Calibration device, corresponding calibration method, and calibration equipment

Abstract

The present invention provides a calibration device and corresponding calibration method for calibrating a chuck, and a calibration instrument, including a calibration card (6) attachable to or within an insertion opening (E) of a wafer prober (1), forming a corresponding substantially closed space when the calibration card (6) is attached, calibration temperature probes (60, 61) attached to the calibration card (6), and a chuck (3) for carrying a wafer (4), the chuck (3) being temperature-controlled to a set temperature by a temperature controller (300) and movable in a lateral direction (x, y) and a height direction (z) by a position controller (350), and a temperature probe (60, 61) mounted on or above the surface (O) of the chuck (3). and an evaluation device (600) connectable to the calibration temperature probes (60, 61), the temperature controller (300), and the position controller (350), the evaluation device (600) being configured to calibrate temperature output values ​​of the one or more temperature probes (S1-S9) based on the current temperatures at the various positions detected by the calibration temperature probes (60, 61).

Description

Technical Field

[0001] The present invention relates to a calibration device and a corresponding calibration method for calibrating a chuck arranged in a wafer prober, and a corresponding calibration instrument.

Background Art

[0002] Today, the functional test of circuits (microchips) incorporated in wafers is carried out on a temperature-controlled chuck of a wafer prober between -60°C and +300°C, and its scale is becoming larger and larger.

[0003] FIG. 7 shows a typical wafer prober device.

[0004] In FIG. 7, reference numeral 1 denotes a wafer prober having a housing 2 with an insertion opening E for removably inserting a test card 5. The test card 5 is sealed from the housing 2 by, for example, a sealing device 10, so that a substantially closed space is formed in the wafer prober 1 when the test card 5 is inserted. The test card 5 has a plurality of test probes 50 (test needles) for testing the wafer 4 or an integrated circuit (not shown) disposed on the upper surface O' of the wafer 4.

[0005] In the space 2, a temperature-controlled chuck 3 for mounting the wafer 4 on the upper side O of the chuck 3 is arranged, and the chuck can be moved in the lateral directions x, y and the height direction z via an adjustment device 30 by a position controller 350. In this case, the directions x, y, z form an orthogonal Cartesian coordinate system.

[0006] Through the temperature controller 300, the temperature of the chuck 3 can be temperature-controlled to the set temperature by a heating device (not shown) and a cooling device (not shown). In particular, the cooling device is used to achieve a temperature lower than room temperature. Inside the chuck 3, a temperature probe S0 is arranged to detect and output the current chuck temperature, and the output value is sent to the temperature controller 300 and displayed by an output device 310 (e.g., a display) connected to the temperature controller 300. Also, the temperature probe S0 can be used by the temperature controller 300 for temperature adjustment.

[0007] Reference numeral 700 represents a probe controller, and the probe controller is connected to the temperature controller 300, the position controller 350, and the test controller 500. The test controller is used to control a test probe 50 (test needle).

[0008] Through the probe controller 700 and the test controller 500, a test program can be executed. Accordingly, the test controller 500 controls the test probe 50 with corresponding test performance. Further, through the probe controller 700, the respective set temperatures of the temperature controller 300 and the respective set positions of the position controller 350 can be specified. The corresponding connection lines between the components 5, 500, 700, 300, 310, 3, and 350 are established via, for example, corresponding bus lines and / or analog lines.

[0009] So far, the temperature accuracy of the local chuck temperature achievable by each integrated circuit has been about 2 °C or more. However, in the new technology, a high temperature accuracy of 0.1 °C or less is required. Such temperature accuracy can be achieved only by calibrating the test settings (chuck, wafer probe, test card) used.

[0010] The most common method for this is the so-called measurement wafer. This (standard silicon) measurement wafer contains a number of temperature sensors (usually 13 to 17). These temperature sensors are connected to an evaluation unit. In this way, the temperature probe can be calibrated. The measurement wafer is placed on the chuck, and the temperature accuracy and temperature distribution are displayed.

[0011] Another method is to place a single sensor (drop sensor) at various temperature measurement points. The determined values are then (usually manually) entered into the correction table of the temperature controller.

[0012] The disadvantage of the measurement wafer is that there are multiple sensors or probes, and the accuracy is limited by their mutual deviation. Similarly, such measurement wafers are usually very expensive.

[0013] The disadvantages of the drop sensor are that the measurement takes time and there is inaccuracy when placing the drop sensor on the surface of the chuck to be measured.

[0014] However, the main disadvantage of both methods (and all other methods known so far) is that the accuracy of the chuck temperature is determined under the influence of an environment different from that during the actual chip test. In most cases, the wafer is placed on a chuck far from the calibration position, and in the subsequent measurement position, it is not even possible to apply a drop sensor.

[0015] This means that it is actually impossible to accurately determine at which exact position and what temperature exists under the microchip being tested during the probing process of the microchip. However, this is exactly the temperature value required during the test. So far, this value has been accurate enough to assume that it is not very different from the value determined by the measurement wafer. However, the accuracy required today is no longer sufficient for this.

[0016] According to German Patent Application Publication No. 102009030471, a calibration method for calibrating a chuck and a corresponding calibration device are known. The chuck provided here is for receiving and holding a test substrate and is equipped with a device for receiving and holding a calibration substrate. The chuck includes a first receiving surface for receiving the test substrate and a second receiving surface for receiving the calibration substrate that is laterally offset with respect to the first receiving surface. The calibration substrate has a planar calibration standard for calibrating the measuring unit of a wafer prober, and below the calibration substrate, a dielectric material or air is arranged at least within the region of the calibration standard. In order to be able to take into account the actual thermal conditions of the test substrate, in particular the thermal influence on known and unknown calibration standards and the electrical behavior of the calibration standards used, it has been proposed to equip the second receiving surface with temperature control means for the calibration substrate.

Summary of the Invention

[0017] The present invention provides a calibration device according to claim 1, a corresponding calibration method according to claim 11, and a calibration device according to claim 15.

[0018] Preferred further embodiments are the subject matter of the respective dependent claims.

[0019] The idea underlying the present invention is a calibration card that can be attached to or integrated into the insertion opening for a test card of a wafer prober, and when the calibration card is attached, a corresponding substantially closed space is formed, as when the test card is inserted, to provide a calibration device having the calibration card.

[0020] The calibration device has a calibration temperature probe attached to the calibration card, and the chuck is accessible using the chuck's position controller so as to be able to detect the respective current temperatures at various positions on the surface of the chuck or on the surface of a wafer mounted on the chuck.

[0021] The calibration machine further includes an evaluation device connectable to a calibration temperature probe, a temperature controller, and a position controller, and is configured to calibrate the temperature output values of one or more temperature probes based on the current temperatures at various positions detected by the calibration temperature probe.

[0022] Advantageously, the chuck temperature can be tested under exactly the same environmental conditions as those in which the microchip will later be actually measured. The temperature probe in the chuck can be calibrated without being removed, and the calibration temperature probe can be easily calibrated independently of the temperature probe in the chuck. The labor in manufacturing is significantly less than that for known wafers for measurement. Human errors in the repetition of the drop sensor method can be eliminated by an automatic machine contact process. By connecting all components to appropriate software, complete automatic calibration becomes possible. The calibrated temperature probe in the chuck enables permanent monitoring of the temperature distribution during the test. Similarly, these temperature probes in the chuck can also accurately report the chuck temperature back to the wafer probe disposed under each chip being tested within each temperature detection sector.

[0023] Therefore, the present invention enables complete calibration related to the position of the chuck and repeated verification of those values by re - calibration. The present invention is suitable for industrial applications due to its robust design and is economical due to the components used.

[0024] According to a further preferred further development, the temperature detection device has a single temperature probe, and the evaluation device is configured to calibrate the temperature output value of the single temperature probe based on the current temperatures at various positions detected by the calibration temperature probe. This enables a particularly simple configuration.

[0025] According to a further preferred embodiment, the temperature detection device has a plurality of temperature probes, and each temperature probe is assigned a temperature detection sector in the chuck for detecting and outputting the respective current chuck temperature. The evaluation device is configured to calibrate the temperature output value of each temperature probe based on the current temperature of the assigned temperature detection sector detected by the calibration temperature probe. Thereby, the local chuck temperature can be recorded particularly accurately.

[0026] According to another preferred embodiment, the temperature controller includes a memory device, and the evaluation device is configured to store the calibrated temperature output values of one or more temperature probes at various positions within the memory device.

[0027] According to another preferred embodiment, the temperature controller includes an output device, particularly a display device, for outputting the calibrated temperature output values of one or more temperature probes at various positions.

[0028] According to another preferred embodiment, the calibration temperature probe has a shaft passing through a calibration card and a thermal resistor, preferably a Pt100 thermal resistor, attached to an end of the shaft.

[0029] According to another preferred embodiment, the calibration temperature probe has a non-contact infrared sensor. Thereby, direct surface contact is avoided.

[0030] According to another preferred embodiment, the calibration temperature probe has a measurement accuracy in the range of 1 mK to 10 mK, particularly 1 mK to 5 mK, and / or the calibration temperature probe has an area detection range in the range of 10 mm 2 ~20 mm 2 Thereby, the chuck temperature can be detected with high accuracy.

[0031] According to a further preferred embodiment, the temperature controller is configured to adjust the set temperature using at least one calibrated temperature probe. This eliminates the need for individual adjustment probes and provides accurate adjustment values.

[0032] According to another preferred embodiment, the calibration card is integrally incorporated with the test card. Thus, the calibration temperature probe and the test probe are included on one and the same card, eliminating the need to replace the card.

[0033] According to a further preferred embodiment, the calibrated temperature probe has a height-adjustable shaft guided through the calibration card. This avoids interference from the calibrated temperature probe and the test probe.

[0034] Embodiments of the present invention will be shown in the drawings and described in more detail in the following description.

Brief Description of the Drawings

[0035]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0036] In these drawings, the same reference numerals represent the same or functionally identical components.

Embodiments for Carrying Out the Invention

[0037] Figure 1a shows a calibration device according to a first embodiment of the present invention in an initial state before calibration, and Figure 1b shows the calibration device according to the first embodiment of the present invention in a calibration state during calibration.

[0038] The illustration of the calibration device according to the first embodiment shown in Figures 1a and 1b is similar to the wafer prober 1 shown in Figure 7, but here, instead of the test card 5 having the test probes 50, a calibration card 6 is installed in the insertion opening E. In addition, the test controller 500 is not shown as it is not necessary for calibration.

[0039] The calibration card 6 is also sealed from the container 2, for example, via the sealing device 10, so that when the calibration card 6 is installed, a corresponding substantially closed space is formed.

[0040] In other embodiments not shown, the calibration card 6 can also be installed and sealed at an insertion opening E that is laterally spaced from the insertion opening E.

[0041] Depending on the design of the calibration card 6, the size of the corresponding closed space may be slightly different from the size of the closed space when the test card 5 is inserted, but since this has nothing to do with the ambient conditions around the chuck 3 during calibration, these ambient conditions correspond to the ambient conditions during testing.

[0042] Calibration temperature probes 60 and 61 are attached to the calibration card 6, and in the calibration mode, the chuck 3 can be approached using the position controller 300 so that the calibration temperature probes 60 and 61 can detect the respective current temperatures at various positions on the surface O of the chuck 3.

[0043] In the first embodiment, the calibration temperature probes 60, 61 have a shaft 60 passing through the calibration card 6, and at the end thereof, a resistor 61 in the form of a Pt100 resistor is (e.g., elastically) attached in the space 2.

[0044] The calibration temperature probes 60, 61 are connected to an evaluation device 600, and the evaluation device 600 is also connected to a temperature controller 300 and a probe controller 700. The evaluation device 600 is set to calibrate the temperature output values of the plurality of temperature probes S1 to S9 based on the current temperatures at various positions detected by the calibration temperature probes 60, 61. In this embodiment, the plurality of temperature probes S1 to S9 are arranged in the chuck 3 instead of a single temperature probe S0 (see FIG. 2). Similar to the test mode, the corresponding calibration mode can be controlled or input by the probe controller 700. The probe controller 700 is connected to the evaluation device 600 via a network connection and / or an analog connection, similar to FIG. 7, and in the same way, the evaluation device 600 is also connected to the temperature controller 300.

[0045] The temperature controller 300 also includes a non-volatile memory device 310 capable of storing the calibrated temperature output values of the temperature probes S1 to S9 at various positions on the chuck 3.

[0046] FIG. 2 shows a schematic plan sectional view of the chuck of the first embodiment along the line A - A' of FIGS. 1a and 1b.

[0047] Figure 2 shows the arrangement of temperature probes S1 to S9 in the chuck 3. Each of the temperature probes S1 to S9 is assigned corresponding temperature detection sectors B1 to B9 in the chuck 3, and these temperature detection sectors B1 to B9 detect and output their respective current chuck temperatures. The output device 600 is configured to calibrate the temperature output values of the respective temperature probes S1 to S9 based on the current temperatures detected by the associated calibrated temperature probes 60, 61 of the temperature detection sectors B1 to B9, and store them in the memory device 310 of the temperature controller 300.

[0048] The adjustment of the input set temperature by the temperature controller 300 is performed using an adjustment probe (not shown) or using one or more calibrated temperature sensors S1 to S9. Here, in each of the temperature sensing sectors B1 to B9, it is possible to perform the adjustment using the respectively assigned temperature probes S1 to S9. Another possibility for adjustment is to perform the adjustment on the average value of all the temperature sensors S1 to S9 or only on the adjacent temperature sensors S1 to S9.

[0049] Figure 3 shows the calibration method according to the second embodiment of the present invention.

[0050] In the calibration method according to Figure 3, in step S1, a wafer prober 1 is provided having an insertion opening E for inserting a test card 5 having a test probe 50 for testing an integrated circuit located on the wafer 4, the insertion opening E being such that a substantially closed space is formed when the test card 5 is inserted.

[0051] In step S2, a chuck 3 is provided which can be temperature-controlled to a set temperature adjustable by the temperature controller 300 for mounting the wafer 4. The chuck 3 is movable in the lateral directions x, y and the height direction z by a position controller 350.

[0052] In step S3, a temperature detection device disposed within the chuck 3 is provided, which has one or more temperature probes S1 to S9 and detects and outputs the respective current chuck temperatures at the positions of the respective temperature probes S1 to S9.

[0053] In step S4, the calibration card 6 is attached within the insertion opening E or to the insertion opening E. In this step S4, when the calibration card 6 is attached, a corresponding substantially closed space is formed, and calibration temperature probes 60, 61 are attached to the calibration card 6.

[0054] In step S5, the position controller 350 is used to move the chuck 3 close to the calibration temperature probes 60, 61, and the calibration temperature probes 60, 61 are used to detect the respective current temperatures at various positions on the surface O of the chuck 3.

[0055] In step S6, calibration of the temperature output values of the one or more temperature probes S1 to S9 is performed based on the current temperatures at various positions detected by the calibration temperature probes 60, 61.

[0056] In step S7, the calibrated temperature output values of the one or more temperature probes (S1 to S9) at various positions are stored, for example, into the memory device 310 of the temperature controller 300 and / or into the probe controller 700.

[0057] FIG. 4 shows the calibration device according to the third embodiment of the present invention in the initial state.

[0058] The third embodiment according to FIG. 4 is different from the first embodiment in that, in the calibration mode, although the current temperature at each of various positions on the surface O of the chuck 3 is not determined, the current temperature at each of various positions on the surface O' of the wafer 4 mounted on the chuck 3 is detected while the wafer 4 is mounted on the chuck 3. This makes it possible to take into account the heat transfer resistance that may exist between the chuck 3 and the mounted wafer 4, and thus enables the temperature in the integrated circuit being tested to be determined more accurately.

[0059] In other respects, the third embodiment is the same as the first embodiment.

[0060] FIG. 5 shows a calibration apparatus according to a fourth embodiment of the present invention in an initial state.

[0061] In the fourth embodiment, the calibration card 6 is integrally integrated with the test card 5 (i.e., integrated therein). In this embodiment, the calibration temperature probes 60', 61 have a shaft 60' that passes through the calibration card 6 or the test card 5 so as to be height adjustable. The corresponding height adjustment can be performed, for example, by an adjustment device 69. By this height adjustment function, the calibration temperature probes 60', 61 configured in the same manner as in the first embodiment have the effect that they do not interfere with the test probe 50 in the test mode and can be retracted upward and position-adjusted behind the test probe 50.

[0062] This embodiment has the particular advantage that it is not necessary to replace the test card 5 and the calibration card 6, and it is only necessary to switch from the test mode to the calibration mode by the probe controller 700.

[0063] FIG. 6 shows a calibration apparatus according to a fifth embodiment of the present invention in an initial state.

[0064] In the fifth embodiment, the calibration card 6 is also integrated integrally with the test card 5. In this embodiment, the calibration temperature probe 65 is a non-contact infrared sensor 65 connected to the evaluation device 600. As a result, direct surface contact with the surface O' of the wafer 4 or the surface O of the chuck 3 can be avoided, and the height adjustment function as in the fourth embodiment can be omitted.

[0065] Thereby, an additional advantage is obtained that calibration or temperature measurement by the calibration temperature probe 65 can be performed on-site during the test.

[0066] In other respects, the fifth embodiment is the same as the fourth embodiment.

[0067] Although the present invention has been described with reference to the preferred embodiments above, the present invention is not limited to these and various modifications are possible.

[0068] In particular, the number and arrangement of the temperature probes in the chuck, and the type of the temperature probe are merely illustrative and are not limited to the examples shown.

Claims

1. A calibration device for calibrating a chuck, comprising: a wafer prober (1) having an insertion opening (E) for inserting a test card (5) having a test probe (50) for testing an integrated circuit located on a wafer (4), the insertion opening (E) forming a substantially closed space when the test card (5) is inserted; a chuck (3) for mounting the wafer (4), the chuck (3) being temperature-controlled to a set temperature adjustable by a temperature controller (300) and movable in the lateral directions (x, y) and the height direction (z) by a position controller (350) via an adjustment device (30); a temperature detection device disposed within the chuck (3), the temperature detection device having one or more temperature probes (S1 to S9) for detecting and outputting the current chuck temperature at the positions of the respective temperature probes (S1 to S9); calibration equipment (6, 60, 61, 600), comprising: a calibration card (6) attachable within or to the insertion opening (E), the calibration card (6) forming a corresponding substantially closed space when attached; calibration temperature probes (60, 61; 60', 61; 65) attached to the calibration card (6), the chuck (3) being accessible via the adjustment device (30) using the position controller (350) so as to be able to detect the current temperature at various positions on the surface (O) of the chuck (3) or on the surface (O') of the wafer (4) mounted on the chuck (3); an evaluation device (600) connected to the calibration temperature probes (60, 61; 60', 61; 65), the temperature controller (300) and the position controller (350), the evaluation device (600) being set to calibrate the temperature output values of the one or more temperature probes (S1 to S9) based on the current temperatures at the various positions detected by the calibration temperature probes (60, 61; 60', 61; 65); and the calibration equipment (6, 60, 61, 600); and a calibration device.

2. The temperature detection device includes a single temperature probe, and the evaluation device (600) is set to calibrate the temperature output value of the single temperature probe based on the current temperatures at the various positions detected by the calibration temperature probes (60, 61; 60', 61; 65). The calibration device according to claim 1.

3. The temperature detection device includes a plurality of temperature probes (S1 to S9), and each temperature probe (S1 to S9) is assigned a temperature detection sector (B1 to B9) for detecting and outputting the respective current chuck temperature within the chuck (3). The evaluation device (600) is set to calibrate the temperature output value of each of the temperature probes (S1 to S9) based on the current temperatures for the assigned temperature detection sectors (B1 to B9) detected by the calibration temperature probes (60, 61; 60', 61; 65). The calibration device according to claim 1.

4. The temperature controller (300) includes a memory device (310), and the evaluation device (600) is set to store the calibrated temperature output values of the one or more temperature probes (S1 to S9) at the various positions within the memory device (310). The calibration device according to any one of claims 1 to 3.

5. The temperature controller (300) includes an output device (320), particularly a display device, for outputting the calibrated temperature output values of the one or more temperature probes (S1 to S9) at the various positions. The calibration device according to any one of claims 1 to 4.

6. The calibration temperature probes (60, 61; 60', 61; 65) have a shaft (60) passing through the calibration card (6), and a thermal resistor (61) is attached to an end of the shaft (60). The calibration device according to any one of claims 1 to 5.

7. The calibration temperature probes (60, 61; 60', 61; 65) include non-contact infrared sensors. The calibration device according to any one of claims 1 to 6.

8. The calibration temperature probe (60, 61; 60', 61; 65) has a measurement accuracy in the range of 1 mK to 10 mK, and / or the calibration temperature probe (60, 61; 60', 61; 65) has an area detection range in the range of 10 mm ２ to 20 mm ２ The calibration device according to any one of claims 1 to 7, which has an area detection range.

9. The temperature controller (300) is set to adjust the set temperature using at least one of the calibrated temperature probes (S1 to S9). The calibration device according to any one of claims 1 to 8.

10. The calibration device according to any one of claims 1 to 9, wherein the calibration card (6) is integrally integrated with the test card (5).

11. The calibration device according to claim 9 or 10, wherein the calibration temperature probes (60, 61; 60', 61; 65) include a shaft (60') that passes through the calibration card (6) in a height-adjustable manner.

12. A calibration method for calibrating a chuck, comprising: providing a wafer prober (1) having an insertion opening (E) for inserting a test card (5) having a test probe (50) for testing an integrated circuit located on a wafer (4), the insertion opening (E) forming a substantially closed space when the test card (5) is inserted (step S1); providing a chuck (3) for mounting the wafer (4), the chuck (3) being temperature-controlled to a set temperature that can be set by a temperature controller (300) and being movable in the lateral directions (x, y) and the height direction (z) by a position controller (350) via an adjustment device (30) (step S2); providing a temperature detection device disposed within the chuck (3), the temperature detection device having one or more temperature probes (S1 to S9) for detecting and outputting the respective current chuck temperatures at the positions of the respective temperature probes (S1 to S9) (step S3); attaching a calibration card (6) within or to the insertion opening (E), the calibration card (6) being attached to form a corresponding substantially closed space and having calibration temperature probes (60, 61; 60', 61; 65) attached thereto (step S4); using the position controller (350) to move the chuck (3) close to the calibration temperature probes (60, 61; 60', 61; 65) via the adjustment device (30), and using the calibration temperature probes (60, 61; 60', 61; 65) to detect the respective current temperatures at various positions on the surface (O) of the chuck (3) or on the surface (O') of the wafer (4) mounted on the chuck (3) (step S5); Based on the current temperature at the various positions detected by the calibration temperature probes (60, 61; 60', 61; 65), a step (S6) of calibrating the temperature output values of the one or more temperature probes (S1 to S9); A calibration method including the above.

13. The calibration method according to claim 12, wherein a step (S7) of storing the calibrated temperature output values of the one or more temperature probes (S1 to S9) at the various positions is executed.

14. The calibration method according to claim 12 or 13, wherein the set temperature is adjusted using at least one of the calibrated temperature probes (S1 to S9).

15. A calibration device (6, 60, 61, 600) used in the calibration device according to any one of claims 1 to 11.

16. A calibration card (6) used in the calibration device according to any one of claims 1 to 11.

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