Semiconductor testing equipment

Abstract

The temperature of the semiconductor wafer during testing is measured with sufficient accuracy. [Solution] The semiconductor testing apparatus 10 performs electrical testing by contacting a probe needle 42 with a die formed on a semiconductor wafer 110. The semiconductor testing apparatus 10 includes a probe card 40 having a probe needle 42 on its bottom surface and a plurality of through holes 41, 44 penetrating its top and bottom surfaces, and an infrared camera 26 provided at a predetermined height from the top surface of the probe card 40, which can image the surface of the die 111 during electrical testing by contacting it with the probe needle 42 through the plurality of through holes 41, 44. The semiconductor testing apparatus 10 further includes a digital signal processing device that converts the brightness distribution in the infrared image captured by the infrared camera 26 into a temperature distribution. The plurality of through holes 41, 44 include portions formed such that the sizes of the plurality of through holes in the infrared image are equal.

Description

Technical Field

[0001] The present invention relates to a semiconductor test apparatus capable of measuring the temperature of a semiconductor wafer during a test.

Background Art

[0002] Conventionally, a semiconductor test system combining a semiconductor test apparatus, also referred to as a semiconductor tester, and a wafer prober has been used. The semiconductor test apparatus electrically tests dies formed in large numbers on the main surface of a semiconductor wafer through probe needles of a probe card. The wafer prober drives the semiconductor wafer so that the probe needles sequentially contact individual dies of the semiconductor wafer. In such a system, it has been required to know the temperature of the semiconductor wafer during the test.

[0003] For this purpose, techniques have been provided for controlling the temperature of a wafer chuck by providing a heater on the wafer chuck on which the semiconductor wafer is placed in the wafer prober (see Patent Document 1), flowing a heat medium through a flow path provided inside the wafer chuck (see Patent Document 2), etc. Also, a technique for forming a temperature sensor on the semiconductor wafer to be tested and detecting the temperature has been provided (see Patent Document 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] In technologies for controlling the temperature of a wafer chuck, electrical testing could cause the die, when energized, to rise above the wafer chuck's temperature, or a temperature distribution could develop within the wafer chuck itself, resulting in an uneven temperature distribution on the semiconductor wafer on which the wafer chuck was placed. Furthermore, in technologies for forming temperature sensors on semiconductor wafers, it was necessary to calibrate the temperature sensor before testing to obtain sufficient accuracy.

[0006] To solve the above-mentioned problems, the inventors of the present invention have devised the following semiconductor testing apparatus. The semiconductor testing apparatus includes an infrared camera capable of imaging a field of view including at least a portion of the top surface of a probe card, and a digital signal processing device that converts the brightness distribution in the infrared image captured by the infrared camera into a temperature distribution. The probe card has through holes formed on its bottom surface so that the surface of the die during electrical testing can be imaged by the infrared camera by contacting probe needles provided therein. The digital signal processing device detects the temperature of the die from the infrared image of the die captured by the infrared camera through the through holes.

[0007] In measuring die temperature using the semiconductor testing apparatus described above, the inventors of the present invention discovered the following phenomenon: The die temperature is detected as lower due to an effect called the "size of source effect" (SSE), and the smaller the through-hole, the lower the detected temperature. In particular, when the distance between the infrared camera and the probe card is short, even if the through-hole size is the same, a through-hole located farther from the optical center of the infrared camera on the probe card appears smaller to the infrared camera, and the die temperature is detected as lower due to the area effect.

[0008] This invention is proposed in view of the above-mentioned circumstances discovered by the inventors of this invention, and aims to provide a semiconductor testing apparatus that can measure the temperature of a semiconductor wafer during testing with sufficient accuracy. [Means for solving the problem]

[0009] A semiconductor testing apparatus according to an embodiment of the present invention is a semiconductor testing apparatus that performs electrical testing by contacting a die formed on a semiconductor wafer with a probe needle. The semiconductor testing apparatus includes a probe card having a probe needle on its bottom surface and a plurality of through holes penetrating its top and bottom surfaces, and an infrared camera provided at a predetermined height from the top surface of the probe card, which can image the surface of the die during electrical testing by contacting it with the probe needle through the plurality of through holes. The semiconductor testing apparatus further includes a digital signal processing device that converts the brightness distribution in the infrared image captured by the infrared camera into a temperature distribution. The plurality of through holes include portions formed such that the sizes of the plurality of through holes in the infrared image are equal. [Effects of the Invention]

[0010] According to the present invention, the temperature of a semiconductor wafer during electrical testing can be measured with sufficient accuracy. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 shows a semiconductor testing system including a semiconductor testing apparatus according to the first embodiment. [Figure 2] Figure 2 is a plan view of a semiconductor wafer. [Figure 3] Figure 3 shows the main components of the semiconductor test system according to the first embodiment. [Figure 4] Figure 4 illustrates the probe card and imaging using an infrared camera according to the first embodiment. [Figure 5A] Figure 5A is a plan view of a portion of the top surface of the probe card according to the first embodiment. [Figure 5B] Figure 5B is a cross-sectional view of a probe card according to the first embodiment. [Figure 6A] Figure 6A is a plan view of a washer according to the first embodiment. [Figure 6B] Figure 6B is a cross-sectional view of a washer according to the first embodiment. [Figure 7A]FIG. 7A is a front view of a part of the top surface of a probe card on which a washer according to the first embodiment is arranged. [Figure 7B] FIG. 7B is a cross-sectional view of a probe card on which a washer according to the first embodiment is arranged. [Figure 8] FIG. 8 is a plan view of a semiconductor wafer to be tested by a semiconductor test system according to the first embodiment. [Figure 9] FIG. 9 is a diagram for explaining imaging by a probe card of a comparative example and an infrared camera. [Figure 10] FIG. 10 is a diagram for explaining imaging by a probe card according to the second embodiment and an infrared camera. [Figure 11A] FIG. 11A is a plan view of a part of the top surface of a probe card according to the second embodiment. [Figure 11B] FIG. 11B is a cross-sectional view of a probe card according to the second embodiment. [Figure 12] FIG. 12 is a diagram for explaining imaging by a probe card according to the third embodiment and an infrared camera. [Figure 13A] FIG. 13A is a plan view of a part of the top surface of a probe card according to the third embodiment. [Figure 13B] FIG. 13B is a cross-sectional view of a probe card according to the third embodiment. [Figure 14] FIG. 14 is a diagram for explaining imaging by a probe card according to the fourth embodiment and an infrared camera.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] Hereinafter, embodiments of a semiconductor test apparatus will be described in detail with reference to the drawings.

[0013] (First Embodiment) Figure 1 shows a schematic configuration of a semiconductor test system including a semiconductor test apparatus 10 according to a first embodiment. The semiconductor test system according to the first embodiment tests a semiconductor wafer 110 on which an integrated circuit is formed, and includes a wafer prober 30 on which the semiconductor wafer 110 is placed, and a semiconductor test apparatus 10. The semiconductor test apparatus 10 includes a test head 20 that is removablely positioned directly above the wafer prober 30, a main body 11 to which the test head 20 is connected via a cable 12 that transmits electrical signals, and a probe card 40. The probe card 40 is attached to the bottom of the test head 20.

[0014] The wafer prober 30 is provided with a wafer chuck 32 for placing and gripping a semiconductor wafer 110 on its top surface. The wafer chuck 32 may grip the placed semiconductor wafer 110 by suction using negative pressure, or it may circulate a heat transfer fluid through a channel provided inside the wafer chuck 32 to maintain a predetermined temperature. The wafer chuck 32 is driven by a drive device 31 in translational and rotational directions (θ direction) in three dimensions (XYZ direction) so that the die of the placed semiconductor wafer 110 sequentially contacts the probe needles 42 formed on the bottom surface of the probe card 40.

[0015] In the semiconductor test apparatus 10, the test head 20 is equipped with a probe tower 22 configured to contact the pads of a probe card 40 attached to its bottom, and an interface board 21 that is electrically connected to the probe tower 22 to transmit and receive signals with a cable 12. The test head 20 is also equipped with an infrared camera 26 positioned at a predetermined height above the top surface of the probe card 40, with the top surface of the probe card 40 included in its field of view. The area around the optical path from the infrared camera 26 to the top surface of the probe card 40 is covered by a cover 27 that blocks external light. The main body 11 is equipped with a digital signal processor (DSP) (not shown) that performs data processing to detect the temperature of the semiconductor wafer 110 based on the infrared image acquired by the infrared camera 26.

[0016] Figure 2 is a plan view of a semiconductor wafer 110 to be tested by a semiconductor test system according to the first embodiment. Numerous dies 111, each with an integrated circuit etched onto it and processed into individual chips in a later process, are arranged on the top surface of the semiconductor wafer 110. These dies are electrically tested by the semiconductor test apparatus 10 through probe needles 42 that contact them sequentially.

[0017] Figure 3 shows the configuration of the main components of a semiconductor test system according to the first embodiment. On the bottom surface of the probe card 40, probe needles 42 are positioned at predetermined locations corresponding to the dies 111 of the semiconductor wafer 110 placed on the wafer chuck 32. In addition, a first through-hole 41 is formed in the probe card 40 at a position corresponding to directly above the die 111 of the test object that the probe needles 42 contact.

[0018] A washer 43 is positioned on the top surface of the probe card 40 so as to cover the first through-hole 41. The washer 43 has a second through-hole 44 formed therein, and the outer circumference of the second through-hole 44 of the washer 43 acts as a shielding plate that blocks the optical path between the first through-hole 41 and the infrared camera 26. As will be described in detail later, the washer 43 is positioned so that a straight line perpendicular to the main surface of the washer 43 and passing through the center of the second through-hole 44 passes through the optical center of the infrared camera 26. To achieve this, the orientation of the washer 43 is adjusted by inserting a fixing rod 45 between the washer 43 and the probe card 40, depending on its position on the probe card 40.

[0019] An infrared camera 26, positioned at a predetermined height from the top surface of the probe card 40, can image the surface of the die 111 under test through a first through-hole 41 located directly above the die 111 and a second through-hole 44 located in the washer 43. Figure 3 shows the optical path 120 from the infrared camera 26 to the die 111 through the first through-hole 41 and the second through-hole 44. The portion of this optical path 120 from the infrared camera 26 to the top surface of the probe card 40 is covered by a cover 27, which blocks the intrusion of external light so as not to affect the imaging of the die 111 by the infrared camera 26.

[0020] Figure 4 illustrates imaging by a probe card 40 and an infrared camera 26 according to the first embodiment. Figure 4(a) is a cross-sectional view of the probe card 40 and infrared camera 26 with a washer 43 placed on them. Figure 4(b) is a plan view of a part of the top surface of the probe card 40. Figure 4(c) is a plan view as recognized by the infrared camera 26. Figure 4 shows the case where the infrared camera 26 and the probe card 40 are placed at close range.

[0021] In Figure 4(a), the infrared camera 26 images a die 111 (not shown in Figure 4(a)) located directly below the bottom surface of the probe card 40 through an optical path 120 from the optical center 261 of the infrared camera 26. The probe card 40 has a plurality of first through holes 41 with a diameter of d2. The washer 43 has a second through hole 44 with a diameter of d1. The washer 43 is oriented such that a straight line perpendicular to the main surface of the washer 43 and passing through the center of the second through hole 44 passes through the optical center 261 of the infrared camera 26, and the outer circumference of the washer 43 is positioned to cover the first through holes 41. As viewed from the optical center 261 of the infrared camera 26, the imaging range 262 of the optical path 120 passing through the second through hole 44 in each washer 43 is equal among the plurality of second through holes 44.

[0022] In Figure 4(b), a plan view of a portion of the top surface of the probe card 40 shows a first through-hole 41 and a projection area 46 projected onto the probe card 40 by the optical path 120 through the second through-hole 44 of the washer 43. In the case of the first through-hole 41 where a perpendicular line passing through the center of the first through-hole 41 passes through the optical center 261 of the infrared camera 26, the projection area 46 is a perfect circle with a diameter of d1. In the case of the first through-hole 41 where a perpendicular line passing through the center of the first through-hole 41 and a straight line passing through the center of the first through-hole 41 and the optical center 261 of the infrared camera 26 intersect at an angle, the projection area 46 is an ellipse with, for example, a major axis of d5.

[0023] The diameter d2 of the first through-hole 41 is set to be larger than the diameter d1 of the second through-hole 44 and to be at least the major axis d5 of the projection area 46. As a result, the entire range of the optical path 120 of the infrared camera 26 that passes through the second through-hole 44 reaches the die 111 through the first through-hole 41.

[0024] Figure 4(c) shows the size of the through-hole recognized by the infrared camera 26, or in other words, the size of the through-hole in the infrared image captured by the infrared camera 26. As explained with reference to Figure 4(a), the washer 43 is positioned such that a straight line perpendicular to the main surface of the washer 43 and passing through the center of the second through-hole 44 passes through the optical center 261 of the infrared camera 26. From the perspective of the optical center 261 of the infrared camera 26, the imaging range 262 is equal among the multiple second through-holes 44. As a result, as shown in Figure 4(c), from the perspective of the infrared camera 26, the size of the second through-hole 44 appears as a perfect circle with a diameter of d1, regardless of the position of the second through-hole 44 on the probe card 40.

[0025] In other words, the sizes of the multiple through-holes in the infrared image captured by the infrared camera 26 are equal regardless of their position on the probe card 40, and the temperature of the die 111 detected through the first through-hole 41 and the second through-hole 44 does not show any difference due to the area effect depending on the position of the through-holes. Therefore, it is possible to reduce the error in the detected temperature of the die 111 due to the position of the through-holes and improve the accuracy of temperature detection of the semiconductor wafer during electrical testing.

[0026] The above outline of imaging by the probe card 40 and infrared camera 26 was explained with reference to Figure 4, showing the first through-hole 41, washer 43, second through-hole 44, and optical path 120 that are included in the same cross-section. In reality, the first through-hole 41 and washer 43 are arranged in two dimensions, in the X and Y directions, on the probe card 40. Next, the detailed shapes of the first through-hole 41 and washer 43 of the probe card 40 and their two-dimensional arrangement will be specifically described.

[0027] Figure 5A is a plan view of a portion of the top surface of a probe card 40 according to the first embodiment. Figure 5A shows an example in which a plurality of first through holes 41 are arranged in a two-dimensional arrangement of 3 rows and 3 columns in a portion of the probe card 40. The shape of the first through holes 41 is, for example, a perfect circle with a diameter of d2. The diameter d2 of the first through holes 41 is larger than the diameter d1 of the second through hole 44 of the washer 43, as described with reference to Figure 4, and is set to be at least the size of the major axis d5 of the projection area 46 obtained by projecting the second through hole 44 onto the probe card 40.

[0028] The shape of the first through-hole 41 is not limited to a perfect circle; for example, it may be a square with side length d2, a rectangle with short side length d2, or an ellipse with minor axis length d2. However, if the shape of the first through-hole 41 is different from a perfect circle, the shape of the outer circumference of the washer 43 must also be such that it can shield the first through-hole 41.

[0029] Figure 5B is a cross-sectional view of the probe card 40 in Figure 5A along VB-VB. The bottom surface of the probe card 40 is provided with a pair of probe needles 42 corresponding to each of the dies 111 under test. In the probe card 40, the first through-hole 41 is formed directly above the dies 111 under test that the pair of probe needles 42 contact.

[0030] Figure 6A is a plan view of the washer 43 according to the first embodiment. Figure 6B is a cross-sectional view of the washer 43 in Figure 6A along VIB-VIB. The washer 43 has a second through hole 44 with a diameter of d1. The shape of the outer circumference of the washer 43 is, for example, a perfect circle with a diameter of d3 and the same center as the second through hole 44.

[0031] The diameter d1 of the second through-hole 44 is made smaller than the diameter d2 of the first through-hole 41 so that the imaging range 262 by the infrared camera 26 is determined by the second through-hole 44. Also, the outer diameter d3 of the washer 43 is made larger than the diameter d2 of the first through-hole 41 in order to shield the first through-hole 41 in which the washer 43 is placed. The outer circumference of the washer 43 only needs to be able to shield the first through-hole 41 in which the washer 43 is placed, and the shape of the outer circumference is not limited to a perfect circle, and the diameter is not limited to d3.

[0032] The washer 43 is preferably capable of efficiently shielding the heat radiated from the die 111 under test, and may contain metal. For example, the washer 43 may contain aluminum, which is an easily processable metal.

[0033] Figure 7A is a front view of a portion of the top surface of a probe card 40 on which a washer 43 according to the first embodiment is placed. Figure 7A shows an example in which the first through-holes 41 are arranged in a two-dimensional 3x3 arrangement on a portion of the probe card 40. Figure 7B is a cross-sectional view along VIIB-VIIB in Figure 7A. As described with reference to Figure 4, the washer 43 is oriented such that a line perpendicular to the main surface of the washer 43 and passing through the center of the second through-hole 44 passes through the optical center 261 of the infrared camera 26. The washer 43 is placed on the probe card 40 such that the outer periphery of the washer 43 covers the first through-hole 41.

[0034] Consider the three washers 43 arranged along VIIB-VIIB in Figures 7A and 7B. The central washer 43 of the three washers 43 is positioned so that its outer circumference is in contact with the top surface of the probe card 40. With this arrangement, the central washer 43 is oriented such that a straight line perpendicular to the main surface of the washer 43 and passing through the center of the second through-hole 44 passes through the optical center 261 of the infrared camera 26. In this case, it is not necessary to adjust the orientation of the washer 43 by placing a fixing rod 45 between the washer 43 and the probe card 40. On the other hand, the washers 43 at both ends of the three washers 43 are adjusted by placing a fixing rod 45 between the washer 43 and the probe card 40 so that a straight line perpendicular to the main surface of the washer 43 and passing through the center of the second through-hole 44 passes through the optical center 261 of the infrared camera 26.

[0035] Similarly, for the washers 43 other than the three washers 43 arranged along VIIB-VIIB in Figure 7A, the orientation of the washers 43 is adjusted by placing a fixing rod 45 between the washer 43 and the probe card 40.

[0036] Figures 7A and 7B show an example where one fixing rod 45 is placed between the washer 43 and the probe card 40 when it is necessary to adjust the orientation of the washer 43, but the number and placement of the fixing rods 45 are not limited to this. By placing multiple fixing rods 45 for one washer 43, it is possible to make the distance from the center of the second through hole 44 to the optical center 261 of the infrared camera 26 equal, regardless of the position of the washer 43 on the probe card 40, as well as the orientation of the washer 43. For example, by placing multiple fixing rods 45 between the washers 43 at the four corners and the probe card 40 in Figure 7A and adjusting the length of each, the distance from the center of the second through hole 44 to the optical center 261 of the infrared camera 26 can be made equal, regardless of the position of the washer 43.

[0037] Furthermore, although not shown in Figures 7A and 7B, a fixing rod 45 may be placed between the central washer 43 of the three washers 43 arranged along VIIB-VIIB and the probe card 40, while maintaining the orientation of the main surface of the washer 43. This may make it easier to fix the washer 43 to the top surface of the probe card 40.

[0038] Figure 8 is a plan view showing the arrangement of the dies 111a to be tested that are simultaneously contacted by the probe needles 42 of the probe card 40, among a plurality of dies 111 formed on the top surface of the semiconductor wafer 110. The dies 111a to be tested are those that are located in positions corresponding to the arrangement of the probe needles 42 provided on the probe card 40, and are contacted by the probe needles 42. The surface of the dies 111a to be tested is imaged by the infrared camera 26 through a first through-hole 41 formed directly above the dies 111a to be tested in the probe card 40 and a second through-hole 44 provided in the washer 43. The probe card 40 allows multiple dies 111a to be tested at once. By repeating the testing of multiple dies 111a within a predetermined area in this manner across the area of ​​the dies 111, the entire die 111 formed on the semiconductor wafer 110 can be tested.

[0039] The semiconductor testing apparatus 10 described above provides an infrared image that includes the top surface of the probe card 40 captured by the infrared camera 26, and the surface of the die 111a under test captured through the first through-hole 41 of the probe card 40 and the second through-hole 44 of the washer 43. While a detailed explanation is omitted, in the infrared image, the brightness distribution corresponding to the light intensity distribution detected by the infrared camera is converted into a temperature distribution by a digital signal processing device, thereby obtaining an image showing the temperature distribution of the die 111a under test and its surroundings. The digital signal processing device may refer to a pre-prepared calibration curve or the like to ensure that the infrared image is accurately converted into a temperature distribution.

[0040] The temperature of the die 111a is obtained by processing the infrared image captured by the infrared camera 26 with a digital signal processing device, ensuring sufficient accuracy. Furthermore, as explained with reference to Figure 4, the sizes of the multiple through-holes in the infrared image captured by the infrared camera 26 are equal regardless of their position on the probe card 40, so the detected temperature of the die 111a does not suffer from area effect differences due to the position of the through-holes. Therefore, the error in the detected temperature of the die 111 due to the position of the through-holes can be reduced, improving the accuracy of temperature detection of the semiconductor wafer during electrical testing. Consequently, the temperature characteristics of the die 111a under test on the semiconductor wafer 110 can be measured with sufficient accuracy.

[0041] Furthermore, probe cards 40 are generally expensive and have long manufacturing times because they are required to ensure that multiple dies 111a and probe needles 42 are in contact with each other at a suitable pressure under various temperature conditions, and to possess good electrical characteristics and durability. Therefore, adjusting the size of the first through-hole 41 of the probe card 40 is disadvantageous in terms of manufacturing cost and time. In contrast, washers 43 and fixing rods 45 are relatively inexpensive and have short manufacturing times, so adjusting the direction and position of the washers 43, the second through-hole 44, or the size of the outer periphery is advantageous in terms of manufacturing cost and time. According to the semiconductor testing apparatus 10 in the first embodiment, the accuracy of temperature detection of semiconductor wafers during electrical testing can be improved by implementing inexpensive and short-term manufacturing measures.

[0042] Here, in order to make the features of the embodiments of the present invention easier to understand, a comparative example of a semiconductor test apparatus will be described. The general configuration of the semiconductor test system including the comparative example semiconductor test apparatus 80 is the same as the general configuration of the semiconductor test system including the semiconductor test apparatus 10 according to the first embodiment shown in Figure 1, except for the configuration of the probe card 40, so the description will be omitted.

[0043] Figure 9 illustrates imaging using a probe card 90 and an infrared camera 26, which are part of a comparative example semiconductor test apparatus 80. Figure 9(a) is a cross-sectional view of the probe card 90 and the infrared camera 26. Figure 9(b) is a plan view of a portion of the top surface of the probe card 90. Figure 9(c) is a plan view recognized by the infrared camera 26. Figure 9 shows the case where the infrared camera 26 and the probe card 90 are placed at close range.

[0044] In Figure 9(a), the infrared camera 26 images the probe card 90 through the optical path 120 from the optical center 261 of the infrared camera 26. The probe card 90 has a plurality of third through holes 91 with a diameter d1.

[0045] In Figure 4(b), a plan view of a portion of the top surface of the probe card 90 shows a third through-hole 91 and a projection area 96 projected onto the probe card 40, the size of which is imaged by an optical path 120 having the same imaging range 262. In the case of a third through-hole 91 where a perpendicular line passing through the center of the third through-hole 91 passes through the optical center 261 of the infrared camera 26, the projection area 96 is a perfect circle with diameter d1 because the third through-hole 91 is projected as is. On the other hand, in the case of a third through-hole 91 where a perpendicular line passing through the center of the third through-hole 91 and a straight line passing through the center of the third through-hole 91 and the optical center 261 of the infrared camera 26 intersect at an angle, the projection area 96 is larger than the third through-hole 91.

[0046] Figure 9(c) shows the size of the through-hole as recognized by the infrared camera 26, or in other words, the size of the through-hole in the infrared image captured by the infrared camera 26. From the perspective of the infrared camera 26, the size of the third through-hole 91 appears to be different depending on the position of the third through-hole 91 on the probe card 40.

[0047] Specifically, in the case of the third through-hole 91 where a perpendicular line passing through the center passes through the optical center 261 of the infrared camera 26, the third through-hole 91 recognized by the infrared camera 26 appears as a perfect circle with a diameter of d1, and is the same size as the actual hole. On the other hand, in the case of the third through-hole 91 where a perpendicular line passing through the center of the third through-hole 91 and a straight line passing through the center of the third through-hole 91 and the optical center 261 of the infrared camera 26 intersect at an angle, the third through-hole 91 recognized by the infrared camera 26 appears as an ellipse with a minor axis of d4, and is smaller than the actual hole.

[0048] As described above, in the comparative example, even among third through-holes 91 of the same actual size, a third through-hole 91 located further away from the optical center 261 of the infrared camera 26 on the probe card 90 is perceived as smaller in size by the infrared camera 26. The smaller the size of the through-hole perceived by the infrared camera 26, the lower the temperature of the die 111 imaged through the through-hole is detected due to the area effect. In other words, the difference in area effect depending on the position of the through-hole causes an error in the detected temperature of the die 111.

[0049] Compared with the comparative examples described above, in the semiconductor testing apparatus 10 according to the first embodiment of the present invention, the sizes of the multiple through-holes in the infrared image captured by the infrared camera 26 are equal regardless of their position on the probe card 40. As a result, the temperature of the detected die 111a does not experience area effect differences due to the position of the through-holes, and therefore the error in the detected temperature of the die 111a due to the position of the through-holes can be reduced.

[0050] In the semiconductor testing apparatus 10 according to the first embodiment, a washer 43, which has a second through-hole 44 provided on a separate flat plate, is placed for each of the first through-holes 41, and the outer circumference of the washer 43 serves as a shielding plate for the first through-holes 41. However, the shielding plate for the first through-holes 41 is not limited to this, and may be, for example, a curved plate provided in common for multiple first through-holes.

[0051] When a curved plate is used as a shielding plate for the first through-hole 41, the plate is curved so that the perpendiculars at positions corresponding to each of the first through-holes 41 on the main surface of the curved plate pass through the optical center 261 of the infrared camera 26. The second through-hole 44 is provided so that the entire range of the optical path 120 that passes through the second through-hole 44 also passes through the first through-hole 41 and reaches the die 111 under test.

[0052] By providing a curved plate and a second through-hole in this manner, the distance from the center of the second through-hole 44 to the optical center of the infrared camera 26 can be made equal among the multiple second through-holes 44. When a curved plate is used as a shielding plate for the first through-hole 41, the size of the through-holes becomes equal in the infrared image captured by the infrared camera 26, similar to the case where a washer 43 is used, thereby improving the accuracy of temperature detection of the die 111a under test.

[0053] (Effects of the first embodiment) According to the semiconductor testing apparatus 10 of the first embodiment, the temperature of the die 111a under test on the semiconductor wafer 110 during testing can be measured with sufficient accuracy by detecting it through through-holes that are of the same size in the infrared image. In other words, the temperature of the semiconductor wafer 110 during testing can be measured with sufficient accuracy. Furthermore, according to the semiconductor testing apparatus 10 of the first embodiment, the accuracy of temperature detection of the semiconductor wafer during electrical testing can be improved by implementing inexpensive and short manufacturing time measures.

[0054] (Second embodiment) Next, a semiconductor test system including the semiconductor test apparatus 10 according to the second embodiment will be described. The semiconductor test apparatus 10 according to the second embodiment differs from the semiconductor test apparatus 10 according to the first embodiment in the configuration of the probe card 40. The general configuration of the semiconductor test system using the semiconductor test apparatus 10 according to the second embodiment is the same as the general configuration of the semiconductor test system including the semiconductor test apparatus 10 according to the first embodiment shown in Figure 1, except for the configuration of the probe card 40, so the explanation will be omitted.

[0055] Figure 10 illustrates imaging by a probe card 40 and an infrared camera 26, which are part of a semiconductor testing apparatus 10 according to a second embodiment. Figure 10(a) is a cross-sectional view of the probe card 40 and the infrared camera 26. Figure 10(b) is a plan view of a part of the top surface of the probe card 40.

[0056] The semiconductor test apparatus 10 according to the second embodiment, shown in Figure 10, differs from the semiconductor test apparatus 10 according to the first embodiment shown in Figure 4 in that the probe card 40 is thicker, and the size and direction of the first through-holes 41 that penetrate the top and bottom surfaces of the probe card 40 are different. In addition, the semiconductor test apparatus 10 according to the second embodiment does not have washers 43 and fixing rods 45 placed on the top surface of the probe card 40. Since the other configurations are the same as those of the semiconductor test apparatus 10 of the first embodiment, common reference numbers will be assigned to the corresponding components.

[0057] In Figure 10(a), the probe card 40 has a thickness, which is, for example, 10 mm or more and 20 mm or less. The first through-hole 41 is provided with a uniform diameter, penetrating the top and bottom surfaces of the probe card 40. The first through-hole 41 may be formed, for example, using a drill. The first through-hole 41a appears on the top surface of the probe card 40, and the first through-hole 41b appears on the bottom surface of the probe card 40.

[0058] The probe card 40 has a plurality of first through holes 41, each corresponding to the die 111a under test. The positions of the first through holes 41b appearing on the bottom surface of the probe card 40 are set so that each of the first through holes 41b is directly above the die 111a under test.

[0059] Each of the multiple first through-holes 41 is positioned such that a straight line passing through the center of the first through-hole 41b appearing on the bottom surface of the probe card 40 and the center of the first through-hole 41a appearing on the top surface of the probe card 40 passes through the optical center 261 of the infrared camera 26. As a result, when the surface of the die 111a under test is imaged by the infrared camera 26 through the first through-holes 41, the imaging range 262 of the optical path 120 reaching the die 111a from the optical center 261 of the infrared camera 26 is equal among the multiple first through-holes 41.

[0060] In other words, the sizes of the multiple first through-holes 41 in the infrared image captured by the infrared camera 26 are equal regardless of their position on the probe card 40. As a result, the temperature of the die 111 detected through the first through-holes 41 does not suffer from area effect differences due to the position of the first through-holes 41. Therefore, errors in the detected temperature of the die 111 due to the position of the first through-holes 41 can be reduced, and the accuracy of temperature detection of the semiconductor wafer during electrical testing can be improved.

[0061] The above outline of imaging by the probe card 40 and infrared camera 26 according to the second embodiment was described with reference to Figure 10, showing the first through-holes 41 and optical path 120 that are included in the same cross-section. In practice, the first through-holes 41 are arranged in two dimensions, in the X and Y directions, on the probe card 40. Next, the detailed shape of the first through-holes 41 of the probe card 40 and their two-dimensional arrangement will be specifically described.

[0062] Figure 11A is a plan view of a portion of the top surface of a probe card 40 according to a second embodiment. Figure 11A shows an example in which a portion of the probe card 40 has a plurality of first through holes 41 arranged in a two-dimensional arrangement of 3 rows and 3 columns. Figure 11B is a cross-sectional view of the probe card 40 of Figure 11A along XIB-XIB. The first through holes 41 may be formed, for example, by a drill with a diameter of d1.

[0063] Of the three first through-holes 41 provided along XIB-XIB, the central first through-hole 41 is positioned perpendicular to the top surface of the probe card 40. Therefore, when viewed from the direction normal to the top surface of the probe card 40, the first through-hole 41a appearing on the top surface of the probe card 40 and the first through-hole 41b appearing on the bottom surface of the probe card 40 overlap, and both have the shape of a perfect circle with a diameter of d1.

[0064] Of the three first through-holes 41 provided along XIB-XIB, the first through-holes 41 at both ends are provided at an angle to the perpendicular line on the top surface of the probe card 40. Therefore, both the first through-hole 41a appearing on the top surface of the probe card 40 and the first through-hole 41b appearing on the bottom surface of the probe card 40 are elliptical in shape. Similarly, the first through-holes 41 other than the three first through-holes 41 arranged along XIB-XIB in Figure 11A are also provided at an angle to the perpendicular line on the top surface of the probe card 40.

[0065] The bottom surface of the probe card 40 is provided with a pair of probe needles 42 corresponding to each die 111 under test. The first through-hole 41b appearing on the bottom surface of the probe card 40 is formed directly above the die 111 under test that the pair of probe needles 42 contact.

[0066] The method for testing the die 111 formed on the semiconductor wafer 110 using the probe card 40 described above, and the method for detecting the temperature of the die 111a under test, are the same as those described in the semiconductor testing apparatus 10 according to the first embodiment, so a detailed explanation will be omitted.

[0067] (Effects of the second embodiment) According to the semiconductor testing apparatus 10 of the second embodiment, when using a thick probe card 40, the temperature of the die 111a under test on the semiconductor wafer 110 during testing can be measured with sufficient accuracy by detecting it through through-holes that are of the same size in the infrared image. In other words, in a test using a thick probe card 40, the temperature of the semiconductor wafer 110 during testing can be measured with sufficient accuracy.

[0068] (Third embodiment) Next, a semiconductor test system including the semiconductor test apparatus 10 according to the third embodiment will be described. The semiconductor test apparatus 10 according to the third embodiment differs from the semiconductor test apparatus 10 according to the first and second embodiments in the configuration of the probe card 40. The general configuration of the semiconductor test system including the semiconductor test apparatus 10 according to the third embodiment is the same as the configuration of the semiconductor test system using the semiconductor test apparatus 10 according to the first embodiment shown in Figure 1, except for the configuration of the probe card 40, so the explanation will be omitted.

[0069] Figure 12 illustrates imaging by a probe card 40 and infrared camera 26, which are part of a semiconductor testing apparatus 10 according to a third embodiment. Figure 12(a) is a cross-sectional view of the probe card 40 and infrared camera 26. Figure 12(b) is a plan view of a part of the top surface of the probe card 40.

[0070] The semiconductor test apparatus 10 according to the third embodiment, shown in Figure 12, differs from the semiconductor test apparatus 10 according to the second embodiment, shown in Figure 10, in the shape of the first through-hole 41 provided in the probe card 40. Since the other configurations are the same as those of the semiconductor test apparatus 10 of the second embodiment, the corresponding components will be given common reference numbers.

[0071] In Figure 12(a), the probe card 40 has a thickness, which is, for example, 10 mm or more and 20 mm or less. The first through-hole 41 penetrates the top and bottom surfaces of the probe card 40, and is provided such that the first through-hole 41a appearing on the top surface of the probe card 40 is larger than the first through-hole 41b appearing on the bottom surface of the probe card 40.

[0072] The probe card 40 has a plurality of first through holes 41, each corresponding to the die 111a under test. The positions of the first through holes 41b appearing on the bottom surface of the probe card 40 are set so that each of the first through holes 41b is directly above the die 111a under test.

[0073] Each of the multiple first through-holes 41 is positioned such that a straight line passing through the center of the first through-hole 41b appearing on the bottom surface of the probe card 40 and a point within the first through-hole 41a appearing on the top surface of the probe card 40 passes through the optical center 261 of the infrared camera 26. Furthermore, the size of the first through-hole 41a appearing on the top surface of the probe card 40 is set to be larger than the size of the first through-hole 41b appearing on the bottom surface of the probe card 40. The first through-holes 41a in Figure 12(a) contain the first through-holes 41a in the second embodiment shown in Figure 10(a), as indicated by the dashed lines for each of the first through-holes 41.

[0074] When the surface of the die 111a under test is imaged through the first through-hole 41, the imaging range 262 by the optical path 120 reaching the die 111a from the optical center 261 of the infrared camera 26 is determined by the size of the first through-hole 41b appearing on the bottom surface of the probe card 40. The shape of the first through-hole 41b is the same as that of the first through-hole 41b in the second embodiment, which is provided such that a straight line passing through the center of the first through-hole 41b appearing on the bottom surface of the probe card 40 and the center of the first through-hole 41a appearing on the top surface passes through the optical center 261 of the infrared camera 26. Therefore, the imaging range 262 is equal across the multiple first through-holes 41, similar to the probe card 40 in the second embodiment.

[0075] In other words, the sizes of the multiple first through-holes 41 in the infrared image captured by the infrared camera 26 become equal regardless of their position on the probe card 40, and the temperature of the die 111 detected through the first through-holes 41 does not exhibit area effect differences due to the position of the first through-holes 41. Therefore, the error in the detected temperature of the die 111 due to the position of the first through-holes 41 can be reduced, and the accuracy of temperature detection of the semiconductor wafer during electrical testing can be improved.

[0076] Furthermore, in the third embodiment, the first through-hole 41 of the probe card 40 is set such that the size of the first through-hole 41a appearing on the top surface of the probe card 40 is larger than the size of the first through-hole 41b appearing on the bottom surface of the probe card 40. This ensures that even if an unwanted protrusion called a "burr" is generated near the first through-hole 41a on the machined surface of the first through-hole 41 when the first through-hole 41 is formed, it does not affect the imaging range 262 determined by the first through-hole 41b as seen by the infrared camera 26. This further reduces the error in the detection temperature of the die 111.

[0077] The above outline of imaging by the probe card 40 and infrared camera 26 according to the third embodiment was described with reference to Figure 12, showing the first through-hole 41 and the optical path 120 included in the same cross-section. Next, the detailed shape of the first through-hole 41 of the probe card 40 and its two-dimensional arrangement will be specifically described.

[0078] Figure 13A is a plan view of a portion of the top surface of a probe card 40 according to a third embodiment. Figure 13A shows an example in which a portion of the probe card 40 has a plurality of first through holes 41 arranged in a two-dimensional arrangement of 3 rows and 3 columns. Figure 13B is a cross-sectional view of the probe card 40 of Figure 13A along XIIIB-XIIIB.

[0079] First, let's describe the central first through-hole 41 of the three first through-holes 41 provided along XIIIB-XIIIB. When viewed from the direction normal to the top surface of the probe card 40, the shape of the first through-hole 41b appearing on the bottom surface of the probe card 40 is a perfect circle with a diameter of d1, and the shape of the first through-hole 41a appearing on the top surface of the probe card 40 is a perfect circle with a diameter greater than d1, namely d6. The central first through-hole 41 is provided such that the straight line connecting the center of the first through-hole 41a appearing on the top surface of the probe card 40 and the center of the first through-hole 41b appearing on the bottom surface is perpendicular to the top surface of the probe card 40. In Figure 13A, the central first through-hole 41 appears as concentric circles: a perfect circle with a diameter of d6 and a perfect circle with a diameter of d1.

[0080] Next, we will describe the two end first through holes 41 of the three first through holes 41 provided along XIIIB-XIIIB. The two end first through holes 41 are provided at an angle to the perpendicular line on the top surface of the probe card 40, with respect to the straight line connecting the center of the first through hole 41a appearing on the top surface of the probe card 40 and the center of the first through hole 41b appearing on the bottom surface. Therefore, the shapes of the first through holes 41a appearing on the top surface of the probe card 40 and the first through holes 41b appearing on the bottom surface are both elliptical.

[0081] Next, we will describe the first through-holes 41 other than the three first through-holes 41 arranged along XIIIB-XIIIB in Figure 13A. Similarly, the first through-holes 41 other than the three first through-holes 41 are provided such that the straight line connecting the center of the first through-hole 41a appearing on the top surface of the probe card 40 and the center of the first through-hole 41b appearing on the bottom surface is at an angle with respect to the perpendicular to the top surface of the probe card 40.

[0082] In Figures 13A and 13B, the first through-hole 41 is shown to be formed such that, when viewed from the optical center 261 of the infrared camera 26, the first through-hole 41a appearing on the top surface of the probe card 40 and the first through-hole 41b appearing on the bottom surface are concentric. However, the center of the first through-hole 41a may be offset from the center of the first through-hole 41b, within the range that encloses the first through-hole 41a in the second embodiment shown in Figure 10(a), when viewed from the optical center 261 of the infrared camera 26.

[0083] The bottom surface of the probe card 40 is provided with a pair of probe needles 42 corresponding to each die 111a under test. The first through-hole 41b appearing on the bottom surface of the probe card 40 is formed directly above the die 111a under test that the pair of probe needles 42 contact.

[0084] The method for testing the die 111 formed on the semiconductor wafer 110 using the probe card 40 described above, and the method for detecting the temperature of the die 111a under test, are the same as those described in the semiconductor testing apparatus 10 according to the first embodiment, so a detailed explanation will be omitted.

[0085] (Effects of the third embodiment) According to the semiconductor testing apparatus 10 of the third embodiment, when using a thick probe card 40, the temperature of the die 111a under test on the semiconductor wafer 110 during testing can be measured with sufficient accuracy by detecting it through through-holes that are of the same size in the infrared image. Furthermore, according to the semiconductor testing apparatus 10 of the third embodiment, even if burrs occur in the first through-hole 41 provided in the probe card 40, it is possible to prevent this from affecting the imaging range 262 of the infrared camera 26. Therefore, the error in the detected temperature of the die 111a can be further reduced.

[0086] (Fourth embodiment) Next, a semiconductor test system including the semiconductor test apparatus 10 according to the fourth embodiment will be described. The semiconductor test apparatus 10 according to the fourth embodiment differs from the semiconductor test apparatus 10 according to the first to third embodiments in the configuration of the probe card 40. The general configuration of the semiconductor test system including the semiconductor test apparatus 10 according to the fourth embodiment is the same as the configuration of the semiconductor test system including the semiconductor test apparatus 10 according to the first embodiment shown in Figure 1, except for the configuration of the probe card 40, so the explanation will be omitted.

[0087] Figure 14 illustrates imaging by a probe card 40 and an infrared camera 26 according to a fourth embodiment. Figure 14(a) is a cross-sectional view of the probe card 40 and the infrared camera 26. Figure 14(b) is a plan view of a part of the top surface of the probe card 40. Figure 14(c) is a plan view as recognized by the infrared camera 26. Figure 14 shows the case where the infrared camera 26 and the probe card 40 are placed at close range.

[0088] In Figure 14(a), the infrared camera 26 images a die 111 (not shown in Figure 14(a)) located directly below the bottom surface of the probe card 40 through the optical path 120 from the optical center 261 of the infrared camera 26. The probe card 40 shows an example in which three first through-holes 41 are provided in a cross-section including the optical center 261 of the infrared camera 26. Of the three first through-holes 41, the central first through-hole 41 has a perpendicular line passing through its center that also passes through the optical center 261 of the infrared camera 26. Of the three first through-holes 41, the two end first through-holes 41 intersect at an angle between the perpendicular line passing through the center of the first through-hole 41 and a straight line passing through the center of the first through-hole 41 and the optical center 261 of the infrared camera 26.

[0089] As shown in the plan view of a portion of the top surface of the probe card 40 in Figure 14(b), of the three first through-holes 41, the shape of the central first through-hole 41 is a perfect circle with a diameter of d1. In contrast, the shapes of the first through-holes 41 at both ends are ellipses, for example, with a major axis of d5. The major axis d5 of the first through-holes 41 at both ends is the size that is imaged on the probe card 40 by an optical path 120 having an equal imaging range 262 from the optical center 261 of the infrared camera 26, and is larger than the diameter d1 of the central first through-hole 41.

[0090] Figure 14(c) shows the size of the through-holes recognized by the infrared camera 26, or in other words, the size of the through-holes in the infrared image captured by the infrared camera 26. As explained with reference to Figures 14(a) and 14(b), the imaging range 262 is equal among the multiple first through-holes 41 when viewed from the optical center 261 of the infrared camera 26. Therefore, as shown in Figure 14(c), when viewed from the infrared camera 26, the size of the first through-holes 41 appears as a perfect circle with a diameter of d1, regardless of the position of the first through-holes 41 on the probe card 40.

[0091] In other words, the sizes of the multiple through-holes in the infrared image captured by the infrared camera 26 become equal regardless of their position on the probe card 40, and the temperature of the die 111 detected through the first through-hole 41 does not exhibit area effect differences due to the position of the through-hole. Therefore, it is possible to reduce the error in the detected temperature of the die 111 due to the position of the through-hole, and improve the accuracy of temperature detection of the semiconductor wafer during electrical testing.

[0092] In Figure 14, the central of the three first through-holes 41 is shown as the case where a perpendicular line passing through the center passes through the optical center 261 of the infrared camera 26. However, the position of the first through-hole 41 is not limited to this. On the probe card 40, a position relatively close to the optical center 261 of the infrared camera 26 is designated as the first position, and a position relatively farther from the optical center 261 is designated as the second position. By making the size of the through-hole at the second position larger than the size of the through-hole at the first position, the sizes of the through-holes at the first and second positions in the infrared image captured by the infrared camera 26 are equal, the error in the detection temperature of the die 111 due to the position of the through-hole can be reduced.

[0093] (Effects of the fourth embodiment) According to the semiconductor testing apparatus 10 of the fourth embodiment, the temperature of the die 111a under test on the semiconductor wafer 110 during testing can be measured with sufficient accuracy by detecting it through through-holes that are of the same size in the infrared image. In other words, the temperature of the semiconductor wafer 110 during testing can be measured with sufficient accuracy.

[0094] (Other embodiments) While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0095] For example, in the semiconductor testing apparatus 10 according to the first embodiment, a washer 43, which has a second through hole 44 provided on a separate flat plate, is placed for each of the first through holes 41, and the outer circumference of the washer 43 serves as a shielding plate for the first through holes 41. However, as mentioned above, the shielding plate for the first through holes 41 is not limited to this, and may be a curved plate that is commonly provided for multiple first through holes.

[0096] Alternatively, for example, the probe card 40 of the semiconductor testing apparatus 10 according to the fourth embodiment may be combined with the probe card 40 according to the second embodiment. That is, the thickness of the probe card 40 may be increased to be the same as that of the probe card 40 according to the second embodiment, and the first through-hole 41 may be provided in the same orientation as that of the probe card 40 according to the second embodiment.

[0097] For example, in the semiconductor test apparatus 10 according to the first to fourth embodiments, the test head 20 was provided separately from the main body 11, and these were connected by a cable 12. However, the configuration of the semiconductor test apparatus 10 is not limited to this, and the main body 11 may not be provided separately from the test head 20, and the test head 20 in Figure 1 may be integrated so that it combines the functions of both the main body 11 and the test head 20. [Explanation of Symbols]

[0098] 10 Semiconductor Test Equipment 11 Main unit 12 Cables 20 test heads 21 Interface boards 22 Probe Towers 26 Infrared Cameras 27 Cover 30 wafer probers 31 Drive unit 32 wafer chucks 40 Probe Cards 41 First through hole 42 Probe needles 43 Washer 44 Second through hole 45 Fixed rod 46 Projection area 110 Semiconductor wafers 111 Die 120 light path 261 Optical Center 262 Imaging range

Claims

1. A semiconductor testing apparatus that performs electrical testing by contacting a die formed on a semiconductor wafer with a probe needle, A probe card having the probe needle on its bottom surface and having a plurality of through holes penetrating its top surface and bottom surface, An infrared camera is provided at a predetermined height from the top surface of the probe card, and can image the surface of the die during electrical testing by contacting the probe needle through the plurality of through holes. A digital signal processing device that converts the brightness distribution in an infrared image captured by the aforementioned infrared camera into a temperature distribution, Equipped with, The plurality of through holes include a portion formed such that the sizes of the plurality of through holes in the infrared image are equal, Semiconductor testing equipment.

2. The semiconductor testing apparatus according to claim 1, wherein the digital signal processing device detects the temperature of the die from an infrared image of the die captured by the infrared camera through the through-hole.

3. Each of the plurality of through holes is A first through-hole formed through the probe card in a direction perpendicular to the top surface of the probe card, A second through-hole is formed in a shielding plate provided on the top surface of the probe card so as to cover the first through-hole, Equipped with, A straight line perpendicular to the main surface of the shielding plate and passing through the center of the second through-hole passes through the optical center of the infrared camera. Between each of the plurality of through holes, the size of the second through hole is equal. The semiconductor testing apparatus according to claim 1.

4. The semiconductor testing apparatus according to claim 3, wherein the size of the first through-hole is larger than the size of the second through-hole.

5. The semiconductor testing apparatus according to claim 3, wherein the shielding plate includes metal.

6. The semiconductor testing apparatus according to claim 3, wherein the shielding plate is a flat plate separated so as to be provided for each of the first through holes.

7. The semiconductor testing apparatus according to claim 3, wherein the shielding plate is a curved plate commonly provided for a plurality of first through holes.

8. Each of the plurality of through holes is The probe card is formed such that a straight line passing through the center of the through hole appearing on the top surface of the probe card and the center of the through hole appearing on the bottom surface of the probe card passes through the optical center of the infrared camera. The semiconductor testing apparatus according to claim 1.

9. Each of the plurality of through holes is The probe card is formed such that a straight line passing through the center of the through-hole appearing on the bottom surface of the probe card and a point within the through-hole appearing on the top surface of the probe card passes through the optical center of the infrared camera. The size of the through-hole appearing on the top surface of the probe card is larger than the size of the through-hole appearing on the bottom surface of the probe card. The semiconductor testing apparatus according to claim 1.

10. The plurality of through holes include through holes at a first position relatively close to the optical center of the infrared camera and through holes at a second position relatively far from the optical center of the infrared camera. The size of the through hole at the second position is larger than the size of the through hole at the first position. The semiconductor testing apparatus according to claim 1.

Images