Method and device for cutting silicon wafer underwater through green wavelength laser

Abstract

The invention relates to a method and device for cutting a silicon wafer underwater through green wavelength laser. The method comprises the steps that the silicon wafer to be machined is fixed in a container containing liquid; an optical path distance for underwater laser cutting exists between the silicon wafer to be processed and the glass at the bottom of the container cover; enabling the liquid in the container to flow and keep stable, and focusing the laser on the surface of the silicon wafer through glass at the bottom of the container cover and the liquid above the silicon wafer; and the laser moves according to a preset path and completes cutting, and chippings generated by cutting are removed through flowing liquid. According to the method and device for underwater cutting of the silicon wafer through the green wavelength laser, by adopting a non-contact machining means, physical pressure on the wafer is reduced, the requirements of the semiconductor industry for a high-precision and low-damage cutting process can be met, meanwhile, flowing liquid can remove chippings generated by cutting, and the cutting efficiency is improved. And the situation that dust and chippings generated in the cutting process pollute the surrounding environment can be effectively prevented.

Description

Technical Field

[0001] The invention relates to the technical field of silicon wafer cutting, and in particular to a method and a device for underwater cutting of silicon wafers using a green wavelength laser. Background Art

[0002] Silicon wafer refers to the silicon chip used in the production of silicon semiconductor integrated circuits. Because of its round shape, it is called a silicon wafer. Various circuit component structures can be processed on the silicon wafer to become an integrated circuit product with specific electrical functions. Traditional silicon wafer cutting technology usually uses a diamond knife for mechanical cutting. This method may damage the silicon wafer because it needs to apply physical pressure to the silicon wafer. At the same time, the dust and debris generated during the mechanical cutting process are easy to pollute the surrounding environment. Therefore, it needs to be improved. Summary of the invention

[0003] Based on this, it is necessary to provide a method and device for underwater cutting of silicon wafers using a green wavelength laser, in response to the problem that traditional silicon wafer cutting technology usually uses a diamond knife for mechanical cutting. This method may damage the silicon wafer due to the need to apply physical pressure to the silicon wafer. At the same time, the dust and debris generated during the mechanical cutting process can easily pollute the surrounding environment.

[0004] The present invention provides a method for underwater cutting of silicon wafers using a green wavelength laser, comprising:

[0005] Fixing a silicon wafer to be processed in a container filled with liquid;

[0006] There is an optical path distance between the silicon wafer to be processed and the bottom glass of the container cover for underwater laser cutting;

[0007] The liquid in the container is made to flow and remain stable, and the laser is focused on the surface of the silicon wafer through the bottom glass of the container cover and the liquid above the silicon wafer;

[0008] The laser moves along a predetermined path to complete the cutting, and the flowing liquid removes the debris produced by the cutting.

[0009] In one of the embodiments, the optical path distance for underwater laser cutting is in the range of 0.1-10 mm.

[0010] In one embodiment, the flow rate of the liquid is in the range of 1-20 L / min.

[0011] In one embodiment, the laser cutting power is 10W-40W, and the laser speed is 600mm / s-2000mm / s.

[0012] In one of the embodiments, the liquid includes deionized water, aqueous solution, or other liquid that is beneficial for underwater silicon wafer cutting.

[0013] The present invention also provides a device for underwater cutting of silicon wafers using a green wavelength laser, comprising:

[0014] A workbench, comprising a first support and a second support, wherein the second support is provided with a first cylinder, and an output end of the first cylinder is provided with a third support;

[0015] A container is fixed on the first support member and has a container cover, wherein the middle portion of the container cover has high light transmittance glass;

[0016] A wafer suction cup is mounted on the inner wall of the container;

[0017] a water pump, mounted on the first support member and having a liquid inlet pipe and a liquid outlet pipe, wherein the water inlet end of the liquid inlet pipe is located on one side of the container, and the water outlet end of the liquid outlet pipe is located on the other side of the container;

[0018] A filter, mounted on the liquid inlet pipe;

[0019] The laser cutter is installed on the third supporting member and has a laser head.

[0020] In one embodiment, the container cover includes a bending portion and a recessed portion, the high light transmittance glass is located in the recessed portion, and the angle of the bending portion is a right angle.

[0021] In one embodiment, the inner wall of the container is fixedly connected to a fourth support member, and the fourth support member divides the inner cavity of the container into a gas cavity and a liquid cavity. A second cylinder is installed in the gas cavity, and the output end of the second cylinder is fixedly connected to a limiting cylinder. The limiting cylinder is located in the liquid cavity, and the wafer suction cup is installed on the inner bottom wall of the limiting cylinder.

[0022] In one embodiment, an X-axis adjustment assembly is installed on the surface of the workbench, and a Y-axis adjustment assembly is installed on the surface of the X-axis adjustment assembly. The X-axis adjustment assembly and the Y-axis adjustment assembly both include a fifth support member, a motor is installed on the surface of the fifth support member, a lead screw is fixedly connected to the output end of the motor, a guide rail is fixedly connected to the surface of the fifth support member, a slider is slidably connected to the guide rail, and the slider is threadedly connected to the lead screw, the fifth support member in the X-axis adjustment assembly is fixed on the workbench, the fifth support member in the Y-axis adjustment assembly is fixed on the slider in the X-axis adjustment assembly, and the first support member is fixed on the slider in the Y-axis adjustment assembly.

[0023] In one of the embodiments, the laser beam emitted by the laser head has a wavelength of 532 nm.

[0024] The above-mentioned method and device for underwater cutting of silicon wafers using green wavelength laser, during the underwater laser cutting process, the laser beam is focused inside the silicon wafer, generating local high temperature to melt or vaporize the material, thereby achieving cutting. By adopting non-contact processing means, the physical pressure on the wafer is reduced, which can meet the semiconductor industry's demand for high-precision, low-damage cutting technology. At the same time, by using the high energy of the laser to perform precise cutting of silicon wafers underwater, the heat-affected zone in the cutting process can be reduced, the cutting quality can be improved, and it is convenient to adapt to changes in the material properties of the silicon wafer, such as a reduction in thickness and an increase in the requirements for cutting quality. In addition, the flowing liquid can remove the debris generated by the cutting, which can effectively prevent the dust and debris generated during the cutting process from polluting the surrounding environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A schematic diagram of a method for underwater cutting of silicon wafers using a green wavelength laser in one embodiment;

[0027] Figure 2 A schematic diagram of the structure of a device for underwater cutting of silicon wafers using a green wavelength laser in one embodiment;

[0028] Figure 3 A schematic diagram of a partial structure of a device for underwater cutting of silicon wafers using a green wavelength laser in one embodiment;

[0029] Figure 4 is a schematic diagram of a cross-sectional structure of a container in an embodiment;

[0030] Figure 5 Schematic diagram of the structure of the Y-axis adjustment component in one embodiment.

[0031] Reference numerals:

[0032] 200, workbench; 210, first support member; 220, second support member; 230, first cylinder; 240, third support member; 300, container; 310, container cover; 311, bending portion; 312, recessed portion; 320, high-transmittance glass; 330, fourth support member; 340, second cylinder; 350, limiting cylinder; 360, gas cavity; 370, liquid cavity; 400, wafer suction cup; 500, water pump; 510, liquid inlet pipe; 520, liquid outlet pipe; 600, filter; 700, laser cutter; 710, laser head; 800, X-axis adjustment assembly; 810, Y-axis adjustment assembly; 811, fifth support member; 812, motor; 813, lead screw; 814, guide rail; 815, slider. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of the present invention are for illustrative purposes only and do not represent the only implementation method.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first feature is directly in contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, a first feature being “above”, “above” or “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below” or “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0037] Unless otherwise defined, all technical and scientific terms used in the specification of the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the specification of the present invention includes any and all combinations of one or more related listed items.

[0038] Combine the following Figure 1-Figure 5 The invention describes a method and a device for underwater cutting of silicon wafers using a green wavelength laser.

[0039] like Figure 1 As shown, in one embodiment, a method for underwater cutting of silicon wafers with a green wavelength laser comprises:

[0040] Step S110, fixing the silicon wafer to be processed in a container filled with liquid.

[0041] Step S120, ensuring that there is an optical path distance between the silicon wafer to be processed and the bottom glass of the container cover for underwater laser cutting.

[0042] Step S130, making the liquid in the container flow and keep it stable, the laser passes through the bottom glass of the container cover and the liquid above the silicon wafer and focuses on the surface of the silicon wafer.

[0043] In step S140, the laser moves along a predetermined path and completes cutting, and the flowing liquid removes debris generated by the cutting.

[0044] The method for underwater cutting of silicon wafers with a green wavelength laser, during the underwater laser cutting process, the laser beam is focused inside the silicon wafer, generating local high temperature to melt or gasify the material, thereby achieving cutting. By adopting a non-contact processing method, the physical pressure on the wafer is reduced, and the semiconductor industry's demand for high-precision, low-damage cutting technology can be met. At the same time, by using the high energy of the laser to perform precise cutting of the silicon wafer underwater, the heat-affected zone in the cutting process can be reduced, the cutting quality can be improved, and changes in the material properties of the silicon wafer, such as a reduction in thickness and an improvement in the requirements for cutting quality, can be easily adapted. Moreover, the flowing liquid can remove the debris generated by the cutting, and can effectively prevent the dust and debris generated during the cutting process from polluting the surrounding environment.

[0045] In this embodiment, the optical path distance for underwater laser cutting is in the range of 0.1-10 mm.

[0046] In this embodiment, the flow rate of the liquid is in the range of 1-20 L / min.

[0047] In this embodiment, the laser cutting power is 10W-40W, and the laser speed is 600mm / s-2000mm / s.

[0048] In this embodiment, the liquid includes deionized water, aqueous solution, and other liquids that are beneficial to underwater silicon wafer cutting.

[0049] like Figure 2 , Figure 3 and Figure 4 As shown, in one embodiment, a device for underwater cutting of silicon wafers using a green wavelength laser includes a workbench 200 , a container 300 , a wafer suction cup 400 , a water pump 500 , a filter 600 and a laser cutter 700 .

[0050] The workbench 200 comprises a first support member 210 and a second support member 220 . A first cylinder 230 is disposed on the second support member 220 . A third support member 240 is disposed at an output end of the first cylinder 230 .

[0051] The container 300 is fixed on the first support member 210 , and the container 300 has a container cover 310 , and a high light-transmittance glass 320 is provided in the middle of the container cover 310 .

[0052] The wafer chuck 400 is installed on the inner wall of the container 300 .

[0053] The water pump 500 is installed on the first support member 210 and has a liquid inlet pipe 510 and a liquid outlet pipe 520 . The water inlet end of the liquid inlet pipe 510 is located on one side of the container 300 , and the water outlet end of the liquid outlet pipe 520 is located on the other side of the container 300 .

[0054] It should be noted that the flow rate of the water pump 500 can be precisely adjusted, the water outlet end of the liquid outlet pipe 520 is higher than the high-transmittance glass 320, and the water inlet end of the liquid inlet pipe 510 is lower than the processing plane of the silicon wafer, so that the water flow can more effectively carry away the debris generated during laser cutting. No matter how fast the water flow rate is, the water surface above the silicon wafer will not fluctuate due to contact with the glass, thereby ensuring stability during laser cutting.

[0055] The filter 600 is installed on the liquid inlet pipe 510 .

[0056] It should be noted that the filter 600 is composed of a housing, a multi-element filter element, a backwash mechanism, and a differential pressure controller. The diaphragm in the housing divides its inner cavity into an upper and lower cavity. The upper cavity is equipped with multiple filter elements, which expands the filtering space and significantly reduces the volume of the filter 600. A backwash suction cup is installed in the lower cavity. During operation, the turbid liquid enters the lower cavity of the filter 600 through the inlet and enters the inner cavity of the filter element through the diaphragm hole. Impurities larger than the gap of the filter element are trapped, and the clean liquid passes through the gap to the upper cavity and is finally sent out from the outlet. The filter 600 uses a high-strength wedge-shaped filter screen, which automatically cleans the filter element through pressure difference control and timing control. When impurities in the filter 600 accumulate on the surface of the filter element, causing the inlet and outlet pressure difference to increase to the set value, or when the timer reaches the preset time, the electric control box sends a signal to drive the backwash mechanism. When the backwash suction cup port is directly opposite to the filter element inlet, the drain valve opens, the system pressure is released and the water is drained, a negative pressure zone appears between the suction cup and the inside of the filter element where the relative pressure is lower than the water pressure outside the filter element, forcing part of the clean circulating water to flow from the outside of the filter element into the inside of the filter element, and the impurity particles adsorbed on the inner wall of the filter element flow into the drum with the water and are discharged from the drain valve, and the inlet and outlet pressure difference of the filter 600 returns to normal or the timer setting time ends.

[0057] The laser cutter 700 is installed on the third support member 240 , and the laser cutter 700 has a laser head 710 .

[0058] It should be noted that the height of the laser head 710 can be adjusted by controlling the first cylinder 230. The wavelength of the laser beam emitted by the laser head 710 is 532nm. By adjusting appropriate laser process parameters such as laser power, scanning speed, focal position, etc. and liquid parameters such as liquid flow rate, underwater optical path, liquid composition, etc., the quality and efficiency of underwater laser cutting can be further improved to obtain silicon wafers that meet the use requirements.

[0059] When the device for underwater cutting of silicon wafers with green wavelength laser is used, the silicon wafer is fixed on the wafer suction cup 400, and then the container 300 is filled with liquid, and the container cover 310 is closed. The 532nm laser is focused on the surface of the silicon wafer to be processed through the high light transmittance glass 320 at the bottom of the container cover 310 and the liquid above the silicon wafer. By adjusting the distance between the wafer and the high light transmittance glass 320, the flow rate of the liquid and the laser parameters, high-quality silicon wafer cutting is achieved. By starting the water pump 500 during the cutting process to keep the liquid in the container 300 at a stable flow rate, a On the one hand, the debris generated by the cutting process is quickly washed away by the flushing of liquid, and the molten area can be quickly solidified to prevent adhesion to the debris. At the same time, it is convenient to wash away a large number of bubbles generated by the interaction of the laser and the liquid. These bubbles can easily cause serious scattering of the laser, and the filter 600 effectively filters the debris and other impurities in the discharged liquid, ensuring the recycling of the liquid during cutting and improving the cutting quality. On the other hand, by adopting non-contact processing methods, the physical pressure on the wafer is reduced, which can meet the semiconductor industry's needs for high-precision, low-damage cutting processes.

[0060] In this embodiment, the container cover 310 includes a bending portion 311 and an inner recess 312 , the high light transmittance glass 320 is located in the inner recess 312 , and the angle of the bending portion 311 is a right angle.

[0061] By specially designing the shape of the container cover 310, the water surface above the silicon wafer will not fluctuate, thus not interfering with the laser cutting beam.

[0062] In this embodiment, the inner wall of the container 300 is fixedly connected to a fourth support member 330, and the fourth support member 330 divides the inner cavity of the container 300 into a gas cavity 360 and a liquid cavity 370. A second cylinder 340 is installed in the gas cavity 360, and the output end of the second cylinder 340 is fixedly connected to a limiting cylinder 350. The limiting cylinder 350 is located in the liquid cavity 370, and the wafer suction cup 400 is installed on the inner bottom wall of the limiting cylinder 350.

[0063] The height of the silicon wafer in the liquid can be conveniently adjusted as needed by controlling the second cylinder 340, and the limiting cylinder 350 can effectively prevent the silicon wafer from being displaced under the impact of the fluid during the cutting process, thereby improving the cutting accuracy.

[0064] In this embodiment, see Figure 5An X-axis adjustment component 800 is installed on the surface of the workbench 200, and a Y-axis adjustment component 810 is installed on the surface of the X-axis adjustment component 800. Both the X-axis adjustment component 800 and the Y-axis adjustment component 810 include a fifth support member 811. A motor 812 is installed on the surface of the fifth support member 811. A lead screw 813 is fixedly connected to the output end of the motor 812. A guide rail 814 is fixedly connected to the surface of the fifth support member 811. A slider 815 is slidably connected to the guide rail 814. The slider 815 is threadedly connected to the lead screw 813. The fifth support member 811 in the X-axis adjustment component 800 is fixed on the workbench 200, the fifth support member 811 in the Y-axis adjustment component 810 is fixed on the slider 815 in the X-axis adjustment component 800, and the first support member 210 is fixed on the slider 815 in the Y-axis adjustment component 810.

[0065] When the X-axis adjustment assembly 800 or the Y-axis adjustment assembly 810 is in use, the motor 812 is started to drive the lead screw 813 to move, and the lead screw 813 drives the slider 815 to move on the guide rail 814, so as to facilitate the adjustment of the position of the silicon wafer on the XY plane.

[0066] The device for underwater cutting of silicon wafers with green wavelength laser, on the one hand, can significantly reduce the heat-affected zone through the cooling effect of the liquid in a liquid environment, protect the physical properties of the material, and avoid deformation or damage of the material. At the same time, cutting under liquid can provide a smoother and more precise cutting edge, reducing the need for subsequent processing. Due to the high cutting accuracy, cutting under liquid can reduce material waste and improve material utilization. On the other hand, the flow of liquid helps to capture and carry away dust and debris, greatly improving the cutting efficiency. At the same time, the flow of liquid effectively solves the problem of interference of bubbles on the laser when the laser interacts with the liquid.

[0067] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above-described embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A method for underwater cutting of silicon wafers using a green wavelength laser, characterized in that: The method includes: Fixing a silicon wafer to be processed in a container filled with liquid; There is an optical path distance between the silicon wafer to be processed and the bottom glass of the container cover for underwater laser cutting; The liquid in the container is made to flow and remain stable, and the laser is focused on the surface of the silicon wafer through the bottom glass of the container cover and the liquid above the silicon wafer; The laser moves along a predetermined path to complete the cutting, and the flowing liquid removes the debris produced by the cutting.

2. The method for underwater cutting of silicon wafers using a green wavelength laser according to claim 1, characterized in that: The optical path distance for underwater laser cutting is in the range of 0.1-10 mm.

3. The method for underwater cutting of silicon wafers using a green wavelength laser according to claim 2, characterized in that: The flow rate of the liquid is in the range of 1-20 L / min.

4. The method for underwater cutting of silicon wafers using a green wavelength laser according to claim 1, characterized in that: The laser cutting power is 10w-40w, and the laser speed is 600mm / s-2000mm / s.

5. The method for underwater cutting of silicon wafers using a green wavelength laser according to any one of claims 1 to 4, characterized in that: The liquid includes deionized water, aqueous solution and other liquids that are beneficial to underwater silicon wafer cutting.

6. A device for underwater cutting of silicon wafers using a green wavelength laser, characterized in that: include: A workbench, comprising a first support and a second support, wherein the second support is provided with a first cylinder, and an output end of the first cylinder is provided with a third support; A container is fixed on the first support member and has a container cover, wherein the middle portion of the container cover has high light transmittance glass; A wafer suction cup is mounted on the inner wall of the container; a water pump, mounted on the first support member and having a liquid inlet pipe and a liquid outlet pipe, wherein the water inlet end of the liquid inlet pipe is located on one side of the container, and the water outlet end of the liquid outlet pipe is located on the other side of the container; A filter, mounted on the liquid inlet pipe; The laser cutter is installed on the third supporting member and has a laser head.

7. The device for underwater cutting of silicon wafers using a green wavelength laser according to claim 6, characterized in that: The container cover comprises a bending portion and an inner concave portion, the high light transmittance glass is located in the inner concave portion, and the angle of the bending portion is a right angle.

8. The device for underwater cutting of silicon wafers using a green wavelength laser according to claim 7, characterized in that: The inner wall of the container is fixedly connected to a fourth support member, and the fourth support member divides the inner cavity of the container into a gas cavity and a liquid cavity. A second cylinder is installed in the gas cavity, and the output end of the second cylinder is fixedly connected to a limiting cylinder. The limiting cylinder is located in the liquid cavity, and the wafer suction cup is installed on the inner bottom wall of the limiting cylinder.

9. The device for underwater cutting of silicon wafers using a green wavelength laser according to claim 8, characterized in that: An X-axis adjustment component is installed on the surface of the workbench, and a Y-axis adjustment component is installed on the surface of the X-axis adjustment component. Both the X-axis adjustment component and the Y-axis adjustment component include a fifth support member, a motor is installed on the surface of the fifth support member, a lead screw is fixedly connected to the output end of the motor, a guide rail is fixedly connected to the surface of the fifth support member, a slider is slidably connected to the guide rail, and the slider is threadedly connected to the lead screw, the fifth support member in the X-axis adjustment component is fixed on the workbench, the fifth support member in the Y-axis adjustment component is fixed on the slider in the X-axis adjustment component, and the first support member is fixed on the slider in the Y-axis adjustment component.

10. The device for underwater cutting of silicon wafers using a green wavelength laser according to any one of claims 6 to 9, characterized in that: The wavelength of the laser beam emitted by the laser head is 532nm.

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