Semiconductor test apparatus and wafer prober

Abstract

To measure a temperature of a semiconductor wafer being tested with a sufficient accuracy.SOLUTION: A semiconductor test apparatus 10 is configured to perform an electrical test by bringing a probe needle 42 of a probe card 40 into contact with a die formed on a semiconductor wafer 110, and includes: an infrared camera 26 provided at a predetermined height from a top surface of the probe card 40 and capable of capturing an image of a field of view including at least a part of the top surface of the probe card 40; and a digital signal processing device configured to convert a luminance distribution in an infrared image captured by the infrared camera 26 into a temperature distribution. The probe card 40 has a through-hole 41 formed so that the surface of the die under the electrical test can be imaged by the infrared camera 26 by contacting a probe needle 42 provided on a bottom surface thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor testing apparatus and a wafer prober capable of measuring the temperature of a semiconductor wafer under test. [Background technology]

[0002] Conventionally, a semiconductor test system has been used that combines a semiconductor test device, also called a semiconductor tester, which electrically tests multiple dies formed on the main surface of a semiconductor wafer using probe needles of a probe card, with a wafer prober that drives the semiconductor wafer so that the probe needles sequentially contact each individual die on the semiconductor wafer. In such a system, it is required to know the temperature of the semiconductor wafer during testing.

[0003] For this reason, there are provided techniques for controlling the temperature of a wafer chuck in a wafer prober, by providing a heater to the wafer chuck on which the semiconductor wafer is placed (see Patent Document 1), or by flowing a heat medium through a flow path provided inside the wafer chuck (see Patent Document 2).There is also provided a technique for detecting the temperature by forming a temperature sensor on the semiconductor wafer to be tested (see Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 02-008141 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-192485 [Patent Document 3] Japanese Patent Application Publication No. 11-126807 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology for controlling the temperature of a wafer chuck assumes that the semiconductor wafer placed on the wafer chuck is at the same temperature as the wafer chuck, but during electrical testing, the die that is energized may heat up from the temperature of the wafer chuck. Furthermore, a temperature distribution may occur within the wafer chuck itself, causing the temperature of the semiconductor wafer placed on the wafer chuck to become uneven. With the technology for forming a temperature sensor on the semiconductor wafer, the temperature sensor must be calibrated before testing to achieve sufficient accuracy.

[0006] The present invention has been proposed in view of the above-mentioned circumstances, and has as its object to provide a semiconductor testing apparatus and a wafer prober that are capable of measuring the temperature of a semiconductor wafer under test with sufficient accuracy. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the semiconductor testing apparatus of the present invention is a semiconductor testing apparatus that performs electrical testing by contacting probe needles of a probe card with dies formed on a semiconductor wafer, and includes an infrared camera that is arranged at a predetermined height from the top surface of the probe card and is capable of capturing an image of a field of view that includes at least a portion of the top surface of the 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, and the probe card has a through hole formed so that the probe needles arranged on the bottom surface of the probe card can contact the through hole and capture an image of the surface of the die during electrical testing from the infrared camera.

[0008] The digital signal processor may detect the temperature of the die from an infrared image of the die captured by the infrared camera through the through-hole. The probe card may further include a cover that covers an optical path from the infrared camera to the top surface of the probe card to block intrusion of light from outside.

[0009] The probe card may further include an interface board electrically connected to the probe card. The probe card may further include a main body that houses the digital signal processing device, a test head that houses the infrared camera and the interface board, and a cable that transmits signals between the main body and the test head. The probe card may be attached to the test head.

[0010] The probe card may further include a main body housing a digital signal processing device and a cable for transmitting signals between the main body and the interface board. The interface board is installed in an optical path from the infrared camera to the top surface of the probe card so that its bottom surface faces the top surface of the probe card with a predetermined gap formed therebetween, and the infrared camera can capture an image of a field of view including at least a portion of the top surface of the interface board instead of the probe card, and the interface board may have a through-hole formed so that the infrared camera can capture an image of the surface of the die through the through-hole of the probe card. The probe card may be attached to the interface board.

[0011] The wafer prober of the present invention is a wafer prober that sequentially brings dies formed on a semiconductor wafer into contact with probe needles of a probe card for electrical testing, and includes a wafer chuck that places the semiconductor wafer on its top surface so that the top surface of the semiconductor wafer on which the dies are formed faces the bottom surface of the probe card on which the probe needles are provided, a driving device that drives the wafer chuck so that the dies sequentially come into contact with the probe needles, an infrared camera that is located at a predetermined height from the top surface of the probe card and can capture an image of a field of view that includes at least a portion of the top surface of the 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, and the probe card has through holes formed so that the surface of the die that is in contact with the probe needles provided on its bottom surface can be captured by the infrared camera.

[0012] A semiconductor wafer testing method according to the present invention includes: bringing probe needles into contact with dies formed on the semiconductor wafer to perform electrical testing; using an infrared camera to capture images of the surfaces of the dies undergoing electrical testing through through holes in a probe card; and using a digital signal processing device to detect the temperature of the dies from the infrared images captured by the infrared camera. [Effects of the Invention]

[0013] According to the present invention, the temperature of a semiconductor wafer during electrical testing can be measured with sufficient accuracy. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 illustrates a semiconductor test system according to a first embodiment. [Figure 2] FIG. 1 is a plan view of a semiconductor wafer. [Figure 3] FIG. 1 is a diagram illustrating a main part of a semiconductor test system. [Figure 4] FIG. 1 is a diagram illustrating imaging by an infrared camera. [Figure 5] FIG. 10 is a diagram showing an image showing the temperature distribution of a die. [Figure 6] FIG. 10 is a diagram showing a semiconductor test system including a semiconductor test device according to a modified example. [Figure 7] FIG. 10 illustrates a semiconductor test system according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of a semiconductor testing device and a wafer prober will be described in detail with reference to the drawings.

[0016] (First embodiment) 1 is a diagram showing a schematic configuration of a semiconductor test system according to a first embodiment. The semiconductor test system according to the first embodiment tests a semiconductor wafer 110 on which integrated circuits are formed, and includes a wafer prober 30 on which the semiconductor wafer 110 is placed, and a semiconductor test apparatus 10 including a test head 20 removably disposed directly above the wafer prober 30 and connected to a main body 11 via a cable 12 for transmitting electrical signals. A probe card 40 is attached to the bottom of the test head 20.

[0017] The wafer prober 30 is provided with a wafer chuck 32 that holds a semiconductor wafer 110 on its top surface. The wafer chuck 32 may hold the placed semiconductor wafer 110 by suction using negative pressure, or may maintain the wafer chuck 32 at a predetermined temperature by circulating a heat transfer medium through a flow path provided inside the wafer chuck 32. The wafer chuck 32 is driven by a driving device 31 in translation in three dimensions (X, Y, and Z directions) and in a rotational direction (θ direction) so that the dies of the placed semiconductor wafer 110 sequentially come into contact with the probe needles 42 formed on the bottom surface of the probe card 40.

[0018] In the semiconductor testing apparatus 10, the test head 20 is provided with a probe tower 22 configured to contact pads of a probe card 40 attached to the bottom, and an interface board 21 electrically connected to the probe tower 22 for transmitting and receiving signals to and from the cable 12. The test head 20 is also provided with an infrared camera 26 at a predetermined height above the top surface of the probe card 40, the infrared camera 26 having a field of view that includes the top surface of the probe card 40. The periphery of the optical path from the infrared camera 26 to the top surface of the probe card 40 is covered with a cover 27 that blocks light from outside. The main body 11 is provided 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.

[0019] 2 is a plan view of a semiconductor wafer 110 to be tested by a semiconductor test system. On the top surface of the semiconductor wafer 110 are arranged a number of dies 111, each of which has an integrated circuit burned into it and will be processed into individual chips in a later process. These dies are electrically tested by the semiconductor test equipment 10 through the probe needles 42 which contact them in turn.

[0020] 3 is a diagram showing the configuration of the main parts of the semiconductor test system. Probe needles 42 are arranged on the bottom surface of probe card 40 at predetermined positions corresponding to dies 111 of semiconductor wafer 110 placed on wafer chuck 32. In addition, through holes 41 are formed at positions corresponding to directly above die 111 to be tested with which probe needles 42 come into contact.

[0021] Infrared camera 26, which is provided at a predetermined height from the top surface of probe card 40, can also capture images of the surfaces of these test target dies 111 through through-holes 41 provided directly above dies 111. Fig. 3 shows an optical path 120 that runs from infrared camera 26 to die 111 through through-hole 41. The portion of this optical path 120 that runs from infrared camera 26 to the top surface of probe card 40 is covered with cover 27, which blocks the intrusion of external light so as not to affect the imaging of die 111 by infrared camera 26.

[0022] 4A and 4B are diagrams illustrating imaging by the infrared camera 26. FIG. 4A is a plan view of a portion of the top surface of a probe card 40 included in the field of view of the infrared camera 26. A plurality of through holes 41 are arranged on the top surface of the probe card 40. FIG. 4B is a cross-sectional view of the probe card 40 of FIG. 4A taken along the cutting line IVB-IVB. The through holes 41 in the probe card 40 are formed directly above the die 111 to be tested, with which a pair of probe needles 42 come into contact.

[0023] FIG. 4(c) is a plan view showing the arrangement of test target dies 111a, among the multiple dies 111 formed on the top surface of the semiconductor wafer 110, with which the probe needles 42 of the probe card 40 simultaneously make contact. The test target die 111a is the die 111 that is located at a position corresponding to the arrangement of the probe needles 42 provided on the probe card 40 and with which the probe needles 42 make contact. The surface of the test target die 111a is imaged by the infrared camera 26 through a through-hole 41 formed in the probe card 40 directly above the test target die 111a. The probe card 40 can test multiple test target dies 111a at once. By repeating this testing of multiple test target dies 111a within a predetermined area over the area of ​​the die 111, all of the dies 111 formed on the semiconductor wafer 110 can be tested.

[0024] 5 is an image showing the temperature distribution of the die 111. This image is an infrared image including the top surface of the probe card 40 captured by the infrared camera 26 and the surface of the test die 111 captured through the through-hole 41 of the probe card 40. The brightness distribution corresponding to the distribution of the amount of light detected by the infrared camera is converted into a temperature distribution by a digital signal processor, and the image shows the temperature distribution of the test die 111a and its surroundings. The digital signal processor may refer to a calibration curve or the like prepared in advance so that the infrared image is accurately converted into a temperature distribution.

[0025] As described above, the semiconductor testing apparatus 10 can measure the temperature of the die 111a under test that is in contact with the probe needles 42 of the probe card 40 on the semiconductor wafer 110 under test. The temperature of the die 111 is obtained by processing an infrared image captured by the infrared camera 26 with a digital signal processing device, ensuring sufficient accuracy. Therefore, the temperature characteristics of the die 111a under test on the semiconductor wafer 110 can be measured with sufficient accuracy. In other words, the temperature of the semiconductor wafer 110 under test can be measured with sufficient accuracy.

[0026] In the semiconductor test equipment 10, the test head 20 is provided separately from the main body 11, and they are connected by the cable 12. However, the configuration of the semiconductor test equipment 10 is not limited to this, and the main body 11 may not be provided separately from the test head 20, but may be configured as an integrated unit such that the test head 20 in FIG. 1 has the functions of both the main body 11 and the test head 20.

[0027] (Variation) Fig. 6 is a diagram showing a semiconductor test system according to a modified example. The semiconductor test apparatus 10 according to the modified example differs from the semiconductor test apparatus 10 shown in Fig. 1 in that, instead of the test head 20 connected to the cable 12, an interface board 24 is provided in the optical path from the infrared camera 26 to the top surface of the probe card 40, with the bottom surface facing the top surface of the probe card 40 across a predetermined gap, and the cable 12 is attached to this interface board 24. Since the other configurations are the same as those of the semiconductor system according to Fig. 1, the corresponding components are denoted by the same reference numerals.

[0028] In this modification, an interface board 24 is provided in the optical path from the infrared camera 26 to the top surface of the probe card 40, so that the field of view of the infrared camera 26 includes the top surface of the interface board 24 instead of the top surface of the probe card 40. The interface board 24 has a through-hole 24a formed at least directly above the through-hole 41 of the probe card 40 so that the infrared camera 26 can image the surface of the die 111 to be tested through the through-hole 41 formed in the probe card 40. The optical path from the infrared camera 26 to the top surface of the interface board 24 is covered by a cover 27, which blocks the incidence of light from outside. The probe card 40 is attached to the interface board 24 and is electrically connected to the interface board 24 via a probe tower 22 provided on the bottom surface of the interface board 24.

[0029] 1, the semiconductor testing apparatus 10 of the modified example can measure the temperature of the semiconductor wafer 110 under test with sufficient accuracy by measuring the temperature of the die 111a under test that is in contact with the probe needles 42 of the probe card 40 on the semiconductor wafer 110 under test. The semiconductor testing apparatus 10 of the modified example replaces the test head 20 of FIG. 1 with a single interface board 24, making it easier to handle and reducing the burden on the user. Furthermore, because the infrared camera 26 is exposed, it is easier to adjust the optical system including the infrared camera 26.

[0030] (Second embodiment) 7 is a diagram showing a schematic configuration of a semiconductor test system according to a second embodiment. The semiconductor test system according to the second embodiment differs from the semiconductor test system according to the first embodiment shown in FIG. 1 in that an infrared camera 26 and a cover 27 are provided on the wafer prober 30. Since the other configurations are similar to those of the semiconductor test system according to the first embodiment, the same reference numerals will be used for corresponding components.

[0031] In the semiconductor test system of the second embodiment, a digital signal processing device that detects the temperature of the semiconductor wafer 110 from an infrared image captured by the infrared camera 26 is provided in the wafer prober 30 instead of the main body 11 of the semiconductor test apparatus 10. As with the semiconductor test apparatus 10 of the first embodiment, the wafer prober 30 can measure the temperature of the semiconductor wafer 110 under test with sufficient accuracy from an infrared image of the surface of the die 111 under test captured by the infrared camera 26. Furthermore, in the wafer prober 30 of the second embodiment, the infrared camera 26 is exposed when the test head 20 is removed, making it easy to adjust the optical system including the infrared camera 26. [Explanation of symbols]

[0032] 10. Semiconductor testing equipment 11 Main unit 12 Cable 20 Test Head 21 Interface board 22 Probe Tower 26 Infrared Camera 27 Cover 30 Wafer prober 31 Drive unit 32 Wafer chuck 40 probe cards 41 Through hole 42 probe needle 110 Semiconductor wafer 111 Die

Claims

1. A semiconductor testing device that performs an electrical test by bringing probe needles of a probe card into contact with dies formed on a semiconductor wafer, an infrared camera that is provided at a predetermined height from the top surface of the probe card and that can capture an image of a field of view that includes at least a part of the top surface of the probe card; a digital signal processing device that converts the brightness distribution in the infrared image captured by the infrared camera into a temperature distribution; Including, The probe card has through holes formed on the bottom surface thereof so that the probe needles can contact the through holes and capture images of the surface of the die during electrical testing from the infrared camera.

2. 2. The semiconductor testing device 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. 2. The semiconductor testing device according to claim 1, further comprising a cover that covers an optical path from said infrared camera to the top surface of said probe card to block intrusion of light from outside.

4. 2. The semiconductor testing device according to claim 1, further comprising an interface board electrically connected to the probe card.

5. a main body that houses the digital signal processing device; a test head housing the infrared camera and the interface board; a cable for transmitting signals between the main body and the test head; The semiconductor testing device according to claim 4, further comprising:

6. 6. The semiconductor testing device according to claim 5, wherein the probe card is attached to the test head.

7. a main body that houses the digital signal processing device; a cable for transmitting signals between the main body and the interface board; The semiconductor testing device according to claim 4, further comprising:

8. 8. The semiconductor testing device of claim 7, wherein the interface board is installed in an optical path from the infrared camera to the top surface of the probe card so that its bottom surface faces the top surface of the probe card with a predetermined gap therebetween, the infrared camera can image a field of view including at least a portion of the top surface of the interface board instead of the probe card, and the interface board has a through hole formed so that the infrared camera can image the surface of the die through the through hole of the probe card.

9. 9. The semiconductor testing device according to claim 8, wherein the probe card is attached to the interface board.

10. A wafer prober that sequentially brings dies formed on a semiconductor wafer into contact with probe needles of a probe card for electrical testing, a wafer chuck for placing the semiconductor wafer on a top surface of the probe card on which the die is formed so that the top surface of the semiconductor wafer faces a bottom surface of the probe card on which the probe needles are provided; a driving device that drives the wafer chuck so that the dies sequentially contact the probe needles; an infrared camera that is provided at a predetermined height from the top surface of the probe card and that can capture an image of a field of view that includes at least a part of the top surface of the probe card; a digital signal processing device that converts the brightness distribution in the infrared image captured by the infrared camera into a temperature distribution; Including, The probe card has through holes formed on the bottom surface thereof so that the surface of the die contacted by the probe needles can be imaged by the infrared camera.

11. A semiconductor wafer testing method using the semiconductor testing device according to any one of claims 1 to 9 or the wafer prober according to claim 10, comprising: conducting an electrical test by contacting the probe needles with a die formed on the semiconductor wafer; the infrared camera imaging the surface of the die under electrical testing through a through-hole in the probe card; the digital signal processor detects the temperature of the die from the infrared image captured by the infrared camera; A semiconductor testing method including:

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