TWM674067U - Device for measuring wafer diameter - Google Patents

Abstract

A device for measuring wafer diameter includes a wafer platform, a standard bracket and a detection unit. The wafer platform has a central axis and is used to dispose the wafer thereon. The standard bracket is fixedly connected to the wafer platform, wherein the standard bracket includes a measurement portion, and the measurement portion and the central axis of the wafer platform has a first distance. The detection unit is used to obtain a second distance between the measurement portion and the edge of the wafer. The first distance and the second distance together determine the diameter of the wafer.

Description

Wafer diameter measurement equipment

This case relates to a wafer diameter measurement device, particularly a wafer diameter measurement device that provides high-accuracy diameter measurement results.

In typical wafer diameter measurement, a common configuration utilizes an edge finder in conjunction with a movable wafer stage. Once the wafer stage, carrying the wafer, moves to the measurement point, a detection unit mounted on the edge finder measures the distance the wafer is obscured by the edge of the edge finder. The distance between the edge and center of the edge finder, based on the pre-set center of the wafer stage, is then calculated. Finally, the wafer radius is calculated by summing these two distances to arrive at the diameter.

In this measurement method, since the wafer stage is mobile, its measurement accuracy depends entirely on whether the wafer stage can accurately move to the preset measurement point to accurately calculate the distance between the edge of the edge finder and the wafer stage. In other words, when the wafer stage moves to the measurement point, the repeatability of its position directly affects the distance from the center of the wafer stage to the edge of the edge finder. Under this premise, in order to improve accuracy, the positioning of the wafer stage must usually be precisely calibrated after each movement, which makes the calibration process complicated and significantly increases time costs.

Therefore, it is necessary to develop a wafer diameter measurement device to improve the above-mentioned deficiencies in the known technology.

The purpose of this case is to provide a wafer diameter measurement device that can effectively reduce operating costs and at the same time improve the measurement accuracy of wafer diameter.

To achieve the aforementioned objectives, this invention provides a wafer diameter measurement device comprising a wafer platform, a standard support, and a detection unit. The wafer platform has a central axis and is used to position a wafer. The standard support is fixedly connected to the wafer platform, wherein the standard support includes a measuring portion, and a first distance is defined between the measuring portion and the central axis of the wafer platform. The detection unit is used to determine a second distance between the measuring portion and the edge of the wafer. The first and second distances together determine the wafer diameter.

In one embodiment, the diameter of the wafer is the difference between the first distance and the second distance.

In one embodiment, the first distance is a constant value.

In one embodiment, the wafer stage is disposed on a transverse axis to move between a loading position and a measurement position, and the detection unit obtains the second distance when the wafer stage is located at the measurement position.

In one embodiment, the second distance is the shortest distance between the measurement portion and the edge of the wafer, and the second distance falls within the detection range of the detection unit.

In one embodiment, the measurement unit is implemented as a plurality of measurement units corresponding to a plurality of wafer sizes respectively.

In one embodiment, the standard holder is implemented as one of a plurality of standard holders, and the plurality of standard holders respectively correspond to a plurality of wafer sizes.

In one embodiment, the detection unit is disposed on the edge finder.

In one embodiment, the detection unit includes at least one of the following: a camera and a light detection unit.

This wafer diameter measurement device utilizes a fixed standard bracket mounted on the wafer platform, effectively reducing the wafer platform position calibration process and the associated time and cost. This advantageous design also enables highly accurate diameter measurement results.

Typical embodiments that embody the features and advantages of this invention will be described in detail in the following description. It should be understood that this invention is capable of various variations in different forms, all of which remain within the scope of this invention, and that the descriptions and illustrations herein are intended for illustrative purposes only and are not intended to limit this invention.

Please refer to Figures 1, 2, and 3. Figure 1 shows a schematic diagram of a wafer diameter measurement device according to an embodiment of the present invention, Figure 2 shows a side view of the wafer diameter measurement device according to an embodiment of the present invention, and Figure 3 shows a side view of the wafer diameter measurement device according to an embodiment of the present invention carrying a wafer. The wafer diameter measurement device 1 of the present invention includes a wafer platform 10, a standard support 20, and a detection unit 30. The wafer platform 10 is used to place a wafer 40 whose diameter is to be measured. The standard support 20 is fixedly connected to the wafer platform 10, for example, by locking, and a measuring portion 21 is provided on the standard support 20. The measurement unit 21 is located near the outer edge of the wafer 40 supported on the wafer stage 10. The detection unit 30 is used to detect the position of objects within its detection range. In one embodiment, the detection unit 30 can be installed on a wafer aligner. In other embodiments, the detection unit 30 can also be installed on other devices in other applications requiring wafer diameter measurement.

The wafer stage 10 is mounted on a traverse axis 50 and moves between a loading position and a measurement position. The loading position is where the wafer stage 10 loads a wafer 40 of a desired diameter, while the measurement position is where the diameter of the loaded wafer 40 is measured. The measurement position also refers to the position where the measurement portion 21 of the standard holder 20 and the edge of the wafer 40 closest to the measurement portion 21 are both within the detection range of the inspection unit 30.

Based on the above configuration, as shown in Figure 3, since the standard bracket 20 is fixedly connected to the wafer platform 10, the first distance D1 between the measurement unit 21 and the center axis C of the wafer platform 10 is a fixed value and remains unchanged. In this case, to obtain the diameter of the wafer 40, it is only necessary to obtain the second distance D2 between the measurement unit 21 and the edge of the wafer 40. By subtracting the second distance D2 from the first distance D1, the radius of the wafer 40 can be calculated, and the diameter of the wafer 40 can be further obtained. Therefore, the diameter of the wafer 40 is determined by the first distance D1 and the second distance D2.

Here, the second distance D2 refers to the distance between the intersection of the line connecting the central axis C and the measurement portion 21 and the edge of the wafer 40, and the measurement portion 21. In other words, the shortest distance between the measurement portion 21 and the edge of the wafer 40. In other words, the measurement position of the second distance D2 at the edge of the wafer 40, the measurement portion 21, and the central axis C are all on the same straight line.

More specifically, in this case, because the standard support 20 mounted on the wafer stage 10 is fixed in position, the first distance D1 between the measurement portion 21 and the center axis C remains constant regardless of the wafer stage 10's position on the traverse axis 50. This eliminates the complex and time-consuming calibration process required to precisely calibrate the wafer stage 10 to a preset fixed position, as is conventional practice, while maintaining measurement accuracy. With this configuration, the inspection unit 30 simply obtains the second distance D2 between the measurement portion 21 and the edge of the wafer 40 during each measurement. The difference between the known first distance D1 and the measured second distance D2 can be used to quickly calculate the radius of the wafer 40, and thus the diameter.

In other words, in the structure of the wafer diameter measurement device 1 of the present invention, by providing a standard support 20 fixed to the wafer platform 10, variables that may affect measurement accuracy in conventional techniques are eliminated. This effectively reduces the need for correcting the positioning of the wafer platform 10 to avoid the influence of these variables, thereby reducing time and cost. When the wafer platform 10 is moved to the measurement position via the traverse axis 50, there is no need for the precise calibration process required in conventional techniques to ensure that the wafer platform 10 is positioned at the preset point. Accurate diameter measurements can be obtained, resulting in a design that combines time and cost-effectiveness with high measurement accuracy.

In practical applications, in one embodiment, the second distance D2 is obtained by rotating the wafer 40 relative to the wafer stage 10 during measurement. The detection unit 30 continuously measures the distance between the measurement portion 21 and the edge of the wafer 40 during the rotation. This value is then substituted into a calculation formula to calculate the second distance D2. This eliminates errors caused by misalignment between the center point of the wafer 40 and the center axis C of the wafer stage 10, further improving measurement accuracy.

The standard holder 20 can be implemented with multiple measurement sections to accommodate wafers of varying sizes. In one embodiment, as shown in Figure 4 , the standard holder 20' can be implemented to include multiple measurement sections 21a, 21b, and 21c, corresponding to wafer sizes of various sizes, such as 12-inch, 10-inch, and 8-inch wafers. This ensures that the corresponding measurement sections and the edges of each wafer fall appropriately within the detection range of the inspection unit 30. It should be noted that as long as the height of the measurement sections does not interfere with the placement of the wafer, the number and location of the measurement sections are not limited and can vary depending on the actual implementation. In other embodiments, different standard holders 20 may be used to correspond to wafers 40 of different sizes. For example, a replaceable standard holder 20 can also be implemented to ensure that the corresponding measurement portion and each wafer edge are properly within the detection range of the detection unit 30. Furthermore, the distance between the measurement portion 21 and the edge of the wafer 40 can also be varied depending on the actual application, as long as it falls within the detection range of the detection unit 30. There is no limitation.

The detection unit 30 can be implemented as various types of detection units as needed. For example, in one embodiment, the detection unit 30 can be implemented as a light detection unit including a light emitter and a light receiver. In another embodiment, the detection unit 30 can also be implemented as a camera. Therefore, there is no limitation; any device that can obtain the second distance D2 between the measurement unit 21 and the edge of the wafer 40 falls within the scope of this invention.

In summary, the wafer diameter measurement device in this case, by installing a fixed standard bracket on a moving wafer platform, provides a measurement reference position that is unaffected by the movement of the wafer platform and a fixed value basis for calculating the wafer diameter. Therefore, the wafer diameter can be accurately measured without the need for precise calibration of the wafer platform's measurement position, significantly simplifying the calibration process and time cost, and further helping to improve the accuracy of wafer diameter measurement.

It should be noted that the above examples are merely preferred embodiments for the purpose of illustrating this invention. This invention is not limited to the examples described. The scope of this invention is determined by the scope of the attached patent application. Furthermore, this invention is subject to various modifications conceived by those skilled in the art, without departing from the intended scope of protection of the attached patent application.

1: Wafer diameter measurement device 10: Wafer stage 20, 20': Standard bracket 21, 21a, 21b, 21c: Measuring unit 30: Detection unit 40: Wafer 50: Transverse axis C: Center axis D1: First distance D2: Second distance

FIG1 is a schematic diagram of a wafer diameter measurement apparatus according to an embodiment of the present invention. FIG2 is a side view of the wafer diameter measurement apparatus according to an embodiment of the present invention. FIG3 is a side view of the wafer diameter measurement apparatus according to an embodiment of the present invention carrying a wafer. FIG4 is a schematic diagram of a standard holder according to another embodiment of the present invention.

10: Wafer platform

20: Standard bracket

21: Measurement Department

30: Detection unit

40: Wafer

50: Transverse axis

C: Center axis

D1: First Distance

D2: Second distance

Claims (9)

A wafer diameter measurement device includes: a wafer platform having a central axis and used to place a wafer; a standard bracket fixedly connected to the wafer platform, wherein the standard bracket includes a measuring portion, and a first distance is defined between the measuring portion and the central axis of the wafer platform; and a detection unit for obtaining a second distance between the measuring portion and the edge of the wafer, wherein the first distance and the second distance together determine the diameter of the wafer. The wafer diameter measurement apparatus as described in claim 1, wherein the diameter of the wafer is the difference between the first distance and the second distance. The wafer diameter measurement device as described in claim 1, wherein the first distance is a constant value. The wafer diameter measurement device as described in claim 1, wherein the wafer platform is set on a lateral axis to move between a loading position and a measurement position, and the detection unit obtains the second distance when the wafer platform is located at the measurement position. The wafer diameter measurement device as described in claim 1, wherein the second distance is the shortest distance between the measuring part and the edge of the wafer, and the second distance falls within the detection range of the detection unit. The wafer diameter measurement device as described in claim 1, wherein the measurement part is implemented as a plurality of measurement parts to correspond to a plurality of wafer sizes respectively. The wafer diameter measurement device as described in claim 1, wherein the standard bracket is implemented as one of a plurality of standard brackets, and the plurality of standard brackets respectively correspond to a plurality of wafer sizes. A wafer diameter measurement device as described in claim 1, wherein the detection unit is arranged on an edge finder. The wafer diameter measurement device as described in claim 1, wherein the detection unit includes at least one of the following: a camera and a light detection unit.