Wafer transfer arm and wafer transfer system

Abstract

The conveying arm includes: a plurality of air nozzles (13, 14) opening on the lower surface (12) of the top plate (11) of the arm; and an inclined portion (15) disposed on the lower surface (12) and inclined radially outward as it moves toward the lower side. When the wafer (W) is attracted and moves toward the lower surface (12), the inclined portion (15) can contact the outer periphery of the wafer (W). The plurality of air nozzles (13, 14) have: an outer air nozzle (13) facing the outer periphery of the wafer W from the upper side; and an inner air nozzle (14) disposed radially inward than the outer air nozzle (13). The air pressure ejected from the outer air nozzle (13) is less than the air pressure ejected from the inner air nozzle (14).

Description

Technical Field

[0001] This invention relates to a wafer transfer arm and a wafer transfer system. This application claims priority to Japanese Patent Application No. 2024-055941, filed on March 29, 2024, the contents of which are incorporated herein by reference. Background Technology

[0002] Previously, wafer testing apparatuses were known for performing functional tests on semiconductor chips mounted on semiconductor wafers (hereinafter sometimes referred to as wafers), such as silicon wafers. These wafer testing apparatuses included a transport arm for transporting the wafers. The transport arm transported (transferred) the wafers to the upper surface of a chuck and then transported the tested (inspected) wafers from the upper surface of the chuck.

[0003] It should be noted that in this specification, the process of using a transfer arm to move the wafer onto the upper surface of the chuck and placing it is sometimes referred to as loading process or simply loading, and the process of using a transfer arm to lift and move the wafer from the upper surface of the chuck is referred to as unloading process or simply unloading.

[0004] In recent years, wafer thinning has been progressing in power devices that use metal films on the underside of wafers as electrodes. Furthermore, wafer diameters are increasing from the previous 8 inches to 12 inches. For example, in TAIKO (registered trademark) wafers, the effective chip formation area located radially inward from the outer periphery is thinner than the outer periphery, and the thickness of this effective chip formation area has been reduced to below 100 μm.

[0005] Patent Document 1 discloses a wafer transfer arm (Bernoulli chuck) that transfers a wafer while holding it from above using Bernoulli's principle. According to the transfer arm utilizing Bernoulli's principle, since the wafer can be held in a non-contact manner, adverse conditions that could damage the thinned wafer can be suppressed, for example, during unloading processes.

[0006] Patent Document 1: International Publication No. 2014 / 084228

[0007] Generally, when loading a wafer onto the upper surface of a chuck using a transfer arm, the wafer's positional offset (eccentricity) relative to the transfer arm in the XY plane (horizontal plane direction) is pre-measured (pre-aligned) by measuring the wafer's peripheral position during transfer. This eccentricity is then reflected (corrected) to the handover position onto the chuck. This ensures the positional accuracy of the wafer and chuck, thereby ensuring the accuracy of testing (inspection).

[0008] However, the thickness of wafers inspected in wafer testing equipment varies greatly depending on the type of device, ranging from thin wafers (less than 100 μm, like the TAIKO (registered trademark) wafers mentioned above) to thick wafers (typical thickness) around 775 μm. While using Bernoulli's principle to hold and transport thick wafers requires a strong air pressure corresponding to the wafer's weight, using the same air pressure to hold and transport thin wafers generates a force that causes the wafer to slide horizontally, potentially leading to positional displacement during transport.

[0009] Additionally, for thinner and / or larger diameter wafers, during transport, such as Figure 8 As shown, this results in a phenomenon where a portion of the outer periphery of wafer W sags (wafer W warping). Specifically, a pair of sags H are generated at approximately 180° rotational symmetry around the central axis (wafer central axis) WC of wafer W. Therefore, the measurement accuracy of the wafer's outer periphery position becomes unstable, making it impossible to ensure pre-alignment measurement accuracy during loading (due to deviations in eccentricity measurement) and the positional accuracy of the wafer relative to the chuck. If the wafer's positional offset relative to the chuck's upper surface exceeds a specified value during loading, it will be considered an error, and the device will stop operating.

[0010] In addition, during the electrical inspection of wafers, the operating status under various temperature conditions is also checked. Specifically, wafers are sometimes loaded onto heated chucks. If a wafer is placed on the upper surface of such a high-temperature chuck, the wafer is held in place by the chuck through vacuum suction, while the wafer undergoes thermal expansion. More specifically, the wafer is subjected to suction forces downwards and expansion forces radially outwards. At this time, the metal film on the lower surface of the wafer may peel off, and the lower surface of the wafer may become tightly bound to the suction holes. If this tight binding occurs, it becomes difficult to peel the wafer from the upper surface of the chuck when returning it to the cassette after the test (unloading becomes difficult). If the wafer cannot be unloaded from the upper surface of the chuck, it is considered an error and the operation of the equipment is stopped. Summary of the Invention

[0011] The purpose of this invention is to provide a wafer transport arm and a wafer transport system that can stably transport wafers of various thicknesses while suppressing wafer positional deviation using Bernoulli's principle. Even for thinner and / or larger diameter wafers, it can suppress wafer warping during transport, stably ensure the loading position accuracy of the wafer and chuck, and stably unload the wafer even when it is secured to the chuck.

[0012] To address the aforementioned issues, the present invention provides the following solution.

[0013] [Method 1 of the present invention]

[0014] A wafer transport arm utilizes Bernoulli's principle to attract and hold a wafer from above. The wafer transport arm includes: an arm top plate centered on a central axis extending in a vertical direction; a plurality of air nozzles opening onto the lower surface of the arm top plate; and an inclined portion disposed on the lower surface and inclined radially outward as it moves downward. When the wafer is attracted by the Bernoulli principle and moves toward the lower surface, the inclined portion can contact the outer periphery of the wafer. The plurality of air nozzles have: an outer air nozzle disposed opposite the outer periphery of the wafer from above; and an inner air nozzle disposed radially inward than the outer air nozzle, wherein the air pressure ejected from the outer air nozzle is less than the air pressure ejected from the inner air nozzle.

[0015] In the wafer transport arm of the present invention, an inclined portion is provided on the lower surface of the arm top plate. Air is ejected from the air outlet, and based on Bernoulli's principle, the wafer is attracted upwards and moves towards the lower surface of the arm top plate, at which point the outer periphery of the wafer contacts the inclined portion. At this time, the outer periphery of the wafer is guided upwards along the inclination of the inclined portion, thereby aligning the wafer's central axis (wafer center axis) to be coaxial (coinciding) with the central axis of the arm top plate, thus achieving wafer alignment. In other words, the inclined portion provides the wafer alignment function.

[0016] This allows for minimizing the positional offset (eccentricity) of the wafer in the XY plane (horizontal plane) during transport. Because it suppresses large positional offsets of the wafer relative to the arm top plate, it also ensures the positional accuracy of the wafer placed on the chuck's upper surface.

[0017] Furthermore, the multiple air nozzles that eject air from the lower surface of the arm top plate include outer air nozzles and inner air nozzles. The outer air nozzles are arranged to overlap with the outer periphery of the wafer when viewed from above. Additionally, the air pressure at the outer air nozzles is lower than the air pressure at the inner air nozzles. In other words, the air pressure at the inner air nozzles is greater than the air pressure at the outer air nozzles.

[0018] When the wafer being transported by the transfer arm is of a thickness of, for example, around 775 μm (typical thickness), air is ejected from the inner air jet outlet with higher air pressure. Thus, even for heavy wafers, the transfer arm can stably attract, hold, and transfer the wafer using Bernoulli's principle.

[0019] Furthermore, when the wafer being transported by the conveyor arm is thin, for example, less than 100 μm, air is ejected from the outer air outlet with lower air pressure. This reduces the likelihood of forces causing the wafer to slide horizontally relative to the top plate of the arm, thereby suppressing wafer positional shift during transport.

[0020] Furthermore, the outer air outlet is positioned opposite the outer periphery of the wafer from above. Therefore, even when transporting thin and / or large-diameter wafers that are prone to warping, negative pressure can be easily applied to the outer periphery of the wafer using Bernoulli's principle. This stably attracts and lifts the outer periphery of the wafer, thus suppressing the phenomenon of a portion of the outer periphery sagging (wafer warping) during transport.

[0021] By preventing wafer warping in this way, the tilting function (centering function) can be stably performed even for thinner and larger diameter wafers.

[0022] Furthermore, by pre-measuring (pre-aligning) the positional offset (eccentricity) of the wafer relative to the XY plane (horizontal plane) of the transport arm during transport, and by controlling the transfer position to the chuck to reflect (correct) this eccentricity, deviations in the measurement of eccentricity can be suppressed.

[0023] Therefore, it can reliably ensure the loading position accuracy between the wafer and the chuck.

[0024] Furthermore, when unloading the wafer from the chuck, air is ejected from the inner air jet outlet, which has a higher air pressure. This creates a greater negative pressure, allowing the wafer to be lifted from the chuck's upper surface with greater force. For example, when loading the wafer onto a heated chuck, even when the suction holes on the chuck's upper surface are tightly engaged with the wafer's lower surface, the transfer arm can stably peel and transfer the wafer from the chuck's upper surface.

[0025] In summary, according to the present invention, wafers of various thicknesses can be stably transported while suppressing positional offset using Bernoulli's principle. Even for thinner and / or larger diameter wafers, wafer warping during transport can be suppressed, the loading position accuracy between the wafer and the chuck can be stably ensured, and the wafer can be stably unloaded even when the wafer is secured to the chuck.

[0026] Therefore, it can suppress the operation stoppage caused by erroneous judgments during the loading and / or unloading processes of the wafer testing equipment, and can perform tests (inspections) efficiently and stably even for wafers that are prone to warping.

[0027] [Method 2 of the present invention]

[0028] According to the wafer transport arm of method 1, the outer air outlet is configured to be adjacent to the inclined portion on the radially inner side of the inclined portion.

[0029] In this case, the outer air jet outlet can be configured to face the outer periphery (peripheral edge) of the wafer. Therefore, the aforementioned effect of the outer air jet outlet is more stable and particularly significant.

[0030] [Method 3 of the present invention]

[0031] According to the wafer transport arm described in method 1 or 2, the outer air nozzle sprays air radially inward along the lower surface of the top plate of the arm.

[0032] In this configuration, the air ejected from the outer air outlet flows radially inward along the lower surface of the arm top plate. This effectively generates a negative pressure between the lower surface of the arm top plate and the upper surface of the wafer, thus more stably enhancing the attraction force.

[0033] [Method 4 of the present invention]

[0034] According to the wafer transport arm of method 3, the outer air outlet and the inner air outlet are arranged at different positions in the circumferential direction.

[0035] In this case, the air ejected radially inward from the outer air nozzle will not pass over the inner air nozzle (opening). Therefore, turbulence in the air ejected from the outer air nozzle can be suppressed, resulting in a more stable negative pressure generated by the outer air nozzle.

[0036] [Method 5 of the present invention]

[0037] The wafer transport arm according to method 3 or 4 further includes an exhaust port, which opens onto the lower surface of the top plate of the arm and is located radially inward from the outer air outlet.

[0038] In this case, air ejected radially inward from the outer air outlet along the lower surface of the arm top plate is discharged through the exhaust port opening on the lower surface. This allows the negative pressure (attraction) to be properly maintained to bring the wafer close to the arm top plate.

[0039] [Method 6 of the present invention]

[0040] According to any one of methods 1 to 5, the inclined portion of the wafer transport arm is provided in six equal intervals in the circumferential direction.

[0041] Compared to, for example, forming the inclined portion as a ring extending around the entire circumference of the lower surface of the arm top plate, the above configuration allows each inclined portion to be formed as an arc shape with a small, easily handled component, thus making it easier to manufacture.

[0042] Furthermore, since the inclined portions are arranged in six evenly spaced sections in the circumferential direction, the following effects are achieved. For example, even if the outer periphery of the wafer accidentally tilts during transport... Figure 8 As shown, when a pair of drooping portions H are positioned between adjacent tilted portions in the circumferential direction (the portions without tilted portions), a pair of non-drooping portions F can also contact the tilted portions at a position 90° off from each drooping portion H around the wafer's central axis WC. Therefore, even if the wafer accidentally warps, the self-aligning effect produced by the tilted portions can be easily obtained in at least a specified direction (e.g., the X or Y direction) in the XY plane (horizontal plane direction).

[0043] [Method 7 of the present invention]

[0044] According to any one of methods 1 to 6, the minimum cross-sectional area of ​​the flow path of the outer air outlet and the pipe component supplying air to the outer air outlet is 19.6 mm² or more.

[0045] Based on the above configuration, even when transporting thin and easily warped wafers, the airflow (L / min) ejected from the outer air outlet can be sufficiently ensured, thus stably suppressing wafer sag. Therefore, the wafer centering function of the tilting portion can be reliably achieved.

[0046] [Embodiment 8 of the present invention]

[0047] A wafer transport system includes: a wafer transport arm according to any one of methods 1 to 7; a chuck on which a wafer transported by the wafer transport arm is placed on its upper surface; and a control device that controls air to be ejected from either the outer air outlet or the inner air outlet according to the type and / or weight of the wafer transported to the chuck.

[0048] In the wafer transport system of the present invention, the control device controls the air ejection to obtain optimal suction force based on the type (device type, etc.) and / or weight (thickness, etc.) of the wafers loaded and processed onto the chuck. For example, the control device determines whether air should be ejected from the outer air ejection port (weak air) or from the inner air ejection port (strong air) based on pre-stored specification data of each wafer and controls the execution accordingly.

[0049] Specifically, the control device performs control as described below, for example.

[0050] When the wafer being transported is thick (typically around 775 μm) and relatively heavy, the control device controls the ejection of air from the inner air outlet with higher air pressure. This ensures a stable attraction even for heavy wafers, enabling stable wafer transport.

[0051] Furthermore, when the wafer being transported is thin (e.g., 100 μm or less), and the wafer type is a lightweight and easily warped wafer such as a power device with a metal film on its lower surface, the control device controls the air to be ejected from the outer air nozzle with lower air pressure. Therefore, even for lightweight wafers, it is less likely to generate forces that would cause the wafer to slide horizontally, thereby suppressing large positional shifts during transport. In addition, the aforementioned function of the outer air nozzle also helps to suppress wafer warping.

[0052] In this way, the transfer of wafers using the attraction forces corresponding to their various types and / or weights can be automatically performed by a control device.

[0053] [Method 9 of the present invention]

[0054] According to the wafer transport system of method 8, when the control device lifts the wafer from the upper surface of the chuck using the wafer transport arm, it controls the air to be ejected from the inner air outlet.

[0055] In the above configuration, during the process of unloading the wafer from the upper surface of the chuck, regardless of the type and / or weight of the wafer, the control device controls the ejection of air (strong air) from the inner air outlet. Therefore, a high attraction force can be obtained, so that even if the wafer is accidentally stuck to the upper surface of the chuck, the wafer can be unloaded stably.

[0056] [Method 10 of the present invention]

[0057] According to the wafer transport system of method 8 or 9, the control device stores measurement data of the displacement of the wafer placed on the upper surface of the chuck relative to the chuck, and controls the use of the measurement data as a correction value when placing other wafers to be transported subsequently on the upper surface of the chuck.

[0058] Even for wafers of the same type and / or weight, the warpage of the transported wafers varies between wafers (e.g., due to differences in manufacturing batches). Furthermore, the degree of self-aligning function obtained by the tilting section also varies depending on the amount of warpage of each wafer.

[0059] Therefore, in the above configuration of the present invention, the control device stores measurement data of the position offset (displacement) of the wafer loading position, and uses this measurement data as a correction value (offset value) for wafers subsequently loaded onto the chuck (reflecting the offset value in the handover position to the chuck). Thus, regardless of, for example, the manufacturing batch, at least for the second (second sheet) and subsequent wafers, the loading position accuracy between the wafer and the chuck can be consistently improved.

[0060] [Method 11 of the present invention]

[0061] According to the wafer transport system of method 10, the control device stores measurement data of the displacement amount and corresponds the measurement data to the transport angle of the wafer around the wafer's central axis, and uses the measurement data as a correction value based on the transport angle of the wafer around the wafer's central axis.

[0062] Considering the layout of electrical circuits and / or electronic components on the card substrate and the reduction of circuit length, probe cards used for functional testing of semiconductor chips mounted on wafers are installed in the wafer testing apparatus at the optimal mounting angle. Furthermore, the mounting angle of the probe cards varies depending on the angle of the electrical test instrument (tester) (left entry, rear entry) and / or the layout of the electrical circuits and / or electronic components within the tester. Specifically, the mounting angle of the probe cards is set in four ways (0°, 90°, 180°, 270°) based on the 90-degree unit around the wafer's central axis.

[0063] Furthermore, for wafers loaded into the chuck, the wafer transport angle around the wafer's central axis is determined based on the probe card's mounting angle. That is, the wafer transport angle around the wafer's central axis is also set in four 90-degree units around the wafer's central axis (0°, 90°, 180°, 270°). Therefore, when transporting thin and easily warped wafers, the angular position of the easily sagging portion around the wafer's central axis varies according to the aforementioned transport angle. Consequently, the self-aligning function obtained by the tilting portion also varies according to the aforementioned transport angle.

[0064] Therefore, in the above configuration of the present invention, the control device stores measurement data of the position offset (displacement) of the wafer loading position, corresponds the measurement data to the transport angle of the wafer around the wafer's central axis, and uses the measurement data as a correction value (offset value) for wafers subsequently loaded and processed onto the chuck at the same transport angle (reflecting the offset value to the handover position onto the chuck). Since the optimal offset value can be added to the handover position (XY coordinate) of the chuck according to each transport angle of the wafer, the loading position accuracy between the wafer and the chuck can be stably improved regardless of the wafer transport angle.

[0065] [Method 12 of the present invention]

[0066] According to the wafer transport system of method 10 or 11, the control device stores measurement data of the displacement amount and corresponds the measurement data to the type and / or weight of the wafer, and uses the measurement data as a correction value according to the type and / or weight of the wafer.

[0067] The warpage of transported wafers is affected by the type of wafer (device type, etc.) and / or weight (thickness, etc.). Furthermore, the degree of self-aligning function obtained by the tilting section varies depending on the amount of warpage of each wafer.

[0068] Therefore, in the above configuration of the present invention, the control device stores measurement data of the position offset (displacement) of the wafer loading position, corresponds this measurement data to the type and / or weight of the transported wafer, and uses this measurement data as a correction value (offset value) for wafers of the same type and / or weight subsequently loaded into the chuck (reflecting the offset value in the handover position to the chuck). Thus, regardless of the type and / or weight of the wafer, the loading position accuracy between the wafer and the chuck can be consistently improved.

[0069] [Method 13 of the present invention]

[0070] According to any one of methods 10 to 12, the control device stores measurement data of the displacement amount and corresponds the measurement data to a predetermined wafer testing device provided with a wafer transport arm for placing the wafer on the upper surface of the chuck, and uses the measurement data as a correction value when other wafers are subsequently placed on the upper surface of the chuck in the predetermined wafer testing device.

[0071] The accuracy of the loading position between the wafer and the chuck varies between different wafer testing setups. This is because, even if the specifications of the wafer testing setups are the same, there are physical differences (minor individual variations) such as the air pressure (air flow rate) ejected from the air outlet of the transport arm and / or the self-aligning function of the tilting section.

[0072] Therefore, in the above configuration of the present invention, the control device stores measurement data of the position offset (displacement) of the wafer loading position, corresponds this measurement data to a specified wafer testing apparatus, and uses this measurement data as a correction value (offset value) for the wafer subsequently loaded and processed onto the chuck in the same specified wafer testing apparatus (reflecting the offset value to the handover position to the chuck). Thus, even when using multiple wafer testing apparatuses, the loading position accuracy between the wafer and the chuck can be consistently improved in each wafer testing apparatus.

[0073] [Method 14 of the present invention]

[0074] According to any one of embodiments 8 to 13, the control device stores measurement data of the displacement of the wafer placed on the upper surface of the chuck relative to the chuck, and when the measurement data is greater than an allowable value, controls the use of the measurement data as a correction value when the wafer is lifted from the chuck by the wafer transport arm and placed on the upper surface of the chuck again.

[0075] In the above configuration, if the wafer placed on the upper surface of the chuck experiences a large positional offset in the XY plane direction (horizontal plane direction) (the positional offset exceeds a preset allowable value), the control device retryes the loading process. Furthermore, during this retry, since the previous positional offset of the same wafer is used as a correction value, the positional offset (displacement) of the wafer after the reloading process is significantly suppressed to a smaller value.

[0076] Therefore, it can not only prevent the wafer testing equipment from stopping due to incorrect judgment during loading, but also significantly improve the loading position accuracy between the wafer and the chuck.

[0077] According to the above-described method of the present invention, the wafer transport arm and wafer transport system can stably transport wafers of various thicknesses while suppressing wafer position deviation using Bernoulli's principle. Even for thinner and / or larger diameter wafers, the wafer warping phenomenon during transport can be suppressed, the loading position accuracy between the wafer and the chuck can be stably ensured, and the wafer can be stably unloaded even when the wafer is fastened to the chuck. Attached Figure Description

[0078] Figure 1 This is a schematic side view (side sectional view) of the wafer transport arm and wafer transport system of this embodiment.

[0079] Figure 2 This is a side view (side sectional view) schematically illustrating the function of the inclined portion of the wafer transport arm, wherein a portion of the structural elements of the wafer transport arm is omitted.

[0080] Figure 3 This is a bottom view showing the wafer transport arm, which schematically illustrates the outflow direction of the air ejected from the outer air nozzle and the inner air nozzle.

[0081] Figure 4 This is a bottom view showing a wafer transport arm, illustrating how the transport arm attracts and holds the wafer in place.

[0082] Figure 5 It is Figure 3The V-shaped section is shown in an enlarged bottom view.

[0083] Figure 6 This is a flowchart illustrating an example of the loading process performed by a wafer transport system.

[0084] Figure 7 This is a side view (side sectional view) schematically showing the chuck and wafer of a wafer transport system in a modified embodiment of this invention.

[0085] Figure 8 It is a three-dimensional diagram schematically showing the state of a warp-prone wafer deformed by its own weight (the state of producing a drooping portion). Detailed Implementation

[0086] The wafer transport arm 10, wafer transport system 20, and wafer testing apparatus 1 according to one embodiment of the present invention will be described with reference to the accompanying drawings. The wafer testing apparatus 1 of this embodiment is a device for performing functional checks (electrical checks) on semiconductor chips mounted on semiconductor wafers (wafers) W such as silicon wafers, and is referred to as a probe, etc.

[0087] like Figure 1 As shown, the wafer testing apparatus 1 includes a wafer transport system 20, a chuck moving unit (not shown), a probe card (not shown), and an electrical test measuring device (not shown). The wafer transport system 20 also includes a wafer transport arm 10, a chuck 21 on its upper surface 22 for holding the wafer W transported by the wafer transport arm 10, and a control device 25. It should be noted that in this embodiment, the wafer transport system 20 is sometimes simply referred to as the transport system 20, and the wafer transport arm 10 is sometimes simply referred to as the transport arm 10.

[0088] The conveying arm 10 is generally circular in shape, and its central axis C extends in the vertical direction. That is, in this embodiment, the direction (axial direction) in which the central axis C of the conveying arm 10 extends corresponds to the vertical direction.

[0089] In this embodiment, the direction orthogonal to the central axis C is called the radial direction. Within the radial direction, the direction closer to the central axis C is called the radial inner direction, and the direction farther from the central axis C is called the radial outer direction.

[0090] In addition, the direction around the central axis C is called the circumferential direction.

[0091] First, the structural components other than the transport system 20 of the wafer testing apparatus 1 will be described.

[0092] Although not specifically illustrated, the chuck moving unit moves the chuck 21 between a loading / unloading position and an inspection position. The loading / unloading position is where the wafer W is placed onto or lifted from the upper surface 22 of the chuck 21 using the transfer arm 10. The inspection position is where the wafer W held by the chuck 21 is tested (inspected) using a probe card and an electrical test instrument. Furthermore, in the loading / unloading position, the chuck moving unit makes fine adjustments to the position of the chuck 21 in the XY plane (horizontal plane direction) under the control of the control device 25, described later.

[0093] Specifically, the chuck moving unit has an XY-axis moving unit and a Z-axis moving unit. The XY-axis moving unit moves the chuck 21 in the XY-axis plane direction, i.e., the horizontal plane direction (the direction of the horizontal plane extending perpendicular to the vertical direction). The Z-axis moving unit moves the chuck 21 in the vertical direction.

[0094] Although not specifically illustrated, the probe card is positioned on the chuck 21 when it is moved to the inspection position, and the chuck 21 is held directly above the wafer W on the upper surface 22. The probe card has multiple probes (contact pins) protruding downward from the probe card. The multiple probes are arranged to face the tiny terminals of the semiconductor chip disposed on the wafer W from above.

[0095] The probe card is detachably mounted on a probe card fixing mechanism (not shown). More specifically, a specified probe card corresponding to the semiconductor chip of the object to be inspected, which is disposed on the wafer W, is appropriately selected from a variety of probe cards, and the probe card is fixed to the probe card fixing mechanism.

[0096] Although not specifically illustrated, the electrical test instrument (tester) measures the information of the semiconductor chip detected by the probes via a contact spring pin mechanism that is electrically connected to each probe of the probe card.

[0097] Next, the structural components of the conveying system 20 will be described.

[0098] The conveyor arm 10 uses Bernoulli's principle to attract and hold the wafer W from above. For example... Figure 1 As shown, the transfer arm 10 is positioned above the chuck 21. The transfer arm 10 performs loading processes, which transfer and place the wafer W onto the upper surface 22 of the chuck 21, and unloading processes, which lift and transfer the tested wafer W from the upper surface 22 of the chuck 21.

[0099] The conveying arm 10 includes: an arm top plate 11 centered on a central axis C; multiple air outlets 13 and 14 opening onto the lower surface 12 of the arm top plate 11; multiple air ducts 16 and 17 supplying air to each air outlet 13 and 14; a switching valve 18 selectively supplying air to the multiple air ducts 16 and 17; and an exhaust port 30 opening onto the lower surface 12 of the arm top plate 11 (see reference). Figure 3 ), and an inclined portion 15 disposed on the lower surface 12 of the top plate 11 and inclined radially outward as it faces downward.

[0100] The top plate 11 is plate-shaped and extends in a direction perpendicular to the vertical direction (horizontal plane direction). In this embodiment, the top plate 11 is a circular plate centered on the central axis C. The lower surface 12 of the top plate 11 is planar and extends in a direction perpendicular to the central axis C.

[0101] The diameter (outer diameter) of the top plate 11 of the arm is larger than the diameter of the circular wafer W conveyed by the conveying arm 10. In this embodiment, the diameter of the wafer W is 8 inches or more. Specifically, the wafer W is an 8-inch wafer or a 12-inch wafer, etc.

[0102] The plurality of air outlets 13, 14 have an outer air outlet 13 arranged opposite to the outer periphery of the wafer W from the top, and an inner air outlet 14 arranged radially inward of the outer air outlet 13.

[0103] The air pressure ejected from the outer air outlet 13 is less than the air pressure ejected from the inner air outlet 14. In other words, the air pressure ejected from the inner air outlet 14 is greater than the air pressure ejected from the outer air outlet 13. The pressure of the air ejected from the outer air outlet 13 (weak air) is, for example, in the range of 80 to 250 kPa, and the pressure of the air ejected from the inner air outlet 14 (strong air) is, for example, in the range of 180 to 500 kPa.

[0104] like Figure 3 As shown, a plurality of outer air outlets 13 are provided. The plurality of outer air outlets 13 are arranged at intervals from each other in the circumferential direction. In this embodiment, six outer air outlets 13 are provided at equal intervals in the circumferential direction.

[0105] Furthermore, multiple inner air outlets 14 are provided. These multiple inner air outlets 14 are arranged at intervals from each other in the circumferential direction. In this embodiment, six inner air outlets 14 are provided at equal intervals in the circumferential direction.

[0106] Furthermore, the outer air outlet 13 and the inner air outlet 14 are arranged at different positions in the circumferential direction. The outer air outlet 13 and the inner air outlet 14 are arranged alternately in the circumferential direction.

[0107] like Figure 3 and Figure 4 As shown, in this embodiment, the outer air outlet 13 is arranged opposite to the outermost peripheral edge We of the outer periphery of the wafer W. Furthermore, as in... Figure 3 As indicated by the arrow, the outer air outlet 13 ejects air radially inward (towards the central axis C) along the lower surface 12 of the top plate 11 of the arm.

[0108] The exhaust port 30 is located radially inward from the outer air outlet 13. Additionally, the exhaust port 30 is located radially inward from the inner air outlet 14. In this embodiment, the exhaust port 30 is radially positioned between the inner air outlet 14 and the central axis C. The exhaust port 30 is triangular in shape, with one of the three vertices of the triangle facing radially inward (towards the central axis C).

[0109] The outer air outlet 13 and the exhaust port 30 are arranged at different positions in the circumferential direction. Multiple exhaust ports 30 are provided. These multiple exhaust ports 30 are arranged at intervals in the circumferential direction. In this embodiment, six exhaust ports 30 are arranged at equal intervals in the circumferential direction.

[0110] Air ejected from the six outer air outlets 13 converges at the central axis C. Furthermore, to reduce the force generated by air collisions that causes the wafer W to move away from the wafer transport arm 10, six exhaust ports 30 are provided, and exhaust is performed after each outer air collision. This appropriately maintains a negative pressure that keeps the wafer W close to the wafer transport arm 10.

[0111] In addition, the inner air outlet 14 ejects air in a vortex-like flow (rotating air) in the entire area (all directions) surrounding the opening of the inner air outlet 14. The opening of the inner air outlet 14 is a circular hole.

[0112] like Figure 1 As shown, the plurality of air ducts 16 and 17 have an outer air duct 16 connected to and supplying air to the outer air outlet 13, and an inner air duct 17 connected to and supplying air to the inner air outlet 14. The outer air duct 16 and the inner air duct 17 constitute independent (separate) airflow paths.

[0113] The minimum cross-sectional area of ​​the flow path of the outer air outlet 13 and the duct component (outer air duct 16) supplying air to the outer air outlet 13 is, for example, 19.6 mm. 2 above.

[0114] The switching valve 18 selectively supplies air from an air supply source (not shown) to either the outer air duct 16 or the inner air duct 17. That is, the switching valve 18 selectively supplies air to either the outer air outlet 13 or the inner air outlet 14 via the outer air duct 16 or the inner air duct 17.

[0115] like Figure 2 As shown, when wafer W is attracted based on Bernoulli's principle and moves closer to the lower surface 12 of the arm top plate 11, the tilting portion 15 can contact the outer periphery (peripheral portion We) of wafer W. Furthermore, while moving upwards, wafer W is guided by the tilting portion 15, thereby bringing the wafer's central axis WC close to the central axis C of the arm top plate 11 (conveyor arm 10), and the wafer W is centered so that these central axes WC and C substantially coincide with each other. It should be noted that in... Figure 2 The diagrams of air nozzles 13 and 14, air ducts 16 and 17, and switching valve 18 are omitted.

[0116] like Figure 3 and Figure 5 As shown, in this embodiment, a resin guide member 19 is mounted on the lower surface 12 of the arm top plate 11, and an inclined portion 15 is formed on the guide member 19. The guide member 19 is fixed to the outer periphery of the lower surface 12 by screws or the like. Multiple guide members 19 are provided. The multiple guide members 19 are arranged at intervals from each other in the circumferential direction. In this embodiment, six guide members 19 are provided at equal intervals in the circumferential direction. Each guide member 19 is in the shape of an arcuate plate extending in the circumferential direction.

[0117] In this embodiment, inclined portions 15 are provided on each guide member 19. That is, multiple inclined portions 15 are provided. The multiple inclined portions 15 are arranged at intervals from each other in the circumferential direction. In this embodiment, six inclined portions 15 are provided at equal intervals in the circumferential direction.

[0118] More specifically, the inclined portion 15 is disposed at the radially inner end of the lower surface of the guide member 19, or at the middle portion of the lower surface of the guide member 19 located between the two radial ends. In addition, the inclined portion 15 extends in an arc shape along the entire length of the guide member 19 extending in the circumferential direction.

[0119] Additionally, the outer air outlet 13 opens onto the lower surface 12 by cutting off a portion of the radially inner end of the guide member 19. For example... Figure 5As shown, in this embodiment, the opening of the outer air nozzle 13 is a semi-circular hole protruding radially inward. The outer air nozzle 13 is arranged adjacent to the inclined portion 15 on the radially inner side of the inclined portion 15.

[0120] like Figure 1 As shown, the chuck 21 is cylindrical or disc-shaped. The chuck 21 has a diameter (outer diameter) larger than the wafer W. Additionally, the chuck 21 has a temperature control unit (not shown). The temperature control unit has at least a heating unit. Alternatively, the temperature control unit may also have a cooling unit. Through the temperature control unit, the chuck 21 is heated or cooled to a specified temperature and maintained at that temperature.

[0121] Additionally, the chuck 21 has an upper surface 22 for mounting the wafer W and an adsorption hole (not shown) opening into the upper surface 22. The upper surface 22 is a planar shape extending in a direction perpendicular to the vertical direction (horizontal plane direction). The adsorption hole is, for example, a circular hole. Although not specifically shown, the adsorption hole is connected to an air suction unit such as a vacuum pump via flow paths and pipe components within the chuck.

[0122] The wafer W, loaded onto the upper surface 22 of the chuck 21 by the loading process of the conveyor arm 10, is attracted by air suction through the suction hole by the air suction unit (vacuum adsorption), thereby being adsorbed and held on the upper surface 22. That is, the chuck 21 holds the wafer W by vacuum adsorption. In the state of being adsorbed and held by the chuck 21, the wafer W is moved together with the chuck 21 to the inspection position and inspected by a probe card and an electrical test instrument.

[0123] The control device 25 controls the air to be ejected from either the outer air outlet 13 or the inner air outlet 14, depending on the type and / or weight of the wafer W being transported to the chuck 21.

[0124] Specifically, the control device 25 performs the control as described below, for example.

[0125] When the thickness of the transported wafer W is, for example, about 775 μm (typical thickness) and the weight of the wafer W is relatively heavy, the control device 25 controls the switching valve 18 to operate and ejects high-pressure air from the inner air outlet 14 through the inner air duct 17.

[0126] In addition, when the thickness of the transported wafer W is thin, for example, less than 100 μm, and the type of wafer W is a power device with a metal film on the lower surface, and the wafer W is lightweight and easily warped, the control device 25 controls the switching valve 18 to operate, and low-pressure air is ejected from the outer air outlet 13 through the outer air duct 16.

[0127] In addition, when the control device 25 lifts the wafer W from the upper surface 22 of the chuck 21 using the conveying arm 10 (i.e., during unloading), it controls the air to be ejected from the inner air outlet 14 regardless of the type and / or weight of the wafer W.

[0128] Furthermore, the control device 25 acquires the displacement (position offset) of the wafer W, which is placed on the upper surface 22 of the chuck 21 during the loading process, relative to the position of the chuck 21 via a measurement unit such as a camera and / or sensor (not shown), and stores the measurement data. Moreover, when other wafers W are subsequently placed on the upper surface 22 of the chuck 21, the control device 25 performs control by using the aforementioned measurement data as a correction value (offset value). Specifically, it adjusts the junction position (XY coordinates) of the chuck 21 by adding a correction value, and reflects this adjustment in the loading process.

[0129] In addition, the control device 25 stores the displacement measurement data and corresponds the measurement data to the transport angle of the wafer W around the wafer center axis WC (for example, four types: 0°, 90°, 180°, and 270° centered on the wafer center axis WC), and uses the above measurement data as a correction value according to the transport angle of the wafer W around the wafer center axis WC.

[0130] In addition, the control device 25 stores the displacement measurement data and corresponds the measurement data to the type and / or weight of the wafer W, and uses the measurement data as a correction value according to the type and / or weight of the wafer W.

[0131] In addition, the control device 25 stores measurement data of the displacement during loading processing and corresponds the measurement data to a specified wafer testing device 1 equipped with a conveying arm 10 for placing wafer W on the upper surface 22 of chuck 21. The measurement data is then used as a correction value when other wafers W are placed on the upper surface 22 of chuck 21 in the same specified wafer testing device 1.

[0132] Furthermore, the control device 25 stores measurement data of the displacement of the wafer W, which is placed on the upper surface 22 of the chuck 21, relative to the position of the chuck 21. If the measured data exceeds an allowable value, the control device performs the following operation: the wafer W is lifted from the chuck 21 using the transfer arm 10, and when the wafer W is placed back on the upper surface 22 of the chuck 21, the measured data is used as a correction value. It should be noted that the allowable value is preset, for example, according to the type of wafer W being transferred.

[0133] Figure 6 This is a flowchart illustrating an example of the loading process performed by the wafer transport system 20 of this embodiment.

[0134] exist Figure 6If air is ejected from air outlets 13 and 14, the conveying arm 10 attracts the wafer W by a negative pressure generated based on Bernoulli's principle (step S01). As the wafer W rises towards the lower surface 12 of the arm top plate 11, it comes into contact with the inclined portion 15, thereby being guided by the inclined portion 15 in the XY plane direction (horizontal plane direction). Thus, the wafer W is centered so that the wafer's central axis WC is approximately coaxial with the central axis C of the conveying arm 10 (step S02).

[0135] If no offset value (correction value) is added to the junction position (XY coordinates) of chuck 21 (step S03: Yes), the control device 25 moves chuck 21 to the junction position without adding an offset value (step S05). Alternatively, if an offset value is added to the junction position (XY coordinates) of chuck 21 (step S03: No), the control device 25 adds the offset value to the junction position (step S04) and moves chuck 21 to the junction position (step S05).

[0136] If air ejection stops from air outlets 13 and 14, the wafer W descends and is placed on the upper surface 22 of the chuck 21 (step S06). A measurement unit such as a camera and / or sensor measures the displacement (position offset) of the wafer W relative to the upper surface 22 of the chuck (step S07).

[0137] If the displacement of wafer W is within the allowable value (step S08: Yes), the control device 25 stores the displacement as an offset value (step S11) and ends the series of loading processes. The stored offset value is reflected in the next loading process.

[0138] Additionally, if the displacement of wafer W is outside the allowable range (step S08: No), control device 25 stores the displacement as the offset value for the next step (step S09) and moves chuck 21 to the handover position (step S10). Air is ejected again from air outlets 13 and 14, and conveying arm 10 attracts wafer W by negative pressure generated based on Bernoulli's principle (step S01), performing the same process as described above (retry process).

[0139] The wafer transport arm 10, wafer transport system 20, and wafer testing apparatus 1 of this embodiment, as described above, achieve the following excellent effects.

[0140] In the wafer transport arm 10 of this embodiment, an inclined portion 15 is provided on the lower surface 12 of the arm top plate 11. Air is ejected from air outlets 13 and 14, and according to Bernoulli's principle, the wafer W is attracted upwards and moves towards the lower surface 12 of the arm top plate 11. At this time, the outer periphery of the wafer W contacts the inclined portion 15. Simultaneously, the outer periphery of the wafer W is guided upwards along the inclination of the inclined portion 15, and the central axis of the wafer W (wafer central axis WC) is aligned to be coaxial (coinciding) with the central axis C of the arm top plate 11, thereby positioning the wafer W. That is, the inclined portion 15 provides the wafer W alignment function.

[0141] Therefore, the positional offset (eccentricity) of the wafer W in the XY plane direction (horizontal plane direction) during transport can be suppressed to a small extent. Since a large positional offset of the wafer W relative to the arm top plate 11 can be suppressed, the positional accuracy of the wafer W placed on the upper surface 22 of the chuck is also ensured.

[0142] Furthermore, the plurality of air nozzles 13, 14 that eject air from the lower surface 12 of the arm top plate 11 include an outer air nozzle 13 and an inner air nozzle 14. The outer air nozzle 13 is configured to overlap with the outer periphery of the wafer W when viewed from above. Additionally, the air pressure at the outer air nozzle 13 is lower than the air pressure at the inner air nozzle 14. In other words, the air pressure at the inner air nozzle 14 is greater than the air pressure at the outer air nozzle 13.

[0143] When the wafer W being transported by the transport arm 10 has a thickness of, for example, about 775 μm (typical thickness), air is ejected from the inner air outlet 14, which has a higher air pressure. Thus, even for a heavy wafer W, the transport arm 10 can stably attract, hold, and transport the wafer W using Bernoulli's principle.

[0144] Furthermore, when the wafer W being transported by the transport arm 10 is thin, for example, less than 100 μm, air is ejected from the outer air outlet 13, which has a lower air pressure. As a result, it is less likely to generate a force that would cause the wafer W to slide horizontally relative to the top plate 11 of the arm, thereby suppressing the possibility of wafer W shifting position during transport.

[0145] Furthermore, the outer air outlet 13 is configured to face the outer periphery of the wafer W from above. Therefore, even when transporting thin or large-diameter wafers that are prone to warping, the attractive force can be easily applied to the outer periphery of the wafer W. The outer periphery of the wafer W can be stably attracted and lifted, thus suppressing the phenomenon of a portion of the outer periphery of the wafer W sagging (wafer W warping) during transport.

[0146] By preventing warping of wafer W in this way, even for thinner and larger diameter wafer W, the above-mentioned tilting portion 15 can stably exert its effect (centering function).

[0147] Furthermore, by pre-measuring (pre-aligning) the positional offset (eccentricity) of the wafer W relative to the transport arm 10 in the XY plane direction (horizontal plane direction) during transport, and by controlling the transfer position of the wafer W to the chuck 21 to reflect (correct) this eccentricity, it is possible to suppress deviations in the measurement results of the eccentricity.

[0148] This ensures the stable accuracy of the loading position between the wafer W and the chuck 21.

[0149] Furthermore, when unloading the wafer W from the chuck 21, air is ejected from the inner air outlet 14, which has a higher air pressure. This results in a stronger suction force, allowing the wafer W to be lifted from the upper surface 22 of the chuck with greater force. For example, when the wafer W is loaded onto the heated chuck 21, even when the suction holes on the upper surface 22 of the chuck are in a tightly engaged state with the lower surface of the wafer W, the wafer W can be stably peeled off from the upper surface 22 of the chuck and transferred using the transfer arm 10.

[0150] In summary, according to this embodiment, wafers of various thicknesses can be stably transported while suppressing wafer W positional shift using Bernoulli's principle. Even for thinner and / or larger diameter wafers W, wafer W warping during transport can be suppressed, ensuring stable loading position accuracy between wafer W and chuck 21. Furthermore, wafer W can be stably unloaded even when it is secured to chuck 21.

[0151] Therefore, it can suppress the operation stoppage caused by erroneous judgments during the loading and / or unloading processes of the wafer testing apparatus 1, and can perform tests (inspections) efficiently and stably even for wafers W that are prone to warping.

[0152] Specifically, in the embodiments of this implementation, the position offset (displacement) of the loading position when a flat wafer W of normal thickness and not easily warped is placed on the upper surface 22 of the chuck is measured. In 180 loading processes, the deviation of the displacement in the X direction is suppressed to within 30 μm, and the deviation of the displacement in the Y direction is suppressed to within 42 μm.

[0153] In addition, the results of measuring the position offset (displacement) of the loading position when the thin and easily warped wafer W is placed on the upper surface 22 of the chuck showed that, in 180 loading processes, the displacement deviation in the X direction was suppressed to within 148 μm and the displacement deviation in the Y direction was suppressed to within 155 μm.

[0154] In addition, in this embodiment, the outer air outlet 13 is disposed adjacent to the inclined portion 15 on the radially inner side of the inclined portion 15.

[0155] In this configuration, the outer air outlet 13 can be positioned opposite the outer peripheral side (peripheral portion We) of the outer periphery of the wafer W. Therefore, the aforementioned effects produced by the outer air outlet 13 become more stable and significantly enhanced.

[0156] In addition, in this embodiment, the outer air outlet 13 sprays air radially inward along the lower surface 12 of the arm top plate 11.

[0157] In this case, the air ejected from the outer air outlet 13 flows radially inward along the lower surface 12 of the arm top plate 11. As a result, a negative pressure can be effectively generated between the lower surface 12 of the arm top plate 11 and the upper surface of the wafer W, thereby increasing the attractive force more stably.

[0158] In addition, in this embodiment, the outer air outlet 13 and the inner air outlet 14 are arranged at different positions in the circumferential direction.

[0159] In this case, the air ejected radially inward from the outer air outlet 13 will not pass over the inner air outlet 14 (the opening). Therefore, turbulence in the air ejected from the outer air outlet 13 can be suppressed, thereby making the attraction force generated by the outer air outlet 13 more stable.

[0160] In addition, in this embodiment, an exhaust port 30 is provided that opens into the lower surface 12 of the top plate 11, and the exhaust port 30 is disposed radially inward from the outer air outlet 13.

[0161] In this case, air ejected radially inward from the outer air outlet 13 along the lower surface 12 of the arm top plate 11 is discharged from the exhaust port 30 opening on the lower surface 12. Thus, a negative pressure (attraction) can be appropriately maintained to bring the wafer W close to the arm top plate 11.

[0162] Additionally, a portion of the air ejected from the inner air outlet 14 can also be discharged from the exhaust port 30. In this case, the aforementioned negative pressure effect can also be appropriately maintained.

[0163] Furthermore, in this embodiment, six inclined portions 15 are provided at equal intervals in the circumferential direction. For example, compared to the case where the inclined portions 15 are formed as an annular shape extending around the entire circumference of the lower surface 12 of the arm top plate 11, according to the above configuration, each inclined portion 15 can be formed as an arc shape with a small, easily handled component (guide component 19 is used in this embodiment), thereby making it easier to manufacture.

[0164] Furthermore, since the inclined portions 15 are arranged in six evenly spaced sections in the circumferential direction, the following effects are achieved. For example, even if the outer periphery of the wafer W is accidentally tilted during transport... Figure 8 As shown, when the wafer W is tilted downwards, and a pair of tilted portions H are positioned between adjacent tilted portions 15 in the circumferential direction (the portions without tilted portions 15), a pair of non-tilted portions F can also contact the tilted portions 15 at positions offset from each tilted portion H around the wafer central axis WC. Therefore, even if the wafer W is accidentally warped, the self-aligning effect produced by the tilted portions 15 can be easily obtained in at least one of the specified directions (e.g., the X or Y direction) in the XY plane direction (horizontal plane direction).

[0165] Furthermore, in this embodiment, the minimum cross-sectional area of ​​the flow path of the outer air outlet 13 and the duct component (outer air duct 16) supplying air to the outer air outlet 13 is set to 19.6 mm. 2 above.

[0166] Based on the above configuration, even when transporting a thin and easily warped wafer W, the air flow rate (L / min) ejected from the outer air outlet 13 is sufficiently ensured, thus stably suppressing the sagging phenomenon of the outer periphery of the wafer W. Therefore, the centering function of the tilting portion 15 on the wafer W can be stably obtained.

[0167] In addition, the wafer transport system 20 of this embodiment includes the wafer transport arm 10, chuck 21 and control device 25 described above. The chuck 21 holds the wafer W transported by the wafer transport arm 10 on its upper surface 22. The control device 25 controls the ejection of air from either the outer air outlet 13 or the inner air outlet 14 according to the type and / or weight of the wafer W transported to the chuck 21.

[0168] In the wafer transport system 20 of this embodiment, the control device 25 controls the air ejection to obtain optimal suction force based on the type (device type, etc.) and / or weight (thickness, etc.) of the wafers W loaded and processed onto the chuck 21. For example, based on the pre-stored specification data of each wafer W, the control device 25 determines whether air is ejected from the outer air ejection port 13 (weak air) or from the inner air ejection port 14 (strong air) and controls the execution accordingly.

[0169] Specifically, the control device 25 performs the control as described below, for example.

[0170] When the thickness of the wafer W being transported is, for example, about 775 μm (typical thickness), and the wafer W is relatively heavy, the control device 25 controls the ejection of air from the inner air outlet 14, which has a higher air pressure. Therefore, even for a heavy wafer W, a stable attractive force can be obtained, thereby enabling stable transport of the wafer W.

[0171] Furthermore, when the wafer W being transported is thin, for example, less than 100 μm, and is a lightweight and easily warped wafer such as a power device with a metal film on its lower surface, the control device 25 controls the ejection of air from the outer air outlet 13, which has a lower air pressure. Therefore, even for a lightweight wafer W, it is less likely to generate a force that would cause the wafer W to slide horizontally, thereby suppressing large positional shifts in the wafer W during transport. In addition, the aforementioned function of the outer air outlet 13 also helps to suppress wafer W warping.

[0172] In this way, the control device 25 can automatically transport each wafer W using the attraction force corresponding to its various types and / or weights.

[0173] In addition, in this embodiment, when the wafer W is lifted from the upper surface 22 of the chuck 21 by the wafer transport arm 10, the control device 25 controls the air to be ejected from the inner air outlet 14.

[0174] In the above configuration, when unloading the wafer W from the upper surface 22 of the chuck, regardless of the type and / or weight of the wafer W, the control device 25 controls the ejection of air (strong air) from the inner air outlet 14. Therefore, a high attractive force can be obtained, so that even if the wafer W is accidentally stuck to the upper surface 22 of the chuck, the wafer W can be unloaded stably.

[0175] In addition, in this embodiment, the control device 25 stores measurement data of the displacement of the wafer W placed on the upper surface 22 of the chuck 21 relative to the position of the chuck 21, and performs control by using the above measurement data as a correction value when placing other wafers W to be transported later on the upper surface 22 of the chuck 21.

[0176] Even for wafers W of the same type and / or weight, the warpage of the transported wafers W varies between each wafer W (e.g., due to differences in manufacturing batches). Furthermore, the degree of self-aligning function obtained by the tilting portion 15 also varies depending on the amount of warpage of each wafer W.

[0177] Therefore, in the above configuration of this embodiment, the control device 25 stores measurement data of the position offset (displacement) of the loading position of the wafer W, and uses this measurement data as a correction value (offset value) for the wafer W subsequently loaded into the chuck 21 (reflecting the offset value in the handover position to the chuck 21). Thus, regardless of, for example, the manufacturing batch, at least for the second (second sheet) and subsequent wafers W, the loading position accuracy between the wafer W and the chuck 21 can be consistently improved.

[0178] In addition, in this embodiment, the control device 25 stores the measurement data of the displacement and corresponds the measurement data to the transport angle of the wafer W around the wafer center axis WC, and uses the above measurement data as a correction value according to the transport angle of the wafer W around the wafer center axis WC.

[0179] Considering the arrangement area (layout) of electrical circuits and / or electronic components on the card substrate and the reduction of circuit length, the probe card for functional testing of the semiconductor chip mounted on the wafer W is mounted on the wafer testing apparatus 1 at the optimal mounting angle. Furthermore, the mounting angle of the probe card varies depending on the angle of the electrical test measuring instrument (tester) (left entry, rear entry) and / or the layout of the electrical circuits and / or electronic components within the tester. Specifically, the mounting angle of the probe card is set in four units (0°, 90°, 180°, 270°) in 90-degree units around the wafer's central axis WC.

[0180] Furthermore, for the wafer W loaded and processed onto the chuck 21, the transport angle of the wafer W around the wafer central axis WC is determined based on the mounting angle of the probe card. That is, the transport angle of the wafer W around the wafer central axis WC is also set in four 90-degree units around the wafer central axis WC (0°, 90°, 180°, 270°). Therefore, when transporting a thin and easily warped wafer W, the angular position of the easily sagging portion H around the wafer central axis WC varies according to the aforementioned transport angle. Consequently, the self-aligning function obtained by the tilting portion 15 also varies according to the aforementioned transport angle.

[0181] Therefore, in the above configuration of this embodiment, the control device 25 stores measurement data of the position offset (displacement) of the loading position of the wafer W, corresponds this measurement data to the transport angle of the wafer W around the wafer central axis WC, and uses this measurement data as a correction value (offset value) for the wafer W subsequently loaded and processed onto the chuck 21 at the same transport angle (reflecting the offset value onto the handover position to the chuck 21). Since the optimal offset value can be added to the handover position (XY coordinate) of the chuck 21 according to each transport angle of the wafer W, the loading position accuracy between the wafer W and the chuck 21 can be stably improved regardless of the transport angle of the wafer W.

[0182] In addition, in this embodiment, the control device 25 stores the measurement data of the displacement and corresponds the measurement data to the type and / or weight of the wafer W, and uses the above measurement data as a correction value according to the type and / or weight of the wafer W.

[0183] The warpability of the transported wafer W is affected by the type of wafer W (device type, etc.) and / or weight (thickness, etc.). Furthermore, the degree of self-aligning function obtained by the tilting portion 15 varies depending on the amount of warp of each wafer W.

[0184] Therefore, in the above configuration of this embodiment, the control device 25 stores measurement data of the position offset (displacement) of the loading position of the wafer W, corresponds this measurement data to the type and / or weight of the transported wafer W, and uses this measurement data as a correction value (offset value) for wafers of the same type and / or weight that are subsequently loaded into the chuck 21 (reflecting the offset value in the handover position to the chuck 21). Thus, regardless of the type and / or weight of the wafer W, the loading position accuracy between the wafer W and the chuck 21 can be consistently improved.

[0185] In addition, in this embodiment, the control device 25 stores the measurement data of the displacement and corresponds the measurement data to a predetermined wafer testing device 1 equipped with a conveying arm 10 for placing wafer W on the upper surface 22 of chuck 21. Then, when other wafers W are placed on the upper surface 22 of chuck 21 in the predetermined wafer testing device 1, the above measurement data is used as a correction value.

[0186] The loading position accuracy between the wafer W and the chuck 21 varies among the wafer testing apparatus 1. This is because even if the specifications of the wafer testing apparatus 1 are the same, there are physical differences (minor individual differences) such as the air pressure (air flow rate) ejected from the air outlets 13 and 14 of the conveying arm 10 and / or the self-aligning function of the tilting part 15.

[0187] Therefore, in the above configuration of this embodiment, the control device 25 stores measurement data of the position offset (displacement) of the loading position of the wafer W, corresponds this measurement data to a predetermined wafer testing apparatus 1, and uses this measurement data as a correction value (offset value) for the wafer W subsequently loaded and processed onto the chuck 21 in the same predetermined wafer testing apparatus 1 (reflecting the offset value onto the handover position to the chuck 21). Thus, even when using multiple wafer testing apparatuses 1, the loading position accuracy between the wafer W and the chuck 21 can be stably improved in each wafer testing apparatus 1.

[0188] In addition, in this embodiment, the control device 25 stores measurement data of the displacement of the wafer W placed on the upper surface 22 of the chuck 21 relative to the position of the chuck 21, and when the above measurement data is greater than the allowable value, when the wafer W is lifted from the chuck 21 by the transfer arm 10 and placed on the upper surface 22 of the chuck 21 again, the control is performed to use the above measurement data as a correction value.

[0189] In the above configuration, when the wafer W placed on the upper surface 22 of the chuck 21 experiences a large positional shift in the XY plane direction (horizontal plane direction) (the positional shift exceeds a preset allowable value), the control device 25 retryes the loading process. Furthermore, during this retry, since the previous positional shift of the same wafer W is used as a correction value, the positional shift (displacement) of the wafer W after the reloading process is significantly suppressed to a smaller value.

[0190] Therefore, it can not only prevent the wafer testing device 1 from stopping due to incorrect judgment during loading, but also significantly improve the loading position accuracy between the wafer W and the chuck 21.

[0191] Specifically, in the embodiments of this implementation, the loading process was retried using a thin and easily warped wafer W. The position offset (displacement) of the wafer W after the reloading process was measured. In 850 loading processes, the deviation of the displacement in the X direction was suppressed to within 60 μm, and the deviation of the displacement in the Y direction was suppressed to within 39 μm.

[0192] This invention is not limited to the embodiments described above. For example, as will be explained below, modifications to the configuration can be made without departing from the spirit of this invention. It should be noted that in the illustrations of the modified examples, the same reference numerals are used to denote the same configuration as in the embodiments described above. The differences will be mainly explained below.

[0193] In the above embodiments, although the loading and unloading processes are described for a wafer W that is in the shape of a circular plate with a certain thickness and whose lower surface is entirely flat, the process is not limited thereto.

[0194] Figure 7 This is a schematic side view (side sectional view) of the chuck 21 and wafer W provided in the wafer transport system 20 of a modified embodiment described above. It should be noted that structural elements of the transport system 20 other than those described above are omitted from the illustration.

[0195] like Figure 7As shown, in this modified example, the wafer W has a thick-walled portion 101 disposed on the outer periphery of the wafer W and in the shape of an annular plate, and a thin-walled portion 102 disposed radially inward of the thick-walled portion 101 and thinner than the thick-walled portion 101. Furthermore, the thin-walled portion 102 has a chip forming effective region 103 with a diameter smaller than the diameter of the thin-walled portion 102. The wafer W in this modified example is, for example, a TAIKO (registered trademark) wafer.

[0196] Furthermore, the chuck 21 has a circular concave stepped portion 22a and a convex surface 22b disposed on the outer periphery of the upper surface 22 of the chuck 21. The convex surface 22b is disposed radially inward of the upper surface 22 than the stepped portion 22a and protrudes upward from the stepped portion 22a, and serves to support the thin-walled portion 102 of the wafer W. The diameter of the convex surface 22b is smaller than the diameter of the thin-walled portion 102, and equal to or greater than the diameter of the effective chip forming region 103.

[0197] More specifically, corresponding to the case where the lower surface of the wafer W has a multi-segment shape, the upper surface 22 of the chuck 21 has a multi-segment shape (a convex two-segment shape) with a convex surface 22b and a stepped portion 22a. In order to stably load this type of wafer W onto the upper surface 22 of the chuck, the diameter of the convex surface 22b needs to be smaller than the diameter of the thin-walled portion 102 of the wafer W. In addition, when testing the semiconductor chip of the wafer W, the diameter of the effective chip forming area 103 needs to be smaller than or equal to the diameter of the convex surface 22b.

[0198] Therefore, in order to ensure that a larger chip forms an effective area 103 and increase the number of effective chips (total number of chips) (i.e., to increase the profit margin per wafer), the diameter of the convex surface 22b needs to be set to be closer to the diameter of the thin-walled portion 102 of the wafer W.

[0199] In this variation, similar to the embodiment described above, the positional accuracy of the wafer W placed on the upper surface 22 of the chuck is stably ensured by the transport arm 10. Therefore, the diameter of the convex surface 22b can be set to be closer to the diameter of the thin-walled portion 102 of the wafer W, thereby increasing the area of ​​the convex surface 22b. By increasing the area of ​​the convex surface 22b, the effective chip formation area 103 of the wafer W can be expanded. By expanding the effective chip formation area 103, the number of effective chips (total number of chips) increases, thereby increasing the profit margin per wafer W (per wafer unit).

[0200] The present invention can combine the various components described in the above embodiments and modifications without departing from the spirit of the invention, and can also make additions, omissions, substitutions and other changes to the components. Furthermore, the present invention is not limited to the above embodiments, etc., but is limited only by the claims.

[0201] Industrial availability

[0202] The wafer transport arm, wafer transport system, and wafer testing apparatus of the present invention can stably transport wafers of various thicknesses while suppressing wafer positional deviation using Bernoulli's principle. Even for thinner and / or larger diameter wafers, wafer warping during transport can be suppressed, ensuring stable loading position accuracy between the wafer and the chuck. Furthermore, wafers can be stably unloaded even when they are securely fastened to the chuck. Therefore, stable inspection and efficient wafer manufacturing are possible. This makes it industrially applicable.

[0203] Explanation of reference numerals in the attached figures

[0204] 1. Wafer Testing Equipment

[0205] 10 wafer transfer arms

[0206] 11. Arm Top Plate

[0207] 12 Lower surface

[0208] 13. Outer air nozzle (air nozzle outlet)

[0209] 14. Inner air nozzle (air nozzle outlet)

[0210] 15 Inclined section

[0211] 20 Wafer Transfer System

[0212] 21 Chuck

[0213] 22 Upper surface

[0214] 25 Control device

[0215] 30 Exhaust port

[0216] C Central axis

[0217] W wafer

[0218] WC wafer center axis

Claims

1. A wafer transport arm that uses negative pressure generated by ejected air to attract and hold a wafer from above, the wafer transport arm comprising: Multiple air nozzles open onto the lower surface of the top plate of the arm; as well as An inclined portion is provided on the lower surface and tilts radially outward as it faces downward. When the wafer is attracted by the negative pressure and moves towards the lower surface, the inclined portion can contact the outer periphery of the wafer. The plurality of air outlets have: An outer air outlet is configured to face the outer periphery of the wafer from above; and The inner air outlet is located radially inward compared to the outer air outlet. The air pressure ejected from the outer air outlet is less than the air pressure ejected from the inner air outlet.

2. The wafer transfer arm according to claim 1, wherein, The outer air outlet is configured to be adjacent to the inclined portion on the radially inner side of the inclined portion.

3. The wafer transport arm according to claim 1, wherein, The outer air outlet sprays air radially inward along the lower surface of the top plate of the arm.

4. The wafer transport arm according to claim 3, wherein, The outer air outlet and the inner air outlet are located at different positions in the circumferential direction.

5. The wafer transport arm according to claim 3, It also includes an exhaust port, which opens onto the lower surface of the arm top plate. The exhaust port is located radially inward than the outer air outlet.

6. The wafer transport arm according to claim 1, wherein, The inclined portions are arranged in six equal intervals in the circumferential direction.

7. The wafer transport arm according to claim 1, wherein, The minimum cross-sectional area of ​​the flow path for the outer air outlet and the duct component supplying air to the outer air outlet is 19.6 mm. 2 above.

8. A wafer transport system, comprising: The wafer transport arm as described in claim 1; A chuck, on which a wafer conveyed by the wafer transport arm is placed on its upper surface; as well as Control device, The control device controls the air to be ejected from either the outer air outlet or the inner air outlet, depending on the type and / or weight of the wafer being transported to the chuck.

9. The wafer transport system according to claim 8, wherein, When the control device lifts the wafer from the upper surface of the chuck using the wafer transfer arm, it controls the air to be ejected from the inner air outlet.

10. The wafer transport system according to claim 8, wherein, The control device stores measurement data of the displacement of the wafer placed on the upper surface of the chuck relative to the chuck, and controls the use of the measurement data as a correction value when placing other wafers subsequently transported on the upper surface of the chuck.

11. The wafer transport system according to claim 10, wherein, The control device stores the measurement data of the displacement, corresponds the measurement data to the transport angle of the wafer around the wafer's central axis, and uses the measurement data as a correction value based on the transport angle of the wafer around the wafer's central axis.

12. The wafer transport system according to claim 10, wherein, The control device stores measurement data of the displacement, corresponds the measurement data to the type and / or weight of the wafer, and uses the measurement data as a correction value according to the type and / or weight of the wafer.

13. The wafer transport system according to claim 10, wherein, The control device stores the measurement data of the displacement and corresponds the measurement data to a predetermined wafer testing device equipped with a wafer transport arm that places the wafer on the upper surface of the chuck. The measurement data is then used as a correction value when other wafers are placed on the upper surface of the chuck in the predetermined wafer testing device.

14. The wafer transport system according to claim 8, wherein, The control device stores measurement data of the displacement of the wafer placed on the upper surface of the chuck relative to the chuck, and when the measurement data is greater than the allowable value, it controls the use of the measurement data as a correction value when the wafer is lifted from the chuck by the wafer transport arm and placed on the upper surface of the chuck again.

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