Wafer transfer position monitoring method for a bonding apparatus

Abstract

The application provides a wafer transfer position monitoring method of a bonding device, which comprises the following steps: providing two wafers; performing edge trimming treatment on the edge of one of the wafers to form a ring-shaped groove with a predetermined width inwardly on the edge of the wafer; growing an oxide layer on the surface of the wafer where the ring-shaped groove is located and not covering the ring-shaped groove; performing chemical mechanical grinding thinning and surface flattening treatment on the oxide layer; performing surface cleaning on the thinned and surface-flattened oxide layer; bonding the wafer and the other wafer through the cleaned oxide layer on the bonding device to form a bonded wafer; performing annealing treatment on the bonded wafer; and performing ultrasonic scanning microscope detection on the annealed bonded wafer, judging whether the relative positions of the two wafers transferred on the bonding device are deviated or not by whether the widths of the clamping grooves of the bonded wafer are the same, so as to monitor the wafer transfer position of the bonding device. The wafer transfer position of the bonding device can be monitored.

Description

Technical Field

[0001] The present invention relates to the field of integrated circuit manufacturing technology, and in particular to a method for monitoring the wafer transfer position of a bonding device. Background Art

[0002] Wafer bonding technology is primarily used in the manufacturing of integrated circuits (ICs) such as microelectromechanical systems (MEMS), image sensors (CIS), and memory, and is a key process in the entire process flow. Bonding technology significantly impacts pattern alignment in subsequent photolithography processes during wafer manufacturing and determines the overall wafer yield. High wafer alignment accuracy is required in bonding equipment, and the initial wafer transfer position plays a crucial role. This initial position significantly impacts wafer deformation during the bonding process and the distortion of the pattern after bonding. Currently, bonding equipment relies primarily on transfer position calibration during maintenance, without an effective method for monitoring wafer transfer position. Summary of the Invention

[0003] The object of the present invention is to provide a method for monitoring the wafer transfer position of a bonding device, so as to solve the problem that the wafer transfer position of the bonding device is not monitored.

[0004] To achieve the above-mentioned object, the present invention provides a method for monitoring the wafer transfer position of a bonding device, comprising:

[0005] Two wafers are provided;

[0006] Trimming the edge of one of the wafers to form an annular groove of a predetermined width inwardly from the edge of the wafer;

[0007] growing an oxide layer on the surface of the wafer where the annular groove is located without covering the annular groove;

[0008] Perform chemical mechanical polishing to thin the oxide layer and perform surface flattening treatment;

[0009] Surface cleaning of the thinned and surface-planarized oxide layer;

[0010] Bonding the wafer to another wafer via the cleaned oxide layer on a bonding device to form a bonded wafer;

[0011] Annealing the bonded wafer;

[0012] The annealed bonded wafers are inspected using an ultrasonic scanning microscope. By checking whether the width of the bonding grooves is the same, it is determined whether the relative positions of the two wafers transferred on the bonding device are offset, thereby monitoring the wafer transfer position of the bonding device.

[0013] Furthermore, the wafer transfer position monitoring method of the bonding device provided by the present invention determines that the relative positions of the two wafers transferred on the bonding device have not shifted when the clamping groove widths of the bonding wafers are the same, and determines that the transfer positions of the two wafers have been aligned before bonding.

[0014] Furthermore, the wafer transfer position monitoring method of the bonding device provided by the present invention determines that the positions of the two wafers transferred on the bonding device have shifted when the clamping groove widths of the bonding wafers are different, and determines that the transfer positions of the two wafers are not aligned before bonding.

[0015] Furthermore, in the wafer transfer position monitoring method of the bonding equipment provided by the present invention, when the widths of the clamping groove of the bonding wafer are different on both sides in at least a certain direction, the side where the clamping groove width is larger is determined as the offset direction.

[0016] Furthermore, in the wafer transfer position monitoring method of the bonding equipment provided by the present invention, the clamping groove refers to the distance between the inner edge of the annular groove of the wafer with the annular groove formed in the bonding wafer and the outer contour edge of the other wafer.

[0017] Furthermore, the wafer transfer position monitoring method of the bonding equipment provided by the present invention performs surface cleaning on the thinned and surface-planarized oxide layer through a wet process.

[0018] Furthermore, in the wafer transfer position monitoring method of the bonding equipment provided by the present invention, the annular groove of the wafer has a depth of 100 μm to 200 μm and a width of 1000 μm to 2000 μm.

[0019] Furthermore, the wafer transfer position monitoring method of the bonding equipment provided by the present invention grows an oxide layer on the wafer without covering the annular groove using a chemical vapor deposition device.

[0020] Furthermore, the wafer transfer position monitoring method of the bonding equipment provided by the present invention is to grow an oxide layer on the wafer with a thickness of to

[0021] Furthermore, the wafer transfer position monitoring method of the bonding equipment provided by the present invention has a thickness of the thinned and surface-planarized oxide layer of to

[0022] Compared with the prior art, the wafer transfer position monitoring method of the bonding equipment provided by the present invention is to form a bonded wafer by setting an annular groove on one of the two wafers and growing an oxide layer, and then bonding it with the other wafer through the oxide layer. After detection by an ultrasonic scanning microscope, the width of the clamping groove of the bonded wafer is measured. By judging whether the width of the clamping groove of the bonded wafer is the same, it is judged whether the relative position of the two wafers transferred on the bonding equipment is offset, so as to realize the monitoring of the wafer transfer position of the bonding equipment. The monitoring data can be used to provide a calibration reference for subsequent wafer bonding, so as to adjust the transfer position by calibrating the bonding equipment and guiding the bonding equipment to ensure that the transfer position of the wafer can be aligned before the subsequent wafer bonding, thereby improving the stability of the bonding equipment and improving the product process stability and yield. The monitoring data refers to the width of the clamping groove in different directions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the side structure of the second wafer;

[0024] Figure 2 1 is a schematic diagram of the side view structure of the first wafer;

[0025] Figure 3 is a side view schematic diagram of the structure of trimming the first wafer to form an annular groove;

[0026] Figure 4 is a schematic top view of the structure of trimming the first wafer to form an annular groove;

[0027] Figure 5 is a schematic side view of the structure of the oxide layer formed on the first wafer;

[0028] Figure 6 is a schematic side view of the structure for thinning and surface flattening the oxide layer generated on the first wafer;

[0029] Figure 7 It is a schematic diagram of the side view structure of two wafers bonded together to form a bonded wafer;

[0030] Figures 8 and 9 It is a schematic diagram of the top view of the structure of ultrasonic scanning microscope inspection of the bonded wafer;

[0031] As shown in the figure:

[0032] 100. Bonding wafers;

[0033] 110. a first wafer, 111. an annular groove;

[0034] 120, second wafer;

[0035] 130, oxide layer;

[0036] 140, clamping groove;

[0037] W1, left width;

[0038] W2, right side width. DETAILED DESCRIPTION

[0039] The following is a detailed description of the metal wire hole-digging structure and method proposed by the present invention, combined with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clarify the purpose of illustrating the embodiments of the present invention.

[0040] An embodiment of the present invention provides a method for monitoring a wafer transfer position of a bonding device, which may include:

[0041] Step S1, please refer to Figures 1 to 2 , two wafers are provided, and the two wafers are set to be a first wafer 110 and a second wafer 120.

[0042] Step S2, please refer to Figures 3 and 4 The edge of one of the wafers is trimmed to form an annular groove 111 of a predetermined width inwardly along the edge of the wafer. In this step S2, the annular groove 111 is provided on the first wafer 110, while the second wafer 120 is not provided with an annular groove. As a variation, the annular groove can also be provided on the second wafer 120 while the first wafer 110 is not provided with an annular groove. The annular groove 111 on the first wafer 110 can have a depth of 100 μm to 200 μm and a width of 1000 μm to 2000 μm. The depth and width parameters of the annular groove 111 can be adjusted as needed.

[0043] Step S3, please refer to Figure 5 , an oxide layer 130 is grown on the surface of the annular groove 111 of the first wafer 110 and does not cover the annular groove 111. That is, the first wafer 110 has two surfaces, one is a flat surface, and the other is a surface with the annular groove 111, and the oxide layer 130 is generated on the surface with the annular groove 111. The thickness of the oxide layer 130 grown on the first wafer 110 can be to

[0044] Step S4, please refer to Figure 6 , the oxide layer 130 is subjected to chemical mechanical polishing thinning and surface flattening treatment; the thickness of the thinned and surface flattened oxide layer 130 can be to The thickness of the generated oxide layer 130 is to This is to ensure that the thickness of the thinned and surface-planarized oxide layer 130 meets the requirements, thereby improving the bonding quality.

[0045] In step S5 , the thinned and surface-planarized oxide layer 130 is cleaned. The surface cleaning may be performed by a wet process or other cleaning process.

[0046] Step S6, please refer to Figure 7 , the wafer (the first wafer 110 ) is bonded to another wafer (the second wafer 120 ) on a bonding device through the cleaned oxide layer 130 to form a bonded wafer 100 .

[0047] Step S7 , performing annealing treatment on the bonded wafer 100 .

[0048] Step S8, please refer to Figures 8 and 9 After annealing, the bonded wafers 100 are inspected using a scanning ultrasonic microscope (CSAM). By checking whether the widths of the clamping grooves 140 of the bonded wafers 100 are consistent, the relative positions of the two wafers being transferred on the bonding equipment are determined to be offset, thereby monitoring the wafer transfer position of the bonding equipment. If the conditions are met, the bonded wafers 100 can also be scanned and inspected using other microscopes.

[0049] Please refer to Figure 9 , when the widths of the clamping grooves 140 of the bonding wafers 100 are the same, it is determined that the relative positions of the two wafers conveyed on the bonding device have not shifted, and it is determined that the conveying positions of the two wafers before bonding have been aligned. Taking the horizontal direction as an example, the width W1 on the left side of the clamping groove 140 is the same as the width W2 on the right side of the clamping groove 140, that is, it is monitored that the wafer conveying positions of the bonding device have been aligned. At this time, the first wafer 110 and the second wafer 120 completely overlap, that is, the outer contour edges of the two wafers completely overlap, and the annular groove 111 overlaps with the clamping groove 140, that is, the width of the annular groove 111 is the same as the width of the clamping groove 140. The clamping groove 140 refers to the distance between the inner edge of the annular groove 111 of the wafer with the annular groove 111 formed in the bonding wafer 100 and the outer contour edge of the other wafer. The same width of the clamping grooves is included in the error range or within the predetermined range.

[0050] Please refer to Figure 8 When the widths of the clamping grooves 140 of the bonding wafers 100 are different, it is determined that the positions of the two wafers transferred on the bonding device have shifted, and it is determined that the transfer positions of the two wafers were not aligned before bonding.

[0051] Please refer to Figure 9In order to determine the offset direction, an embodiment of the present invention provides a method for monitoring the wafer transfer position of a bonding device. When the widths of the clamping groove 140 of the bonding wafer 100 are different on both sides in at least a certain direction, the side where the clamping groove 140 has a larger width is determined to be the offset direction. Taking the horizontal direction as an example, if the width W1 of the left side of the clamping groove 140 is smaller than the width W2 of the right side of the clamping groove 140, the transfer positions of the two wafers of the bonding wafer are offset and misaligned. That is, the second wafer 120 is offset to the right relative to the first wafer 110 in the horizontal direction. From a relative perspective, the first wafer 110 is offset to the left relative to the second wafer 120 in the horizontal direction. Figure 9 Only one direction is shown as an example; actual offsets may occur in multiple directions. To facilitate monitoring of the offset direction of the wafer transfer position, monitoring can be performed simultaneously in the horizontal and vertical directions. This involves comparing the widths of the clamping grooves 140 on both sides of the bonded wafer 100 in the horizontal direction and the widths of the clamping grooves 140 on both sides of the bonded wafer 100 in the vertical direction. This allows calibration of the subsequent bonded wafer transfer position using the clamping groove 140 width data in the four directions of up, down, left, and right.

[0052] Please refer to Figure 5 The wafer transfer position monitoring method of the bonding device provided in the embodiment of the present invention can grow the oxide layer 130 on the wafer without covering the annular groove 111 through a chemical vapor deposition (CVD) device.

[0053] The embodiment of the present invention provides a method for monitoring the wafer transfer position of a bonding device. After an annular groove 111 is set on one of the two wafers and an oxide layer 130 is grown, the wafer is bonded to the other wafer through the oxide layer 130 to form a bonded wafer 100. After detection by an ultrasonic scanning microscope, the width of the clamping groove 140 of the bonded wafer 100 is measured. By determining whether the widths of the clamping grooves 140 of the bonded wafers 100 are the same, it is determined whether the relative positions of the two wafers transferred on the bonding device are offset, thereby monitoring the wafer transfer position of the bonding device. The monitoring data can be used to provide a calibration reference for subsequent wafer bonding, so as to adjust the transfer position for calibration guidance of the bonding device, ensure that the transfer position of the wafer can be aligned before subsequent wafer bonding, improve the stability of the bonding device, and enhance the product process stability and yield. The monitoring data refers to the width of the clamping groove 140 in different directions.

[0054] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims of the present invention.

Claims

1. A method for monitoring the wafer transfer position of a bonding device, characterized in that: include: Two wafers are provided; Trimming the edge of one of the wafers to form an annular groove of a predetermined width inwardly from the edge of the wafer; growing an oxide layer on the surface of the wafer where the annular groove is located without covering the annular groove; Perform chemical mechanical polishing to thin the oxide layer and smooth the surface; Surface cleaning of the thinned and surface-planarized oxide layer; Bonding the wafer to another wafer via the cleaned oxide layer on a bonding device to form a bonded wafer; Annealing the bonded wafer; The annealed bonded wafers are inspected using an ultrasonic scanning microscope. By checking whether the widths of the clamping grooves of the bonded wafers are the same, it is determined whether the relative positions of the two wafers transported on the bonding device are offset, so as to monitor the wafer transport position of the bonding device. The clamping groove refers to the distance between the inner edge of the annular groove of the wafer with the annular groove formed in the bonded wafer and the outer contour edge of the other wafer.

2. The wafer transfer position monitoring method of the bonding equipment according to claim 1, wherein: When the widths of the clamping grooves of the bonding wafers are the same, it is determined that the relative positions of the two wafers conveyed on the bonding device have not shifted, and it is determined that the conveying positions of the two wafers have been aligned before bonding.

3. The wafer transfer position monitoring method of the bonding equipment according to claim 1, wherein: When the widths of the clamping grooves of the bonding wafers are different, it is determined that the positions of the two wafers transferred on the bonding device have shifted, and it is determined that the transfer positions of the two wafers were misaligned before bonding.

4. The wafer transfer position monitoring method of the bonding equipment according to claim 3, wherein: When the widths of the clamping groove of the bonding wafer are different on both sides in at least a certain direction, the side where the clamping groove width is larger is determined as the offset direction.

5. The wafer transfer position monitoring method of the bonding equipment according to claim 1, wherein: The thinned and surface-planarized oxide layer is cleaned by a wet process.

6. The wafer transfer position monitoring method of the bonding equipment according to claim 1, wherein: The annular groove of the wafer has a depth of 100 μm to 200 μm and a width of 1000 μm to 2000 μm.

7. The wafer transfer position monitoring method of the bonding equipment according to claim 1, wherein: An oxide layer is grown on the wafer without covering the annular groove using a chemical vapor deposition device.

8. The wafer transfer position monitoring method of the bonding equipment according to claim 1, wherein: The thickness of the oxide layer grown on the wafer is to 9. The wafer transfer position monitoring method of the bonding equipment according to claim 8, wherein: The thickness of the thinned and surface-planarized oxide layer is to

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