Wafer transfer apparatus integrated with a levelness monitoring system

Abstract

A wafer transfer device integrating a levelness monitoring system includes a wafer cassette carrier, a pick-and-place device, and a detection device. The pick-and-place device includes a pick-and-place module, a tray assembly, and a monitoring unit. The detection device includes an initialization setting unit, a data acquisition unit, a comparison unit, a calculation unit, and a result output unit. This wafer transfer device adds the detection device to an existing equipment platform, enabling the device to monitor the levelness of the first wafer to be picked up from the wafer cassette on the carrier in real time. If the levelness of the wafer is found to be insufficient, it is deemed unqualified, and an alarm is triggered, thereby preventing defective processing of subsequent wafers in the entire wafer cassette.

Description

Technical Field

[0001] This invention relates to the field of chip manufacturing technology, and in particular to a wafer transfer device integrating a levelness monitoring system. Background Technology

[0002] In the semiconductor industry, wafer and chip manufacturing involves a very long process, with back-end processes alone including cleaning, oxidation, photolithography, etching, deposition, and ion implantation. Throughout these lengthy processes, each wafer is transported between workstations by a wafer carrier. Each wafer carrier is a sealed container holding multiple wafers, which are then processed on various worktables by robotic arms. With the rapid development of the 12-inch wafer market in China, the performance requirements for corresponding wafer carriers are becoming increasingly stringent. Besides the basic requirements for wafer protection and storage safety, the carriers also need to ensure safe docking with equipment such as robotic arms during wafer transport.

[0003] The ensuing problem is how to ensure precise docking of the wafer with the robotic arm during the transport of large-size wafers, preventing tilting or slippage. Wafers typically have a high surface finish, and even slight tilting can cause them to slip. Even if the wafer is not tilted, inaccurate positioning during placement into the processing equipment by the robotic arm can lead to processing failures, as wafer processing is done at the nanometer scale. Therefore, not only is extremely high precision required for the levelness of the robotic arm, but also for the levelness of the slots within the wafer carrier used to hold the wafers. Thus, it is necessary to test not only the levelness of the slots within the fabricated wafer carrier but also the levelness of the wafers placed on the transfer platform during transport to ensure product quality, avoid the risk of wafer scratches or even fragmentation, and maximize production yield. This is because the wafer carrier placed on the transfer platform may tilt due to certain errors. Summary of the Invention

[0004] In view of this, the present invention provides a wafer transfer device integrating a levelness monitoring system to meet the above-mentioned technical requirements.

[0005] A wafer transfer device integrating a levelness monitoring system includes a wafer cassette support, a wafer pick-and-place device, and a detection device mounted on the pick-and-place device. The wafer cassette support supports a wafer cassette containing wafers. The pick-and-place device includes at least one pick-and-place module. Each pick-and-place module includes a tray assembly and a monitoring unit mounted on one side of the tray assembly. The tray assembly is used to pick up the wafers. The monitoring unit is used to acquire height values ​​h of multiple test points on the picked-up wafer. i The detection device includes an initialization setting unit, a data acquisition unit, a comparison unit, a calculation unit, and a result output unit. The initialization setting unit is used to set the upper limit Ulim and lower limit Llim of the acceptable height value monitored by the monitoring unit when the tray assembly holds a wafer. The data acquisition unit is used to acquire height values ​​h at multiple points on the test wafer placed in the wafer cassette through the monitoring unit. i The comparison unit is used to compare the height values ​​h of multiple test points. i The height value h is compared with the upper limit Ulim and lower limit Llim set by the initialization setting unit, respectively. i If the height value is less than the upper limit Ulim or greater than the lower limit Llim, then the test point is considered a qualified test point, and the i height values ​​h are judged one by one. i The number of qualified test points (C) is determined by determining whether each test point is a qualified test point. The calculation unit 44 calculates the pass rate (P) of the multiple test points. The result output unit is used to output whether the wafer cell is excellent, good, or unqualified based on the calculated value of the calculation unit. When P is greater than or equal to 95%, the wafer cell is judged to be excellent; when P is less than 95% but greater than or equal to 90%, the wafer cell is judged to be excellent but requires monitoring; when P is less than 90%, the wafer cell is considered unqualified.

[0006] Furthermore, the wafer cassette carrier stage includes a base and a transfer platform disposed on the base, and the wafer cassette is fixedly placed on the transfer platform.

[0007] Furthermore, the pick-and-place device includes a three-axis motion module and at least one rotary module disposed on the three-axis motion module, wherein at least one of the pick-and-place modules is disposed on the rotary module.

[0008] Furthermore, the rotating module includes a rotary cylinder that drives the tray assembly to rotate back and forth by 90 degrees.

[0009] Furthermore, the rotating module has two components: one rotating module drives one pick-and-place module to pick up material from the wafer cassette, and the other rotating module drives another pick-and-place module to place the picked-up material into the processing equipment for processing.

[0010] Furthermore, when acquiring monitoring data, the tray assembly only moves horizontally under the action of the three-axis motion module to insert into the wafer cassette, and when it does not move in the vertical direction to support the wafer, the monitoring unit monitors the height value of the wafer.

[0011] Furthermore, when the data acquisition unit acquires the height value, and when the tray assembly only contacts the wafer and does not lift it, the monitoring unit monitors the height value of the wafer.

[0012] Furthermore, the tray assembly is provided with a U-shaped groove for the monitoring signal of the monitoring unit to pass through.

[0013] Compared with existing technologies, the wafer transfer equipment integrated with a levelness monitoring system provided by this invention, by adding the detection device—that is, adding the detection device to the existing equipment platform—allows the wafer transfer equipment to monitor the levelness of the first wafer to be picked up from the wafer cassette on the machine in real time. If the levelness of the wafer is insufficient, it is judged as unqualified and an alarm is triggered, thereby preventing subsequent wafer defects in the entire wafer cassette. Specifically, the detection device includes an initialization setting unit, a data acquisition unit, a comparison unit, a calculation unit, and a result output unit. The initialization setting unit is used to set the range of acceptable height values, i.e., upper and lower limits. The data acquisition unit monitors the height values ​​h of i test points using the monitoring unit on the existing equipment. i Then the comparison unit will assign the height value h i The test points are compared with the set range of acceptable heights to determine whether each point is acceptable. The calculation unit then calculates the pass rate of these test points, and the result output unit outputs the result. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a wafer transfer device integrating a levelness monitoring system, provided by the present invention.

[0015] Figure 2 This is a block diagram of the detection device. Detailed Implementation

[0016] The following provides a more detailed description of specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the scope of protection of the present invention.

[0017] like Figures 1 to 2 The diagram shown illustrates the structure of a wafer transfer device integrating a levelness monitoring system provided by this invention. The wafer transfer device includes a machine base 10, a wafer cassette carrier 20 mounted on the machine base 10, a wafer loading / unloading device 30 mounted on the machine base 10 for loading and unloading wafers, and a detection device 40 mounted on the wafer loading / unloading device 30. It is conceivable that the wafer transfer device integrating the levelness monitoring system also includes other functional modules, such as mounting components, electrical connection components, etc., which are well-known to those skilled in the art and will not be described in detail here.

[0018] The machine 10 is used to carry the above-mentioned functional modules, so it should be designed to ensure that the above-mentioned functional modules can work normally. It will not be described in detail here.

[0019] The wafer cassette carrier 20 includes a base 21 mounted on the machine tool 10 and a transfer platform 22 mounted on the base 21. The base 21 supports and secures the transfer platform 22, and its structure is configured according to actual needs. The transfer platform 22 is designed to be compatible with wafer cassettes of corresponding sizes. Since wafer cassettes come in at least 6-inch, 8-inch, and 12-inch sizes, the transfer platform 22 helps improve the compatibility of the base 21. The side of the transfer platform 22 facing the base 21 has a structure for connection and fixation with the base 21, such as a snap-fit ​​structure, which is a technology known to those skilled in the art. The side of the transfer platform 22 facing the wafer cassette has a connection and fixation structure that mates with the wafer cassette, which is also existing technology and will not be described further here. When testing a specific type of wafer cassette, the wafer cassette must first be fixedly mounted on the adapter 22, and then the adapter 22 together with the wafer cassette is fixed to the base 21, thus completing the fixation of the wafer cassette. Using the adapter 22 not only reduces costs but also helps improve assembly efficiency.

[0020] The pick-and-place device 30 includes a three-axis motion module 31 mounted on the machine base 10, a rotary module 32 mounted on the three-axis motion module 31, and at least one pick-and-place module 33 mounted on the rotary module 32. The three-axis motion module 31 drives the rotary module 32 and the pick-and-place module 33 to move in the X, Y, and Z directions, allowing the pick-and-place module 33 to extend into the wafer cassette for picking and placing a specific wafer. The three-axis motion module 31 itself is existing technology, consisting of components such as a servo motor, guide rail, slider, and lead screw to achieve movement in three mutually perpendicular directions. The rotary module 32 can move in three dimensions along with the three-axis motion module 31 while also rotating, facilitating the interchange between the pick-and-place module 33 and the storage position. The storage position refers to the location of the wafer cassette. The processing position refers to the location for wafer processing, which is not shown in the figure. The rotating module 32 includes a rotary cylinder, and the pick-and-place module 33 is assembled on the output end of the rotary cylinder. Since the rotary cylinder only needs to complete a 90-degree back-and-forth rotation, this can be accomplished with sufficient precision. Under the action of the rotary cylinder, the pick-and-place module 33 completes the picking and placing of materials. In this embodiment, there are two rotating modules 32, thus allowing two pick-and-place modules 33 to alternately pick and place materials. One pick-and-place module 33 picks materials from the wafer cassette, while the other picks and places the picked-up material into the processing equipment for processing. This improves pick-and-place efficiency and keeps the processing equipment continuously operational.

[0021] The pick-and-place module 33 includes a tray assembly 331 mounted on the rotating module 32 and a monitoring unit 332 mounted on one side of the tray assembly 331. One end of the tray assembly 331 is fixed to the rotating module 32, while the other end is suspended to facilitate insertion between multiple wafers in a wafer cassette. The tray assembly 331 has a U-shaped groove through which the monitoring signal from the monitoring unit 332 can pass. The monitoring unit 332 is positioned between the two pick-and-place modules 33 and includes a detector. The detector can be an infrared detector that measures distance to determine whether a wafer is mounted on the tray assembly 331. Under normal operating conditions, the monitoring unit 332 monitors whether a wafer is on the tray assembly 331. During testing, the monitoring unit 332 obtains test data, which will be described in detail below in conjunction with the detection device 40.

[0022] The detection device 40 includes an initialization setting unit 41, a data acquisition unit 42, a comparison unit 43, a calculation unit 44, and a result output unit 45. The initialization setting unit 41 is used to set the upper limit Ulim and lower limit Llim of the acceptable height value monitored by the monitoring unit 332 when the tray assembly 331 is holding a wafer. When the tray assembly 331 is holding a wafer, if it contacts the wafer but does not lift it, the monitoring unit 332 should monitor its height value. That is, when the tray assembly 331 only moves horizontally under the action of the three-axis motion module 31 to insert into the wafer cassette, and does not move vertically to lift the wafer, the monitoring unit 332 should monitor the height value of the wafer. If the measured height value h of the i-th test point... i If the height value is outside the range of Ulim and Llim, it is considered unacceptable or non-compliant. The data acquisition unit 42 is used by the monitoring unit 332 to acquire the height values ​​of multiple points on the test wafer placed in the wafer cassette. The test wafer should be a qualified wafer with perfectly level surface. The test wafer is placed in a test slot of the wafer cassette, and then the pick-and-place device 30 extends below the test wafer to acquire data; specifically, the monitoring unit 332 acquires the data. The monitoring unit 332 uses its distance detector to acquire data from multiple test points on the test wafer, i.e., the height values ​​h of the multiple test points. i And record the value of i.

[0023] The comparison unit 43 is used to compare the height values ​​h of multiple test points. i The height value h is compared with the upper limit Ulim and lower limit Llim set by the initialization setting unit 41, respectively. If the height value h is... i If the height value is less than the upper limit Ulim or greater than the lower limit Llim, then the test point is considered a qualified test point. This process is repeated for each i-th height value h. i Whether a point is a qualified test point or not, thus determining the number of qualified points (C).

[0024] The calculation unit 44 is used to calculate the pass rate of multiple test points, that is, the pass rate P is:

[0025] .

[0026] The result output unit 45 is used to determine whether the wafer cell is excellent, good, or unqualified based on the output of the calculation unit 44. When P is greater than or equal to 95%, the wafer cell is considered excellent; when P is less than 95% but greater than or equal to 90%, the wafer cell is considered good but requires monitoring; when P is less than 90%, the wafer cell is considered unqualified.

[0027] It is conceivable that the wafer transfer device integrating the levelness monitoring system also includes a display. This display can directly show the results of the result output unit 45, such as "Excellent," "Accepted," and "Unacceptable," allowing users to quickly understand the properties of the wafer cassette.

[0028] Compared with existing technologies, the wafer transfer equipment integrated with a levelness monitoring system provided by this invention, by adding the detection device 40 (i.e., adding the detection device 40 to the existing equipment platform), enables the wafer transfer equipment to monitor the levelness of the first wafer to be picked up from the wafer cassette on the placement table 10 in real time. If the levelness of the wafer is insufficient, it is determined to be unqualified and an alarm is triggered, thereby preventing subsequent wafer defects in the entire wafer cassette. Specifically, the detection device 40 includes an initialization setting unit 41, a data acquisition unit 42, a comparison unit 43, a calculation unit 44, and a result output unit 45. The initialization setting unit 41 is used to set the range of acceptable height values, i.e., upper and lower limits. The data acquisition unit 42 monitors the height values ​​h of i test points using the monitoring unit 332 on the existing equipment. i Then the comparison unit 43 will assign the height value h i The pass rate of each test point is calculated by comparing it with the set range of qualified height values. Then, the result output unit 45 outputs the result.

[0029] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions or improvements within the spirit of the present invention are covered within the scope of the claims of the present invention.

Claims

1. A wafer transfer device integrating a levelness monitoring system, characterized in that: The wafer transfer equipment integrated with a levelness monitoring system includes a wafer cassette support, a wafer pick-and-place device, and a detection device mounted on the pick-and-place device. The wafer cassette support supports the wafer cassette, which contains wafers. The pick-and-place device includes at least one pick-and-place module, which includes a tray assembly and a monitoring unit mounted on one side of the tray assembly. The tray assembly is used to pick up the wafers, and the monitoring unit is used to acquire the height values ​​h of multiple test points on the picked-up wafers. i The detection device includes an initialization setting unit, a data acquisition unit, a comparison unit, a calculation unit, and a result output unit. The initialization setting unit is used to set the upper limit Ulim and the lower limit Llim of the qualified height value monitored by the monitoring unit when the tray assembly holds a wafer. The data acquisition unit is used to acquire the height values ​​h of multiple points on the test wafer placed in the wafer cassette through the monitoring unit. i The test wafer is a qualified wafer whose levelness is completely qualified. The comparison unit is used to compare the height values ​​h of multiple test points. i The height value h is compared with the upper limit Ulim and lower limit Llim set by the initialization setting unit, respectively. i If the height value is less than the upper limit Ulim and greater than the lower limit Llim, then the test point is considered a qualified test point, and the i height values ​​h are judged one by one. i The calculation unit determines whether a test point is qualified or not to obtain C qualified test points. The calculation unit then calculates the pass rate P for the multiple test points. ， The result output unit is used to output whether the wafer cell is excellent, good, or unqualified based on the calculation value of the calculation unit. When P is greater than or equal to 95%, the wafer cell is judged to be excellent. When P is less than 95% but greater than or equal to 90%, the wafer cell is judged to be acceptable but needs to be monitored. When P is less than 90%, the wafer cell is considered unqualified.

2. The wafer transfer device integrating a levelness monitoring system as described in claim 1, characterized in that: The wafer cassette carrier stage includes a base and a transfer platform disposed on the base, and the wafer cassette is fixedly placed on the transfer platform.

3. The wafer transfer device integrating a levelness monitoring system as described in claim 1, characterized in that: The pick-and-place device includes a three-axis motion module and at least one rotary module disposed on the three-axis motion module, wherein at least one of the pick-and-place modules is disposed on the rotary module.

4. The wafer transfer device integrating a levelness monitoring system as described in claim 3, characterized in that: The rotating module includes a rotary cylinder that drives the tray assembly to rotate back and forth by 90 degrees.

5. The wafer transfer device integrating a levelness monitoring system as described in claim 3, characterized in that... The rotating module has two components: one rotating module drives one pick-and-place module to pick up material from the wafer cassette, and the other rotating module drives another pick-and-place module to place the picked-up material into the processing equipment for processing.

6. The wafer transfer device integrating a levelness monitoring system as described in claim 3, characterized in that: When acquiring monitoring data, the tray assembly moves horizontally and inserts into the wafer cassette only under the action of the three-axis motion module, and when it does not move in the vertical direction to support the wafer, the monitoring unit monitors the height value of the wafer.

7. The wafer transfer device integrating a levelness monitoring system as described in claim 1, characterized in that: When the data acquisition unit acquires the height value, and when the tray assembly is only in contact with the wafer and not lifting it, the monitoring unit monitors the height value of the wafer.

8. The wafer transfer device integrating a levelness monitoring system as described in claim 1, characterized in that: The tray assembly is provided with a U-shaped groove for the monitoring signal of the monitoring unit to pass through.

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