CN116949579A - Separation method for silicon carbide ingot - Google Patents
Separation method for silicon carbide ingot Download PDFInfo
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- CN116949579A CN116949579A CN202310839189.2A CN202310839189A CN116949579A CN 116949579 A CN116949579 A CN 116949579A CN 202310839189 A CN202310839189 A CN 202310839189A CN 116949579 A CN116949579 A CN 116949579A
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- Prior art keywords
- silicon carbide
- etching
- carbide ingot
- ingot
- separation method
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- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 98
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 96
- 238000000926 separation method Methods 0.000 title claims description 12
- 238000005530 etching Methods 0.000 claims abstract description 80
- 235000012431 wafers Nutrition 0.000 claims abstract description 38
- 238000000034 method Methods 0.000 claims abstract description 36
- 238000001312 dry etching Methods 0.000 claims abstract description 21
- 230000004888 barrier function Effects 0.000 claims abstract description 15
- 239000007789 gas Substances 0.000 claims description 11
- 238000000059 patterning Methods 0.000 claims description 10
- 238000010329 laser etching Methods 0.000 claims description 5
- 238000007648 laser printing Methods 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 21
- 239000013078 crystal Substances 0.000 description 20
- 238000005520 cutting process Methods 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000000903 blocking effect Effects 0.000 description 6
- 229910003460 diamond Inorganic materials 0.000 description 6
- 239000010432 diamond Substances 0.000 description 6
- 238000001039 wet etching Methods 0.000 description 6
- 229920002120 photoresistant polymer Polymers 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- 238000001259 photo etching Methods 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 239000000110 cooling liquid Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000002173 cutting fluid Substances 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000006552 photochemical reaction Methods 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000009281 ultraviolet germicidal irradiation Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
- C30B33/08—Etching
- C30B33/10—Etching in solutions or melts
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/36—Carbides
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The present application provides a method of separating a silicon carbide ingot, clamping the silicon carbide ingot such that a length direction of the silicon carbide ingot extends horizontally; forming a plurality of etching barrier patterns surrounding the cylindrical surface on the cylindrical surface of the silicon carbide ingot, the plurality of etching barrier patterns having intervals therebetween, respectively; etching is performed simultaneously with the etching gas so that a plurality of individual wafers are formed. The application performs dry etching of a silicon carbide ingot by forming an etching resistance pattern on the surface of the silicon carbide ingot. The etching process has the advantages that the etching gas is used for simultaneously carrying out double sides in the etching process, the ingot is rotated to enable the etching to be more uniform, the etching speed and the rotating speed are continuously changed according to different etching depths, so that the utilization rate of the silicon carbide ingot is greatly improved, meanwhile, the etched surface is better in uniformity, the thinning step can be omitted, meanwhile, the process time of CMP is reduced, and the cost is lower. Since the micro damage of dry etching is less, the yield of the product is better.
Description
Technical Field
The application relates to the technical field of silicon carbide and silicon carbide ingots, in particular to a method for separating silicon carbide ingots.
Background
Due to the improvement of technology, new requirements of high frequency, high voltage, high power, high temperature, radiation resistance and the like are put forward for semiconductor materials. Silicon carbide has a good forbidden bandwidth, breakdown electric field strength, thermal conductivity and saturated electron drift velocity, and is widely used in the field of semiconductors. The cutting process of silicon carbide ingots is therefore particularly important, and the quality and accuracy of the processing of silicon carbide wafers has a great impact on their further use. The silicon carbide ingot is generally processed by adopting a wet etching technology, and the defects of uneven etching linewidth and the like are gradually eliminated due to poor fidelity of wet etching patterns. Currently, the silicon carbide ingot is cut in the market according to the cutting principle into free mortar slices and fixed wire cuts.
The cost of equipment required by free mortar slicing is low, silicon carbide crystal grains in cutting fluid are driven to roll by wires, and crystal bars are cut in a continuous mode, but produced wafers are easy to produce uneven thickness, chippings are easy to produce at cut parts, the recycling difficulty of silicon carbide particles is increased, and resource waste and environmental pollution are easy to cause. The fixed wire cutting equipment has higher cost and time saving, and when cutting the crystal bar, the slicing equipment cuts the crystal bar through cutting particles (such as diamond particles) on the cutting wire and cools the crystal bar by using cooling liquid, thereby generating wafers with uniform thickness, and the wire cutting has the advantages of high cutting speed, high processing precision and the like. However, compared with the traditional silicon, the silicon carbide has high hardness, high wear resistance, high corrosion resistance and higher high-temperature strength, and the existing slicing equipment and operation of the silicon carbide crystal bar are mostly carried out at a linear speed of 400-700 m/min, so that the slicing quality of the silicon carbide crystal bar is poor. However, if the linear speed of the existing slicing equipment and operation is increased, the problems such as cutting line breakage are easily caused. The cutting method reduces the service life of the diamond wire, and needs frequent replacement, and meanwhile, the wire cutting method has slower production speed and higher loss, and cannot realize mass production.
Disclosure of Invention
In order to overcome the defects of frequent replacement of cutting lines, high silicon carbide ingot loss and low production speed in the prior art, the application provides a method for separating silicon carbide ingots, which can solve the defects.
In one aspect of the present application, a method for separating a silicon carbide ingot is provided, which includes clamping the silicon carbide ingot such that a length direction of the silicon carbide ingot extends horizontally, forming a plurality of etching barrier patterns surrounding the cylindrical surface on the cylindrical surface of the silicon carbide ingot with spaces therebetween, respectively, dry etching the silicon carbide ingot with an etching gas such that a plurality of individual wafers are formed, dry or wet unmasking each wafer having been separated to form a single wafer. The silicon carbide crystal ingot is ensured to be uniformly etched, the width of the obtained silicon carbide wafer is uniform, and the etching efficiency is greatly improved by adopting simultaneous processing of two sides.
Further, the gap width of the etching blocking pattern corresponds to the thickness of the wafer to be formed, the etching blocking pattern can avoid being etched by etching gas, the silicon carbide crystal ingot part covered by the etching blocking pattern is protected, the silicon carbide wafer obtained by etching is thinner, the time of the subsequent CMP process is shortened, meanwhile, the problem that more silicon carbide is ground in the CMP process due to the fact that the silicon carbide wafer obtained by cutting is too thick is solved, and the material loss is reduced.
Further, the gap thickness of the etched impedance pattern is between 100 and 700 mu m, silicon carbide removed by etching is reduced, and material loss is reduced.
Further, the silicon carbide ingot is rotated during the dry etching process to make the etching more uniform, avoiding the single direction etching, resulting in brittle fracture of the silicon carbide wafer.
Further, the rotation speed is set within the range of 10-5000r/min, and the rotation speed lower than 10r/min is too slow, so that the production efficiency is reduced, and the rotation speed higher than 5000r/min is not uniform in silicon carbide crystal etching, so that the silicon carbide wafer is subjected to brittle fracture in the etching process.
Further, the speed of rotation was gradually adjusted from 5000r/min to 10r/min.
Further, the rate of dry etching is adjusted with the depth of etching.
Further, the dry etching speed is set between 1 and 100 mu m/min, the rotation speed and the etching speed of the silicon carbide crystal ingot are changed according to the etching depth of the silicon carbide crystal ingot, the quality of an etching section can be reduced when the etching speed is too high, the production efficiency can be influenced when the etching speed is too low, and the productivity is too low; the scheme ensures that the silicon carbide wafer obtained by etching has better surface uniformity, reduces surface micro-damage and improves the yield.
Further, the upper and lower etching gases of the dry etching synchronously finish double-sided etching on the silicon carbide ingot, and the double-sided etching shortens the process time and simultaneously reduces the probability of brittle fracture.
Further, the forming mode of the etching barrier pattern comprises any one of photoetching patterning, laser etching patterning and printing patterning, and different forming modes of the etching barrier pattern are selected according to different application fields of the silicon carbide wafer.
The application provides a silicon carbide ingot separation method, which is characterized in that a plurality of etching blocking patterns encircling a cylinder are formed on the surface of the cylinder of the silicon carbide ingot, the width of each etching blocking pattern is the same as the thickness of the required silicon carbide ingot, the thinning step is omitted, the CMP process time is reduced, and the loss caused by subsequent polishing is reduced. The dry etching is adopted, the dry etching is synchronously carried out through the upper etching gas and the lower etching gas, and the crystal is rotated in the etching process to enable the crystal to be etched more uniformly. The gaps between the etching barrier patterns are narrower, silicon carbide removed by etching is reduced, loss of silicon carbide crystal ingots is reduced, and the material utilization rate is greatly improved. And removing redundant colloid in the wafer by dry etching or wet etching to obtain the finished silicon carbide wafer. According to the silicon carbide crystal ingot separation method provided by the application, the obtained silicon carbide wafer has better surface uniformity, the production cost is lower, and the silicon carbide wafer obtained by dry etching has less micro damage, so that the yield is higher.
Drawings
The drawings illustrate embodiments and together with the description serve to explain the principles of the application. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.
Figure 1 is a schematic flow chart of a silicon carbide ingot separation process in accordance with an embodiment of the application,
FIG. 2 is a schematic illustration of silicon carbide ingot etching in accordance with an embodiment of the application.
Reference numerals in the drawings: 101-etching a blocking pattern, 102-silicon carbide ingot cylinder, 103-silicon carbide ingot center axis.
Detailed Description
The following describes examples of the application to better understand the application, and many of the intended advantages of other embodiments and examples can be appreciated from the detailed description that follows. It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising" does not exclude the presence of additional identical elements in a process, method, article, or apparatus that comprises an element. Components of embodiments may be positioned in a number of different orientations, and so directional terminology, such as "top," "bottom," "left," "right," "up," "down," etc., is used with reference to the orientation of the figures to describe some embodiments. It is to be understood that the directional terminology is used for purposes of illustration and not limitation.
The SiC wafer is widely applied, along with the development of technology, the conventional chemical etching cannot meet the current requirement on the SiC wafer, and the dry etching gradually reaches the brand-new angle. Fig. 1 is a schematic flow chart of silicon carbide ingot separation in an embodiment of the application, and fig. 2 is a schematic flow chart of silicon carbide ingot etching in an embodiment of the application, clamping a silicon carbide ingot cylinder 102 so that the length direction of the silicon carbide ingot cylinder 102 extends horizontally. The silicon carbide ingot cylinder 102 surface is formed with a plurality of etching barrier patterns 101 surrounding the silicon carbide ingot cylinder 102 in any one of a photolithography patterning, a laser etching and a printing patterning, with gaps between the etching barrier patterns 101. The silicon carbide ingot cylinder 102 rotates around the silicon carbide ingot center axis 103, dry etching is synchronously performed through upper and lower etching gases, etching is performed according to the etching speed and the rotation speed of the silicon carbide ingot cylinder which are regulated according to different etching depths, and the surface residual glue of the obtained wafer is removed through dry etching or wet etching, so that the single crystal wafer is obtained
In this embodiment, the pattern thickness of the etching barrier pattern corresponds to the thickness of the wafer to be formed, the part uncovered by the etching barrier pattern 101 is etched and removed, and the wafer with good uniformity on the surface is obtained by adjusting the rotation speed and the etching rate of the silicon carbide ingot at different etching depths, so that the thinning step is omitted, and the CMP process time is reduced. Meanwhile, brittle fracture of the silicon carbide wafer in the processing process is avoided, and the yield is improved.
In another preferred embodiment, the etching barrier pattern is formed by any one of photoetching patterning, laser etching patterning and printing patterning, a layer of photoresist is coated on the surface of the silicon carbide crystal ingot to be etched, the etching barrier pattern is formed on the surface of the silicon carbide crystal ingot to be etched by UV irradiation through a mask, and the part which is not covered by the photoresist is removed by a plasma etching technology.
In another preferred embodiment, a layer of photoresist is coated on the surface of the silicon carbide ingot, after the etching is completed to obtain a wafer, the photoresist is left on the surface of the obtained wafer, and the photoresist on the surface of the single crystal wafer is removed by dry etching or wet etching.
In another preferred embodiment, the laser etching is mainly divided into direct etching and induced etching, wherein the focused laser beam is adopted to directly irradiate the surface of the diamond film, and the rapid etching of the diamond is completed through a photochemical process and a thermal process, so that the processing process is simple. The induced etching is to put diamond in a certain gas, and make the gas and the substrate generate photochemical reaction under the irradiation of laser, thereby achieving the etching purpose. At present, a large number of two modes are combined for forming and processing the diamond film, and the microstructure manufactured by the method has the advantages of neat edge, large depth-to-width ratio, high precision, high efficiency, low cost and the like, has the flexibility in manufacturing, and is suitable for mass production.
In another preferred embodiment, the gap thickness of the etching resistance pattern is between 100 and 700 mu m, and silicon carbide is reduced from being etched and removed in the process of simultaneously polishing the silicon carbide ingot by etching gas up and down, so that the utilization rate of the silicon carbide ingot is improved.
In another preferred embodiment, the silicon carbide ingot is rotated during etching to make the etching more uniform, wherein the speed of rotation is set in the range of 10-5000r/min, and the speed of rotation is gradually adjusted from 5000r/min to 10r/min as the etching progresses, and the speed is decelerated every 10r/min as a unit of speed. In the embodiment, the surface uniformity of the silicon carbide wafer obtained by controlling the rotation speed of the silicon carbide ingot is better, the brittle fracture of the silicon carbide wafer in the etching process is reduced, the micro damage of the silicon carbide wafer is reduced, and the yield is improved.
In another preferred embodiment, the step of adjusting the rate of dry etching with the depth of etching, the rate of dry etching is set between 1-100 μm/min. Compared with the traditional wet etching, the CMP process time of the silicon carbide wafer obtained in the embodiment is reduced, the cost is lower, and the yield of the wafer is improved.
The foregoing is a preferred embodiment of the present application, and it will be apparent to those skilled in the art that various modifications and variations can be made to the embodiment of the present application without departing from the spirit and scope of the application. In this manner, the application is also intended to cover such modifications and variations as come within the scope of the appended claims and their equivalents.
Claims (10)
1. A method for separating a silicon carbide ingot, comprising:
clamping the silicon carbide ingot such that a length direction of the silicon carbide ingot extends horizontally;
forming a plurality of etching barrier patterns surrounding the cylindrical surface on the cylindrical surface of the silicon carbide ingot, wherein a plurality of etching barrier patterns are respectively provided with intervals;
dry etching the silicon carbide ingot with an etching gas so as to form a plurality of individual wafers;
each wafer which is separated is subjected to dry or wet mask removal to form a single wafer.
2. The method of separating a silicon carbide ingot according to claim 1, wherein the gap width of the etch stop pattern corresponds to the thickness of the wafer to be formed.
3. The method of separating a silicon carbide ingot as set forth in claim 2 wherein the etch resistance pattern has a gap thickness of between 100 and 700 μm.
4. A separation method for a silicon carbide ingot according to claim 3 wherein the silicon carbide ingot is rotated during the dry etching to make etching more uniform.
5. A separation method for a silicon carbide ingot according to claim 4 wherein the speed of rotation is set in the range of 10-5000 r/min.
6. A separation method for a silicon carbide ingot as claimed in claim 5 wherein the speed of rotation is adjusted stepwise from 5000r/min to 10r/min as etching progresses.
7. A separation method for a silicon carbide ingot according to claim 1 comprising the step of adjusting the rate of the dry etch with the depth of the etch.
8. The separation method for silicon carbide ingot according to claim 7, wherein the dry etching speed is set between 1 and 100 μm/min.
9. The separation method for silicon carbide ingot according to claim 1, wherein the double-sided etching is completed on the silicon carbide ingot by synchronizing the upper and lower etching gases of the dry etching.
10. The method of claim 1, wherein the etching barrier pattern is formed by a method comprising photolithographic patterning, laser etching and/or printing patterning.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310839189.2A CN116949579A (en) | 2023-07-10 | 2023-07-10 | Separation method for silicon carbide ingot |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310839189.2A CN116949579A (en) | 2023-07-10 | 2023-07-10 | Separation method for silicon carbide ingot |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116949579A true CN116949579A (en) | 2023-10-27 |
Family
ID=88441930
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310839189.2A Pending CN116949579A (en) | 2023-07-10 | 2023-07-10 | Separation method for silicon carbide ingot |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116949579A (en) |
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2023
- 2023-07-10 CN CN202310839189.2A patent/CN116949579A/en active Pending
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