are mounted in the upper part of the first closed-loop air path (120). The water cooler (126) is mounted on the frame (14) within the upper part of the first closed-loop air path (120).

[0049] The cartridges (28A and 28B) are positioned together with the slot assemblies (18A and 18B) and are located within the lower half of the first closed loop air path (120).

[0050] When in use, current is supplied to the first fan motor (124). The first fan motor (124) rotates the first fan (122). The first fan (122) recirculates air clockwise through the first closed-loop air path (120).

[0051] The water cooler (126) then cools the air in the first closed-loop air path (120). The air then flows over the cartridges (28A or 28B) through the slot assemblies (18A and 18B). The cartridges (28A or 28B) are then cooled by the air through convection.

[0052] FIG. 3 illustrates a tester device (10) according to 3-3 of FIG. 1. A frame (14) defines a second closed-loop air path (150). The tester device (10) further includes a temperature changing device in the form of a second fan (152), a second fan motor (154), and a water cooler (156). An electric heater or damper is not provided as in FIG. 2. Air inlet and outlet openings (not shown) may be opened to change the first closed-loop air path (150) into an open air path, where air at room temperature passes through the frame (14) without being recirculated.

[0053] A closed loop path is particularly useful in a clean room environment because it allows less particulate matter to be released into the air. The second fan (152) and the second fan motor (154) are located in the upper part of the second closed loop air path (150). The water cooler (156) is located slightly downstream from the second fan (152) within the second closed loop air path (150). The motherboard (60) and channel module boards (62) forming part of the slot assemblies (18A and 18B) are located within the lower part of the second closed loop air path (150).

[0054] When in use, current is supplied to the second fan motor (154) which rotates the second fan (152). The second fan (152) then recirculates air clockwise through the second closed-loop air path (150). The air is cooled by a water cooler (156). The cooled air then passes over the motherboard (60) and channel module boards (62) so that heat is transferred from the motherboard (60) and channel module boards (62) to the air via convection.

[0055] Air recirculated through the first closed-loop air path (120) of FIG. 1 is separated from the air in the second closed-loop air loop (150) of FIG. 3 by the continuous sealed separator wall (112) shown in FIG. 1. The continuous sealed front wall (104) shown in FIG. 1 prevents air from escaping out of the first closed-loop air path (120).

[0056] As illustrated in FIGS. 2 and 3, the same cooling system (240) used in FIG. 1 is also used to cool the water coolers (126). As illustrated in FIG. 4, a plenum (160) separates the first closed-loop air path (120) from the second closed-loop air path (150) in all areas except those provided by a continuous sealed separator wall (112). The frame (14) has left and right walls (162 and 164) that further define the closed-loop air paths (120 and 150).

[0057] FIGS. 5A, 5B, and 5C illustrate a method in which cartridges (30C, 30D, and 30E) can be inserted or removed at any time while all other cartridges are being used to test devices on wafers and may be in various states of temperature ramps. FIG. 6 illustrates the concept in more detail. At time (T1), the first cartridge is inserted into the frame (14), while the second cartridge is outside the frame (14). At T1, heating of the first cartridge is initiated. Between T1 and T2, the temperature of the first cartridge increases from room temperature, i.e., about 22°C, to a testing temperature of 50°C to 150°C, which is higher than room temperature, at T2. At T2, power is applied to the first cartridge, and the devices within the first cartridge are tested. At T3, the second cartridge is inserted into the frame (14), and heating of the second cartridge is initiated. At T4, testing of the first cartridge is terminated. At T4, cooling of the first cartridge is also initiated. At T5, the second cartridge reaches a testing temperature, power is supplied to the second cartridge, and the wafer within the second cartridge is tested. At T6, the second cartridge reaches a temperature close to room temperature and is removed from the frame (14). The third cartridge can then be inserted in place of the first cartridge. At T7, testing of the second cartridge is terminated, and its cooling is initiated. At T8, the second cartridge is cooled to or close to room temperature and is removed from the frame (14).

[0058] Different tests may be performed at different temperatures. For example, a cartridge may be inserted and the test may be run at room temperature. Another test may be performed during an upward ramp in temperature. An additional test may be performed at an elevated temperature. An additional test may be performed during a downward ramp in temperature. Two of these tests may be a single test performed from one temperature stage to the next.

[0059] As illustrated in FIG. 7, one slot assembly (18A) may be removed or inserted into the frame (14). The slot assembly (18A) may be inserted or removed while other slot assemblies within the frame (14) are used to test the devices of the wafers, as described with reference to FIG. 6.

[0060] As shown in FIG. 8a, the backing board (74) includes a circuit board (500), a contactor (502), a plurality of pins (504), a securing ring (506), a fastener (508), and a post (510).

[0061] The circuit board (500) is made mainly of insulating material and has a circuit (not shown) formed therein. Contacts (512) are formed on the lower side (514) of the circuit board (500). A threaded opening (516) is formed inside the lower side (514).

[0062] The contactor (502) has a plurality of pin openings (518), post openings (520), and fastener openings (522) formed through it from the upper side (524) to the lower side (526). Each pin opening of the pin openings (518) has a first section (528) and a second section (530). Both the first and second sections (528 and 530) are circular when viewed in a plane. The first section (528) has a larger diameter than the second section (530). Because the diameter of the first section (528) is larger than the diameter of the second section (530), the first section (528) is wider than the second section (530) when viewed in the side cross-sectional view of FIG. 8a.

[0063] The post opening (520) has a first section (534) and a second section (536). Both the first section (534) and the second section (536) are circular when viewed in a plane. The diameter of the first section (534) is larger than the diameter of the second section (536). Because the diameter of the first section (534) is larger than the diameter of the second section (536), the first section (534) is wider than the second section (536) when viewed in the side view of FIG. 8a. The first and second sections (534 and 536) have vertical side walls. A horizontal landing (538) connects the vertical side walls of the first and second sections (534 and 536).

[0064] Each pin (504) includes an electrically conductive retainer portion (542), a coil spring (544), and first and second end pieces (546 and 548). The first end piece (546) has a first inner portion (550) and a first tip (552). The second end piece (548) has a second inner portion (554) and a second tip (556). The coil spring (544) and the first and second inner portions (550 and 554) are retained in the retainer portion (542) with the coil spring (544) positioned between the first and second inner portions (550 and 554). The first and second tips (552 and 556) each protrude out of the upper and lower ends of the retainer portion (542).

[0065] The upper surface of the first tip (552) forms a terminal (560). The lower end of the second tip (556) forms a contact (562). The coil spring (544) and the first and second end pieces (546 and 548) are made of metal and thus an electrically conductive material. The coil spring (544) and the first and second end pieces (546 and 548) form a conductor capable of conducting current between the terminal (560) and the contact (562).

[0066] Individual pins are inserted into individual pin openings (518) through the upper side (524). The second tip (556) is slightly smaller than the second section (530) so that it passes through the second section (530) and protrudes from the lower side (526). The retainer portion (542) is slightly narrower than the first section (528) but wider than the second section (530) to prevent the pin (504) from coming out of the lower side (526). When the pin (504) is fully inserted into the pin opening (518), and before the contactor (502) is mounted on the circuit board (500), the first tip (552) still protrudes upward from the upper side (524) of the contactor (502).

[0067] The post (510) has a stand-off (564), a force transfer part (566), and a force delivery part (568). The post (510) is made of a single piece of metal or other material selected for its strength compared to the strength and brittleness of the ceramic material of the contactor (502).

[0068] The post (510) is inserted into the post opening (520) through the upper side (524). The stand-off (564) and the force transfer section (566) are slightly narrower than the second section (536). The force delivery section (568) is slightly narrower than the first section (534) but wider than the second section (536). The lower surface (570) of the force delivery section (568) is adjacent to the landing (538). This prevents the post (510) from coming out of the lower side (526).

[0069] The post (510) has a surface (572) in a plane parallel to the surface of the lower side (526) and below that surface when the post (510) is fully inserted as shown in FIG. 8a. When the post (510) is fully inserted, the force delivery portion (568) has a surface (574) in the same plane as the upper side (524).

[0070] The circuit board (500) is positioned on top of the contactor (502). Each contact of the contacts (512) contacts an individual terminal of the terminals (560). Since the terminals (560) are in a plane above the plane of the upper side (524), the lower side (514) is initially separated from the upper side (524).

[0071] The fastener (508) has a threaded shaft (578) and a head (580). The ring (506) has a ring opening (582). The ring (506) is positioned on the lower surface (584) of the contactor (502). The threaded shaft (578) is inserted from the bottom through the ring opening (582) and through the fastener opening (522). The head (580) contacts the lower surface of the ring (506). The head (580) is then rotated so that the thread on the threaded shaft (578) screws onto the thread on the threaded opening (516). The threading action moves the circuit board (500) closer to the contactor (502) and the ring (506). The lower side (514) eventually contacts the upper side (524). The contacts (512) move the first end piece (546) downward into the pin opening (518) until the terminals (560) are in the same plane as the upper side (524). The coil spring (544) is compressed and thus slightly deformed to allow relative movement of the second end piece (546) toward the second end piece (548).

[0072] The lower side (514) has a section that is suspended relative to the surface (574) forming part of the post (510). Since the post (510) is adjacent to the circuit board (500), the post (510) is in a position to transfer force to the circuit board (500) through the surface (572).

[0073] A plurality of electronic devices are formed in the first wafer (32A). Each electronic device has a plurality of terminals (588) on the upper surface (590) of the first wafer (32A). When the backing board (74) and the first wafer (32A) are brought together, the first wafer (32A) is aligned with the backing board (74) to ensure that each terminal of the terminals (588) contacts an individual contact of the contacts (562).

[0074] While the pressure below the lower surface (592) of the thin chuck (72) and the upper surface (594) of the circuit board (500) is maintained at atmospheric pressure, vacuum pressure is generated in the area between the upper surface (590) and the lower surface (526). The pressure difference generates equal and opposite forces (F1 and F2) on the circuit board (500) and the thin chuck (72).

[0075] As illustrated in FIG. 8b, forces (F1 and F2) move the backing board (74) relative to the wafer (32A) and thin chuck (72). The coil springs (544) are further compressed to allow the second end piece (548) to move into the pin opening (518). Each coil spring (544) is deformed for its spring force, e.g., F3. The force (F1), however, is still greater than the sum of all the combined forces (F3). The upper surface (590) eventually comes to a stop upon hitting the surface (572) of the stand-off (564). Because the post (510) is adjacent to the circuit board (500), the stand-off (564) prevents the upper surface (590) from moving closer to and in contact with the lower side (526) of the contactor (502). The first wafer (32A) transfers power (F4) onto the stand-off (564). The power transfer section (566) transfers power (F4) through the second section (536) of the post opening (520). The power delivery section (568) receives power (F4) from the power transfer section (566) and delivers the power (F4) to the circuit board (500) through the surface (574).

[0076] Therefore, it can be seen that the force (F4) is not transmitted by the contactor (502), thereby preventing stresses that could cause damage to the contactor (502) of the brittle ceramic material. Instead, the force (F4) is transferred directly from the electronic device in the form of the first wafer (32A) onto the circuit board (500) through the post (510).

[0077] In the embodiment described in FIGS. 8a and 8b, the contactor (502) functions as a support board through which the post opening (520) passes. The circuit board (500) functions as a backing structure on the first side of the support board, comprising at least a circuit board having a contact (512). The pin (504) functions as a conductor having a contact (562) that contacts a terminal (508) on an electronic device positioned on the second side of the support board opposite the first side of the support board. The retainer portion (542) functions as a portion of the conductor held by the support board. The conductor further has a terminal (560) connected to the contact (512) on the circuit board (500). A spring in the form of a coil spring (544) is provided. A thin chuck (72) functions as a force generating device on the side of an electronic device in the form of a first wafer (32A) opposite the support board. The force generating device and the support board are movable relative to each other to move the electronic device closer to the support board and to deform the spring. A post (510) has a stand-off (564) having a surface (572) on a plane spaced apart from the plane of the surface of the support board to prevent the electronic device from moving closer to the support board, a force transfer portion (566) extending from the stand-off (564) at least partially through the post opening (520), and a force delivery portion (568) extending from the force transfer portion (566), said force delivery portion (568) which is maintained by a backing structure.

[0078] FIG. 9a illustrates a part of a tester device (10) used for inserting a cartridge into each slot assembly, for example, into a slot assembly (18A), and for removing it from therein. The components of the tester device (10) illustrated in FIG. 9a include a frame (300), a part of a first slot assembly (18A), a first slot assembly interface (40), a retaining structure (302), a horizontal transport device (304), a vertical transport device (306), a beam spring (308), and a locking mechanism (310).

[0079] The frame (300) includes first and second mounts (312 and 314) spaced apart from each other. A horizontal conveyor (304) is a slide mounted between the first and second mounts (312 and 314). A retaining structure (302) is mounted for sliding movement along the horizontal conveyor (304). Opposite ends of a beam spring (308) are mounted on the first and second mounts (312 and 314), respectively.

[0080] The locking mechanism (310) includes a connecting lever (316), a control lever (318), and a pressure lever (320). The control lever (318) is mounted to a first mount (312) via a pivot connection (322). The vertical carrier (306) is a rigid beam. A connection (324) connects the center points of the vertical carrier (306) and the beam spring (308) to each other. The pressure lever (320) has a first link (326) rotatably connected to the control lever (318) and a second link (328) rotatably connected to the end of the vertical carrier (306). In the unlocked configuration shown in FIG. 9a, line (330) connects the pivot connection (322) to the second link (328), and the first link (326) is to the left of line (330).

[0081] When in use, the first cartridge (28A) is positioned on the retaining structure (302). The first cartridge (28A) is then moved from left to right into the first slot assembly (18A) together with the retaining structure (302). The placement and movement of the first cartridge (28A) may be performed manually or using a robot.

[0082] The retaining structure (302) slides along the horizontal conveying device (304). The connecting lever (316) connects the end of the control lever (318) to the retaining structure (302). When the retaining structure (302) moves horizontally along the horizontal conveying device (304), the connecting lever (316) rotates the control lever (318) counterclockwise relative to the pivot connection (322).

[0083] The first link (326) rotates counterclockwise together with the control lever (318). The pressure lever (320) translates the movement of the first link (326) into the downward movement of the second link (328). Initially, the downward movement is small, but when the first cartridge (28A) is fully inserted into the first slot assembly (18A), the vertical movement becomes more pronounced and the vertical transport device (306) engages the first cartridge (28A) with the first slot assembly (18A). The horizontal transport device (304) is therefore operable to move the first cartridge (28A) horizontally from a first position to a second position into the first slot assembly (18A), and the vertical transport device (306) is operable to move the first cartridge (28A) and the first slot assembly (18A) in a first vertical direction relative to each other so as to engage the slot assembly interface (40) with the cartridge interface on the first cartridge (28A).

[0084] The control lever (318) is shown in the unlocked position of FIG. 9a, which is on the first side of the line (330) connecting the first link (326) to the pivot connection (322) and the second link (328). From the unlocked position shown in FIG. 9a, the control lever (318) rotates through a compressed position in which the first link (326) is aligned with the pivot connection (322) and the second link (328), and the vertical conveyor (306) is deformed through the connection (324) by the beam spring (308) bending the beam spring (308) with its spring force. The control lever (318) continues to rotate from the compressed position to the locked position as shown in FIG. 9b and FIG. 10. In the locked position, the first link (326) is on the right side of the line (330), thus on the second side of the line (330) opposite the first side. Because the first link (326) has passed through the line (330) and the beam spring (308) has deformed against its spring force, the first cartridge (28A) is locked in the appropriate position relative to the slot assembly interface (40).

[0085] The system can be unlocked by moving the retaining structure (302) from right to left. The control lever (318) rotates clockwise and the first link (326) moves from right to left along the line (330). The vertical transport device (306) moves upward, i.e., in the second vertical direction opposite to the first vertical direction, to release the first cartridge (28A) from the slot assembly interface (40). Further movement of the retaining structure (302) along the horizontal transport device (304) removes the first cartridge (28A) from the first slot assembly (18A).

[0086] FIG. 11 illustrates a cartridge (340) according to a further embodiment of the present invention, comprising a column subassembly (342), a board-and-socket subassembly (344), and a plurality of leads (346).

[0087] FIG. 12 illustrates a portion of the column subassembly (342), a portion of the board-and-socket subassembly (344), and one lead of the leads (346).

[0088] FIG. 13 illustrates detail A of FIG. 12, including a portion of the column subassembly (342), a portion of the board-and-socket subassembly (344), and a portion of the lead (346). FIG. 13 also illustrates a first electronic device (348).

[0089] The column subassembly (342) includes a thin chuck (350), a first column anchor (352), and a first column post (354). The thin chuck (350) has an upper surface (356) having an opening (358) formed on the upper surface (356). The first column anchor (352) and the first column post (354) are machined from a single piece of metal. Both the first column anchor (352) and the first column post (354) have circular cross-sections in individual planes parallel to the axis of the first column post (354) when viewed in a plan view. The cross-section of the first column anchor (352) is larger than the cross-section of the first column post (354).

[0090] The first row anchor (352) is inserted into the opening (358) through the upper surface (356). The first row post (354) extends upward from the first row anchor (352). Most of the first row post (354) is located above the upper surface (356). The first row anchor (352) has an upper end with a first row surface (360). The first row anchor (352) is press-fitted into the opening (358) to a desired depth, where the first row surface (360) is located at a desired distance from the upper surface (356).

[0091] The first column post (354), the first column anchor (352), and the thin chuck (350) are all made of metals and are therefore excellent thermal conductors. Compared to the cross-section of the first column post (354), the cross-section of the first column anchor (352) is larger, so there is more heat transfer from the first column anchor (352) to the thin chuck (350).

[0092] The board-and-socket subassembly (344) includes a circuit board (362), a socket (364), a first set of pins (366) for an electronic device, and a first set of pins (368) for a detector. The pins (366 and 368) are pogo pins that include springs and can be compressed against the spring forces of the springs.

[0093] The socket (364) includes a lower portion (370) and an upper portion (372). Each pin of the pins (366 and 368) is held within the socket (364) between the lower portion (370) and the upper portion (372). The upper portion (372) has a first recessed formation (376) for holding a first electronic device (348). Each pin of the pins (366) has an individual contact (378) extending above the surface of the first recessed formation (376). Each pin of the pins (368) has an individual contact (380) extending above the upper surface (382) of the upper portion (372).

[0094] The contacts (380) of the pins (368) are all in the same plane. The contacts (378) of the pins (366) are all in the same plane. The plane of the contacts (380) is parallel to the plane of the contacts (378) and lies above that plane. The terminals (392) of the pins (368) are all in the same plane as the terminals (392) of the pins (366).

[0095] A circuit (not shown) is formed in the circuit board (362). Contacts (388) are formed within the lower surface (390) of the circuit board (362).

[0096] The socket (364) is positioned on the circuit board (362). The circuit board (362) is thus positioned between the thin chuck (350) and the socket (364). Each pin of the pins (366 and 368) initially has an individual terminal (392) that extends downward from the lower surface (394) of the lower part (370). The individual terminal of the terminal (392) contacts the individual contact of the contacts (388). The pins (366 and 368) are compressed against their spring force until the lower surface (394) contacts the upper surface (390). The terminals (392) of the pins (366 and 368) move into the socket (364) until they are in the same plane as the lower surface (394). The socket (364) is then permanently mounted on the circuit board (362).

[0097] The socket (364) has a first socket column opening (398) formed through it from the lower side to the upper side. The circuit board (362) has a first circuit board column opening (400) formed through it from the lower side to the upper side. The first socket column opening (398) is aligned with the first circuit board column opening (400). The column subassembly (342) and the board-and-socket subassembly (344) are initially disconnected from each other as illustrated in FIG. 11. The board-and-socket subassembly (344) is then positioned over the column subassembly (342). The first circuit board column opening (400) is positioned over the upper end of the first column post (354). The board-and-socket subassembly (344) is then lowered further until the first column post (354) passes through the first socket column opening (398). The lower surface (402) of the circuit board (362) stops on the upper surface (356) of the thin chuck (350). The first column post (354) is loosely fitted into the first socket column opening (398) and the first circuit board column opening (400). Because the first column post (354) is slightly longer than the combined lengths of the first socket column opening (398) and the first circuit board column opening (400), it extends above the upper surface (356). The first column surface (360) is therefore located just above the upper surface of the first recessed formation (376). The contacts (378) are located on the plane above the plane of the first column surface (360) in this stage.

[0098] The socket (364) is made of electrical and thermal insulating material. Pins (366 and 368) provide electrical conductors through the socket (364). The circuit board (362) is also made of electrical and thermal insulating material. Contacts (388) form part of an electrical circuit within the insulating material of the circuit board (362). A first column post (354) provides a thermally conductive path between the first recessed formation (376) and the first column anchor (352) connected to the thin chuck (350). The first column post (354) is electrically and thermally insulated from the electrical conductors within the socket (364) and the circuit board (362). Heat will be conducted primarily through the first column post (354) rather than through the socket (364) and the circuit board (362) of insulating material.

[0099] The lead (346) includes a circuit board (406) and a heat sink (408). The cartridge (340) further has a first photodetector (410), a first adjustable component (412), and a first coil spring (414).

[0100] The circuit board (406) is made of electrical and thermal insulating material. Electrically conductive terminals (416) are formed on the lower surface (418) of the circuit board (406). The terminals (416) form part of a circuit (not shown) formed within the circuit board (406).

[0101] A first photodetector (410) is attached to the upper surface (420) of a circuit board (406). The first photodetector (410) is connected to terminals (416) through a circuit within the circuit board (406). One terminal of the terminals (416) may, for example, provide power to the first photodetector (410). When light comes over the first photodetector (410), the first photodetector (410) converts the energy of the light into output power. The other terminal (416) may function as an output contact connected to the first photodetector (410) to measure the output power.

[0102] The first adjustable component (412) has a pusher plate (422), side walls (424) extending upward from the pusher plate (422), and a lip (426) extending outward from the side walls (424). A first opening (428) is formed in the circuit board (406). The first adjustable component (412) is inserted into the first opening (428). The pusher plate (422) then extends downward from the lower surface (418). The lip (426) stops on the upper surface (420). The first opening (428) is slightly larger than the width between the side walls (424). The difference in widths causes the first adjustable component (412) to rotate about the first axis (432) relative to the circuit board (406) by a small amount of just a few degrees. The difference in widths also causes the first adjustable component (412) to rotate clockwise and counterclockwise about a second axis (434) that is in the ground and orthogonal to the first axis (432) relative to the circuit board (406). This orthogonal rotation allows for a small amount of gimbaling of the first adjustable component (412) relative to the circuit board (406).

[0103] The heat sink (408) has a first recess (436). A first coil spring (414) is inserted between the side walls (424). The lower end of the first coil spring (414) rests on the upper surface (438) of the pusher plate (422). The upper end of the first coil spring (414) extends above the lip (426). The heat sink (408) is positioned on the circuit board (406) with the upper end of the first coil spring (414) positioned within the first recess (436). The lower surface (440) of the heat sink (408) is initially spaced apart from the upper surface (420). The first coil spring (414) is compressed and deformed against its spring force as the heat sink (408) moves toward the circuit board (406). The lower surface (440) comes into contact with the upper surface (420). The heat sink (408) is then secured to the circuit board (406) by fasteners (not shown). A small force generated by the first coil spring (414) then biases the first adjustable component (412) away from the lower surface (418).

[0104] The pusher plate (422) has a first opening (442) therein. The heat sink (408) defines the first cavity (444). A light-absorbing coating is formed on the surfaces of the first cavity (444).

[0105] When in use, the first electronic device (348) is inserted into the first recessed formation (376). The terminals (446) on the lower side of the first electronic device (348) come into contact with the contacts (378). The lower surface (448) of the first electronic device (348) is spaced apart from the first column surface (360) in this stage.

[0106] The lead (346) is positioned on the board-and-socket subassembly (344). The lead (346) is then moved toward the board-and-socket assembly (344). Each terminal of the terminals (416) contacts the individual contacts of the contacts (380). The lower surface (450) of the pusher plate (422) contacts the upper surface (452) of the first electronic device (348). The lower surface (448) of the first electronic device (348) is still spaced apart from the first column surface (360).

[0107] The operator manually presses, thereby moving the lead (346) further toward the board-and-socket subassembly (344). Each pin of the pins (366 and 368) is compressed against its spring forces and thus elastically presses the contacts (378 and 380) against the spring forces of the springs within the pins (366 and 368). The lower surface (448) of the first electronic device (348) contacts the first column surface (360).

[0108] If there is an angular misalignment between the lower surface (448) of the first electronic device (348) and the first column surface (360), the first electronic device (348) is rotated by the first column surface (360) until the lower surface (448) is in the same plane as the first column surface (360). Rotation of the first adjustable component (412) relative to the lead (346) allows the lower surface (448) of the first electronic device (348) to seat relative to the first column surface (360). Excellent thermal contact between the first column surface (360) and the lower surface (448) is thus ensured. The first coil spring (414) is compressed to accommodate the height of the first electronic device (348). Additionally, the first adjustable component (412) is rotatably mounted on a lead (346) so that the first electronic device (348) can rotate the first adjustable component (412) relative to the first column surface (360). The lead (346) is then secured to the board-and-socket subassembly (344).

[0109] The socket (364) and leads (346) jointly form an electronic device holder that holds the first electronic device (348). A cartridge interface (not shown) on the circuit board (362) provides power and communication to and from the contacts (388). The pins (366) provide power and communication to the first electronic device (348) through the terminals (446).

[0110] The first electronic device (348) may include, for example, a laser or other light transmitter. The first electronic device (348) may, for example, have a laser transmitter on its upper surface (452). When power and communication are provided to one contact of the contacts (378) functioning as an input contact and one terminal of the terminals (446) functioning as an input terminal, the laser transmitter of the first electronic device (348) transmits laser light into the first cavity (444) through the first opening (442) and through the first coil spring (414) and side walls (424).

[0111] Most of the light is absorbed by the light-absorbing material on the surfaces of the first cavity (444) and thus converted into heat. The heat is conducted through the heat sink (408).

[0112] A small proportion of light is reflected from the surfaces of the first cavity (444) and detected by the first light detector (410). The first light detector (410) is powered through an electrical conductor formed by one contact of the contacts (388), one pin of the pins (368), one terminal of the terminals (416), and a circuit formed within the circuit board (406). When the first light detector (410) detects light, it converts the light into power. The magnitude of the power is related to the magnitude of the light detected by the light detector (410). The first photodetector (410) then provides power to the circuit board (362) and ultimately to the cartridge interface on the circuit board (3620) through a conductor jointly formed by the circuit within the circuit board (406), one terminal of the terminals (416), one pin of the pins (368), and one contact of the contacts (388).

[0113] Even if the first photodetector (410) is on the opposite side of the first electronic device (348) rather than the circuit board (362), the circuit board (406) and the pins (368) provide a measurement channel connecting the first photodetector (410) to the circuit board (362). In a similar manner, a detector of a type other than a photodetector may be used to detect features of the electronic device other than light transmitted by the electronic device. For example, it may be possible to create a similar measurement channel by detecting current on a terminal on the upper surface of the electronic device and through a pin located in a socket for the circuit board above the electronic device and the circuit board below the electronic device. In this arrangement, a pin such as pin (368) can function as a detector measurement pin that is held by the socket and forms part of the measurement channel.

[0114] The temperature of the first electronic device (348) is controlled by conducting heat through the first heat post (354). The first electronic device (348) may be heated or cooled, for example, through the first heat post (354). The first electronic device (348) may be cooled, for example, by transferring heat from the first electronic device (348) to the thin chuck (350) through the first heat post (354) and the first heat anchor (352). The first electronic device (348) may be heated by transferring heat from the thin chuck (350) to the first electronic device (348) through the first heat anchor (352) and the first heat post (354).

[0115] The thin chuck (350) is on the side of the first electronic device (348) opposite the heat sink (408). Thus, it can be seen that the temperature of the first electronic device (348) can be controlled independently of heat dissipation by the heat sink (408) due to the laser light transmitted by the first electronic device (348).

[0116] Referring again to FIG. 12, a plurality of electronic devices can be tested using one socket (364) and one lead (346). The socket (364) includes, for example, a second row anchor (352A), a second row post (354A), a second row surface (360A), a second set of pins for a second electronic device (366A), a second set of pins (368A), a second recessed formation (376A) for a second electronic device (not shown), a second socket row opening (398A), a second circuit board row opening (400A), a second photodetector (410A), a second adjustable component (412A), a second coil spring (414A), a second opening (428A), a second recess (436A), a second opening (442A), and a second cavity (444A). Similar reference numbers indicate similar components and functions.

[0117] Light transmitted by the first and second electronic devices can be independently detected by the first and second photodetectors (410 and 410A). Heat is dissipated through the same heat sink (408) due to the light from the first and second electronic devices. A plurality of pins (454) are connected to the heat sink (408) and extend from it. Heat is conducted to the pins (454) and then convected from the pins (454) into the surrounding air. The pins (454) thus function as heat dissipation devices thermally connected to the heat sink (408) to remove heat from the heat sink (408).

[0118] The temperatures of the first and second electronic devices are jointly controlled through the same thin chuck (350). For example, when the electronic devices are cooled, heat is conducted through the first and second heat posts (354 and 354A) to the first and second heat anchors (352 and 352A), respectively, and then from the first and second heat anchors (352 and 352A) to the thin chuck (350).

[0119] The first and second electronic devices are independently rotatable to contact the first and second column surfaces (360 and 360A), respectively. The independent rotation of the first and second electronic devices is allowed and controlled by the independent gimbaling of the first and second adjustable components (412 and 412A) with respect to the lead (346).

[0120] Referring again to FIG. 11, 16 sockets (364) are attached to a circuit board (362). Each socket (364) has an individual lead (346). Each lead (346) has an individual fixing form (460), and each socket (364) has an individual fixing form (462). The lead (346) is moved toward the socket (364). The lead (346) is then pressed into the socket (364) as described above. The fixing forms (460 and 462) then interlock with each other to secure the lead (346) to the socket (364) and maintain thermal and electrical integrity.

[0121] The thin chuck (350) has a number of heat posts fixed thereto in 16 groups of 16. Each group of heat posts is inserted through an individual socket of the sockets (364). Electronic devices held by all 16 sockets (364) are held at their temperatures using a single thin chuck (350).

[0122] A cartridge interface (464) is formed on the lower surface of the circuit board (362). The cartridge interface (464) is connected to the contacts (388) shown in FIG. 13 via a circuit (not shown). The cartridge interface (464) is used to connect the cartridge (340) to an electrical tester as described below. A thin chuck (350) is thermally connected to a thermal chuck as described below. The thermal chuck functions as a temperature changing device that controls the heat transferred to or from the thin chuck (350).

[0123] Following testing of the electronic devices, the cartridge (340) is removed from the system, the leads (346) are stripped, and the electronic devices are removed from the sockets (364).

[0124] The thermal post (354) also functions as a post that transfers force in a manner similar to the embodiment described in FIG. 8a and FIG. 8b. The lead (346) functions as a force generating device. A portion of the force generated by the lead (346) is balanced by forces generated by springs within the pins (366 and 368). The remaining force not balanced by the pins (366 and 368) is taken by a stand-off of the post (364) having a surface (360) to support the electronic device (348) and prevent movement of the electronic device (348) closer to the base of the recessed formation (376). The central portion of the post (354) functions as a force transfer portion extending from the stand-off through the opening (398). The circuit board (362) and the thin chuck (350) jointly form a backing structure. The lower part of the post (354) generally delivers force to a backing structure. Specifically, force is delivered through a thermal anchor (352) to a thin chuck (350) that forms part of the backing structure. The press fit between the thermal anchor (352) and the thin chuck (350) is strong enough to keep the force from moving the thermal anchor (352) relative to the thin chuck (350).

[0125] FIG. 14a illustrates embodiments of FIG. 11, FIG. 12 and FIG. 13 and further illustrates details thereof including fasteners (600) and posts (602).

[0126] The post opening (604) and the fastener opening (606) are formed through the socket (364). The post opening (520) has a first section (608) and a second section (610). The second section (610) is wider than the first section (608). The first section (608) may be formed, for example, through the upper part (372), and the second section (610) may be formed through the lower part (370). A landing (612) connects the first section (608) to the second section (610).

[0127] The post (602) has a stand-off (614), a force transfer portion (616), and a force delivery portion (618). The post (602) is inserted from the bottom into the post opening (604) until the surface (620) of the force delivery portion (618) is adjacent to the landing (612). The threaded shaft (622) of the fastener (600) is inserted from the top through the fastener opening (606). The head (624) is then rotated so that the thread on the threaded shaft (622) screws onto the thread in the threaded opening (626) within the thin chuck (350). Since the thin chuck (350) is made of metal, it provides excellent anchoring for the fastener (600). As the fastener (600) is rotated further, the column (624) moves closer to the circuit board (362). The springs of the pins (366) are slightly compressed, and the lower side (630) of the post (602) comes into contact with the circuit board (362).

[0128] As illustrated in FIG. 14b, when the operator presses the lead (346) over the socket (364), the pusher plate (422) generates a force (F1) equal to and opposite to the reactive force (F2) generated in the thin chuck (350). The springs of the pins (366) are compressed against the spring forces (F3) of their springs. The pusher plate (422) and the first electronic device (348) continue to move closer to the socket (364) until the lower surface (448) of the electronic device (348) comes into contact with the surface (632) of the stand-off (614). The surface (632) prevents further movement of the electronic device (348) toward the socket (364).

[0129] The stand-off (614) receives power (F4) from the electronic device (348). The power transfer section (566) transfers power through the first section (608) of the post opening (604). The power delivery section (618) receives power from the power transfer section (566) and delivers the power to the circuit board (362). The circuit board (362) delivers the power to the thin chuck (350).

[0130] Therefore, it can be seen that the material of the socket (364) is not exposed to force (F4) and damage to the socket (364) can be eliminated.

[0131] A socket (364) provides a support board through which a post opening (604) passes. A circuit board (362) on a first side of the support board provides a backing structure and has a contact (388). A pin (366) forms a conductor having a contact (378) that contacts a terminal (446) on an electronic device (348) positioned on the side of the support board opposite the first side of the support board. The conductor has a portion retained in the support board and a terminal (392) connected to the contact (388) on the circuit board (362). A spring is provided within the pin (366). A pusher plate (422) forms a force generating device on the side of the electronic device (348) opposite the support board. The force generating device and the support board are movable relative to each other to move the electronic device (348) closer to the support board and deform the spring. The post (602) has a stand-off (614) having a surface (632) on a plane spaced apart from the plane of the surface of the support board to prevent the electronic device (348) from moving closer to the support board. The power transfer portion (616) extends at least partially from the stand-off (614) through the post opening (604). The power delivery portion (618) extends from the power transfer portion (616). The power delivery portion (618) is held by a backing structure.

[0132] FIG. 15 illustrates additional components of a tester device (10) used to accurately control the voltages supplied to electronic devices (634) being tested. The electronic devices (634) may be, for example, positioned across the surface of a wafer (636) or individual devices maintained within a layout of sockets.

[0133] Many semiconductor devices require a constant current versus a constant voltage supply. One example of this is the burn-in (or aging) of Vertical Cavity Surface Emitting Laser (VCSEL) wafers. The following challenges exist:

[0134] A VCSEL wafer has a very large number of devices in a very small area. For example, assume that a VCSEL wafer has 50,000 devices within a 3-inch circle.

[0135] The cost of 50,000 constant current sources would make the system cost too high for cost-effective burn-in.

[0136] Routing 50,000 power lines into a 3-inch circle would be very difficult, if not impossible.

[0137] For further explanation, the following assumptions can be made:

[0138] Since VCSELs are diodes, there is almost no power to the ground shorts.

[0139] "Opening" can occur at much higher frequencies due to some VCSELs becoming "open" or due to poor contact with the wafer.

[0140] The internal resistance of the VCSEL is substantial (about 100 ohms for a 10 mA VCSEL) and very consistent (within 1%) across the wafer.

[0141] There is a high possibility of building very accurate (within 1%) voltage sources.

[0142] It is possible to measure current with considerable accuracy for a voltage source.

[0143] Most VCSEL wafers have a common cathode that limits the ability to arrange VCSELs in series.

[0144] For the sake of example, assume the following:

[0145] VCSEL burn-in requires about 2.5 Volts and 10 mA.

[0146] Assume the system has 1024 power channels with up to 5 Volts and 200 mA per channel.

[0147] Assume that the system can provide constant current or constant voltage per channel.

[0148] Assume the goal is to burn in a quarter wafer (12,500 VCSELs) in a single step.

[0149] The following is a list of existing burn-in circuit options:

[0150] (1) Individual constant current sources. This provides an accurate, measurable current to all VCSELs, but presents the following problems:

[0151] Only about 2% of the wafer can be burned in at each stage (1024 channels for 50,000 devices).

[0152] The "cost" per VCSEL is 1 channel. Even if additional channels are added, the cost will remain 1 channel per VCSEL.

[0153] Even if the system could be scaled to 12,500 channels (the minimum number of channels required to burn in 1 / 4 of a wafer), routing 12,500 power channels to a 3-inch wafer area would be impossible or cost-inefficient.

[0154] (2) Series wiring. This would require arranging about 13 VCSELs in series and driving them with a constant current source, but presents the following problems:

[0155] Since all VCSELs have a common cathode, it is not possible to wire the wafers of VCSELs in series.

[0156] This will require a current source of over 30 Volts and 10 mA. It is very difficult to protect such high voltages from current surges.

[0157] (3) Parallel wiring with a current source. Driving approximately 13 VCSELs in parallel with a constant current source. This will require a 2.5 Volt, 130 mA current source. This system presents the following problems:

[0158] For every VCSEL with an "open" or bad probe contact, the extra current is distributed among the remaining VCSELs in the group. Therefore, each VCSEL will receive about 8% of the extra current (130 mA / 12 VCSELs) for every bad VCSEL in the group.

[0159] It would not be known that if the voltage does not shift significantly due to the open VCSEL, the other 12 VCSELs that received the wrong burn-in current and the resulting defective devices may avoid detection.

[0160] (4) Parallel wiring with a voltage source. This system will drive 13 VCSELs in parallel with a constant current source. The voltage source is selected to be the voltage required for all 13 VCSELs to receive a current of 10 mA. This system presents the following problems:

[0161] When a VCSEL is open, the total current in the group will be slightly lower. For all open VCSELs, the group current will be 10 mA lower (e.g., 140 mA versus 150 mA for the group). The remaining VCSELs in the group will still receive 10 mA.

[0162] The stability of the current per VCSEL within the group is excellent. In the worst case, it is the accuracy of the voltage supply (<1%) and the consistency of the internal resistance of the VCSEL (<1% across the wafer). Therefore, the current through each VCSEL will be consistent within 2% across the wafer using a parallel voltage source.

[0163] If the VCSEL is short-circuited (which is highly unlikely), the overcurrent protection for the power channel will shut down that power channel, allowing the other channels to continue operating.

[0164] Existing solutions can therefore be summarized as follows:

[0165] Circuit 1 is an ideal circuit, but cost and technical issues exclude it.

[0166] Circuit 2 cannot be used on a common cathode VCSEL wafer.

[0167] Circuit 3 is the most common failure mode, "open", which leads to very poor results in devices.

[0168] Circuit 4 provides excellent results in almost all cases and is very cost-effective.

[0169] Circuit 4 (parallel wiring with a voltage source) presents the following problems.

[0170] To ensure that VCSELs receive the appropriate current, an accurate voltage must be selected for the voltage source.

[0171] The appropriate voltage is a function of several factors:

[0172] VCSEL configuration. The design of the VCSEL determines the voltage at the desired current.

[0173] VCSEL fabrication process variations per wafer. Due to process variations, the voltage at a given current can vary from wafer to wafer.

[0174] VCSEL fabrication process variations across the wafer. The voltage at a given current can vary from devices near the wafer edge to devices at the center of the wafer.

[0175] The voltage at a specific current varies with temperature. Not only the heat added for burn-in, but also the device's own internal heating can change the voltage at a given current.

[0176] As the VCSEL ages, its voltage-to-current relationship changes. Therefore, even if the voltage was accurate at the beginning of the burn-in cycle, the appropriate voltage at the end is likely to decrease.

[0177] FIG. 15 merely illustrates the electronic devices (634) of the first group (group 1) of clusters (clusters 1 to 4) of electronic devices (634) located in an area near the edge of the wafer (636). It should be understood that there are 16 groups (groups 1 to 4) of clusters, each group has 64 clusters, and each cluster has 12 electronic devices (634).

[0178] The electronic devices (634) of the first cluster (cluster 1) are connected in parallel to each other through conductors forming part of the wafer (636) or by an external device forming part of the tester device (10). Additional clusters (clusters 2 to 4) of electronic devices (not shown) are located in additional regions of the first group (group 1). Each cluster has an individual set of 12 electronic devices connected to each other in parallel. The electronic devices forming one cluster are not electrically connected to the electronic devices forming part of any other cluster.

[0179] The tester device (10) includes a cluster selector switch (638), a current detector (640), a static filter (642), an outlier filter (644), a sample size filter (646), a voltage targeting system (648), a voltage source (650), and first and second voltage regulators (652 and 654).

[0180] Each cluster provides a separate current output to the cluster selector switch (638). The cluster selector switch (638) is adjustable to selectively connect the current detector (640) to the individual current outputs of the current outputs (660). Current from the individual current outputs (660) is transferred to ground (662) through the current detector (640).

[0181] The cluster selector switch (638) is typically operated to connect each current output of the current outputs (660) to the current detector (640). The current detector (640) thus detects currents from each cluster of the clusters.

[0182] The current detector (640) provides an output to a static filter (642). The static filter (642) is adapted to remove current readings for individual clusters that are higher or lower than a set limit. The static filter (642) typically processes data for all clusters simultaneously to remove data for clusters that have current readings that are higher or lower than a set limit.

[0183] The static filter (642) passes the data to the outlier filter (644). The outlier filter (644) removes current readings for individual clusters that are extremely higher or lower than the median for a group of clusters. The outlier filter (644) passes the data to the sample size filter (646). The sample size filter (646) stops computing the average of current readings for clusters containing the cluster if the number of channels (devices) for the cluster is too small.

[0184] The voltage source (650) is connected to the input voltage terminals of the first group of electronic devices (634) via a voltage regulator (652). The voltage source (650) is additionally connected to the input terminals of the second group of electronic devices via a voltage regulator (654). Similarly, the voltage source (650) is connected to the electronic devices of the additional groups via additional voltage regulators (not shown).

[0185] The voltage targeting system (648) receives data from the sample size filter (646) and adjusts the voltage regulators (652 and 654) based on the data.

[0186] FIG. 16 illustrates a method of testing multiple electronic devices (634) using the components of the tester device (10) of FIG. 15.

[0187] In 700, multiple electronic devices are maintained in clusters as described above. In 702, a voltage source (650) is connected to the electronic devices (634) of the first cluster. As described above, the voltage source (650) is connected to the electronic devices (634) to provide voltage to the electronic devices (634) of the first cluster in parallel. In 704, the voltage source (650) is connected to the electronic devices of the second cluster via a voltage regulator (652) to provide voltage to the electronic devices of the second cluster in parallel. Similarly, in 706, the voltage source (650) is connected to the electronic devices of the third cluster via a voltage regulator (652) to provide voltage to the electronic devices of the third cluster in parallel. The voltage source (650) may similarly be connected to additional clusters of electronic devices via a voltage regulator (642) to provide voltage to each of the electronic devices in parallel.

[0188] Referring to FIG. 17, the slope of the curve is calculated by first determining the voltage estimates "A" and "B". Steps 708 through 724 of FIG. 16 correspond to the calculation of the slope.

[0189] At 708, the first initial voltage estimate "V A " is performed and the first initial current of the result "I A" is measured using the current detector (640) of FIG. 15. The voltage source (650) of FIG. 15 provides a first initial voltage estimate for the electronic devices (634) of the first cluster in parallel. The second, third, and additional clusters are treated similarly to the first cluster. For example, the voltage source (650) provides a first initial voltage estimate for the electronic devices of the second cluster in parallel.

[0190] The cluster selector switch (638) of FIG. 15 is switched sequentially through current outputs (660) from individual clusters of the first group. When the cluster selector switch (638) is connected to the current output (660) of the first cluster, the current detector (640) measures a first initial current from the electronic devices (634) of the first cluster. The first initial current from the electronic devices (634) of the first cluster measured by the current detector (640) is the total current of the electronic devices (634) of the first cluster in parallel. When the cluster selector switch (638) is switched to the current output (660) of the second cluster, the second cluster undergoes treatment similar to the first cluster, as indicated by the dash line between 704 and 710 in FIG. 16. Similarly, by continuously switching the cluster selector switch (638) to subsequent current outputs (660), the current detector (640) measures the first initial current for each individual cluster's electronic devices.

[0191] The current detector (640) provides current measurements to the static filter (642) of FIG. 15. As can be seen more clearly in FIG. 16, multi-stage filtering (710) including static filtering (712), outlier filtering (714), and sample size filtering (716) is performed. As shown in FIG. 16, the static filter (642) of FIG. 15 performs static filtering in 712.

[0192] FIG. 18 illustrates static filtering in more detail. Individual currents from the first and second groups are shown. Static filtering removes current readings that are higher or lower than a set limit, for example, less than 2 and greater than 6. Static filtering may also remove a first initial current reading for an individual cluster within an individual group that is higher or lower than a set limit, for example. Any given cluster may have an "open" VCSEL and therefore may not return an accurate total current for all VCSELs. The current limit can be used to determine whether any given reading appears accurate.

[0193] Following static filtering, the data is processed at 714 in FIG. 16 to perform outlier filtering with the outlier filter (644) in FIG. 15. FIG. 19 illustrates outlier filtering in more detail. Outlier filtering removes data that is extremely high or low compared to the median of the data; for example, + / -20%. Outlier filtering may also remove first initial current readings for individual clusters that are extremely high or low compared to the median for the group, for example. Additional filtering may use statistical methods to determine whether the first initial current reading of a given channel is abnormal.

[0194] Following outlier filtering, the data is processed at 716 in FIG. 16 to perform sample size filtering with the sample size filter (646) of FIG. 16. Sample size filtering is exemplified in FIG. 20. Sample size filtering stops computing the average of the first initial current readings of the groups if the number of remaining clusters is too small, for example, <10. If too few clusters remain for appropriate computations in any group, the average computation of surrounding groups may be used. Two sample groups are included to show how the filtering proceeds. After outlier filtering, too few clusters remain in the second group to provide a reliable computation for the voltage. In that case, the average of the other group is used.

[0195] At 720 in Fig. 16, the second voltage estimate "V B " is performed and the second initial current of the result "I B " is measured. The second initial voltage estimate is applied in the same way as the first initial voltage estimate in 708. The second initial voltage current is measured for each cluster of clusters.

[0196] In 722, multi-stage filtering is performed on data containing second initial currents from clusters. The multi-stage filtering performed in 722 is the same as the multi-stage filtering performed in 710.

[0197] Figure 17 illustrates the positions of the first and second initial currents after passing through multi-stage filtering at 710 and 722. Current measurements are plotted on the Y-axis and time is plotted on the X-axis. The current slope is given by the following equation:

[0198] Slope = (V B -V A ) / ( I B -IA )

[0199] The slope is therefore calculated by dividing the difference between the second and first initial voltages for the first group of electronic devices by the difference between the second and first initial currents for the first group of electronic devices.

[0200] The steps described above (708, 712, and 724) are executed by the voltage targeting system (648) of FIG. 15. The voltage targeting system (648) controls a voltage regulator (652) to provide voltages to the electronic devices of individual clusters. The voltage targeting system (648) then stores the calculated slope in memory.

[0201] Following the computation of the slope and the storage of the slope at 724 in FIG. 17, the voltage targeting system (648) may use the slope to set and retarget test voltages applied to each cluster of electronic devices (634). The setting and retargeting of test voltages are exemplified by steps (726 to 736) of FIG. 16.

[0202] At 726, the conjecture is the first test voltage (V G The first test current (I) of the result is performed on ) G ) is measured. It should be understood from the above description and FIG. 15 that the voltage targeting system (648) sets the voltage regulator (652) so that the voltage source (650) applies a first test voltage to the electronic devices (634) of the first cluster in parallel. It should also be understood that the first test current for the electronic devices (634) of the first cluster, measured by the current detector (640), is the total current of the electronic devices (634) of the first cluster in parallel.

[0203] The second and third clusters of the first group undergo similar processing. Each additional cluster therefore has an individual first test voltage applied to the devices of the cluster and a first test current measured from the devices.

[0204] Following the measurement of the first test currents from the clusters, the data of the first test currents proceeds through multi-stage filtering (730). Multi-stage filtering (730) is performed on the first test currents in a manner similar to the multi-stage filtering (710) performed on the first initial currents from the clusters and the multi-stage filtering (722) performed on the second initial currents from the first group of clusters.

[0205] In 732, a first comparison is performed between the first test current and the target current. Specifically, the measured first test current is subtracted from the target current. The difference is recorded as the amount of current error to be corrected. FIG. 17 shows the first initial estimate ("G"), target current (I T ) and current error (I T -I G The first initial current is plotted as a result of ).

[0206] At 734 in FIG. 16, retargeting is performed. A second test voltage is computed, and the first test voltage is adjusted to the second test voltage. As shown in FIG. 17, the second test voltage is calculated according to the following equation:

[0207] V G +( I T -I G ) * slope

[0208] The first comparison in 732 therefore forms the basis for voltage adjustment in 734.

[0209] Figure 16 indicates that the process starting from 726 can be repeated by using the retargeted voltage as the first test voltage, measuring the test current, and calculating the retargeted voltage.

[0210] The dashed lines from 702 and 706 in FIG. 16 indicate that the second and third groups of clusters receive treatment similar to that of the first group of clusters. In the given example, a voltage source (650) provides voltage to the electronic devices of the second group through a voltage regulator (654). The voltages applied to the electronic devices of the first and second groups can be controlled independently in the manner described above. In a similar manner, a separate voltage regulator provides voltage to the electronic devices of a separate group. Although only a single current detector (640) is shown, it should be understood that multiple current detectors may be included in the system to detect currents from one or more clusters within one or more groups.

[0211] As mentioned above, parallel wiring with a voltage source has separate economic advantages. Additionally, the voltage retargeting process ensures that accurate voltages are applied to devices connected using parallel wiring with a voltage source to ensure that the devices receive accurate currents according to their specifications, as described above.

[0212] Clusters can be selected to match wafer processing (or other) factors that may affect voltage / current relationships.

[0213] It is not surprising that devices near the edge of the wafer have different characteristics from devices near the center of the wafer.

[0214] Clusters can be selected so that edge devices are analyzed into other edge devices and central devices are analyzed into other central devices.

[0215] The retargeting process is highly convergent and not sensitive to slight errors.

[0216] For example, assume that the initial voltage / current computation was not performed correctly and the slope of the result is off by 20%.

[0217] For the first retargeting step, it is assumed that the computed voltage is 50% incorrect (i.e., the current is 50% incorrect).

[0218] The first retargeting will attempt to correct a 50% current error to a slope with a 20% error. The net correct will be 10% incorrect (50% * 20%).

[0219] The next retargeting step will correct this 10% error and miscompute by another 20%. This correction will be only 2% wrong (10% * 20%).

[0220] Therefore, after only two retargeting steps, with a 50% starting error and a 20% slope error, the current of the result is now within 2%.

[0221] This exemplifies the fast convergence of this retargeting algorithm. More typically, the gradient will be computed to be within approximately 5% and the initial current will be within 20%. Subsequently, only a single step is required to be within 1% of the accurate current.

[0222] Although certain exemplary embodiments have been described and illustrated in the accompanying drawings, it should be understood that the invention is not limited to the specific configurations and arrangements shown and described, as these embodiments are merely illustrative and are not intended to limit the invention, and modifications may occur to those skilled in the art.

Claims

Claim 1 As a cartridge, a support board through which a post opening passes; a backing structure on a first side of the support board comprising at least a circuit board having a contact; a conductor having a contact for contacting a terminal on an electronic device positioned on a second side of the support board opposite the first side of the support board, a portion held by the support board and a terminal connected to the contact on the circuit board, a spring; a force generating device on the side of the electronic device opposite the support board, wherein the force generating device and the support board are movable relative to each other to move the electronic device closer to the support board and deform the spring; A cartridge comprising a post having a stand-off having a surface in a plane spaced apart from the plane of the surface of the support board to prevent movement of the electronic device closer to the support board, a power transfer portion extending from the stand-off at least partially through the post opening, and a power delivery portion extending from the power transfer portion, wherein the power delivery portion is maintained by the backing structure. Claim 2 In claim 1, the conductor is a pin, the pin comprises first and second tips on the spring and opposite sides of the spring, and the movement of the first and second tips toward each other compresses the spring, cartridge. Claim 3 In claim 2, the contact of the conductor is a cartridge, which is the end of the first tip. Claim 4 In claim 2, the terminal of the conductor is the end of the second tip, a cartridge. Claim 5 In claim 1, the power delivery portion is wider than the power transfer portion, cartridge. Claim 6 In claim 5, the post is a cartridge that prevents the power delivery portion from coming out of the post opening because the power transfer portion is wider than the power delivery portion. Claim 7 In claim 6, the post opening has a first section and a second section wider than the first section so that a landing is defined between the first section and the second section, and the force delivery portion is adjacent to the landing, cartridge. Claim 8 In claim 1, the post has a surface on the power delivery portion and on the side of the post opposite the surface of the stand-off, and the surface on the power delivery portion is adjacent to the backing structure for transferring power, cartridge. Claim 9 In claim 1, the spring is a cartridge that deforms the spring with respect to its spring force. Claim 10 A cartridge according to claim 1, wherein, when in use, the stand-off receives power from the electronic device, the power transfer portion transfers the power from the stand-off at least partially through the post opening, and the power delivery portion receives the power from the power transfer portion and delivers the power to the backing structure. Claim 11 In claim 1, the force generating device is a chuck located below a wafer having a plurality of electronic devices, the support board is a contactor, the circuit board has a plurality of contacts, and the cartridge further comprises a plurality of conductors, wherein each conductor has a plurality of conductors having a plurality of conductors for contacting a plurality of terminals on one of the electronic devices, a plurality of portions held by the contactor, and a plurality of terminals connected to the plurality of conductors on the circuit board. Claim 12 In claim 1, the support board is a socket having a formation for holding the electronic device, the force generating device is a lead located above the electronic device, the backing structure includes a chuck of a thermally conductive material, and the circuit board is supported by the chuck, a cartridge. Claim 13 In claim 12, the post is a cartridge that is a thermal post passing through an opening in the circuit board and supported by the chuck. Claim 14 In claim 13, the cartridge further comprises a thermal anchor maintained by the above chuck, wherein the thermal post extends from the thermal anchor. Claim 15 In claim 12, the post has a surface on the power delivery portion and on the side of the post opposite the surface of the stand-off, and the surface on the power delivery portion is adjacent to the backing structure for transferring power, cartridge. Claim 16 A method for testing an electronic device using a cartridge, comprising: positioning a backing structure on a first side of a support board, the backing structure comprising at least a circuit board having contacts; connecting a contact of a conductor to a terminal on an electronic device positioned on a second side of the support board opposite the first side of the support board, wherein the conductor has a portion maintained by the support board and a terminal connected to the contact on the circuit board; positioning a force generating device on the side of the electronic device opposite the support board; moving the force generating device and the support board relative to each other to move the electronic device closer to the support board and deform a spring against its spring force; blocking the movement of the electronic device closer to the support board by a post having a stand-off having a surface on a plane spaced apart from the plane of the surface of the support board; receiving a force from the electronic device by the stand-off of the post; and through a post opening formed at least partially through the support board A method for testing an electronic device using a cartridge, comprising: transferring at least partially the force from the stand-off to a force transfer portion of the post extending from the stand-off through the post opening; receiving the force to a force delivery portion of the post extending from the force transfer portion, wherein the force delivery portion is maintained by the backing structure; and delivering the force to the backing structure.

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