Wafer slicing method based on heating-assisted laser processing and wafer

Abstract

The invention discloses a wafer slicing method based on heating-assisted laser processing and a wafer, which are applied to the technical field of semiconductor wafer processing, and comprises the following steps: heating the wafer to a preset temperature; the preset temperature is smaller than the melting temperature of the wafer; laser is focused at the preset depth of the wafer at the preset temperature, so that a laser irradiation area and a crack propagation area located on the outer side of the laser irradiation area are formed at the preset depth of the wafer; and moving the focusing position of the laser at the preset depth of the wafer at the preset temperature, so that the crack propagation areas on the outer sides of the adjacent laser irradiation areas are connected to form a main crack, and separating the wafer. Due to the combined action of laser and external heating, uniform thermal stress can be generated to stretch the tip of the micro-crack, so that the nano-crack is smoother during growth, further, lower joint cutting loss can be achieved, and the surface quality of a tangent plane is improved. By heating the wafer in advance, thermal stress distribution in the wafer can be more uniform, and wafer breakage caused by thermal stress concentration during laser irradiation is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor wafer processing, and in particular to a wafer slicing method based on heating-assisted laser processing and a wafer. Background Art

[0002] Silicon carbide is currently the third-generation semiconductor material with the most promising application prospects. It has unique advantages such as wide bandgap, high thermal conductivity, and strong working reliability. Silicon carbide has stable mechanical properties, with a Mohs hardness of up to 9.5, second only to diamond. It has stable chemical properties and does not react with strong acids and alkalis. It has stable thermal properties, does not exist in liquid under normal pressure, and will sublimate at 2000℃. It is the core material for high-power electronic devices in the fields of satellite communications, high-voltage power transmission and transformation, and electric vehicles. However, the excellent physical and chemical properties of silicon carbide also lead to problems such as difficulty in processing silicon carbide wafers and low yield. Silicon carbide slicing technology is the basis of silicon carbide device manufacturing, accounting for 47% of the cost of silicon carbide devices. At present, the industry still uses electroplated diamond multi-wire cutting of silicon carbide ingots. However, this technology still has many problems, such as wire cutting cannot obtain thinner wafers, and the surface quality of slices is poor (such as cracks, pits and other surface defects). And due to the line width limitation of electroplated diamond multi-wire sawing, each silicon carbide slicing will cause a kerf loss of about 100 μm to 200 μm, and 40% of the silicon carbide material will be lost in the form of dust, which affects the silicon carbide wafer yield and yield and increases production costs. Therefore, how to provide a wafer slicing method with lower kerf loss is an urgent problem that technicians in this field need to solve. Summary of the invention

[0003] The object of the present invention is to provide a wafer slicing method based on heating-assisted laser processing and a wafer with lower kerf loss.

[0004] In order to solve the above technical problems, the present invention provides a wafer slicing method based on heating-assisted laser processing, comprising:

[0005] Heating the wafer to a preset temperature; the preset temperature is lower than the melting temperature of the wafer;

[0006] Focusing the laser at a preset depth of the wafer at the preset temperature, so that the wafer forms a laser irradiation area at the preset depth and a crack extension area outside the laser irradiation area;

[0007] The laser is moved to a focus position at a preset depth of the wafer at the preset temperature, so that crack extension areas outside adjacent laser irradiation areas are connected to form a main crack, thereby separating the wafer.

[0008] Optionally, heating the wafer to a preset temperature includes:

[0009] The wafer is placed on a heating platform and heated to the preset temperature.

[0010] Optionally, the preset temperature ranges from 400° C. to 1000° C., including endpoint values.

[0011] Optionally, the wafer includes a silicon carbide wafer and a silicon carbide ingot.

[0012] Optionally, when the wafer is a silicon carbide ingot, the step of focusing the laser at a preset depth of the wafer at the preset temperature is repeated until the laser is moved to a focusing position at the preset depth of the wafer at the preset temperature, so as to repeatedly separate the wafer from the silicon carbide ingot.

[0013] Optionally, also include:

[0014] Polishing the cut surface of the separated wafer.

[0015] Optionally, the preset depth has a value range of 160 μm to 250 μm, including endpoint values.

[0016] Optionally, the spot size of the laser is no greater than 3 μm, and the laser power is 3 W to 5 W, including endpoint values.

[0017] Optionally, moving the laser to a focus position at a preset depth of the wafer at the preset temperature comprises:

[0018] Based on a scanning speed of 10 mm / s to 20 mm / s, a scanning interval of 100 μm to 200 μm moves the focusing position of the laser at a preset depth of the wafer at the preset temperature.

[0019] The present invention also provides a wafer, which is a wafer separated by any of the above-mentioned wafer slicing methods based on heating-assisted laser processing.

[0020] The present invention provides a wafer slicing method based on heating-assisted laser processing, comprising: heating the wafer to a preset temperature; the preset temperature is lower than the melting temperature of the wafer; focusing the laser at a preset depth of the wafer at the preset temperature, so that the wafer forms a laser irradiation area at the preset depth and a crack extension area outside the laser irradiation area; moving the laser to a focusing position at a preset depth of the wafer at the preset temperature, so that the crack extension areas outside adjacent laser irradiation areas are connected to form a main crack, thereby separating the wafer.

[0021] By heating the wafer first, and then laser slicing the wafer in the heated state, a laser irradiation area and a crack extension area outside the laser irradiation area will be generated based on the position of the laser direct irradiation during laser irradiation. The crack extension area causes the wafer material to melt, vaporize, and solidify to form nanocracks based on the laser irradiation. Due to the combined effect of the laser and external heating, uniform thermal stress can be generated to stretch the microcrack tips, making the nanocracks grow more smoothly. By moving the focal position of the laser, multiple periodic nanocracks can be generated and connected to each other to form a main crack, thereby separating the wafer. Under the action of the external heating field, the roughness of the wafer section can be made smaller, so that the wafer slicing method has lower kerf loss and improves the surface quality of the section.

[0022] At the same time, the laser slicing method is a non-contact processing method, which avoids the contact between diamond wire, cutting fluid and other materials and the wafer, thereby avoiding contamination and damage to the wafer, and solving problems such as wafer slicing tool wear and low processing efficiency. And by pre-heating the wafer, the thermal stress distribution in the wafer can be made more uniform, thereby reducing problems such as wafer breakage caused by thermal stress concentration during laser irradiation.

[0023] The present invention also provides a wafer, which also has the above-mentioned beneficial effects, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A flow chart of a wafer slicing method based on heating-assisted laser processing provided by an embodiment of the present invention;

[0026] Figure 2 A flowchart of a specific wafer slicing method based on heating-assisted laser processing provided by an embodiment of the present invention;

[0027] Figure 3 for Figure 2 The corresponding device schematic diagram;

[0028] Figure 4 This is a picture of nanocracks generated inside silicon carbide;

[0029] Figure 5 The three-dimensional morphology and optical micrograph of the cross section of silicon carbide;

[0030] Figure 6A comparison of the surface roughness and cutting seam morphology formed by heat-assisted laser processing and laser processing alone. DETAILED DESCRIPTION

[0031] The core of the present invention is to provide a wafer slicing method based on heating-assisted laser processing. In the slicing method of the prior art, mechanical force is usually applied to the wafer to finally separate the wafer. However, the mechanical force will cause large kerf loss in wafer slicing. In the traditional diamond wire cutting process, it usually takes 10 minutes to 16 minutes to cut a 5mm×5mm silicon carbide wafer, and due to the line width limitation of diamond wire cutting, each cutting will produce a kerf loss of about 150μm. In the process of cutting a 6-inch silicon carbide ingot, up to 40% of the silicon carbide becomes waste in the form of dust. In addition, there are knife marks on the surface of the wafer obtained by the traditional wire cutting process, and the surface roughness is 10μm~30μm. It is usually necessary to grind and polish a 50μm thick silicon carbide wafer to remove the knife marks and make the surface smooth.

[0032] The present invention provides a wafer slicing method based on heating-assisted laser processing, including: heating the wafer to a preset temperature; the preset temperature is lower than the melting temperature of the wafer; focusing the laser at a preset depth of the wafer at the preset temperature, so that the wafer forms a laser irradiation area at the preset depth and a crack extension area outside the laser irradiation area; moving the laser to a focusing position at a preset depth of the wafer at the preset temperature, so that the crack extension areas outside adjacent laser irradiation areas are connected to form a main crack, thereby separating the wafer.

[0033] By heating the wafer first, and then laser slicing the wafer in the heated state, a laser irradiation area and a crack extension area outside the laser irradiation area will be generated based on the position of the laser direct irradiation during laser irradiation. The crack extension area causes the wafer material to melt, vaporize, and solidify to form nanocracks based on the laser irradiation. Due to the combined effect of the laser and external heating, uniform thermal stress can be generated to stretch the microcrack tips, making the nanocracks grow more smoothly. By moving the focal position of the laser, multiple periodic nanocracks can be generated and connected to each other to form a main crack, thereby separating the wafer. Under the action of the external heating field, the roughness of the wafer section can be made smaller, so that the wafer slicing method has lower kerf loss and improves the surface quality of the section.

[0034] At the same time, the laser slicing method is a non-contact processing method, which avoids the contact between diamond wire, cutting fluid and other materials and the wafer, thereby avoiding contamination and damage to the wafer, and solving problems such as wafer slicing tool wear and low processing efficiency. And by pre-heating the wafer, the thermal stress distribution in the wafer can be made more uniform, thereby reducing problems such as wafer breakage caused by thermal stress concentration during laser irradiation.

[0035] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] Embodiment 1

[0037] Please refer to Figure 1 , Figure 1 A flow chart of a wafer slicing method based on heat-assisted laser processing provided in an embodiment of the present invention.

[0038] See also Figure 1 In an embodiment of the present invention, a wafer slicing method based on heating-assisted laser processing includes:

[0039] S101: heating the wafer to a preset temperature.

[0040] In the embodiment of the present invention, the preset temperature is lower than the melting temperature of the wafer. Since the purpose of the external heating field of the wafer in this application is to make the thermal stress distribution inside the wafer more uniform during the subsequent laser irradiation, the preset temperature reached by the wafer in this step needs to be lower than the melting temperature of the wafer, that is, the heating process in this step will not affect the physical properties of the wafer.

[0041] The wafer in this embodiment can be a silicon carbide wafer, or a silicon wafer, etc., and the specific material of the wafer is not specifically limited in this embodiment. In this embodiment, the preset temperature ranges from 400°C to 1000°C, including endpoint values. That is, this step usually heats the wafer to between 400°C and 1000°C. Taking silicon carbide wafers as an example, the physical properties of silicon carbide wafers with a temperature between 400°C and 1000°C will not change. Furthermore, in this embodiment, the above-mentioned wafers include silicon carbide wafers and silicon carbide ingots, that is, the wafer slicing method based on heating-assisted laser processing provided in this embodiment can be specifically applied to the wafer thinning process, as well as the process of cutting ingots.

[0042] S102: focusing the laser at a preset depth of the wafer at a preset temperature, so that a laser irradiation area and a crack extension area outside the laser irradiation area are formed at the preset depth of the wafer.

[0043] In this step, it is first necessary to focus the laser at a preset depth of the wafer while keeping the wafer at a preset temperature. At this time, the laser will heat the laser focus position at the preset depth in the wafer, and the heating temperature can reach 3000°C. Therefore, the laser can make the wafer at the laser focus position melt, vaporize, and solidify in sequence, and nanocracks will be generated outside the laser irradiation position, forming a laser irradiation area corresponding to the laser direct irradiation position, and a crack extension area corresponding to the nanocrack generation area. The above-mentioned nanocrack generation process is that the wafer stretches the microcrack tip under the uniform thermal stress generated by the joint action of the laser and the external heating field, so that the nanocrack grows. Generally speaking, the above-mentioned laser irradiation area and crack extension area will be formed in the horizontal direction at the preset depth of the wafer, so as to achieve wafer slicing.

[0044] S103: moving the laser to a focus position at a preset depth of the wafer at a preset temperature, so that the crack extension areas outside the adjacent laser irradiation areas are connected to form a main crack, and the wafer is separated.

[0045] In this step, the focal position of the laser in the wafer is usually moved in the plane where the preset depth of the wafer is located, so as to slice the wafer from the horizontal direction. Specifically, the change of the focal position in the wafer can be achieved by moving the wafer or moving the laser or moving the wafer and the laser at the same time. At present, the commonly used method is to move the focal position of the laser in the wafer along a straight line in a fixed horizontal plane, so as to form a laser irradiation area distributed along a straight line, and crack extension areas located on both sides of the laser irradiation area. Usually in this step, the laser will be controlled to scan repeatedly inside the wafer, generating multiple periodically divided laser irradiation areas and crack extension areas, and the nanocracks in the crack extension areas between adjacent laser irradiation areas will be connected to each other to expand to form a main crack, based on which the wafer can be separated to achieve slicing.

[0046] A wafer slicing method based on heating-assisted laser processing provided by an embodiment of the present invention heats the wafer first, and then laser slices the wafer in a heated state. When the laser is irradiated, a laser irradiation area and a crack extension area outside the laser irradiation area are generated based on the position of direct laser irradiation. The crack extension area melts, vaporizes, and solidifies the wafer material to form nanocracks based on the laser irradiation. Due to the combined effect of the laser and external heating, uniform thermal stress can be generated to stretch the microcrack tips, making the nanocracks grow more smoothly. By moving the focal position of the laser, multiple periodic nanocracks can be generated and connected to each other to form a main crack, thereby separating the wafer. Under the action of the external heating field, the roughness of the wafer section can be made smaller, so that the wafer slicing method has lower kerf loss and improves the surface quality of the section.

[0047] At the same time, the laser slicing method is a non-contact processing method, which avoids the contact between diamond wire, cutting fluid and other materials and the wafer, thereby avoiding contamination and damage to the wafer, and solving problems such as wafer slicing tool wear and low processing efficiency. And by pre-heating the wafer, the thermal stress distribution in the wafer can be made more uniform, thereby reducing problems such as wafer breakage caused by thermal stress concentration during laser irradiation.

[0048] The specific contents of the wafer slicing method based on heating-assisted laser processing provided by the present invention will be described in detail in the following invention embodiments.

[0049] Embodiment 2

[0050] Please refer to Figures 2 to 6 , Figure 2 A flowchart of a specific wafer slicing method based on heating-assisted laser processing provided by an embodiment of the present invention; Figure 3 for Figure 2 The corresponding device schematic diagram; Figure 4 This is a picture of nanocracks generated inside silicon carbide; Figure 5 The three-dimensional morphology and optical micrograph of the cross section of silicon carbide; Figure 6 A comparison of the surface roughness and cutting seam morphology formed by heat-assisted laser processing and laser processing alone.

[0051] See also Figure 2 In an embodiment of the present invention, a wafer slicing method based on heating-assisted laser processing includes:

[0052] S201: placing the wafer on a heating platform and heating it to a preset temperature.

[0053] See also Figure 3 In this step, a heating platform, such as an electromagnetic heating platform, can be used to continuously heat the wafer. Of course, in this embodiment, there is no specific limitation on the specific structure of the heating platform, which depends on the specific situation.

[0054] S202: focusing the laser at a preset depth of the wafer at a preset temperature, so that a laser irradiation area and a crack extension area outside the laser irradiation area are formed on the wafer at the preset depth.

[0055] In this step, the pulse laser is usually first adjusted to low power mode. In this mode, the CCD (charge coupled device) can be used to observe and confirm that the laser is irradiating the upper surface of the wafer. Then the Z axis of the mobile platform connected to the heating platform is adjusted to minimize the laser spot size in the CCD field of view. At this time, the focus position of the laser is determined to be on the wafer surface. Finally, the mobile platform can be adjusted to determine the processing coordinate parameters so that the wafer can be sliced ​​based on the processing coordinate parameters.

[0056] After determining that the focal position of the laser is located on the surface of the wafer, this step will further control the Z-axis of the mobile platform to focus the high-energy density pulsed laser through the objective lens at a preset depth below the upper surface of the wafer. The preset depth is usually in the range of 160μm to 250μm, including the endpoint value. The angle of the above-mentioned objective lens is usually not greater than 2.1mm, the spot size of the laser is usually not greater than 3μm, the numerical aperture (Na) of the objective lens is usually not less than 0.6, and the laser power of the above-mentioned laser is usually 3W~5W, including the endpoint value. The repetition frequency of the laser is usually 200 kHz, the pulse width of the laser is usually 200 ns, and the laser wavelength is usually 532 nm. Of course, in this embodiment, there is no specific limitation on the various parameters of the laser, which depends on the specific situation.

[0057] S203: moving the laser to a focus position at a preset depth of the wafer at a preset temperature, so that the crack extension areas outside the adjacent laser irradiation areas are connected to form a main crack, and the wafer is separated.

[0058] This step is basically the same as S103 in the above embodiment. For details, please refer to the above embodiment, which will not be described here. In this step, the focus position of the laser in the wafer is usually moved by controlling the movement of the mobile platform on the X-axis and Y-axis. This step can specifically include: based on a scanning speed of 10mm / s~20mm / s, the scanning interval of 100μm~200μm moves the focus position of the laser at a preset depth of the wafer at the preset temperature. That is, in this embodiment, the scanning speed is usually 10 mm / s to 20 mm / s, the laser overlaps scanning, and the scanning interval D is usually 100μm to 200μm. The pulsed laser overlaps scanning to melt, vaporize, and solidify the silicon carbide in the laser action area to produce nanocracks, forming the above-mentioned laser irradiation area and crack extension area. As the laser focus position moves, periodic nanocracks can be generated inside the wafer. Under the joint action of the thermal stress generated by the heating stage and the laser focus, the nanocracks grow and connect to form a main crack, separating the wafer.

[0059] In this embodiment, the high energy density pulse laser is focused inside the wafer to form local high temperature and high pressure, so that the wafer in the laser irradiation area melts, vaporizes, and solidifies to form nanocracks. Due to the combined effect of the thermal field generated by the laser repeated scanning and the heating assistance, a smaller and uniform thermal stress can be generated to stretch the nanocrack tip, so that the nanocrack expands and forms a crack extension zone on both sides of the laser irradiation area. The crack extension zone usually forms a nanocrack with a length of about 100μm to 200μm and a width of 81nm to 212nm, such as Figure 4In this step, laser is used to repeatedly scan the wafer at intervals of 100 μm to 200 μm, and periodic nanocracks are formed inside the wafer. Under the action of heating assistance and laser, the nanocracks are connected to each other to separate the silicon carbide wafer.

[0060] Since the temperature distribution formed by laser focusing inside the wafer is approximately Gaussian, the temperature near the laser focus is very high, which can reach about 3000°C, but in the area of ​​several hundred microns near the laser focus, the temperature of the material is only room temperature (e.g., 30°C), which will form a very high temperature difference and generate strong thermal stress, which may cause the wafer to break. In this embodiment, when the wafer is heated to a preset temperature, such as 400°C, the temperature difference around the laser focus and at the focus is significantly reduced, and the thermal stress generated is also reduced, thereby avoiding the breakage of the wafer, while reducing the roughness of the cut surface, and generating a crack structure with a size of less than 300 nm, thereby reducing the kerf loss of the silicon carbide wafer.

[0061] like Figure 5 As shown, the method provided in this embodiment uses laser and external heating to separate the silicon carbide wafer, and the cut surface is flat, without defects such as cracks and breakages. The average surface roughness of the cut surface is between 72nm and 81nm. The cut surface consists of two parts. One part is the laser irradiation area where the pulsed laser directly acts, and its surface is relatively rough. There are some raised micron structures at the edge of the laser irradiation area. The height difference Sz of the micron structure is usually around 1.821μm. Because there is still a certain temperature difference at the edge of the laser irradiation area, the silicon carbide wafer is broken. Further selection of flat-top laser or beam shaping can effectively solve this problem and improve the surface flatness of the wafer. In this embodiment, the average surface roughness of the laser irradiation area is 133 nm. The second part is the area where nanocracks grow, that is, the crack extension area. The wafer cut surface formed in this embodiment is smooth and flat, close to the requirements of mirror cutting, with an average surface roughness of 34 nm.

[0062] In this embodiment, when the wafer is a silicon carbide ingot, that is, when this embodiment specifically implements the process of cutting the ingot, this embodiment can repeatedly perform the steps of focusing the laser at the preset depth of the wafer at the preset temperature, and moving the laser to the focus position of the preset depth of the wafer at the preset temperature, so as to repeatedly separate the wafer from the silicon carbide ingot. That is, this embodiment can repeatedly cut the ingot by repeatedly performing the above S202 to S203.

[0063] S204: Polishing the cut surface of the separated wafer.

[0064] After the wafer is separated, a cut surface, i.e., a separation surface, is generated. In this step, the cut surface of the wafer can be further polished to improve the flatness of the wafer surface. Since the surface roughness of the wafer separated in this embodiment can be less than 300nm, the time used for polishing can be greatly reduced and the loss of the wafer caused by polishing can be reduced.

[0065] like Figure 6 As shown, Figure 6 The three-dimensional morphology and SEM (scanning electron microscope) morphology comparison diagram of the silicon carbide wafer separated by the combined action of laser and external heating field and the silicon carbide section separated by laser only in this embodiment. It can be seen that the external heating field heating can make the silicon carbide wafer produce more uniform thermal stress, the silicon carbide section morphology is flatter, and the cracks are straighter. This illustrates the superiority of laser and external heating field heating to separate silicon carbide wafers.

[0066] The present embodiment provides a wafer slicing method based on heating-assisted laser processing, which generates nanocracks through the combined action of laser and external electric field and regulates their growth to separate wafers, thereby avoiding the contamination and damage of the wafer surface caused by the contact separation of traditional diamond wire cutting, and improving the quality of the cut surface. The efficiency of heating-assisted laser processing to generate nanocracks to separate silicon carbide wafers exceeds that of traditional diamond wire cutting (laser processing speed can reach 20 mm / s), and the slices of laser-induced nanocrack peeling are thinner, with a thickness of about 160 μm to 250 μm.

[0067] The kerf loss generated when laser-induced nanocrack growth is used to separate wafers is less than the kerf loss of diamond wire cutting. Due to the line width limitation of diamond wire cutting, each cut will produce a kerf loss of 100μm to 200μm. In the process of cutting a 6-inch silicon carbide ingot, up to 40% of the silicon carbide becomes waste in the form of dust. When laser-induced nanocrack growth is used to separate silicon carbide wafers, the kerf loss generated each time is about 300 nm. When cutting silicon carbide ingots of the same thickness, the silicon carbide kerf loss is reduced by 99.9%. Heating-assisted laser processing can separate more wafers, improve the yield of silicon carbide wafers, and reduce production costs.

[0068] After the wafer is cut by diamond wire, it needs to go through a polishing process to eliminate the knife marks left on the wafer surface during the diamond wire cutting process. The surface roughness is usually between 10μm and 30μm. A wafer with a thickness of 50μm needs to be ground and polished to remove the knife marks and make the surface flat. In this embodiment, the silicon carbide wafer is separated by laser-induced nanocracks. The surface roughness (Sa) can be as low as 72 nm, the surface height difference (Sz) is as high as 3.7μm, and the thickness of silicon carbide lost during the grinding process is less than 10μm. The method provided in this embodiment can reduce the loss of silicon carbide wafers during the grinding and polishing process, improve the yield of silicon carbide wafers, and reduce production costs.

[0069] Embodiment 3

[0070] The present invention also provides a wafer, which is specifically a wafer separated by a wafer slicing method based on heating-assisted laser processing provided by any of the above-mentioned embodiments of the invention.

[0071] Since the wafer slicing method based on heating-assisted laser processing provided in the above-mentioned invention embodiment can produce a wafer with very low surface roughness, the wafer provided in this embodiment can have very low surface roughness. The specific preparation process for slicing the wafer has been described in detail in the above-mentioned invention embodiment, and will not be repeated here.

[0072] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0073] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0074] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0075] Finally, it should be noted that the terms "comprises", "includes" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0076] The above is a detailed introduction to a wafer slicing method and wafer based on heating-assisted laser processing provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A wafer slicing method based on heat-assisted laser processing, characterized in that: include: Heating the wafer to a preset temperature; the preset temperature is lower than the melting temperature of the wafer; Focusing the laser at a preset depth of the wafer at the preset temperature, so that the wafer forms a laser irradiation area at the preset depth and a crack extension area outside the laser irradiation area; The laser is moved to a focus position at a preset depth of the wafer at the preset temperature, so that crack extension areas outside adjacent laser irradiation areas are connected to form a main crack, thereby separating the wafer.

2. The method according to claim 1, characterized in that: Heating the wafer to a preset temperature involves: The wafer is placed on a heating platform and heated to the preset temperature.

3. The method according to claim 1, characterized in that The preset temperature ranges from 400° C. to 1000° C., including endpoint values.

4. The method according to claim 1, characterized in that The wafers include silicon carbide wafers and silicon carbide ingots.

5. The method according to claim 4, characterized in that When the wafer is a silicon carbide ingot, the steps of focusing the laser at a preset depth of the wafer at the preset temperature and moving the laser to a focusing position at the preset depth of the wafer at the preset temperature are repeated to repeatedly separate the wafer from the silicon carbide ingot.

6. The method according to claim 1, characterized in that Also includes: Polishing the cut surface of the separated wafer.

7. The method according to claim 1, characterized in that The preset depth has a value range of 160 μm to 250 μm, including the endpoint values.

8. The method according to claim 1, characterized in that: The spot size of the laser is no greater than 3 μm, and the laser power is 3W to 5W, including end points.

9. The method according to claim 8, characterized in that Moving the laser to a focus position at a predetermined depth of the wafer at the predetermined temperature comprises: Based on a scanning speed of 10 mm / s to 20 mm / s, a scanning interval of 100 μm to 200 μm moves the focusing position of the laser at a preset depth of the wafer at the preset temperature.

10. A wafer, characterized in that: A wafer separated by the wafer slicing method based on heat-assisted laser processing as described in any one of claims 1 to 9.

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