Spring Probe Contact Assembly

Abstract

A compliant probe contact assembly for use in a test system for testing integrated circuit devices is provided. The contact assembly includes an upper plunger having a first shoulder separating an upper shaft from a lower shaft, and a retainer proximate an end of the lower shaft. The contact assembly includes first and second receiving pieces that engage the upper plunger. The first and second receiving pieces each include a second shoulder with a shoulder stop. The contact assembly includes a biasing member. When the contact assembly is assembled, the biasing member is captured between a bottom of the first shoulder and the shoulder stops of the first and second receiving pieces. The upper plunger separates sides of the upper portions of the first and second receiving pieces. Sides of the lower portions of the first and second receiving pieces contact each other.

Description

[Technical Field]

[0001] The present disclosure relates generally to the field of microcircuit testing (e.g., chips of semiconductor devices, integrated circuits, etc.). More specifically, the present disclosure relates to a spring-loaded probe contact assembly that provides electrical connection to a device under test (DUT). [Background technology]

[0002] The manufacturing process for microcircuits cannot guarantee that every microcircuit will function perfectly. Because the dimensions of individual microcircuits are tiny and the process is highly complex, small or subtle imperfections in the manufacturing process often result in defective devices. Assembly of defective microcircuits onto circuit boards is relatively expensive. Attachment typically requires soldering the microcircuit to the circuit board. Removing a microcircuit once mounted on a circuit board is problematic because the act of melting the solder a second time can ruin the circuit board. Therefore, if a microcircuit has a defect, the circuit board itself may also be ruined, at which point any added value to the circuit board is lost. For these reasons, microcircuits are typically tested before being assembled onto the circuit board. Each microcircuit must be tested in a way that identifies all defective devices while not inappropriately identifying good devices as defective. Frequent occurrence of either type of error can add significant costs to the circuit board manufacturing process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2012 / 0129408 Summary of the Invention [Problem to be solved by the invention]

[0004] Microcircuit test equipment itself is very complex. First, the test equipment must make precise, low-resistance, temporary, nondestructive electrical contact with each closely spaced microcircuit contact. Because microcircuit contacts are small and closely spaced, even a slight mis-contact can result in an inaccurate connection. Further challenges for microcircuit test equipment arise during automated testing. Test equipment may test 100 or more devices per minute. Such high test volumes can cause wear on the tester contacts that make the electrical connections to the microcircuit terminals during testing.

[0005] Other considerations exist. Good, inexpensive tester contacts are advantageous. Because test equipment is expensive, minimizing replacement time is also desirable. When test equipment is offline for extended periods of time for routine maintenance, the cost of testing each individual microcircuit increases. Current test equipment has an array of test contacts that mimics the terminal pattern of the microcircuit. The array of test contacts is supported by a structure that maintains precise alignment of the contacts relative to one another. The test contacts are mounted on a load board (i.e., a printed circuit board (PCB)) that has conductive pads that electrically connect to the test contacts. The load board pads are connected to circuit paths that carry signals and power between the test equipment electronics and the test contacts.

[0006] Socket designs for ball grid array (BGA) packages and / or other array-style integrated circuit packages provide simple yet robust and reliable electrical contact. Therefore, test contactors are often designed and manufactured with spring-loaded contacts. The spring-loaded contacts form a temporary electrical connection between the device under test (DUT) and a load board. Each contact (or contact assembly) connects a specific terminal (e.g., a signal and power (S&P) terminal) on the device under test (DUT) to a specific pad on the load board. It should be understood that the device under test (DUT) can have a ball grid array (BGA) package or other suitable package. For example, the device under test (DUT) can be a pad device, a peripheral device, etc. [Means for solving the problem]

[0007] The embodiments disclosed herein provide solutions that address each of the problems discussed above. The embodiments disclosed herein provide a compliant spring-loaded probe contact assembly that includes an upper plunger (a device under test (DUT) plunger) and a pair of receivers (also known as lower plungers, printed circuit board (PCB) plungers, or load board plungers). The upper plunger and the pair of receivers are entrapped by a biasing member, such as a compliant compression spring.

[0008] The probe contact assembly disclosed herein provides a significant improvement over existing designs, improving the electrical and mechanical performance of spring-loaded probes. The probe contact assembly disclosed herein is enabled to use multiple manufacturing techniques to manufacture the plunger components of the spring-loaded probe contact assembly. The probe contact assembly is not limited to the use of one single technique. Because the probe contact assembly disclosed herein is enabled to use a homogeneous alloy DUT-side tip, it uses two identical PCB-side plunger components manufactured using a flat forming process such as etching, stamping, waterjet cutting, or electroforming (e-forming). The use of two PCB-side plunger components that contact PCB pads is beneficial for electrical redundancy.

[0009] The internal shape of the probe contact assembly can be designed such that the shape (e.g., the internal shape of the spring) is capable of capturing and holding a component (e.g., within the internal volume of the spring) while providing a reliable sliding interconnection between the upper plunger and the receiving part pair. The probe contact assemblies disclosed herein do not rely on deformation, crimping, snapping, or spring press-fit of a latch (or latches). In the probe contact assemblies disclosed herein, the shape of the components alone is capable of capturing the probe contact assembly when the probe contact assembly is assembled. The probe contact assembly may not physically come off during normal use.

[0010] The probe contact assemblies disclosed herein can reduce the overall length of the assembly, as well as lower the inductance of the probe and improve radio frequency (RF) performance. In contrast, existing latching and press-fit technologies may require long areas to achieve positive latching (positive locking) or features large enough to allow for crimping or deformation to securely hold the assembly.

[0011] The probe contact assemblies disclosed herein can be used in standard socket housings, most commonly precision-machined, and are extremely compact, while their inherent low inductance makes them essential for testing 5G and other high-frequency semiconductor devices. The probe contact assembly's external spring geometry and internal assembly design allow for a large degree of compliance in the probe contact assembly, which is important when testing ball grid array (BGA) packages or when testing multiple devices under test (DUTs) at once, due to the additional mechanical tolerances of the test system.

[0012] The probe contact assembly disclosed herein can have components captured within a spring volume that ensures that the sliding interfaces (e.g., between the side of the receiving part and the inner shaft of the upper plunger) always make contact with one another. The fit between these components can ensure reliable electrical contact of the plunger. The receiving part is then allowed to contact the inner wire surface of the spring, which is desirable as a redundant contact element in the system and can minimize the risk of radio frequency (RF) resonances that may be induced at undesired frequencies.

[0013] Also disclosed is a compliant probe contact assembly for a test system for testing integrated circuit devices. The contact assembly includes an upper plunger. The upper plunger includes a first shoulder separating the upper shaft from the lower shaft and a retainer proximate an end of the lower shaft. The contact assembly also includes first and second receiving pieces configured to engage the upper plunger. The first and second receiving pieces each include a second shoulder having a shoulder stop. The contact assembly further includes a biasing member. When the contact assembly is assembled, the biasing member is captured between a bottom of the first shoulder and the shoulder stops of the first and second receiving pieces. The upper plunger separates sides of the upper portions of the first and second receiving pieces. Sides of the lower portions of the first and second receiving pieces contact each other.

[0014] Also disclosed is a test system for testing integrated circuit devices. The test system includes a device under test (DUT), a load board, and a compliant probe contact assembly. The contact assembly includes an upper plunger having a first shoulder separating an upper shaft from a lower shaft and a retainer proximate an end of the lower shaft. The contact assembly also includes first and second receiving pieces configured to engage the upper plunger, each of the first and second receiving pieces having a second shoulder with a shoulder stop. The contact assembly further includes a biasing member. When the contact assembly is assembled, the biasing member is captured between a bottom of the first shoulder and the shoulder stops of the first and second receiving pieces. The upper plunger separates sides of the upper portions of the first and second receiving pieces. Sides of the lower portions of the first and second receiving pieces contact each other. The upper plunger includes a DUT interface configured to engage the DUT. The ends of the first and second receiving pieces are configured to engage with a load board.

[0015] Also disclosed is a compliant probe contact assembly for a test system for testing integrated circuit devices. The contact assembly includes a plunger having a retainer proximate the end of a lower shaft, and first and second receiver plates having top and bottom portions. Each receiver plate has a longitudinal receiving aperture sized to receive only a portion of the retainer. The receiving apertures are not wide enough for the retainer to pass through the receiving aperture. The contact assembly also includes a biasing member. The first and second receiver plates are aligned relative to each other so that the first and second receiver plates are gradually closer together at the bottom than at the top. When the contact assembly is assembled, the biasing member surrounds at least a portion of the plunger and receives the first and second receiving component plates, thereby holding the first and second receiving component plates in physical and electrical contact with the retainer as the plunger moves long through the receiving openings in the first and second receiving component plates.

[0016] Reference is made to the accompanying drawings, which form a part of this disclosure and which illustrate exemplary embodiments in which the systems and methods described herein may be practiced. [Brief explanation of the drawings]

[0017] [Figure 1A] 1 is a perspective view of a portion of a test system for receiving a device under test DUT for testing, according to an embodiment. [Figure 1B] 2 is a perspective bottom view of a device under test DUT, according to an embodiment. [Figure 1C] 1 is a side view of a portion of a test system for receiving a device under test DUT, according to an embodiment. [Figure 1D] 1D is a side view of the test system of FIG. 1C with a device under test DUT electrically engaged therewith, according to an embodiment. [Figure 2A] 10 is a side view of an upper plunger of a probe contact assembly for a test system, according to an embodiment. [Figure 2B] 2B is a perspective view of the upper plunger of FIG. 2A, according to an embodiment. [Figure 3A] 1 is a front view of a receiving component of a probe contact assembly for a test system, according to an embodiment. [Figure 3B] 3B is a perspective view of the receiving piece of FIG. 3A, according to an embodiment. [Figure 4A] 10 is a side view of a spring of a probe contact assembly for a test system, according to an embodiment. [Figure 4B] 4B is a perspective view of the spring of FIG. 4A, according to an embodiment. [Figure 5A] 1 is a front view of a probe contact assembly for a test system, according to an embodiment. [Figure 5B] 5B is a side view of the probe contact assembly of FIG. 5A, according to an embodiment. [Figure 5C] 5B is a perspective view of the probe contact assembly of FIG. 5A, according to an embodiment. [Figure 5D] 5B is a top view of the probe contact assembly of FIG. 5A, according to an embodiment. [Figure 5E] 5B is a bottom view of the probe contact assembly of FIG. 5A, according to an embodiment. [Figure 6A] FIG. 10 is a front view of a probe contact assembly (compressed state) for a test system according to another embodiment. [Figure 6B] FIG. 6B is a side view of the probe contact assembly of FIG. 6A according to another embodiment. [Figure 6C] FIG. 6B is a perspective view of the probe contact assembly of FIG. 6A according to another embodiment. [Figure 6D] FIG. 6B is a top view of the probe contact assembly of FIG. 6A according to another embodiment. [Figure 6E] FIG. 6B is a bottom view of the probe contact assembly of FIG. 6A according to another embodiment. [Figure 7A] 1 is a top view of a probe contact assembly for a test system, according to one embodiment. [Figure 7B] 7B is a front view of the probe contact assembly of FIG. 7A, according to an embodiment. [Figure 7C] 7B is a cross-sectional view of the probe contact assembly of FIG. 7A taken along line AA, according to an embodiment. [Figure 7D] 7B is a cross-sectional view of the probe contact assembly of FIG. 7A taken along line BB, according to one embodiment. [Figure 8A] FIG. 10 is a top view of a probe contact assembly (compressed state) for a test system according to another embodiment. [Figure 8B] FIG. 8B is a front view of the probe contact assembly of FIG. 8A according to another embodiment. [Figure 8C] 8B is a cross-sectional view of the probe contact assembly of FIG. 8A taken along line CC according to another embodiment. [Figure 8D] 8B is a cross-sectional view of the probe contact assembly of FIG. 8A taken along line DD according to another embodiment. [Figure 9A] 1 is a front view of a probe contact assembly for a test system, according to one embodiment. [Figure 9B] 9B is a cross-sectional view of the probe contact assembly of FIG. 9A taken along line EE, according to one embodiment. [Figure 10A] 1 is a cross-sectional perspective view of multiple probe contact assemblies housed in a socket housing, according to an embodiment. [Figure 10B] 10B is an enlarged view of portion F1 of FIG. 10A showing the probe contact assembly housed in the contact cavity of the socket housing, according to an embodiment. [Figure 11A] FIG. 10 is a cross-sectional perspective view of multiple probe contact assemblies (compressed state) housed in a socket housing according to another embodiment. [Figure 11B] 11B is an enlarged view of portion F2 of FIG. 11A showing a probe contact assembly housed in a contact cavity of a socket housing according to another embodiment. [Figure 12A] 10 is a front view of a receiving part (in its as-manufactured flat state) of a probe contact assembly for a test system according to another embodiment. [Figure 12B] 12B is a perspective view of the receiving piece of FIG. 12A in a folded state according to another embodiment. [Figure 13A] FIG. 1 is a perspective view of a probe contact assembly according to one embodiment. [Figure 13B] FIG. 10 is a perspective view of a probe contact assembly in a compressed state according to another embodiment. [Figure 14A] FIG. 10 is a front view of a receiving part (in its as-manufactured flat state) of a probe contact assembly for a test system according to yet another embodiment. [Figure 14B] 14B is a perspective view of the receiving piece of FIG. 14A in a folded state according to yet another embodiment. [Figure 15A] 1 is a perspective view of a probe contact assembly, according to an embodiment. [Figure 15B] FIG. 10 is a perspective view of a probe contact assembly in a compressed state according to another embodiment. [Figure 16A] 10 is a front view of a receiving component of a probe contact assembly for a test system according to yet another embodiment; [Figure 16B] 16B is a perspective view of the receiving piece of FIG. 16A according to yet another embodiment. [Figure 17A] FIG. 2 is a front view of a probe contact assembly, according to an embodiment. [Figure 17B] 17B is a side view of the probe contact assembly of FIG. 17A, according to an embodiment. [Figure 17C] 17B is a perspective view of the probe contact assembly of FIG. 17A, according to an embodiment. [Figure 17D] FIG. 10 is a front view of a probe contact assembly in a compressed state according to another embodiment. [Figure 17E] FIG. 17D is a side view of the probe contact assembly of FIG. 17D according to another embodiment. [Figure 17F] FIG. 17D is a perspective view of the probe contact assembly of FIG. 17D according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Like numbers refer to like parts throughout. Test contactors (i.e., parts of test assemblies including alignment plates, sockets, etc.) often provide electrical connection to a DUT, including its signal and power (S&P) terminals, by making metal-to-metal contact with a printed circuit board (e.g., a load board including its signal and power (S&P) terminals, etc.). A compliant contact assembly provides testing advantages by accommodating variations in the DUT package. It will be understood that the term "compliance" refers to the property of a material to undergo elastic deformation or volume change when subjected to an applied force. Compliance may be equal to the reciprocal of stiffness.

[0019] The terminals of the device under test (DUT) are temporarily electrically connectable to corresponding contact pads on the load board by a series of conductive contacts. The terminals may be pads, balls, wires (leads), or other contacts. Each terminal is connected to a contact, which is electrically connected to a respective contact pad on the load board.

[0020] The embodiments disclosed herein provide a low-inductance, low-cost spring-loaded probe contact assembly with high performance (e.g., high radio frequency (RF) performance). The height of the contact assembly is scalable. In one embodiment, the height of the contact assembly can be on the order of 1 mm, and the diameter of the contact assembly or spring can be on the order of 100 microns to 250 microns.

[0021] FIG. 1A is a perspective view of a portion of a test system 100 for receiving a device under test DUT 110 for testing, according to an embodiment. The test system 100 includes a test assembly 120 for a device under test (DUT) 110 (e.g., a microcircuit, etc.). The test assembly 120 includes a load board 170 supporting an alignment plate 160 having an alignment opening (or aperture) 130. The alignment opening 130 precisely defines the X and Y (referring to coordinate indices X and Y, where coordinate X is perpendicular to coordinate Y and coordinate Z is perpendicular to the plane of X and Y) positioning of the device under test (DUT) 110 in the test assembly 120. If the device under test (DUT) 110 has orientation features, it is common to include cooperating features in the alignment opening 130. The load board 170 includes connection pads on its surface that are connected to cables 180 by signal and power (S&P) conductors. The cables 180 are connected to electronics that perform electrical testing of the device under test (DUT) 110. Cable 180 may be very short if the test electronics are integrated with test assembly 120, or may be built into test assembly 120, or may be longer if the test electronics are on a separate chassis. It will be understood that cable 180 is optional. In alternative embodiments, load board 170 may be connected to the test electronics by any other suitable means, such as, but not limited to, spring-loaded probes.

[0022] The test contact array 140, which has a large number of individual test contact elements, precisely mirrors the signal and power (S&P) terminals (see 112 in FIG. 1B ) carried on the surface of the device under test (DUT) 110. When the device under test (DUT) 110 is inserted into the alignment opening 130, the signal and power (S&P) terminals of the device under test (DUT) 110 are precisely aligned with the test contact array 140. The test assembly 120 is designed to accommodate the test contact array 140 incorporating devices. The test contact array 140 is mounted on a socket 150. The individual test contacts of the test contact array 140 are preferably formed on and within the socket 150 using well-known photolithography and laser machining processes. The socket 150 has alignment features, such as holes or edge patterns, located in the area between the alignment plate 160 and the load board 170 to provide precise alignment of the socket 150 with corresponding protruding features on the alignment plate 160. All of the test contacts in test contact array 140 are precisely aligned with alignment features in socket 150. In this manner, the test contacts in test contact array 140 are precisely aligned and positioned in alignment openings 130.

[0023] FIG. 1B illustrates a perspective bottom view of a device under test (DUT) 110, according to an embodiment. The device under test (DUT) 110 (e.g., a microcircuit, etc.) includes a top major surface (not shown) and a bottom major surface 114 opposite the top major surface in the Z direction (see coordinate indices X, Y, and Z in FIG. 1A). In one embodiment, the device under test (DUT) 110 may have a ball grid array (BGA) package. In some embodiments, the device under test (DUT) 110 may have a flat no-lead package, such as a quad flat no-lead (QFN) or dual flat no-lead (DFN). The flat no-lead FN, also known as a micro lead frame (MLF) and small-outline no-leads (SON), is a surface mount technology that connects the device under test (DUT) 110 to the surface of, for example, a socket 150 or other printed circuit board (PCB) without through-holes. In one embodiment, the flat no-lead is enabled as a near-chip-scale plastic-encapsulated package made of a planar copper lead frame substrate. Peripheral lands (e.g., terminals 112) on the bottom of the package provide electrical connection to the socket 150 or printed circuit board PCB. The flat no-lead package can have exposed thermally conductive pads to improve heat transfer from the device under test (DUT) 110 (e.g., to the printed circuit board PCB). The quad flat no-lead QFN package is similar to the quad flat package (QFP). In one embodiment, the device under test (DUT) 110 can be a leaded package such as a wafer level chip scale package (WL-CSP), a thin small outline package (TSOP), or a diode outline (DO) package.

[0024] Figure 1C is a side view of a portion of test system 100 for receiving a device under test DUT 110, according to an embodiment. Figure 1D is a side view of test system 100 of Figure 1C with a device under test DUT 110 electrically engaged, according to an embodiment.

[0025] As shown in FIG. 1C , the device under test (DUT) 110 is placed on the test assembly 120, electrical testing is performed, and then the device under test (DUT) 110 is removed from the test assembly 120. All electrical connections are made by pressing components into electrical contact with other components; no soldering or desoldering is performed at any time during testing of the device under test (DUT) 110. Because the entire electrical testing procedure lasts only a fraction of a second, rapid and accurate placement of the device under test (DUT) 110 is important for efficient use of the test system 100. High throughput of the test assembly 120 typically requires robotic handling of the device under test (DUT) 110. In most cases, an automated mechanical system places the device under test (DUT) 110 on the test assembly 120 before testing and removes the device under test (DUT) 110 after testing is complete. The handling and placement mechanism may use mechanical and optical sensors to monitor the position of the device under test DUT 110, and may use a combination of translational and rotational actuators to align and place the device under test DUT 110 on or within the test assembly 120. Alternatively, the device under test DUT 110 may be placed manually or by a combination of manual and automated devices.

[0026] The device under test (DUT) 110 typically includes signal and power (S&P) terminals (112; see also terminals 112 in FIG. 1B ) for connection to a socket 150 or other printed circuit board (PCB). The terminals may be located on one side of the device under test (DUT) 110 or on both sides of the device under test (DUT). While all of the terminals 112 are preferably accessible from one side of the device under test (DUT) 110 for use in the test assembly 120, it will be understood that there may be one or more elements on the other side of the device under test (DUT) 110, or that there may be other elements and / or terminals on the other side that may not be tested by accessing the terminals 112. Each terminal 112 may be formed as a small pad on the button side of the device under test (DUT) 110, or in some cases as a lead (e.g., hemispherical) protruding from the body of the device under test (DUT) 110. Prior to testing, the pads or leads (terminals 112) are attached to electrical leads that connect internally to other leads, other electrical components, and / or one or more chips within the device under test (DUT). Because the volume and size of the pads or leads can be controlled fairly precisely, there are usually few challenges due to pad-to-pad or lead-to-lead size or placement variations. During testing, the terminals 112 remain rigid, preventing solder melting and reflow.

[0027] The terminals 112 may be laid out in any suitable pattern on the surface of the device under test (DUT) 110. In some cases, the terminals 112 may reside on a roughly square grid, which is the origin of the equation describing the device under test (DUT) 110, ball grid array (BGA), wafer level chip scale package (WL-CSP), quad flat no-lead (QFN), dual flat no-lead (DFN), thin small outline package (TSOP), or diode outline (DO) of a leaded component. They may also deviate from the rectangular grid, for example, with irregular spacing or shapes. It will be understood that the specific locations of the terminals are selected so that the corresponding locations of pads on the load board 170 and contacts on the socket 150 or housing match the locations of the terminals 112, and may vary as needed. Typically, the spacing between adjacent terminals 112 ranges from 0.25 to 1.5 mm, and this spacing is commonly referred to as "pitch." When viewed from the side, as in FIG. 1C, the device under test (DUT) 110 displays a line of terminals 112 with arbitrary gaps or irregular spacing. These terminals 112 are generally made to be planar, or as planar as possible in a typical manufacturing process. In many cases, if a chip or other element is present on the device under test DUT 110, the protrusion of the chip will typically be less than the protrusion of the terminals 112 away from the device under test DUT 110.

[0028] The test assembly 120 of FIG. 1C includes a load board 170 (printed circuit board PCB board). The load board 170 includes a load board substrate 174 and circuitry used to electrically test the device under test (DUT) 110. Such circuitry can include drive electronics enabled to generate one or more AC voltages having one or more specific frequencies and detection electronics enabled to sense the response of the device under test (DUT) 110 to such drive voltages. The detection can include current and / or voltage detection at one or more frequencies. In general, it is highly desirable that features on the load board 170 align with corresponding features on the device under test (DUT) 110 when mounted. Typically, both the device under test (DUT) 110 and the load board 170 are mechanically aligned to one or more positioning features on the test assembly 120. The load board 170 may include one or more mechanical positioning features, such as fiducials or precisely positioned holes and / or edges, that ensure that the load board 170 is precisely secured onto the test assembly 120. These positioning features typically ensure the lateral alignment (X, Y, see FIG. 1A) and / or vertical alignment (Z, see FIG. 1A) of the load board 170 as well.

[0029] Generally, the load board 170 can be a relatively complex and expensive component. The housing and / or test assembly 120 serves many functions, including protecting the contact pads 172 of the load board 170 from wear and damage. Such an additional element may be an interposer socket (150). The socket 150 is also mechanically aligned to the load board 170 by appropriate positioning features (not shown) and resides within the test assembly 120 above the load board 170 and opposite the DUT 110. The socket 150 includes electrically conductive contacts 152 that extend longitudinally outward on either side of the socket 150. Each conductive contact 152 may include a resilient element, such as a spring, elastomer, or other suitable material, and is capable of conducting electrical current from the load board 170 to the DUT 110 with sufficiently low resistance or impedance. Each conductive contact 152 may be a single conductive unit or may be formed as a combination of conductive elements. Each conductive contact 152 connects one contact pad 172 on the load board 170 to one terminal 112 on the device under test (DUT) 110, although testing may involve one or more contact pads 172 connecting to a single terminal 112, or multiple terminals 112 connecting to a single contact pad 172. While the text and figures assume a single conductive contact 152 connects a single contact pad 172 to a single terminal 112, it will be understood that any of the tester elements disclosed herein may be used to connect one or more contact pads 172 to a single terminal 112, or one or more terminals 112 to a single contact pad 172. Note that the contact forms an electrical connection 154 between the terminal 112 and the contact pad 172.

[0030] Typically, the socket 150 electrically connects contact pads 172 on the load board 170 with the bottom contact surface of the device under test (DUT) 110. Although the socket 150 is designed to be relatively easy to remove and replace compared to removing and replacing the load board 170, the socket 150 is considered part of the test assembly 120 herein. During operation, the test assembly 120 includes the load board 170, the socket 150, and a mechanical structure (not shown) that mounts and holds them in place. Each device under test (DUT) 110 is placed relative to the test assembly 120, electrically tested, and removed from the test assembly 120. A single socket 150 can test many devices under test (DUT) 110 before wearing out, typically performing several thousand tests or more before requiring replacement. It is generally desirable for socket 150 replacement to be relatively quick and easy so that the test assembly 120 experiences minimal downtime for socket replacement. In some cases, the speed of socket 150 replacement may even be more important than the actual cost of each socket 150, so that increased tester uptime provides significant cost savings during operation.

[0031] FIG. 1C illustrates the relationship between the test assembly 120 and the DUT 110. When each DUT 110 is tested, it is placed on a suitable robotic handler with sufficiently precise placement characteristics so that specific terminals 112 on the DUT 110 can be accurately and reliably positioned (in X, Y, and Z, see FIG. 1A ) relative to corresponding conductive contacts 152 on the socket 150 and corresponding contact pads 172 on the load board 170. The robotic handler (not shown) brings each DUT 110 into contact with the test assembly 120. The amount of force depends on the number of terminals 112 being tested, the force used on each terminal, the exact configuration of the test, including typical manufacturing and alignment tolerances, etc. Typically, the force is applied by a mechanical handler (not shown) of the tester acting on the DUT 110. Generally, the force is generally longitudinal, generally normal to the load board 170.

[0032] 1D shows the test assembly 120 and the device under test DUT 110 in contact, with sufficient force being applied to the device under test DUT 110 to engage the conductive contacts 152, thereby forming an electrical connection 154 between each terminal 112 and a corresponding contact pad 172 on the load board 170.

[0033] 2A is a side view of an upper plunger 200 of a probe contact assembly for a test system, according to an embodiment. FIG. 2B is a perspective view of the upper plunger 200 of FIG. 2A, according to an embodiment. It should be understood that the probe contact assembly (e.g., the conductive contacts 152 of FIGS. 1C and 1D) may be a compliant spring-loaded probe contact assembly.

[0034] In an embodiment (see, e.g., FIGS. 5A-5C ), the probe contact assembly includes an upper plunger 200 (DUT plunger), a biasing member (400, shown as a compliant compression spring), and a pair of receivers 300 (also known as lower plungers, printed circuit board (PCB) plungers, or load board plungers). It should be understood that the receivers 300 are preferably, but not necessarily, identical or matched pairs. It should also be understood that in one embodiment, the biasing member (400) can be a spring or other object(s) other than a spring, enabling it to provide the necessary resilience. The top of the upper plunger 200 is configured to engage with a signal and power (S&P) terminal of the DUT. It should be understood that the signal and power (S&P) terminal of the DUT can be a pin, pad, lead, ball, line, or the like. In one embodiment, the top of upper plunger 200 is configured to engage solder balls of a ball grid array (BGA) package. One or more bottom portions of receiving component 300 are configured to engage signal and power (S&P) terminals of a printed circuit board PCB (i.e., load board). It should be understood that the signal and power (S&P) terminals of the printed circuit board PCB can be pins, pads, leads, lines, etc. In one embodiment, the bottom(s) of receiving component 300 are configured to engage pads on the printed circuit board PCB, which make electrical contact to a test fixture. It should be understood that receiving component 300 can be two separate identical components or a single, integrated component.

[0035] 2A and 2B, in one embodiment, the upper plunger 200 includes a device under test (DUT) interface 210 (the top portion of the upper plunger 200), a device under test (DUT) side shaft 220, a plunger shoulder 230, an inner shaft 240, and a retainer 250. In an embodiment, the retainer 250 includes a retainer end 260.

[0036] In one embodiment, the device under test DUT interface 210 can be a crown-shaped interface configured to engage with ball grid array BGA balls (signal & power (S&P) terminals of the device under test DUT). In other embodiments, the shape of the device under test DUT interface 210 can be conical, spear-shaped, round, flat, etc., depending on the interface type of the terminals of the device under test DUT.

[0037] In one embodiment, the DUT shaft 220 can have a cylindrical shape or other suitable shape. The diameter of the plunger shoulder 230 is larger than the diameter of the DUT shaft 220. The plunger shoulder 230 can be configured to stop movement of the upper plunger 200 within the socket housing (see detailed description in FIGS. 10A-11B ) in the height direction (vertical or Z direction, see FIG. 1A ) of the probe contact assembly so that the probe contact assembly is retained within the socket housing. In one embodiment, the plunger shoulder 230 extends from the DUT shaft 220 toward the inner shaft 240 such that the size / diameter of the plunger shoulder 230 gradually increases and then gradually decreases. In one embodiment, the maximum width or diameter of the plunger shoulder 230 can be the same as or close to the outer diameter of the spring 400, or can be between the outer diameter and the inner diameter of the spring 400.

[0038] In one embodiment, the inner shaft 240 can be configured as a contact interface to a mating receiving piece (e.g., a planar receiving piece) 300 that can be slid along the length of the inner shaft 240 to make electrical contact. The diameter of the inner shaft 240 is smaller than the diameter of the plunger shoulder 230 (and the diameter of the device under test (DUT) shaft 220). In an embodiment, the inner shaft 240 can have a cylindrical shape or any other suitable shape.

[0039] The retainer 250 is configured to hold the probe contact assembly together. In embodiments, the retainer 250 may have a knob shape or other suitable shape that may be partially received within the receiving opening 320 of the receiving part(s) 300 (see FIGS. 3A and 3B ). The retainer end 260 of the retainer 250 may have a conical, chamfered end that aids in assembly of the probe contact assembly. In one embodiment, the retainer 250 extends from the inner shaft 240, and the size / diameter of the retainer 250 gradually increases toward the conical, chamfered retainer end 260 and then gradually decreases thereafter. It should be understood that the diameter of the retainer 250 may be larger than the width of the receiving opening 320 to prevent the retainer 250 from passing through. A portion of the conical retainer end 260 can be sized to be partially received within the receiving opening 320 so that the conical retainer end 260 slides along the receiving opening 320 when the upper plunger 200 is pushed (e.g., by a device under test (DUT)). The sliding can preferably occur on the inner circumferential surface of the receiving opening 320. The retainer end 260 need not be conical, but can be any shape that facilitates (a) passing partially through the receiving opening 320 and (b) sliding along the inner circumferential surface with minimal friction, yet fully maintaining electrical integrity and / or contact. The angle between the receiving piece 300 and the retainer end 260 can facilitate this objective.

[0040] 2A and 2B , in one embodiment, the diameter of the plunger shoulder 230 may be on the order of 80% of the minimum DUT pitch. The minimum DUT pitch may refer to the center-to-center spacing between the most adjacent signal and power (S&P) terminals of the DUT. The minimum DUT pitch may be on the order of 300 microns. The spacing between the most adjacent signal and power (S&P) terminals of the DUT may be on the order of 30 microns. The diameter of the inner shaft 240 may be on the order of 50% of the diameter of the plunger shoulder 230. The diameter of the retainer 250 may be on the order of 20% larger than the diameter of the inner shaft 240. The length of the inner shaft 240 may be on the order of 10% longer than the length of the spring 400 when it is fully compressed (see FIGS. 4A and 4B ).

[0041] In one embodiment, the upper plunger 200 can be computer numerically controlled (CNC) turned on an automatic lathe machine. The upper plunger 200 can be plated or made from a solid metal or alloy material, such as a homogeneous alloy comprising a copper alloy, a palladium alloy, or the like. In an embodiment, the upper plunger 200 can be constructed from a flat metal element. In an embodiment, the upper plunger 200 can be plated with gold or other conductive material. In an embodiment, the height of the upper plunger 200 can be about 500 microns to about 600 microns.

[0042] Figure 3A is a front view of a receiving part 300 of a probe contact assembly for a test system, according to an embodiment. Figure 3B is a perspective view of the receiving part 300 of Figure 3A, according to an embodiment.

[0043] It should be understood that Figures 3A and 3B show one of a pair of receiving parts (receivers) 300. In an embodiment, two receiving parts 300 are used in the probe contact assembly. The receiving parts 300 can be manufactured as flat parts using etching, stamping, electroforming (e-forming), water jet cutting, or other suitable manufacturing processes. The material of the receiving parts 300 can be a copper alloy or other suitable metal alloy. The receiving parts 300 can be gold plated to enhance lubricity and conductivity.

[0044] In one embodiment, the receiving piece 300 includes a top 380, a receiving opening 320 having an up-stop 310 and a clearance area 325, a receiving body 330, two receiving piece shoulders 350 (widthwise) each having a shoulder stop 340, and a protrusion 360 having an end 370 (which reduces in width in the Z direction). In one embodiment, the receiving opening 320 extends vertically (heightwise) from the up-stop 310 to a position near the bottom of the receiving piece shoulders 350. In the widthwise direction (from one receiving piece shoulder 350 to the other receiving piece shoulder 350), the width of the bottom of the receiving opening 320 gradually decreases. In one embodiment, the receiving opening 320 can be large enough to receive a portion of the retainer 250, but narrow enough that the retainer 250 cannot pass through the receiving opening 320. The receiving opening 320 may be of uniform width along its length or may gradually widen towards the bottom to aid in the movement of the retainer 250, but still not be wide enough for the retainer 250 to pass through.

[0045] In one embodiment, the receiving opening 320 is where the retainer 250 of the upper plunger 200 slides vertically (e.g., from the uncompressed state to the compressed state of the probe contact assembly, or vice versa). In the uncompressed state, the retainer 250 of the upper plunger 200 is allowed to rest on the upstop 310 of the receiving opening 320. The receiving body 330 preferably has a tapered outer surface, and the taper can be designed to force the pair of receiving parts 300 together so that, in the assembled state of the probe contact assembly, the sides (of the pair of receiving parts 300) narrow with a gradually narrowing gap, such as a "V" or substantially "V" shape (see, e.g., FIGS. 5A-6C ), to form a single contact point on the printed circuit board PCB. Thus, the bottom ends of the pair of receiving parts 300 are closely spaced and / or drawn closely adjacent to each other. Shoulder stop 340 may be configured to rest against the end coils of spring 400. Receiving piece shoulder (or flange) 350 may be the widest portion of receiving piece 300, allowing it to be used to securely retain the probe contact assembly in a socket housing (see, e.g., FIGS. 10A-11B). End 370 of protrusion 360 provides a contact surface that contacts the signal and power (S&P) terminals of a printed circuit board PCB.

[0046] In one embodiment, the thickness of the receiving piece 300 (into the plane of the page as viewed in FIG. 3A ) remains constant. The width or diameter (maximum width or diameter) of the receiving piece shoulder 350 can be between the outer diameter of the spring 400 and the inner diameter of the spring 400. The extra clearance area 325 can be configured to prevent the retainer 250 from bottoming out on the receiving piece 300 (e.g., in a compressed state). The upstop 310 is configured to provide an upstop for the retainer 250 when the probe contact assembly is in an uncompressed state. The receiving body 330 can taper by at least about 10% from the upstop 310 to the lower portion of the receiving body 330 (the length of the tapered portion is shown vertically as “L”). That is, the width of the receiving body 330 gradually increases (tapers) along the “L” direction within the length of the “L” portion, thereby increasing (tapering) the width of the receiving opening 320. The width of receiving opening 320 can be reduced at the bottom portion (bottom of the "L" portion) of receiving opening 320 (e.g., to prevent retainer 250 from descending toward the printed circuit board). The rounded bottom surface of end 370 can be configured to provide good contact with a pad on the printed circuit board PCB.

[0047] In embodiments, receiving component 300 can be made of beryllium copper, copper alloy, nickel or nickel alloy, etc. Receiving component 300 can be manufactured through etching, via metal additive manufacturing, electroforming, etc. In embodiments, receiving component 300 can be plated with gold, etc. In embodiments, receiving component 300 can have a height of 400 microns or about 400 microns. It should be understood that the bottom of receiving component 300 can be flat, rounded, etc. Receiving component 300 can be manufactured at low cost by various methods (e.g., etching, electrical discharge machining, electroforming, stamping).

[0048] It should also be understood that the interior (e.g., within the receiving opening 320) and exterior (on the receiving body 330) of the receiving piece (receiving base) 300 can be tapered (the length of the tapered portion is shown as "L" in the vertical (perpendicular) direction). The tapered portion can facilitate compression without jamming or binding, and can ensure that the receiving piece 300 gradually narrows so that a V-shape or the like can be maintained (e.g., from an uncompressed state to a compressed state, or vice versa). It should also be understood that the sides (thickness direction) of the upper portion of the receiving piece 300 (e.g., above or near the upstop 310) can slide along and on the inner shaft 240 (e.g., from an uncompressed state to a compressed state, or vice versa). The sides (thickness direction) of the lower portion of the receiving piece 300 (e.g., above or near the end 370) can contact each other.

[0049] 4A is a side view of a spring 400 of a probe contact assembly for a test system, according to an embodiment. FIG. 4B is a perspective view of the spring 400 of FIG. 4A, according to an embodiment. It should be understood that the biasing member (a resilient member, such as spring 400) can serve two functions: (1) it can provide compression or resilience between the upper plunger 200 and the receiving part(s) 300, and (2) it can keep the combination of the upper plunger 200 and the receiving part(s) 300 together during normal operation, not only preventing them from separating but also ensuring electrical contact between the upper plunger 200 and the receiving part(s) 300, thereby providing an electrical path between the device under test (DUT) and the load board 170.

[0050] In one embodiment, the spring 400 (having a spring body 410 and two end coils (412, 414)) is a compression spring wound on a precision winding machine from resilient metal wire. The end coils (412, 414) of the spring can be "closed" to minimize gaps between the end coils (412, 414), for example, to aid in assembly. It should be understood that there is some gap between the spring coils in the spring body 410. The wire of the spring 400 has a consistent wire diameter. The outer diameter of the spring 400 is consistent throughout its length. The number of coil turns of the spring 400 can vary depending on electrical and mechanical requirements. The spring 400 can be made of a metal, such as a stainless steel alloy. The spring 400 can be gold-plated to improve the electrical performance of the probe contact assembly and to provide lubrication when the probe contact assembly is compressed.

[0051] It should be appreciated that when compressed, the resilient spring 400 provides or can provide z-axis (height) compliance to the socket. The inner diameter, outer diameter, and wire diameter of the spring 400 are each constant. The spacing between the coils of the spring 400 can tolerate compression, and when the probe contact assembly 500 is in a compressed state, the coils of the spring 400 can still be spaced apart, except for the end coils (412, 414), which can have little gap (i.e., the spring 400 may not deform, allowing it to last longer).

[0052] Figure 5A is a front view of a probe contact assembly 500 for a test system, according to one embodiment. Figure 5B is a side view of the probe contact assembly 500 of Figure 5A, according to an embodiment. Figure 5C is a perspective view of the probe contact assembly 500 of Figure 5A, according to an embodiment. Figure 5D is a top view of the probe contact assembly 500 of Figure 5A, according to an embodiment. Figure 5E is a bottom view of the probe contact assembly 500 of Figure 5A, according to an embodiment.

[0053] 5A-5E show the probe contact assembly 500 in an uncompressed state. It should be understood that the uncompressed state may refer to the state in which the probe contact assembly 500 is assembled and the spring 400 is in a free or uncompressed state. As shown in FIG. 5B, the two receiving pieces 300 are assembled together starting from the bottom of the probe contact assembly 500, so that the sides of the lower portions of the receiving pieces 300 contact each other in a "V" or substantially "V" shape. The spring 400 is captured between the plunger shoulder 230 of the upper plunger 200 and the shoulder stop 340 of the receiving piece shoulder 350 of the receiving piece 300. The retainer 250 of the upper plunger 200 rests against the upstop 310 of the receiving opening 320 of the receiving piece 300. The receiving body 330 of the receiving part 300 (which extends from one shoulder stop 340 to the top 380 and then laterally to another shoulder stop 340) is constrained against the inner diameter of the spring 400, allowing the probe contact assembly 500 to be self-contained and therefore unable to come apart.

[0054] It will be appreciated that the above-described retention system (i.e., retainer 250 with spring 400 holding the components of probe contact assembly 500 together) can be more robust than existing technologies that rely on latches. In contrast, because latch features must be precisely manufactured to function properly, latches on the components often wear during use of the probe or probe assembly, resulting in a loss of retention force. The lack of latch limitations in the retention system disclosed herein allows the receiving component 300 to be retained on the retainer 250 with wider manufacturing tolerances, reducing cost and complexity.

[0055] Figure 6A is a front view of a probe contact assembly 500 (compressed state) for a test system according to another embodiment. Figure 6B is a side view of the probe contact assembly 500 of Figure 6A according to another embodiment. Figure 6C is a perspective view of the probe contact assembly 500 of Figure 6A according to another embodiment. Figure 6D is a top view of the probe contact assembly 500 of Figure 6A according to another embodiment. Figure 6E is a bottom view of the probe contact assembly 500 of Figure 6A according to another embodiment.

[0056] 6A-6E show the probe contact assembly 500 in a compressed state. It should be understood that the compressed state may refer to a state in which the probe contact assembly 500 is assembled and the spring 400 is fully compressed. The probe contact assembly 500 can be compressed when a device under test (DUT) (e.g., a semiconductor device) is pressed down onto the tip of the probe contact assembly 500 (e.g., a crown-shaped interface, etc.). The resulting spring force ensures a good electrical contact interface with the device under test (DUT). As shown in FIG. 6B, in the compressed state, the retainer 250 of the upper plunger 200 is moved to the bottom of the receiving opening 320 of the receiving part(s) 300, and the "V"-shaped configuration of the receiving part 300 remains in place. The "V"-shaped configuration provides good sliding contact between the upper plunger 200 (the inner shaft 240) and the receiving part 300 (the side of the upper portion of the receiving part 300). It should be appreciated that in the compressed state, due to the shape of receiving opening 320 and retainer 250 , a clearance area 325 exists between retainer 250 and the bottom of receiving opening 320 .

[0057] It should be understood that during testing, for better radio frequency RF performance, most of the current and resistance may be from the upper plunger 200 and receiving piece 300 (which form the primary path of the current), and that the current may be partial or minimal through the spring 400.

[0058] Figure 7A is a top view of a probe contact assembly 500 for a test system, according to an embodiment. Figure 7B is a front view of the probe contact assembly 500 of Figure 7A, according to an embodiment. Figure 7C is a cross-sectional view of the probe contact assembly 500 of Figure 7A along line AA, according to an embodiment. Figure 7D is a cross-sectional view of the probe contact assembly 500 of Figure 7A along line BB, according to an embodiment. Figures 7A-7D show the probe contact assembly 500 in an uncompressed state.

[0059] FIG. 8A is a top view of a probe contact assembly 500 (compressed state) for a test system according to another embodiment. FIG. 8B is a front view of the probe contact assembly 500 of FIG. 8A according to another embodiment. FIG. 8C is a cross-sectional view of the probe contact assembly 500 of FIG. 8A along line CC according to another embodiment. FIG. 8D is a cross-sectional view of the probe contact assembly 500 of FIG. 8A along line DD according to another embodiment. FIGS. 8A-8D show the probe contact assembly 500 in a compressed state. In the compressed state, the entire retainer 250 or a portion of the retainer 250 extends outward from the spring 400. The top of the retainer 250 resides at or near the shoulder stop 340.

[0060] Figure 9A is a front view of a probe contact assembly 500 for a test system, according to an embodiment. Figure 9B is a cross-sectional view of the probe contact assembly 500 of Figure 9A along line EE, according to an embodiment. Figures 9A-9B show the probe contact assembly 500 in an uncompressed state.

[0061] As shown in FIG. 9B , the inner shaft 240 of the upper plunger 200 separates the receiving pieces 300 from one another at the top of the receiving pieces 300. Four corners of the receiving pieces 300 (two outer corners for each receiving piece 300) contact the inner surface of the spring 400. The shape of the retainer 250 and receiving pieces 300 and the inner diameter of the spring 400 are configured such that if there is an outward bias force (toward the outside of the spring 400) attempting to disassemble the probe contact assembly 500, the receiving piece 300 may be restricted by pushing into the spring 400. It should be understood that there is no press fit between the receiving piece 300 and the spring 400 so that the receiving piece 300 can slide along the length of the inner shaft 240.

[0062] Figure 10A is a cross-sectional perspective view of multiple probe contact assemblies 500 housed in a socket housing (housing) 600, according to an embodiment. Figure 10B is an enlarged view of a portion F1 of Figure 10A, showing the probe contact assemblies 500 housed in contact cavities (e.g., counterbores, countersunk holes, etc.) of the socket housing 600, according to an embodiment. Figures 10A-10B show the probe contact assemblies 500 in an uncompressed state.

[0063] Figure 11A is a cross-sectional perspective view of multiple probe contact assemblies 500 (in a compressed state) housed in a socket housing 600, according to an embodiment. Figure 11B is an enlarged view of a portion F2 of Figure 11A, showing the probe contact assemblies 500 housed in contact cavities (e.g., counterbores, countersunk holes, etc.) of the socket housing 600, according to an embodiment. Figures 11A-11B show the probe contact assemblies 500 in a compressed state.

[0064] As shown in FIGS. 10A-11B, the socket 150 (see FIGS. 1A-1D ) includes a socket housing 600. The socket housing 600 includes a housing body 650 having a plurality of cavities or holes (e.g., counter-drilled holes, counter-bores, counter-bored holes, etc.) 680, each configured to receive a probe contact assembly 500. In one embodiment, the socket housing 600 may be made of a non-conductive material such as plastic, ceramic, or the like. A thin retainer plate 640 is configured to hold the probe contact assembly 500 in place at the bottom of the probe contact assembly 500. The retainer plate 640 may be a flat plate with a simple through-hole 660 or may be a counter-bored plate to reduce the overall complexity of the socket 150 (including the socket housing 600 and the probe contact assembly 500). In one embodiment, the thickness of the retainer plate 640 can be approximately 0.05 mm. The retainer plate 640 can be attached and secured to the housing body 650 by screws, tape, or other methods. The cavity or hole 680 includes a first cavity (e.g., a counterbore hole, etc.) 630, a housing up stop 610, and a second cavity 620.

[0065] As shown in FIGS. 10A and 10B , each of the probe contact assemblies 500 is capable of being positioned within the housing cavity (cavity 680) in an uncompressed or free state. The plunger shoulder 230 rests against the housing up stop 610. The housing up stop 610 is configured to prevent or stop the plunger shoulder 230 from moving upward toward the device under test (DUT) 110. The bottom of the receiving component shoulder 350 of the receiving component 300 rests against the retainer plate 640. The retainer plate 640 is configured to prevent or stop the receiving component shoulder 350 from moving downward toward the printed circuit board (PCB) (load board). The upper portions of the device under test DUT interface 210 and the device under test DUT-side shaft 220 are disposed outside or above the first cavity 630. The lower portion of the device under test DUT-side shaft 220 is housed within the first cavity 630. The plunger shoulder 230 and spring 400 are housed within the second cavity 620. The protrusion 360 and its end 370 extend through the through-hole 660 in the retainer plate 640, with a portion of the protrusion 360 and / or its end 370 disposed outside or below the through-hole 660. In one embodiment, the diameter of the first cavity 630 is smaller than the diameter of the second cavity 620 and smaller than the diameter of the plunger shoulder 230. The diameter of the through-hole 660 is smaller than the diameter of the second cavity 620 and smaller than the width of the receiving part shoulder 350, but larger than the width of the protrusion 360 and its end 370.

[0066] When the probe contact assembly 500 is in a compressed state, the socket 150 is attached to a printed circuit board PCB (not shown), and the DUT 110 (e.g., the terminals 112 of the DUT 110) compress the probe contact assembly 500. As shown in FIGS. 11A-11B , the probe contact assembly 500 is fully compressed by the DUT 110. The DUT interface 210 is pressed down to or near the top surface of the socket housing 600. The plunger shoulder 230 is pressed down from the housing up stop 610 into the second cavity 620. The spring 400 is compressed. The end 370 of the protrusion 360 is at or near the bottom surface of the retainer plate 640. The receiving part shoulder 350 is pressed up from the retainer plate 640 into the second cavity 620. In one embodiment, the compressed length of the probe contact assembly is approximately 1 mm.

[0067] It should be understood that the shape (eg, circular, etc.) or diameter of the probe contact assembly 500 may correspond to the shape (eg, circular, etc.) or diameter of the cavity of the socket housing 600 .

[0068] Figure 12A is a front view of a receiving part 301 (in a flat state as manufactured) of a probe contact assembly for a test system according to another embodiment. Figure 12B is a perspective view of the receiving part 301 of Figure 12A (in a folded state) according to another embodiment.

[0069] It should be understood that the receiving piece 301 can be a single, integral piece. That is, the receiving piece 301 can be replaced by a single piece made of two separate receiving pieces 300 joined together (e.g., joined at or near the ends 370 of the projections 360) and then folded to create a "V" shaped assembly (see FIG. 12B). The folded receiving piece 301 is then allowed to snap onto the upper plunger 200. It should also be understood that a probe contact assembly having a single, integral receiving piece 301 can function similarly to an embodiment having two separate receiving pieces 300.

[0070] Figure 13A is a perspective view of a probe contact assembly 501 according to one embodiment. Figure 13B is a perspective view of a probe contact assembly 501 according to another embodiment in a compressed state. The probe contact assembly 501 includes an upper plunger 200, a spring 400, and an integrated receiving piece 301. Figure 13A shows the probe contact assembly 501 in an uncompressed state. Figure 13B shows the probe contact assembly 501 in a compressed state.

[0071] Figure 14A is a front view of a receiving part 302 (in a flat state as manufactured) of a probe contact assembly for a test system according to yet another embodiment, and Figure 14B is a perspective view of the receiving part 302 of Figure 14A (in a folded state) according to yet another embodiment.

[0072] It should be understood that the receiving piece 302 can be a single, integral piece. That is, the receiving piece 302 can be replaced with a single piece in which two separate receiving pieces 300 are made to join together (e.g., joined at or near the sides of the receiving piece shoulder 350) and then folded sideways to create a "V" shaped assembly. The folded receiving piece 302 can then be snapped onto the upper plunger 200. It should also be understood that a probe contact assembly having a single, integral receiving piece 302 can function similarly to an embodiment having two separate receiving pieces 300.

[0073] Figure 15A is a perspective view of a probe contact assembly 502 according to an embodiment. Figure 15B is a perspective view of a probe contact assembly 502 in a compressed state according to another embodiment. The probe contact assembly 502 includes an upper plunger 200, a spring 400, and a receiving piece 302. Figure 15A shows the probe contact assembly 502 in an uncompressed state. Figure 15B shows the probe contact assembly 502 in a compressed state.

[0074] Figure 16A is a front view of a receiving part 303 of a probe contact assembly for a test system according to yet another embodiment. Figure 16B is a perspective view of the receiving part 303 of Figure 16A according to yet another embodiment. Receiving part 303 is the same as receiving part 300 except that receiving part 303 includes a gap 390 to allow receiving part 303 to be fabricated on top 380. Gap 390 extends from receiving opening 320 to the outer top surface of receiving part 303.

[0075] Figure 17A is a front view of a probe contact assembly 503 according to an embodiment. Figure 17B is a side view of the probe contact assembly 503 of Figure 17A according to an embodiment. Figure 17C is a perspective view of the probe contact assembly 503 of Figure 17A according to an embodiment. Figure 17D is a front view of the probe contact assembly 503 in a compressed state according to another embodiment. Figure 17E is a side view of the probe contact assembly 503 of Figure 17D according to another embodiment. Figure 17F is a perspective view of the probe contact assembly 503 of Figure 17D according to another embodiment. The probe contact assembly 503 includes an upper plunger 200, a spring 400, and a pair of receiving pieces 303.

[0076] The description of the invention and its applications set forth herein is illustrative and is not intended to limit the scope of the invention. Variations and modifications of the embodiments disclosed herein are possible, and practical alternatives and equivalents to the various elements of the embodiments will be apparent to those skilled in the art upon review of this patent document. These and other variations and modifications of the embodiments disclosed herein can be made without departing from the scope and spirit of the invention.

[0077] (Aspect) It should be noted that any one of the following aspects can be combined with each other. Aspect 1. A contact assembly (contact assembly, contact point assembly) for a test system for testing integrated circuit devices, the contact assembly including an upper plunger, first and second receiving parts (first and second retainers) configured to engage the upper plunger, and a biasing member. The upper plunger includes a first shoulder separating the upper shaft from the lower shaft and a retainer adjacent the end of the lower shaft. The first and second receiving parts each include a second shoulder having a shoulder stop. When the contact assembly is assembled, the biasing member is captured between a bottom of the first shoulder and the shoulder stops of the first and second receiving parts. The upper plunger separates the sides of the upper portions of the first and second receiving parts. The sides of the lower portions of the first receiving piece and the second receiving piece contact each other, a bias member.

[0078] Aspect 2. The retainer, the lower shaft, and the upper portions of the first receiving part and the second receiving part are constrained in the internal space of the bias member. 2. The contact assembly of embodiment 1.

[0079] Aspect 3. When the contact assembly is assembled, the first receiving piece and the second receiving piece form a substantially V-shape. The contact assembly of embodiment 1 or embodiment 2.

[0080] Aspect 4. When the contact assembly is assembled, the contact assembly has an uncompressed state and a compressed state. When the contact assembly is in an uncompressed state, the retainer rests against upstops of the receiving apertures of the first and second receiving parts. The contact assembly according to any one of embodiments 1 to 3.

[0081] Aspect 5. When the contact assembly is in a compressed state, the retainer is present near the bottom of the receiving openings of the first receiving part and the second receiving part, and a clearance area is formed between the bottom of the receiving openings and the retainer. 5. The contact assembly of embodiment 4.

[0082] Aspect 6. The first receiving part and the second receiving part are separate components. The contact assembly according to any one of embodiments 1 to 5.

[0083] Aspect 7. The first receiving part and the second receiving part are joined together to form a single integral component. The contact assembly according to any one of embodiments 1 to 6.

[0084] Aspect 8. The first receiving part and the second receiving part are joined at the lower ends (bottom ends) of the first receiving part and the second receiving part. 8. The contact assembly of embodiment 7.

[0085] Aspect 9. The first receiving piece and the second receiving piece are joined at second shoulders of the first receiving piece and the second receiving piece. 8. The contact assembly of embodiment 7.

[0086] Aspect 10. The first receiving part and the second receiving part each have a gap at the top of the first receiving part and the second receiving part. The contact assembly according to any one of embodiments 1 to 9.

[0087] Aspect 11. A test system for testing integrated circuit devices. The test system includes a device under test (DUT), a load board, and a contact assembly as a compliant probe contact assembly. The contact assembly includes an upper plunger, first and second receiving pieces configured to engage the upper plunger, and a biasing member. The upper plunger includes a first shoulder separating the upper shaft from the lower shaft and a retainer proximate an end of the lower shaft. The first and second receiving pieces each include a second shoulder having a shoulder stop. When the contact assembly is assembled, the biasing member is captured between a bottom of the first shoulder and the shoulder stops of the first and second receiving pieces. The upper plunger separates sides of the upper portions of the first and second receiving pieces. Sides of the lower portions of the first and second receiving pieces contact each other. The upper plunger includes a device under test (DUT) interface configured to engage with a device under test (DUT). Ends of the first and second receiving parts are configured to engage with a load board. A bias member.

[0088] Aspect 12. The device under test (DUT) is a device having a ball grid array (BGA) package. 12. The test system of embodiment 11.

[0089] Aspect 13. The test system further includes a housing configured to accommodate the contact assembly. The test system according to embodiment 11 or embodiment 12.

[0090] Aspect 14. The test system further includes a socket, the socket including the housing and the contact assembly, the socket configured to provide paths from inputs and outputs of the device under test (DUT) to inputs and outputs of the load board, respectively. 14. The test system of embodiment 13.

[0091] Aspect 15. The housing includes a hole configured to receive the contact assembly. The hole includes an upstop between a first cavity and a second cavity. The second cavity has a diameter larger than the diameter of the first cavity. 14. The test system of embodiment 13.

[0092] Aspect 16. The hole upstop is configured to prevent the first shoulder from moving upward toward the device under test (DUT). 16. The test system of embodiment 15.

[0093] Aspect 17. The test system further includes a retainer plate disposed on the bottom of the housing. 16. The test system of embodiment 15.

[0094] Aspect 18. The retainer plate includes a through hole configured to allow the lower ends (bottom ends) of the first receiving part and the second receiving part to pass through. 18. The test system of embodiment 17.

[0095] Aspect 19. The diameter of the through hole is smaller than the diameter of the second cavity of the housing. 19. The test system of embodiment 18.

[0096] Aspect 20. A contact assembly for a test system for testing integrated circuit devices, the contact assembly being a compliant probe contact assembly. The contact assembly includes a plunger having a retainer proximate an end of a lower shaft, first and second receiving component plates having a top and a bottom, each having a longitudinal receiving opening sized to receive only a portion of the retainer, the receiving openings not being wide enough for the retainer to pass through the receiving opening, and a biasing member. The first and second receiving component plates are aligned relative to each other so that the bottoms are gradually closer to each other than the tops. When the contact assembly is assembled, the biasing member surrounds at least a portion of the plunger and receives the first and second receiving component plates, thereby maintaining physical and electrical contact between the first and second receiving component plates and the retainer as the plunger travels through the receiving openings of the first and second receiving component plates.

[0097] The terms used herein are for the purpose of describing particular embodiments and are not intended to be limiting. The terms "a," "an," and "the" include the plural unless expressly indicated otherwise. As used herein, the terms "comprises" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components.

[0098] With regard to the foregoing description, it should be understood that changes may be made in details, particularly in matters of the materials of construction employed and the shape, size, and arrangement of parts without departing from the scope of the present disclosure. The specification and described embodiments are exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

Claims

1. 1. A contact assembly as a compliant probe contact assembly for a test system for testing an integrated circuit device, the contact assembly comprising: an upper plunger including a first shoulder separating the upper shaft from the lower shaft and a retainer adjacent an end of the lower shaft; a first receiving piece and a second receiving piece configured to engage the upper plunger, each of the first receiving piece and the second receiving piece including a second shoulder having a shoulder stop; a bias member; It is equipped with When the contact assembly is assembled, the bias member is captured between a bottom of the first shoulder and the shoulder stops of the first and second receiving pieces, the upper plunger separates sides of the upper portions of the first and second receiving pieces, and sides of the lower portions of the first and second receiving pieces contact each other. Contact assembly.

2. the retainer, the lower shaft, and the upper portions of the first and second receiving pieces are constrained within the internal space of the bias member; The contact assembly of claim 1 .

3. When the contact assembly is assembled, the first receiving part and the second receiving part form a gradually narrowing gap. The contact assembly of claim 1 .

4. When the contact assembly is assembled, the contact assembly has an uncompressed state and a compressed state; When the contact assembly is in the uncompressed state, the retainer rests against upstops of the receiving openings of the first and second receiving parts. The contact assembly of claim 1 .

5. When the contact assembly is in the compressed state, the retainer is present near the bottom of the receiving openings of the first receiving part and the second receiving part, and a clearance area is formed between the bottom of the receiving openings and the retainer. The contact assembly of claim 4 .

6. the first receiving part and the second receiving part are separate components; The contact assembly of claim 1 .

7. the first receiving part and the second receiving part are joined together to form a single integral part; The contact assembly of claim 1 .

8. the first receiving part and the second receiving part are joined at lower ends of the first receiving part and the second receiving part; The contact assembly of claim 7 .

9. the first receiving piece and the second receiving piece are joined at the second shoulders of the first receiving piece and the second receiving piece; The contact assembly of claim 7 .

10. each of the first receiving piece and the second receiving piece having a gap at the top of the first receiving piece and the second receiving piece; The contact assembly of claim 1 .

11. 1. A test system for testing an integrated circuit device, the test system comprising: a device under test (DUT); a load board, and the contact assembly being a compliant probe contact assembly; The contact assembly comprises: an upper plunger including a first shoulder separating the upper shaft from the lower shaft and a retainer adjacent an end of the lower shaft; a first receiving piece and a second receiving piece configured to engage the upper plunger, each of the first receiving piece and the second receiving piece including a second shoulder having a shoulder stop; and a bias member; It is equipped with when the contact assembly is assembled, the bias member is captured between a bottom of the first shoulder and the shoulder stops of the first and second receiving pieces, the upper plunger separates sides of the upper portions of the first and second receiving pieces, and sides of the lower portions of the first and second receiving pieces contact each other; the upper plunger includes a device under test (DUT) interface configured to engage with the device under test (DUT), and ends of the first receiving part and the second receiving part are configured to engage with the load board; Test system.

12. the device under test DUT is a device having a ball grid array (BGA) package; 12. The test system of claim 11.

13. The test system further includes a housing configured to receive the contact assembly.

12. The test system of claim 11.

14. The test system further comprises a socket; the socket comprises the housing and the contact assembly; the socket is configured to provide paths from inputs and outputs of a device under test (DUT) to inputs and outputs of the load board, respectively; 14. The test system of claim 13.

15. the housing includes a bore configured to receive the contact assembly; the hole includes an upstop between the first cavity and the second cavity; The second cavity has a diameter greater than the diameter of the first cavity.

14. The test system of claim 13.

16. the upstop of the hole is configured to prevent the first shoulder from moving upward toward the device under test (DUT).

16. The test system of claim 15.

17. The test system further includes a retainer plate disposed on a bottom of the housing.

16. The test system of claim 15.

18. The retainer plate includes through holes configured to allow lower ends of the first receiving part and the second receiving part to pass through.

18. The test system of claim 17.

19. The diameter of the through hole is smaller than the diameter of the second cavity of the housing.

20. The test system of claim 18.

20. 1. A contact assembly as a compliant probe contact assembly for a test system for testing an integrated circuit device, the contact assembly comprising: a plunger having a retainer adjacent an end of the lower shaft; first and second receiving component plates having a top and a bottom, the first and second receiving component plates having longitudinal receiving openings sized to receive only a portion of the retainer, the receiving openings not being wide enough for the retainer to pass through the receiving openings; and a bias member; It is equipped with the first receiving component plate and the second receiving component plate are aligned with each other such that the bottom portions of the plates are gradually closer to each other than the top portions of the plates; When the contact assembly is assembled, the biasing member surrounds at least a portion of the plunger and receives the first and second receiving component plates, thereby holding the first and second receiving component plates and the retainer in physical and electrical contact with each other as the plunger moves through the receiving opening in the first and second receiving component plates. Contact assembly.

Images