Substrate bonding method and substrate

Abstract

The present invention provides a substrate bonding method and substrate, belonging to the field of semiconductor technology. The substrate bonding method is to open each clamping jaw in turn and remove the gasket at the position of the clamping jaw after aligning the two substrates and before heating and pressing for bonding, and then close and lock until all the gaskets are removed and then pressurized and heated to complete the bonding. The substrate bonding method described in the present invention is a method of removing the gaskets one by one in the open state of the clamping jaws, which can not only reduce the invalid area, but also avoid the misalignment caused by the removal of the gaskets, thereby improving the yield rate. At the same time, the height position of the gasket will not change, and the process of adjusting the height of the gasket in the next alignment process is omitted, thereby improving the working efficiency of the bonding.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a substrate bonding method and a substrate. Background Art

[0002] Since the late 1960s, when Bell Labs in the United States proposed the concept of solid-state imaging devices, solid-state image sensors have developed rapidly and become an important branch of sensor technology. They are an indispensable peripheral for personal computer multimedia and a core device in monitoring equipment.

[0003] In recent years, due to the improvement of integrated circuit design technology and process level, CMOS Image Sensor (CIS) has been more widely used due to its inherent characteristics such as pixel amplification, column parallel structure, high integration, single power supply and low voltage power supply, low cost and low technical threshold. At the same time, the advantages of low cost, single chip, low power consumption and simple design make CIS widely used in low-end pixel products such as security monitoring systems, video phones, camera phones, toys, automobiles and medical electronics.

[0004] CIS wafer bonding refers to the process of bonding two flat wafers face to face and applying certain external conditions such as pressure, temperature, voltage, etc., to generate atomic or molecular bonding forces, such as covalent bonds, metal bonds, molecular bonds, etc., at the interface between the two original wafers, so that the two wafers are bonded into one. The bonding system is divided into two parts, the alignment machine and the bonding machine; the alignment machine is used to align the two bonding surfaces, the wafer bonding clamping device realizes the alignment function of the upper and lower wafer substrates in the alignment machine, and realizes the wafer substrate pressing function in the bonding machine. When the bonding process is completed, the bonding clamping device of the wafer substrate to be bonded is taken out from the bonding machine. The bonding machine and bonding process are one of the key factors affecting the bonding accuracy and bonding effect.

[0005] In the bonding process, bonding glue is coated on the bonding surfaces of the two substrates. Before bonding, the two substrates are in contact with each other, resulting in glue overflow. In addition, due to the effect of gravity, part of the adhesive on the surface of the substrate is easy to contact with the surface of the other substrate before lamination, which easily leads to the difficulty of evacuating part of the area between the two substrates. Then, the subsequent lamination process is not effective or the bonding hinders the gas discharge, resulting in defects such as bubbles and holes. In order to solve the above problems, during bonding, a gasket or a spacer is arranged between the two substrates to separate the two substrates to be bonded, and the two substrates and the gasket or spacer are clamped by a bonding clamping device, and then the bonding operation is performed, such as the Chinese utility model patent "substrate bonding device" with patent document number CN2042894050U and the Chinese invention patent "substrate bonding device and bonding method" with patent document number CN1043621170A. In the above technical scheme, an invalid area will be generated in the area corresponding to the gasket.

[0006] In order to improve the use efficiency of the substrate, the gasket or spacer needs to be pulled out before bonding. However, when the clamping device is clamped, multiple gaskets or spacers are pulled out at the same time by the cylinder operation. The friction between the spacer and the substrate is large, which can easily cause the substrate to deviate and cause the pressing deviation. Generally, the relative deviation between the substrates to be bonded is overcome by improving the alignment accuracy of the alignment process.

[0007] At the same time, in the traditional bonding process, since the gasket or isolation sheet is subjected to the clamping pressure of the clamp during the withdrawal process, its height will be reduced after withdrawal; when it is used to isolate the next group of substrates to be bonded, the height of the gasket or isolation sheet needs to be adjusted again, which increases the workload and reduces work efficiency. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a substrate bonding method and a substrate to improve the alignment accuracy between the bonded substrates and prevent the occurrence of offset.

[0009] The present invention achieves the above technical objectives through the following technical means.

[0010] A substrate bonding method, characterized by comprising:

[0011] Providing a first substrate having a first surface and a second surface opposite to each other;

[0012] Providing a second substrate, wherein the second substrate has a third surface and a fourth surface opposite to each other, the second substrate is located below the first substrate, and the second surface of the first substrate is disposed adjacent to the third surface of the second substrate;

[0013] Providing an adhesive layer, wherein the adhesive layer is coated on the second surface of the first substrate or the third surface of the second substrate;

[0014] Providing a plurality of gaskets, wherein the head of the gasket is located between the first substrate and the second substrate to separate the second surface of the first substrate from the third surface of the second substrate, and the tail of the gasket extends outside the first substrate and the second substrate;

[0015] Providing a clamping device having a plurality of clamping claws for clamping the edges of the first substrate and the second substrate;

[0016] After the first substrate and the second substrate are aligned, the edges of the first substrate and the second substrate are clamped by a clamping jaw, and the clamping device together with the first substrate and the second substrate are moved into the bonding machine chamber; during the bonding process, after vacuuming and preheating, the plurality of clamping jaws and gaskets are operated in turn according to the following steps:

[0017] The clamping jaws are opened to at least separate the clamping jaws from the first surface of the first substrate, and the gasket at the position corresponding to the clamping jaws is pulled out from between the first substrate and the second substrate, so that the edge of the first substrate corresponding to the position of the gasket contacts the edge of the second substrate, and then the clamping jaws are closed to clamp the first substrate and the second substrate;

[0018] Until all the gaskets are pulled away from the first substrate and the second substrate, the upper cover plate applies pressure to the first substrate and the second substrate and heats them to complete the bonding.

[0019] Furthermore, in the alignment process: the first substrate is first placed on the carrier, the heads of the plurality of gaskets extend above the edge of the second surface of the first substrate, and the heads of the gaskets are in contact with the second surface; the third surface of the second substrate is made to face the first substrate, and an alignment process is used to make the edge of the second substrate coincide with the edge of the first substrate, and then the second substrate is placed on the gasket, so that the edge of the third surface of the second substrate is in contact with the head of the gasket, and then the edges of the first surface of the first substrate and the fourth surface of the second substrate are clamped by the clamping device, so that the first substrate and the second substrate are fixed; or:

[0020] The second substrate is first placed on the carrier table, the heads of the plurality of gaskets extend to the edge of the third surface of the second substrate, and the heads of the gaskets are in contact with the third surface; the second surface of the first substrate is made to face the first substrate, and an alignment process is used to make the edge of the first substrate overlap with the edge of the second substrate, and then the first substrate is placed on the gasket, so that the edge of the second surface of the first substrate is in contact with the heads of the gaskets, and then the edges of the first surface of the first substrate and the fourth surface of the second substrate are clamped by the clamping claws of the clamping device to fix the first substrate and the second substrate.

[0021] Furthermore, the gasket and the clamping jaw are arranged adjacent to each other, and the spacing between them is no more than 10 mm; the number of gaskets and clamping jaws is the same, both are 3-6, and are evenly distributed.

[0022] Furthermore, the sizes of the first substrate and the second substrate are 200-300 mm; the distance between the second surface of the first substrate and the third surface of the second substrate separated by the isolation sheet is 1000-2000 μm.

[0023] Furthermore, the second substrate is a wafer, the first substrate is glass, a dam protruding from the second plane is arranged at the edge of the second surface of the first substrate, and the adhesive layer is coated on the dam.

[0024] Furthermore, the thickness of the cofferdam is 20-40 μm.

[0025] Furthermore, the thickness of the adhesive layer is 5-30 μm.

[0026] Furthermore, the connecting part of the clamp is fixedly connected to a connecting rod, and the connection between the clamp and the connecting rod is hingedly mounted on the clamping device. The extension and retraction of the piston of the first cylinder installed in the bonding machine chamber can push the connecting rod and the clamp to rotate around the pin shaft, and the opening and closing of the clamp is controlled by the piston rod of the first cylinder and the connecting rod connected to the connecting part of the clamp through the lever principle.

[0027] Furthermore, the tail of the gasket is connected to the piston rod of the second cylinder, and the gasket can be withdrawn and extended by the extension and retraction of the piston rod of the second cylinder.

[0028] The substrate is manufactured by the substrate bonding method.

[0029] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0030] In the substrate bonding method described in the present invention, the head of the gasket extends to the edge of the two substrates to isolate the two substrates, and the gasket can support the first substrate to achieve the effect of dispersing the pressure of the first substrate. Therefore, before lamination, the two substrates can be prevented from being bonded, so that the area between the two substrates can be ensured to be vacuumed, thereby improving the effect of the lamination process. Before lamination, the present invention removes the gasket from between the first substrate and the second substrate, and then performs lamination, which can reduce the invalid area caused by the gasket and improve the utilization rate of the substrate. In addition, the present invention adopts a method of extracting each gasket one by one, and opens the clamp at the corresponding position of the gasket before extracting the gasket. In the process of extracting the gasket in this way, since the clamp is opened first, the force on the gasket is only the gravity of the first substrate. In the process of extracting, the friction between the gasket and the first substrate and the second substrate is greatly reduced, and the extraction process will not cause the displacement of the first substrate and the second substrate; and after extraction, the height of the gasket will not change. Therefore, this process can avoid the misalignment between the first substrate and the second substrate caused by the removal of the gasket, thereby improving the yield rate; and can keep the height position of the gasket unchanged, omitting the gasket height adjustment process in the next alignment process, thereby improving the bonding work efficiency.

[0031] After the gasket is pulled out, the opened clamping jaws are closed again to lock the edges of the first substrate and the second substrate, thereby preventing the first substrate and the second substrate from shifting during the subsequent removal of other gaskets. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flow chart of the substrate bonding method.

[0033] Figure 2 This is a top view of the two substrates to be bonded after alignment.

[0034] Figure 3 Schematic diagram of the clamping state of the clamping jaws.

[0035] Figure 4 This is a schematic diagram of the gripper opening state.

[0036] Figure 5 FIG. 4 is a schematic diagram of a bonding process according to an embodiment of the present invention.

[0037] In the figure:

[0038] 1-first substrate, 2-second substrate, 3-gasket, 4-clamping jaw, 5-pin shaft, 6-connecting rod, 7-first cylinder, 8-adhesive layer, 101-first surface, 102-second surface 102, 201-third surface, 202-fourth surface, 103-cofferdam. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0040] like Figure 1 As shown, the substrate bonding method of the present invention is applicable to the situation where the edges of the two bonded substrates are separated by a gasket 3. The substrate bonding method provides a first substrate 1, wherein the first substrate 1 has a first surface 101 and a second surface 102 relative to each other; provides a second substrate 2, wherein the second substrate 2 has a third surface 201 and a fourth surface 202 relative to each other, and the second substrate 2 is located below the first substrate 1, and the second surface 102 of the first substrate 1 is adjacent to the third surface 201 of the second substrate 2; provides an adhesive layer 8, wherein the adhesive layer 8 is coated on the second surface 102 of the first substrate 1 or the third surface 201 of the second substrate 2; provides a plurality of gaskets 3, wherein the head of the gasket 3 is located between the first substrate 1 and the second substrate 2, separating the second surface 102 of the first substrate 1 from the third surface 201 of the second substrate 2, and the tail of the gasket 3 extends outside the first substrate 1 and the second substrate 2; provides a clamping device, which has a plurality of clamping claws 4 for clamping the edges of the first substrate 1 and the second substrate 2. The specific bonding process is as follows: Figure 1 As shown, after the first substrate 1 and the second substrate 2 are aligned, the edges of the first substrate 1 and the second substrate 2 are clamped by the clamping jaws 4, and the clamping device together with the first substrate 1 and the second substrate 2 are moved into the bonding machine chamber; the fourth surface 202 of the second substrate 2 is in contact with the carrier of the bonding machine. During the bonding process, after vacuuming and the carrier preheating the second substrate 2, the plurality of clamping jaws 4 and the gasket 3 are operated in turn according to the following steps:

[0041] The clamping jaws 4 are opened to at least separate the clamping jaws 4 from the first surface 101 of the first substrate 1, and the gasket 3 at the corresponding position of the opened clamping jaws 4 is pulled out from between the first substrate 1 and the second substrate 2, so that the edge of the first substrate 1 corresponding to the position of the gasket 3 contacts the edge of the second substrate 2, and then the clamping jaws 4 are closed to clamp the first substrate 1 and the second substrate 2; until all the gaskets 3 are pulled out of the first substrate 1 and the second substrate 2, the upper cover plate applies pressure to the first substrate 1 and the second substrate 2 and heats them to press the first substrate 1 and the second substrate 2 together to complete the bonding.

[0042] The present invention adopts a method of extracting each gasket 3 one by one, and before extracting the gasket 3, the clamping jaw 4 at the corresponding position of the gasket 3 is in an open or semi-open state. In the process of extracting the gasket 3 in this way, since the clamping jaw 4 is opened first, the force on the gasket 3 is only the gravity of the first substrate 1. In the process of extracting the gasket 3, the friction between the gasket 3 and the first substrate 1 and the second substrate 2 is greatly reduced, and the extraction process will not cause the displacement of the first substrate 1 and the second substrate 2; and after the extraction, the height of the gasket 3 will not change. Therefore, the process can avoid the misalignment between the first substrate 1 and the second substrate 2 caused by the extraction of the gasket 3, and improve the yield rate; and can keep the height position of the gasket 3 unchanged, omit the process of adjusting the height of the gasket 3 in the next alignment process, and improve the working efficiency of the bonding. After the gasket 3 is extracted, the clamping jaw 4 is in a locked state again, thereby ensuring the stability of the first substrate and the second substrate. In addition, the edge of the substrate bonded by the bonding method described in the present invention does not have an invalid area caused by the gasket.

[0043] Specifically, the size of the first substrate 1 and the second substrate 2 is 200-300 mm; the distance between the second surface 102 of the first substrate 1 and the third surface 201 of the second substrate 2 separated by the spacer is 1000-2000 μm. The adhesive layer 8 can be coated or printed on any one of the two opposite surfaces of the first substrate 1 and the second substrate 2. The thickness of the adhesive layer 8 is 5-30 μm.

[0044] Preferably, the gasket 3 and the clamping jaw 4 are arranged adjacent to each other, and the spacing between them is not greater than 10 mm; the number of gaskets 3 and the number of clamping jaws 4 are the same, both 3-6, and are evenly distributed, such as Figure 2 The connecting part of the clamping jaw 4 is fixedly connected with a connecting rod 6, and the connecting part of the clamping jaw 4 and the connecting rod 6 is hingedly mounted on the clamping device. The piston extension of the first cylinder 7 installed in the bonding machine chamber can push the connecting rod 6 and the clamping jaw 4 to rotate around the pin 5. The opening and closing of the clamping jaw 4 is controlled by the piston rod of the first cylinder 7 and the connecting rod 6 connected to the connecting part of the clamping jaw 4 through the lever principle. Figure 3 As shown in FIG. 1 , the clamping jaw 4 is in a closed and locked state. At this time, the piston rod of the first cylinder 7 is in a retracted state. Under the action of the spring, the end of the clamping jaw 4 is pressed on the first substrate 1. When the piston rod of the first cylinder 7 extends and presses the connecting rod 6 to rotate around the pin 5, the clamping jaw 4 is separated from the first surface 101 of the first substrate 1 and is in an open state. Figure 4 The tail of the gasket 3 is connected to the piston rod of the second cylinder, and the gasket 3 can be pulled out and extended by the extension and contraction of the piston rod of the second cylinder.

[0045] During the alignment process: the first substrate 1 is first placed on the supporting platform, the heads of the plurality of gaskets 3 extend to the edge of the second surface 102 of the first substrate 1, and the heads of the gaskets 3 are in contact with the second surface 102; the third surface 201 of the second substrate 2 is directed toward the first substrate 1, and an alignment process is used to make the edge of the second substrate 2 coincide with the edge of the first substrate 1, and then the second substrate 2 is placed on the gasket 3, so that the edge of the third surface 201 of the second substrate 2 is in contact with the heads of the gaskets 3, and then the edges of the first surface 101 of the first substrate 1 and the fourth surface 202 of the second substrate 2 are clamped by the clamping device's claws 4, so that the first substrate 1 and the second substrate 2 are fixed. Or: first place the second substrate 2 on the carrier, the heads of the plurality of gaskets 3 extend to the edge of the third surface 201 of the second substrate 2, and the heads of the gaskets 3 contact the third surface 201; make the second surface 102 of the first substrate 1 face the first substrate 1, use the alignment process to make the edge of the first substrate 1 coincide with the edge of the second substrate 2, then place the first substrate 1 on the gasket 3, make the edge of the second surface 102 of the first substrate 1 contact the head of the gasket 3, and then use the clamping device's claws 4 to clamp the edges of the first surface 101 of the first substrate 1 and the fourth surface 202 of the second substrate 2, so that the first substrate 1 and the second substrate 2 are fixed. The specific alignment process is performed in which order according to the above order, depending on whether the first substrate 1 and the second substrate 2 clamped by the clamping device are flipped when they are transferred from the alignment machine to the bonding machine after alignment in the overall design of the equipment.

[0046] like Figure 5 As shown, it is a special embodiment of the bonding method of the present invention, the second substrate 2 is a wafer, the first substrate 1 is glass, and a cofferdam 103 protruding from the second plane is provided at the edge of the second surface 102 of the first substrate 1, and the thickness of the cofferdam 103 is 20-40 μm. The adhesive layer 8 is coated on the cofferdam 103, and the thickness of the adhesive layer 8 is preferably 5-20 μm. In this embodiment, the top surface of the cofferdam 103 at the edge of the first substrate 1 and the edge of the third surface 201 of the second substrate 2 are in contact with the gasket 3, and the bonding process is also the edge where the top surface of the cofferdam 103 at the edge of the first substrate 1 contacts the third surface 201 of the second substrate 2. After bonding, the cofferdam glass CV is permanently bonded to the wafer to achieve the purpose of protecting the photosensitive area.

[0047] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A substrate bonding method, characterized in that: include: providing a first substrate having a first surface and a second surface opposite to each other; Providing a second substrate, wherein the second substrate has a third surface and a fourth surface opposite to each other, the second substrate being located below the first substrate, and the second surface of the first substrate being adjacent to the third surface of the second substrate; Providing an adhesive layer, wherein the adhesive layer is coated on the second surface of the first substrate or the third surface of the second substrate; Providing a plurality of gaskets, wherein the head of the gasket is located between the first substrate and the second substrate to separate the second surface of the first substrate from the third surface of the second substrate, and the tail of the gasket extends outside the first substrate and the second substrate; The distance between the second surface of the first substrate and the third surface of the second substrate separated by the spacer is 1000-2000 μm; A clamping device is provided, comprising a plurality of clamping claws for clamping the edges of the first substrate and the second substrate; the spacer is arranged adjacent to the clamping claws, with a spacing between the two being no greater than 10 mm; After the first and second substrates are aligned, the edges of the first and second substrates are clamped by clamping jaws, and the clamping device together with the first and second substrates are moved into the bonding machine chamber. During the bonding process, after vacuuming and preheating, the plurality of clamping jaws and gaskets are operated in sequence according to the following steps: Opening the clamping jaws to at least separate the clamping jaws from the first surface of the first substrate, pulling the gasket at the position corresponding to the opened clamping jaws out from between the first substrate and the second substrate, so that the edge of the first substrate corresponding to the position of the gasket contacts the edge of the second substrate, and then closing the clamping jaws to clamp the first substrate and the second substrate; Until all the gaskets are pulled away from the first substrate and the second substrate, the upper cover plate applies pressure to the first substrate and the second substrate and heats them to complete the bonding.

2. The substrate bonding method according to claim 1, wherein: During the alignment process: the first substrate is first placed on the carrier, and the heads of the plurality of gaskets extend above the edge of the second surface of the first substrate, and the heads of the gaskets contact the second surface; The third surface of the second substrate is positioned toward the first substrate, and an alignment process is used to align the edge of the second substrate with the edge of the first substrate. The second substrate is then placed on the spacer so that the edge of the third surface of the second substrate contacts the head of the spacer. The jaws of the clamping device then clamp the edges of the first surface of the first substrate and the fourth surface of the second substrate to secure the first substrate to the second substrate. or: The second substrate is first placed on the carrier, with the heads of the plurality of gaskets extending above the edge of the third surface of the second substrate and the heads of the gaskets contacting the third surface; The second surface of the first substrate is made to face the first substrate, and an alignment process is used to make the edge of the first substrate and the edge of the second substrate overlap. Then, the first substrate is placed on the gasket, so that the edge of the second surface of the first substrate contacts the head of the gasket. Then, the claws of the clamping device clamp the edges of the first surface of the first substrate and the fourth surface of the second substrate to fix the first substrate and the second substrate.

3. The substrate bonding method according to claim 1, wherein: The number of spacers and jaws is consistent, 3-6, and evenly distributed.

4. The substrate bonding method according to claim 1, wherein: The size of the first substrate and the second substrate is 200-300 mm.

5. The substrate bonding method according to claim 1, wherein: The second substrate is a wafer, the first substrate is glass, a dam protruding from the second plane is provided at the edge of the second surface of the first substrate, and the adhesive layer is coated on the dam.

6. The substrate bonding method according to claim 5, wherein: The thickness of the cofferdam is 20-40 μm.

7. The substrate bonding method according to claim 1 or 6, wherein: The thickness of the adhesive layer is 5-30 μm.

8. The substrate bonding method according to claim 1, wherein: The connecting part of the clamp is fixedly connected to a connecting rod, and the connection between the clamp and the connecting rod is hingedly mounted on the clamping device. The extension and contraction of the piston of the first cylinder installed in the bonding machine chamber can push the connecting rod and the clamp to rotate around the pin shaft. The opening and closing of the clamp is controlled by the piston rod of the first cylinder and the connecting rod connected to the connecting part of the clamp through the lever principle.

9. The substrate bonding method according to claim 1, wherein: The tail of the gasket is connected to the piston rod of the second cylinder, and the gasket is pulled out and extended by the extension and contraction of the piston rod of the second cylinder.

10. A substrate manufactured by the substrate bonding method according to any one of claims 1 to 9.

Images