Temperature measurement method, wafer chuck, and temperature measurement system

Abstract

Provided are a temperature measurement method, a wafer chuck, and a temperature measurement system, whereby the wafer temperature of a wafer can be measured during probing. The temperature measurement method comprises: acquiring a plurality of chuck temperatures respectively detected by a plurality of temperature sensors of a wafer chuck having a holding surface for holding a wafer and the plurality of temperature sensors provided at positions of different distances from the holding surface in the depth direction; and deriving a wafer temperature of the wafer during probing on the basis of the plurality of chuck temperatures and the total thermal resistance value between the wafer chuck and the position at which the wafer temperature is derived.

Description

Temperature measurement method, wafer chuck, and temperature measurement system

[0001] This disclosure relates to a temperature measurement method, a wafer chuck, and a temperature measurement system.

[0002] A known method for testing wafers involves holding the wafer with a wafer chuck and then probing it with a prober.

[0003] Japanese Patent Publication No. 2019-169547

[0004] Probing causes the wafer temperature to change, and the temperature conditions during testing tend to be more stringent. Therefore, it is desirable to measure the wafer temperature in various ways, such as the surface of the wafer, a specific location within the wafer, and the temperature of devices formed on the wafer.

[0005] This disclosure aims to provide a temperature measurement method, a wafer chuck, and a temperature measurement system capable of measuring the wafer temperature of a wafer during probing.

[0006] To achieve the above objective, the temperature measurement method of the present disclosure acquires a plurality of chuck temperatures detected by each of the plurality of temperature sensors of a wafer chuck having a holding surface for holding a wafer and a plurality of temperature sensors provided at different depths from the holding surface, and derives the wafer temperature of the wafer during probing based on the plurality of chuck temperatures and the total thermal resistance value between the wafer chuck and the position from which the wafer temperature is derived.

[0007] To achieve the above objective, the wafer chuck of this disclosure includes a holding surface for holding a wafer, a bottom surface facing the holding surface and in contact with a temperature control plate for adjusting the temperature of the wafer, and a plurality of temperature sensors provided at positions at different depths from the holding surface.

[0008] To achieve the above objective, the temperature measurement system of the present disclosure comprises a wafer chuck having a holding surface for holding a wafer and a plurality of temperature sensors provided at different depths from the holding surface; a measurement unit that acquires a plurality of chuck temperatures detected by each of the plurality of temperature sensors and the total thermal resistance value between the wafer chuck and the position from which the wafer temperature is derived, and derives the wafer temperature of the wafer during probing based on the plurality of chuck temperatures and the total thermal resistance value between the wafer chuck and the position from which the wafer temperature is derived.

[0009] According to this disclosure, the wafer temperature of a wafer during probing can be measured.

[0010] This is a schematic diagram showing an example of the overall configuration of the wafer test system of the embodiment. This is a cross-sectional view of a part of the wafer chuck. This is a block diagram showing an example of the configuration of the temperature measurement system of the embodiment. This is a functional block diagram showing an example of the configuration of the control device of the embodiment. This is a diagram illustrating a method for deriving the total thermal resistance value during non-probing. This is a diagram illustrating a method for deriving the temperature of the measurement target position on the wafer during probing. This is a flowchart showing an example of the flow of measurement operations during non-probing by the control device of the embodiment. This is a flowchart showing an example of the flow of measurement operations during probing by the control device of the embodiment.

[0011] The embodiments of this disclosure will be described in detail below with reference to the drawings. It should be noted that these embodiments are not intended to limit the technology of this disclosure, and the configuration and operation are merely examples; they can be modified as needed without departing from the spirit of the present invention.

[0012] First, an example of the configuration of the wafer testing system 1 of this embodiment will be described. Figure 1 is a schematic diagram showing an example of the overall configuration of the wafer testing system 1. In the following description, an XYZ Cartesian coordinate system will be used, where the plane parallel to the wafer chuck 18 is the XY plane.

[0013] As shown in Figure 1, the wafer test system 1 comprises a prober 10, a tester 30, and a control device 50.

[0014] The prober 10 brings the probe 25 into contact with the electrodes of each chip on the wafer W. As shown in Figure 1, the prober 10 of this embodiment has a housing 12, a wafer moving mechanism 14, a wafer chuck 18, and a probe card 24. The wafer moving mechanism 14 and the wafer chuck 18 are housed in the housing 12.

[0015] The wafer moving mechanism 14 is mounted on the base 12B of the housing 12 and has a moving mechanism that moves the wafer chuck 18 in each of the three axes of X, Y, and Z, and a rotation mechanism that rotates around the Z axis. Since known technology can be applied to the wafer moving mechanism 14, a detailed explanation is omitted here.

[0016] The upper surface of the wafer chuck 18 is provided with a holding surface 18A for holding a wafer W. As an example, in this embodiment, the wafer chuck 18 holds the wafer W on the holding surface 18A by vacuum suction. The wafer W held by the wafer chuck 18 may be a single wafer or may have multiple chips formed on it.

[0017] The wafer chuck 18 is made of a material such as aluminum, copper, or ceramic with good thermal conductivity.

[0018] Furthermore, a temperature control plate 20 is provided inside the wafer chuck 18 as a heating or cooling source for heating or cooling the wafer W. Various types of temperature control plates can be used for the temperature control plate 20, such as a combination of a heater and a cooling plate, a double-layer structure with a heating layer of a surface heater and a cooling layer with passages for a cooling fluid, or a single-layer structure with a cooling pipe embedded in a heat conductor with a heating heater wrapped around it.

[0019] Furthermore, the wafer chuck 18 of this embodiment has a plurality of temperature sensors, as shown in Figure 2. Figure 2 is a cross-sectional view of a part of the wafer chuck 18. The temperature sensors S1 and S2 are provided between the holding surface 18A and the temperature control plate 20, and are provided at different distances in the depth direction from the holding surface 18A. Specifically, temperature sensor S1 is provided at a position close to the holding surface 18A, and temperature sensor S2 is provided at a position close to the temperature control plate 20. As an example, the temperature sensors S1 and S2 of this embodiment are aligned in the Z-axis direction. In other words, the XY coordinates of temperature sensor S1 and temperature sensor S2 are the same. It is preferable that the temperature sensors S1 and S2 are provided as far apart as possible in the depth direction (Z-axis direction in Figure 2) of the wafer chuck 18. It is also preferable that temperature sensor S1 is provided at a position close to the holding surface 18A of the wafer chuck 18. On the other hand, it is preferable that temperature sensor S2 is provided at a position close to the temperature control plate 20. Furthermore, it is preferable that the temperature sensors S1 and S2 are located below the measurement target position on the wafer W. However, if the in-plane temperature distribution of the wafer chuck 18 can be considered uniform, or if the temperature distribution is known, the temperature sensors S1 and S2 do not need to be located below the measurement target position on the wafer W.

[0020] For example, RTDs (Resistance Temperature Detectors) such as Pt sensors or TCs (Thermocouples) can be used as temperature sensors S1 and S2. Temperature sensors S1 and S2 detect the chuck temperature, which is the temperature of the wafer chuck 18. The detection results are acquired by the control device 50.

[0021] In this embodiment, the distance from the holding surface 18A to the temperature sensor S1 is an example of the first distance of this disclosure, and the temperature sensor S1 in this embodiment is an example of the first temperature sensor of this disclosure. Furthermore, the distance from the holding surface 18A to the temperature sensor S2 in this embodiment is an example of the second distance of this disclosure, and the temperature sensor S2 in this embodiment is an example of the second temperature sensor of this disclosure.

[0022] The wafer chuck 18 is mounted on the wafer moving mechanism 14. The wafer chuck 18 is movable in three axial directions (X-axis, Y-axis, and Z-axis direction) by the wafer moving mechanism 14, and is also rotatable in the rotational direction about the Z-axis.

[0023] A probe card 24 is positioned above the holding surface 18A of the wafer chuck 18. The probe card 24 is detachably attached to the opening in the top plate 12A of the housing 12.

[0024] The probe card 24 is equipped with probes 25. The probes 25 are positioned according to the electrode arrangement of the chip to be tested and are replaced depending on the chip being tested.

[0025] The tester 30 comprises a tester body 31 and an interface 32 provided on the tester body 31. The tester body 31 is held relative to the prober 10 by a support mechanism (not shown). The interface 32 electrically connects the terminals of the tester body 31 to the terminals of the probe card 24. The tester 30 supplies power and various test signals from the terminals of the probe card 24 to the chip on the wafer W and verifies whether the chip is functioning correctly by analyzing the signals output to the electrodes of the chip.

[0026] The control device 50 controls the operation of the entire prober 10. Also, as shown in Figure 3, the control device 50 in this embodiment is provided in the temperature measurement system 2 together with the wafer chuck 18. In the temperature measurement system 2, the control device 50 functions as an example of a measurement unit of the present disclosure that derives the wafer temperature of the wafer W during probing. In this embodiment, the control device 50 derives at least one of the following as the wafer temperature: the surface temperature of the wafer W, the temperature of a predetermined location within the wafer W, and the temperature of a device formed on the wafer W. The function of the control device 50 as a temperature measuring device will be described in detail.

[0027] Figure 3 is a block diagram showing an example of the configuration of the temperature measurement system 2 of this embodiment. As shown in Figure 3, the control device 50 of this embodiment includes a CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53, storage 54, an operation unit 56, a display unit 57, and a communication I / F (Interface) 58. The CPU 51, ROM 52, RAM 53, storage 54, operation unit 56, display unit 57, and communication I / F 58 are connected to each other via a bus 29 such as a system bus or a control bus, enabling the exchange of various information.

[0028] The CPU 51 is a central processing unit that executes various programs, such as the program 55 stored in the storage 54, and controls various parts. The ROM 52 stores various programs and data. The RAM 53 temporarily stores programs or data as a working area. The storage 54 is composed of a storage device such as an HDD (Hard Disk Drive), SSD (Solid State Drive), or flash memory, and stores various programs, such as the program 55, and various data.

[0029] The operation unit 56 is used by the user to input various information and instructions. The operation unit 56 is not particularly limited and may include, for example, various switches, a touch panel, a stylus, a mouse, and a microphone for voice input. The display unit 57 displays the results of wafer temperature derivation and various test results. The operation unit 56 and the display unit 57 may be integrated to form a touch panel display.

[0030] The communication interface 58 is an interface for connecting the control device 50 with the wafer chuck 18, etc. The communication interface 58 can use, for example, wired communication standards such as Ethernet (registered trademark) or FDDI (Fiber Distributed Data Interface), or wireless communication standards such as 4G, 5G, or Wi-Fi (registered trademark).

[0031] FIG. 4 shows an example of a functional configuration of the control device 50. As shown in FIG. 4, the control device 50 includes an acquisition unit 60, a temperature control unit 61, and a derivation unit 62. When the CPU 51 executes the program 55, it functions as the acquisition unit 60, the temperature control unit 61, and the derivation unit 62.

[0032] The acquisition unit 60 acquires the chuck temperature T detected by the temperature sensor S1 Ｓ１ . In addition, the acquisition unit 60 acquires the chuck temperature T detected by the temperature sensor S2 Ｓ２ .

[0033] The temperature control unit 61 controls the temperature of the wafer chuck 18 based on the chuck temperature T detected by the temperature sensor S1 Ｓ１ .

[0034] The derivation unit 62 derives the wafer temperature of the wafer W during probing based on the chuck temperatures T Ｓ１ and T Ｓ２ acquired by the acquisition unit 60, and the total thermal resistance R between the wafer chuck 18 and the position where the wafer temperature is to be derived ＴＯＴＡＬ . The position where the wafer temperature is derived is the measurement target position on the wafer W, for example, the surface of the wafer W.

[0035] As an example, the derivation unit 62 of the present embodiment derives the wafer temperature of the wafer W by linearly interpolating the chuck temperatures T Ｓ１ and T Ｓ２ . As an example, the derivation unit 62 of the present embodiment first derives the total thermal resistance R from the temperature sensor S2 to the measurement target position of the wafer W using the chuck temperatures T Ｓ１ and T Ｓ２ during idling, that is, during non-probing ＴＯＴＡＬ . Then, during testing, that is, during probing, the temperature T of the measurement target position on the wafer W is derived using the chuck temperatures T Ｓ１ , T Ｓ２ , and the total thermal resistance R ＴＯＴＡＬ . ＷＡＦ ＥＲ Hereinafter, the measurement method in the case where the measurement target position of the wafer W is the surface of the wafer W (the surface opposite to the side in contact with the holding surface 18A) will be described.

[0036] First, referring to Figure 5, the total thermal resistance value R during non-probing is ＴＯＴＡＬ The method for deriving this will be explained. Figure 5 shows an example of the temperature distribution in a thermally saturated state during non-probing. Note that Figure 5 shows a state where no chip is mounted on the wafer W, but the wafer W may or may not have a chip mounted on it. If a chip is mounted on the wafer W, the surface WA at the measurement target location will be the surface of the chip. If a chip is not mounted on the wafer W, the surface WA at the measurement target location will be the surface of the wafer W itself. In either case, the surface WA will be referred to as "the surface WA of the wafer W".

[0037] During non-probing phases, the wafer W is overheated by the temperature control plate 20 and heat is dissipated from the surface WA of the wafer W. In other words, the temperature control plate 20 acts as a high-temperature source, and the temperature tends to decrease as it approaches the surface WA of the wafer W. Therefore, the chuck temperature T of the temperature sensor S2 Ｓ２ The temperature sensor S1 measures the chuck temperature T. Ｓ１ It's higher than that.

[0038] Figure 5 shows T' ＷＡＦＥＲ T' is the surface temperature WA of wafer W during non-probing. Ｗ＿ＲＥＡＲ T' is the temperature of the wafer W on the wafer chuck 18 side (the side opposite the surface WA) during non-probing. Ｃ＿ＳＵＲＦ T' is the temperature of the holding surface 18A of the wafer chuck 18 during non-probing. Ｓ１ T' is the chuck temperature detected by the temperature sensor S1 during non-probing. Ｓ２ This is the chuck temperature detected by the temperature sensor S2 during non-probing. Note that T' in this embodiment ＷＡＦＥＲ However, this is an example of the first wafer temperature of this disclosure. Also, the chuck temperature T' of this embodiment. Ｓ１ This is an example of the first chuck temperature of the present disclosure, and the chuck temperature T' of this embodiment. Ｓ２ This is an example of the second chuck temperature of this disclosure.

[0039] Also, R ＷＡＦＥＲThis is the thermal resistance value of wafer W. ＣＯＮＴＡＣＴ This is the thermal contact resistance value between the wafer chuck 18 and the wafer W. ＣＨＵＣＫ This is the thermal resistance value from the temperature sensor S1 to the holding surface 18A.

[0040] Note that the thermal resistance value R ＣＨＵＣＫ This is a known value determined by material properties, design values, etc. Specifically, the thermal resistance value R ＣＨＵＣＫ This is obtained by the following equation (1). In the following equation (1), λ is the thermal conductivity of the wafer chuck 18. L is the distance between temperature sensor S1 and temperature sensor S2. S is the cross-sectional area of ​​the wafer chuck 18 between temperature sensor S1 and temperature sensor S2. ＣＨＵＣＫ = λ －１ ×L×S －１ (1)

[0041] For example, when the wafer chuck 18 is made of aluminum, λ = 240 W / mK and L = 0.005 m, and when the wafer is φ300, S = 0.070875 m. ２ Let's assume that this is the case. In this case, from equation (1) above, R ＣＨＵＣＫ = 2.94 × 10 －４ The value is °C / W.

[0042] From the above, the following relationships in equations (2) to (6) hold true. T' ＷＡＦＥＲ -T' Ｗ＿ＲＥＡＲ = Q' × R ＷＡＦＥＲ (2) T' Ｗ＿ＲＥＡＲ -T' Ｃ＿ＳＵＲＦ = Q' × R ＣＯＮＴＡＣＴ (3) T' Ｓ１ -T' Ｓ２ = Q' × R ＣＨＵＣＫ (4) T' ＷＡＦＥＲ -T' Ｓ２ = Q' × R ＴＯＴＡＬ (5) Caution ＴＯＴＡＬ =ΣR (6)

[0043] In this embodiment, the output section 62 outputs the chuck temperature T' obtained by the temperature sensor S1. Ｓ１ , Chuck temperature T' obtained by temperature sensor S2 Ｓ２ , and known thermal resistance value R ＣＨＵＣＫUsing this, the heat flux Q' during non-probing is derived from equation (4) above. Note that the value of the heat flux Q' is constant in equations (2) to (4) above.

[0044] During non-probing, the surface temperature WA of the wafer W can be measured using temperature sensors such as RTD, TC, and thermal radiation thermometers. Therefore, the surface temperature T' of WA can be measured. ＷＡＦＥＲ The measured value is obtained. The derivation section 62 is the temperature T' which is the measured value. ＷＡＦＥＲ , Chuck temperature T' obtained by temperature sensor S2 Ｓ２ Using the heat flux Q' obtained during non-probing as described above, the total thermal resistance R can be calculated from equation (5) above. ＴＯＴＡＬ Derive the following.

[0045] Next, referring to Figure 6, the temperature T of the measurement target location on the wafer W during probing. ＷＡＦＥＲ The method for deriving this will be explained. Figure 6 shows an example of the temperature distribution in a thermally saturated state during probing.

[0046] During probing, the wafer W generates heat due to the current voltage applied from the probe 25, so heating by the temperature control plate 20 is stopped or cooled. Therefore, the wafer W becomes the source of high temperature, and heat moves from the wafer W towards the temperature control plate 20. Consequently, during probing, the temperature of the wafer W is highest and tends to decrease as it approaches the temperature control plate 20. Therefore, the chuck temperature T of the temperature sensor S1 Ｓ１ The temperature sensor S2 measures the chuck temperature T. Ｓ２ It's higher than that.

[0047] Figure 6 shows T ＷＡＦＥＲ This is the temperature of the surface WA of the wafer W during probing. Ｗ＿ＲＥＡＲ This is the temperature of the wafer W on the wafer chuck 18 side during probing. Ｃ＿ＳＵＲＦ This is the temperature of the holding surface 18A of the wafer chuck 18 during probing. Ｓ１ This is the chuck temperature detected by the temperature sensor S1 during probing, and T Ｓ２This is the chuck temperature during probing detected by the temperature sensor S2. Note that the chuck temperature T in this embodiment is... Ｓ１ This is an example of the third chuck temperature of the present disclosure, and the chuck temperature T of this embodiment Ｓ２ This is an example of the fourth chuck temperature of this disclosure.

[0048] From the above, the following relationships in equations (7) to (10) hold true. ＷＡＦＥＲ -T Ｗ＿ＲＥＡＲ = Q × R ＷＡＦＥＲ (7) T Ｗ＿ＲＥＡＲ -T Ｃ＿ＳＵＲＦ = Q × R ＣＯＮＴＡＣＴ (8) T Ｓ１ -T Ｓ２ = Q × R ＣＨＵＣＫ (9) T ＷＡＦＥＲ -T Ｓ２ = Q × R ＴＯＴＡＬ (10) Furthermore, from equation (10) above, equation (11) below is obtained. ＷＡＦＥＲ = Q × R ＴＯＴＡＬ +T Ｓ２ (11)

[0049] In this embodiment, the output section 62 receives the chuck temperature T obtained by the temperature sensor S1. Ｓ１ The chuck temperature T obtained by the temperature controller S2 Ｓ２ , and the known thermal resistance value R as described above. ＣＨＵＣＫ Using this, the heat flux Q during probing is derived from equation (9) above. Note that the value of the heat flux Q is constant in equations (7) to (10) above.

[0050] The output section 62 receives the chuck temperature T obtained by the temperature sensor S2. Ｓ２ , and the total thermal resistance R derived from the heat flux Q during probing and the data from the non-probing period, as described above. ＴＯＴＡＬ Using the above (11), the temperature T of the surface WA of the wafer W during probing is obtained. ＷＡＦＥＲ You can obtain this.

[0051] Next, the measurement operations performed by the control device 50 during non-probing will be described. Figure 7 shows an example of the flow of measurement operations during non-probing. The measurement operations shown in Figure 7 are performed during non-probing to obtain the total thermal resistance value RＴＯＴＡＬ is executed to derive.

[0052] In step S100 of FIG. 7, the acquisition unit 60 acquires the chuck temperature T' detected by the temperature sensor S1 Ｓ１ and starts acquisition thereof.

[0053] In the next step S102, the temperature control unit 61 controls the chuck temperature T' Ｓ１ based on which the temperature of the temperature adjustment plate 20 is adjusted, thereby starting control of the temperature of the wafer chuck 18.

[0054] In the next step S104, the temperature control unit 61 loads the wafer W to be probed onto the wafer chuck 18. As a result, the wafer W is held on the holding surface 18A of the wafer chuck 18. At this time, since the wafer W is at normal temperature, the temperature of the wafer chuck 18 decreases.

[0055] Therefore, in the next step S106, the temperature control unit 61 determines whether the chuck temperature T' Ｓ１ based on which it is determined whether the temperature of the wafer chuck 18 has stabilized. The determination in step S106 is a negative determination until the temperature stabilizes. On the other hand, when the temperature stabilizes, the determination in step S106 becomes an affirmative determination, and the process proceeds to step S108.

[0056] In step S108, the acquisition unit 60 acquires the temperature T' of the surface WA of the wafer W ＷＡＦＥＲ . Note that the method by which the acquisition unit 60 acquires the temperature T' ＷＡＦＥＲ is not limited. For example, the acquisition unit 60 may acquire the temperature T' ＷＡＦＥＲ from a temperature sensor that detects the temperature T'. Further, for example, when a user inputs the actually measured temperature T' ＷＡＦＥＲ using the operation unit 56 of the control device 50, the acquisition unit 60 may acquire the input temperature T' ＷＡＦＥＲ .

[0057] In the next step S110, the acquisition unit 60 acquires the chuck temperature T' detected by the temperature sensor S2 Ｓ２ .

[0058] In the next step S112, the derivation unit 62 derives the chuck temperature T' as described aboveＳ１ Chuck temperature T' Ｓ２ , and known thermal resistance value R ＣＨＵＣＫ Using this, the heat flux Q' during non-probing is derived from equation (4) above.

[0059] In the next step S114, the derivation section 62 calculates the total thermal resistance value R. ＴＯＴＡＬ The following is derived. As described above, the derivation unit 62 determines the temperature T' of the surface WA. ＷＡＦＥＲ Chuck temperature T' Ｓ２ Using the heat flux Q' derived in step S112 above, the total thermal resistance R can be obtained from equation (5) above. ＴＯＴＡＬ The derivation unit 62 derives the total thermal resistance value R. ＴＯＴＡＬ This is stored in storage 54.

[0060] Thus, according to the control device 50 of this embodiment, the total thermal resistance value R is determined during the non-probing process by the processing in steps S100 to S114. ＴＯＴＡＬ You can obtain this.

[0061] Next, the measurement operations performed by the control device 50 during probing will be described. Figure 8 shows an example of the flow of measurement operations during probing. The measurement operations shown in Figure 8 involve the temperature T of the surface WA of the wafer W during probing. ＷＡＦＥＲ This is performed to derive the result. During probing, the probe 25 applies current and voltage to the tip of the wafer W, causing the wafer W to heat up.

[0062] In step S200 of Figure 8, the acquisition unit 60 receives the chuck temperature T from the temperature sensor S1. Ｓ１ The temperature sensor S2 is used to obtain the chuck temperature T Ｓ２ Obtain it.

[0063] In the next step S202, the lead-out section 62, as described above, chuck temperature T Ｓ１ Chuck temperature T Ｓ２ , and known thermal resistance value R ＣＨＵＣＫ Using this, the heat flux Q during probing is derived from equation (9) above.

[0064] In the next step S204, the derivation unit 62 determines the temperature T of the surface WA of the wafer W. ＷＡＦＥＲThe following is derived. As described above, the derivation section 62 is used to determine the chuck temperature T Ｓ２ , the heat flux Q derived in step S202 above, and the total thermal resistance value R stored in storage 54. ＴＯＴＡＬ Using the above (11), the temperature T of the surface WA of the wafer W during probing is obtained. ＷＡＦＥＲ Derive the following.

[0065] Thus, according to the control device 50 of this embodiment, the temperature T of the surface WA of the wafer W during probing is determined by the processing in steps S200 to S202. ＷＡＦＥＲ You can obtain this.

[0066] As described above, in the temperature measurement method of the above embodiment, the acquisition unit 60 of the control device 50 acquires a plurality of chuck temperatures detected by each of the temperature sensors S1 and S2 of the wafer chuck 18, which has a holding surface 18A for holding the wafer W and temperature sensors S1 and S2 provided at positions with different depths from the holding surface 18A. Then, the derivation unit 62 acquires the total thermal resistance value R between the plurality of chuck temperatures and the wafer chuck 18 and the position from which the wafer temperature is derived. ＴＯＴＡＬ Based on this, the wafer temperature T of wafer W during probing is determined. ＷＡＦＥＲ Derive the following.

[0067] According to the temperature measurement method described above, the wafer temperature of wafer W during probing can be derived by using multiple chuck temperatures detected by temperature sensors S1 and S2 and performing linear interpolation or the like. Therefore, according to the temperature measurement method of this embodiment, the wafer temperature of wafer W during probing can be measured.

[0068] In addition, as an alternative method to this embodiment for measuring the temperature of the wafer chuck 18 during probing, it is also possible to detect heat flow by using a heat flux sensor. However, if the heat flux sensor uses thermocouples connected in series, the temperature measuring part must be insulated, which adds to the labor involved in embedding it in the wafer chuck 18. Furthermore, if the sensor is in sheet form, the measurement in the depth direction of the wafer chuck 18 will be insufficient, resulting in discrepancies in the calculation results at locations far from the sheet.

[0069] In contrast, according to the temperature measurement method of this embodiment, it is sufficient to embed at least two temperature sensors (S1, S2) in the wafer chuck 18, thus reducing the man-hours required for embedding. Furthermore, by increasing the number of temperature sensors embedded, the measurement accuracy can be improved.

[0070] Furthermore, according to the temperature measurement method of this embodiment, since temperature sensors S1 and S2 are provided at positions with different distances in the depth direction, the wafer temperature of the wafer W during probing can be measured accurately even when the wafer W or wafer chuck 18 expands due to heat.

[0071] Furthermore, the thermal contact resistance value R between the wafer chuck 18 and the wafer W is also present. ＣＯＮＴＡＣＴ This value is difficult to calculate using physical quantities and changes depending on the state of both the wafer chuck 18 and the wafer W. In contrast, in the temperature measurement method of the above embodiment, the chuck temperature T' detected by the temperature sensor S1 during non-probing is... Ｓ１ The temperature sensor S2 detected the chuck temperature T' Ｓ２ , and the known value of thermal resistance R ＣＨＵＣＫ From the total thermal resistance value R ＴＯＴＡＬ This is derived. Therefore, according to the temperature measurement method of the above embodiment, the total thermal resistance value R ＴＯＴＡＬ This can be easily and accurately obtained.

[0072] In the above embodiment, a configuration was described in which the temperature sensors S1 and S2 are provided on the wafer chuck 18 side by side in the Z-axis direction. However, if the temperature distribution in the in-plane direction of the wafer chuck 18 can be considered uniform, or if the temperature distribution is known, the temperature sensors S1 and S2 do not need to be provided side by side in the Z-axis direction. In other words, the positions of the temperature sensors S1 and S2 in the in-plane direction may be different.

[0073] Furthermore, although the above embodiment describes a configuration in which the wafer chuck 18 is equipped with two temperature sensors, S1 and S2, the wafer chuck 18 may be equipped with three or more temperature sensors. For example, the wafer chuck 18 may be equipped with three or more temperature sensors located at different positions in the depth direction. In this case, instead of equations (2) to (11) above, the wafer temperature of the wafer W during probing can be measured accurately by using a linear approximation formula or a polynomial approximation formula corresponding to the number of temperature sensors. Also, for example, the wafer chuck 18 may be equipped with multiple sets of two or more temperature sensors located at different positions in the depth direction within its surface. In this case, even if there is a variation in temperature within the surface of the wafer chuck 18, the wafer temperature of the wafer W during probing can be measured accurately.

[0074] Furthermore, if the wafer chuck 18 is equipped with at least one temperature sensor in the in-plane direction to detect and control the temperature in the in-plane direction, the temperature sensor can be used in conjunction with the temperature sensor of the above embodiment that is provided for measuring the wafer temperature of the wafer W during probing. For example, the temperature sensor S1 of the above embodiment may also be used as a temperature sensor for detecting and controlling the temperature in the in-plane direction.

[0075] Furthermore, although the above embodiment describes a configuration in which the program 55 is pre-stored (installed) in the storage 54, the invention is not limited to this. The program 55 may be provided in a form recorded on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Read Only Memory), or USB (Universal Serial Bus) memory. Alternatively, the program 55 may be provided in a form that is downloaded from an external device via a network.

[0076] 1 Wafer test system 2 Temperature measurement system 10 Probe 12 Housing, 12A Top plate, 12B Base 14 Wafer movement mechanism 18 Wafer chuck 18A Holding surface 20 Temperature control plate 24 Probe card 25 Probe 30 Tester 31 Tester body 32 Interface 50 Control unit 51 CPU 54 Storage 55 Program 60 Acquisition unit 62 Output unit S1, S2 Temperature sensor T Ｓ１ , T Ｓ２ Chuck temperature W Wafer, WA Surface

Claims

1. A temperature measurement method for a wafer chuck having a holding surface for holding a wafer and a plurality of temperature sensors provided at different depths from the holding surface, acquiring a plurality of chuck temperatures detected by each of the plurality of temperature sensors, and deriving the wafer temperature of the wafer during probing based on the plurality of chuck temperatures and the total thermal resistance value between the wafer chuck and the position from which the wafer temperature is derived.

2. The temperature measurement method according to claim 1, wherein the wafer temperature is determined to be at least one of the following: the temperature of the surface of the wafer, the temperature of a predetermined location within the wafer, and the temperature of a device formed on the wafer.

3. The temperature measurement method according to claim 1, wherein the plurality of temperature sensors include a first temperature sensor whose distance is a first distance and a second temperature sensor whose distance is a second distance longer than the first distance, and during non-probing, the first chuck temperature detected by the first temperature sensor, the second chuck temperature detected by the second temperature sensor, and the first wafer temperature which is the temperature of the wafer to be measured, are acquired, the total thermal resistance value from the second temperature sensor to the measurement target position is derived using the thermal resistance value of the wafer chuck between the first temperature sensor and the second temperature sensor, the first chuck temperature, the second chuck temperature, and the first wafer temperature, and during probing, the third chuck temperature detected by the first temperature sensor and the fourth chuck temperature detected by the second temperature sensor, and the temperature of the wafer to be measured position during probing is derived using the third chuck temperature, the fourth chuck temperature, the thermal resistance value of the wafer chuck, and the total thermal resistance value.

4. The temperature measurement method according to claim 3, comprising deriving the heat flux during non-probing using the thermal resistance value of the wafer chuck, the first chuck temperature, and the second chuck temperature, and deriving the total thermal resistance value using the heat flux and the first wafer temperature.

5. The temperature measurement method according to claim 3, wherein the heat flux during probing is derived using the third chuck temperature, the fourth chuck temperature, and the thermal resistance value of the wafer chuck, and the temperature of the measurement target position of the wafer during probing is derived using the heat flux, the fourth chuck temperature, and the total thermal resistance value.

6. A wafer chuck comprising: a holding surface for holding wafers; and a plurality of temperature sensors provided between the holding surface and a temperature control plate provided inside for adjusting the temperature of the wafer, and positioned at different depths from the holding surface.

7. A temperature measurement system comprising: a wafer chuck having a holding surface for holding a wafer and a plurality of temperature sensors provided at different depths from the holding surface; a measuring unit that acquires a plurality of chuck temperatures detected by each of the plurality of temperature sensors and the total thermal resistance value between the wafer chuck and the position from which the wafer temperature is derived; and derives the wafer temperature of the wafer during probing based on the plurality of chuck temperatures and the total thermal resistance value between the wafer chuck and the position from which the wafer temperature is derived.

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