CN217493055U - Processing device for forming modified layer in silicon carbide crystal ingot - Google Patents
Processing device for forming modified layer in silicon carbide crystal ingot Download PDFInfo
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- CN217493055U CN217493055U CN202220696717.4U CN202220696717U CN217493055U CN 217493055 U CN217493055 U CN 217493055U CN 202220696717 U CN202220696717 U CN 202220696717U CN 217493055 U CN217493055 U CN 217493055U
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- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 1
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Abstract
The utility model relates to a laser beam machining technical field discloses a processingequipment for forming modified layer inside the carborundum ingot, include: the control unit controls the servo motor to drive the silicon carbide crystal ingot to rotate according to a preset rotating speed; during the rotation, the control unit controls the laser unit to make a linear motion along a radial direction of the silicon carbide ingot at a predetermined rate, and performs laser irradiation on the inside of the silicon carbide ingot during the linear motion. The utility model discloses a rotary motion, laser scanning line motion are made to the carborundum ingot, scan the ingot and form the modified layer, and the modified movement track of laser no longer is the inside reciprocating broken line of crystal, has reduced the extravagant time of broken line motion in-process motor acceleration and deceleration, improves machining efficiency.
Description
Technical Field
The utility model relates to a laser beam machining technical field specifically is a processingequipment who is used for forming modified layer inside the carborundum ingot.
Background
Because the third-generation semiconductor represented by silicon carbide, diamond and gallium nitride has the characteristics of wider forbidden bandwidth, higher thermal conductivity, higher radiation resistance, higher electron saturation drift rate and the like, various devices prepared by taking the third-generation semiconductor as a substrate are more suitable for being applied to the industries of 5G communication, new energy and power electronics. However, the materials have extremely high hardness, so that the processing of the materials is very difficult, the traditional semiconductor wafer separation method, such as mortar cutting, diamond wire cutting and the like, has the phenomena of long time consumption and serious material waste when the wafers are processed, and the invention patent 'CN 110010519A' proposes that pulse laser is focused in an ingot, a modified layer is formed at the focus, and then the wafers are separated from the modified layer, so that the method not only can improve the processing efficiency, but also can greatly reduce the material waste.
However, the conventional laser processing platform, such as patent "CN 110010519A", is usually an XY two-axis linear motion platform, and when such a platform is used to perform scanning processing on the end face of a generally cylindrical ingot, the platform needs to perform reciprocating linear motion by frequent acceleration and deceleration to complete the processing of the whole end face, which is the processing path in the conventional mode as shown in fig. 2; in the whole processing process, the time of platform acceleration and deceleration occupies a large part, and meanwhile, frequent acceleration and deceleration can also cause the instability of the processed crystal ingot on the platform due to inertia, so that the depth of a laser focus in the crystal ingot is influenced, the height of a formed modified layer is inconsistent, and the thickness uniformity of a wafer is poor; the laser energy may be insufficient or excessive in the acceleration and deceleration section, which affects the modification degree of the modified layer and the success rate of the subsequent wafer separation.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to solve traditional laser beam machining platform and scan the problem that leads to the effect not good man-hour to the ingot, provide a processingequipment who is used for forming the modified layer in carborundum ingot inside.
In order to achieve the above object, the present invention provides a processing apparatus for forming a modified layer inside a silicon carbide ingot, comprising: the device comprises a servo motor, a fixing unit, a laser unit and a control unit;
the fixing unit is used for fixing the silicon carbide crystal ingot;
the control unit controls the servo motor to drive the fixing unit to rotate according to a preset rotating speed, so that the silicon carbide crystal ingot fixed on the fixing unit is driven to rotate;
the control unit controls the laser unit to make a linear motion along a radius direction of the silicon carbide ingot at a predetermined rate during the rotation, and performs laser irradiation on the inside of the silicon carbide ingot during the linear motion to form a modified layer at a predetermined depth inside the silicon carbide ingot.
Alternatively, the scanning track of the laser irradiation is a spiral or a plurality of concentric circles with different radii.
Optionally, the fixing unit includes a rotary table for fixing the silicon carbide ingot and a metal chuck for fixing the metal chuck, wherein the rotary table, the metal chuck and the silicon carbide ingot are fixed in concentric circles.
Optionally, the rotary table is provided with an electromagnet, and the metal chuck is fixed on the rotary table in a manner of electromagnetic attraction with the electromagnet.
Optionally, the laser unit comprises at least one laser head, and the control unit controls the at least one laser head to perform linear feed motion or linear uniform motion along the radial direction of the silicon carbide ingot from the center of the silicon carbide ingot to the outer side of the silicon carbide ingot or from the outer side of the silicon carbide ingot to the center of the silicon carbide ingot at a predetermined rate;
when the laser unit comprises at least two laser heads, the at least two laser heads are arranged at intervals along the radius direction of the silicon carbide crystal ingot and respectively irradiate different inner and outer areas on the surface of the silicon carbide crystal ingot so as to realize irradiation of the whole surface of the silicon carbide crystal ingot, wherein in the process that the at least two laser heads irradiate different areas on the surface of the silicon carbide crystal ingot, corresponding focusing depths are set according to the light refractive indexes corresponding to the different areas, so that the heights of modified layers formed by irradiation of the different inner and outer areas of the silicon carbide crystal ingot are consistent.
Optionally, the diameter of a light spot formed by laser irradiation in the silicon carbide crystal ingot is 10-50 um, the distance between adjacent scanning lines in a scanning track of the laser irradiation is the diameter of the light spot or is smaller than the diameter of the light spot, and the overlapping rate of the light spots formed by the laser irradiation is 0-50%.
Optionally, the laser device further comprises a guide rail, and the control unit controls the laser unit to move linearly along the guide rail along the radial direction of the silicon carbide crystal ingot at a predetermined speed.
The utility model has the advantages that: the laser head does slow linear motion through the rotary worktable, the motion is more stable, a more flat and uniform modified layer is formed by the motion track of a concentric circle or a spiral line, so that a better surface type wafer can be obtained, the motion track of laser modification is not a reciprocating broken line in a crystal any more, the time wasted by acceleration and deceleration of a motor in the broken line motion process is reduced, and the processing efficiency and the stability are improved; in addition, the two laser heads work cooperatively, and different laser process conditions can be adopted on the periphery and the inside of the crystal ingot, so that the laser focusing position deviation caused by the edge effect of the crystal can be compensated, the modified layers in the inner part and the edge of the crystal ingot are ensured to be positioned on the same horizontal plane, and the in-chip consistency of the thickness of the wafer is ensured.
Drawings
Fig. 1 is a schematic structural view of a processing apparatus for forming a modified layer inside a silicon carbide ingot according to an embodiment of the present invention when a laser head is one.
Fig. 2 is a schematic diagram of a laser scanning movement track of a conventional laser processing apparatus.
Fig. 3 is a schematic diagram of a laser scanning motion track of a processing device for forming a modified layer inside a silicon carbide ingot when a laser head performs a linear feed motion when the laser head is one.
Fig. 4 is the embodiment of the utility model provides a processing apparatus for forming modified layer inside silicon carbide ingot laser scanning movement track schematic diagram when the laser head carries out sharp uniform motion when the laser head is one.
Fig. 5 is a schematic diagram showing the change of the rotation speed of the silicon carbide ingot when the laser head performs a linear feed motion and the laser pulse frequency is fixed in the processing device for forming a modified layer inside the silicon carbide ingot according to the embodiment of the present invention.
Fig. 6 is a schematic diagram showing the change of the laser pulse frequency when the rotation speed of the silicon carbide ingot is fixed when the laser head performs the linear feed motion when the laser head is one in the processing device for forming the modified layer inside the silicon carbide ingot according to the embodiment of the present invention.
Fig. 7 is a schematic structural view of a processing apparatus for forming a modified layer inside a silicon carbide ingot according to an embodiment of the present invention when there are two laser heads.
Fig. 8 is a schematic view of the scanning area of the first laser head and the second laser head when two laser heads are used in the processing apparatus for forming a modified layer inside a silicon carbide ingot according to the embodiment of the present invention.
Fig. 9a is a schematic diagram of the processing apparatus of the present invention for forming a modified layer inside a silicon carbide ingot, wherein the laser head is a schematic diagram of the depth difference between the modified layer in the inner region and the modified layer in the edge region when scanning the silicon carbide ingot.
Fig. 9b is the utility model discloses a processingequipment for forming modified layer inside the silicon carbide ingot, when the laser head be two and scan the silicon carbide ingot, realize the inside and unanimous schematic diagram of edge modification zone depth of silicon carbide.
Fig. 10 is a schematic diagram of the reason why the embodiment of the present invention is applied to the processing apparatus for forming a modified layer inside a silicon carbide ingot, which causes the inconsistency in the heights of the inside and edge modification regions of silicon carbide when the number of the laser heads is one.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The embodiment of the utility model provides a still provide a technical scheme: a processing apparatus for forming a modified layer inside a silicon carbide ingot, comprising: the device comprises a servo motor, a fixing unit, a laser unit and a control unit;
the fixing unit is used for fixing the silicon carbide crystal ingot;
the control unit controls the servo motor to drive the fixing unit to rotate according to a preset rotating speed, so that the silicon carbide crystal ingot fixed on the fixing unit is driven to rotate;
the control unit controls the laser unit to make a linear motion along the radius direction of the silicon carbide crystal ingot fixed on the fixing unit at a preset speed during the rotation, and performs laser irradiation on the inside of the silicon carbide crystal ingot during the linear motion so as to form a modified layer at a preset depth inside the silicon carbide crystal ingot, wherein the scanning track of the laser irradiation is a spiral line or a plurality of concentric circles with different radiuses.
The diameter of a light spot formed by laser irradiation in the silicon carbide crystal ingot is 10-50 um, the distance between adjacent scanning lines in a scanning track for laser irradiation is the diameter of the light spot or is smaller than the diameter of the light spot, and the overlapping rate of the light spots formed by laser irradiation is 0-50%.
As shown in fig. 1, the fixing unit comprises a rotary table 101 and a metal chuck 102, the metal chuck 102 is used for fixing a silicon carbide ingot 103, wherein the silicon carbide ingot can be fixed on the metal disc with ferromagnetism by gluing or wax sticking, wherein the gluing can be performed by using epoxy resin glue for bonding, the silicon carbide ingot and the metal chuck are fixed in concentric circles, the deviation of the total thickness of the surface of the silicon carbide ingot after bonding is TTV <10um, and the concentricity of the silicon carbide ingot and the metal chuck can be ensured by a positioning pin; the rotary worktable 101 is used for fixing the metal chuck 102, the rotary worktable 101 is provided with an electromagnet, the metal chuck is fixed on the rotary worktable 101 through the electromagnetic attraction mode of the electromagnet, wherein, the metal chuck is placed with the rotary worktable in a concentric circle position, and the concentricity of the metal chuck and the rotary worktable can be ensured through mechanical positioning.
The control unit controls the servo motor 100 to drive the rotary table 101 to rotate according to a preset rotating speed, the rotating speed is adjustable from 50RPM to 5000RPM, and the silicon carbide crystal ingot 103 is adsorbed on the rotary table 101 through the metal chuck 102 and also moves in a rotating mode according to the preset rotating speed.
The processing apparatus for forming a modified layer inside a silicon carbide ingot of the present embodiment further includes a guide rail, and the control unit controls the laser unit to linearly move along the guide rail at a predetermined rate in a radial direction of the silicon carbide ingot fixed to the fixing unit.
The laser unit comprises at least one laser head, the control unit controls the at least one laser head to perform linear feeding motion or linear uniform motion along the radius direction of the silicon carbide crystal ingot fixed on the fixing unit from the center of the silicon carbide crystal ingot to the outer side of the silicon carbide crystal ingot or from the outer side of the silicon carbide crystal ingot to the center of the silicon carbide crystal ingot according to a preset speed, wherein when the laser unit comprises at least two laser heads, the at least two laser heads are arranged at intervals along the radius direction of the silicon carbide crystal ingot fixed on the fixing unit and respectively scan different areas of the surface of the silicon carbide crystal ingot so as to realize scanning of the whole surface of the silicon carbide crystal ingot, the scanning efficiency is improved, and in addition, the at least two laser heads perform irradiation on different areas of the surface of the silicon carbide crystal ingot, setting corresponding focusing depths according to the corresponding optical refractive indexes of different areas, so that the heights of modified layers formed by irradiation in different areas inside and outside the silicon carbide crystal ingot are consistent; specifically, when the laser unit irradiates on the surfaces of different areas in the center and the periphery of the silicon carbide crystal ingot, the rotation speed of the silicon carbide crystal ingot and/or the laser irradiation frequency and the focusing depth are controlled, so that the properties of the modified layer formed by irradiation in the center and the periphery of the silicon carbide crystal ingot are consistent.
As an embodiment, as shown in fig. 1, the laser unit includes a laser head 104, the linear motion includes a linear feeding motion or a linear uniform motion, during the rotation of the silicon carbide ingot 103, the control unit controls the guide rails to drive the laser heads 104 to make a straight feed motion or a straight uniform motion along the radius direction of the silicon carbide ingot fixed on the fixing unit from the center of the silicon carbide ingot to the outer side of the silicon carbide ingot or from the outer side of the silicon carbide ingot to the center of the silicon carbide ingot at a predetermined rate, and the laser head moves linearly while the laser beam continuously provides laser pulses according to the pulse frequency (1 KHz-500 KHz), and the laser pulses are focused at a certain set depth in the silicon carbide crystal ingot to modify the material to form a modified layer.
When linear feeding motion is carried out, the feeding speed is adjustable from 0.01-1.0 mm/step/sec, the rotating speed of the silicon carbide crystal ingot and the feeding speed of the laser head are cooperated with each other, so that the distance between scanned laser spots on a motion track is consistent, the linear feeding motion can be carried out in a mode of changing the rotating speed of the silicon carbide crystal ingot by fixing the laser pulse frequency, or in a mode of changing the rotating speed of the silicon carbide crystal ingot by fixing the rotating speed of the silicon carbide crystal ingot by changing the laser pulse frequency; specifically, the method comprises the following steps: when the laser pulse frequency is fixed, the circular motion track is short near the center of the silicon carbide crystal ingot, the silicon carbide crystal ingot is subjected to a faster rotating speed, the circular motion track is long near the outer side of the silicon carbide crystal ingot, the silicon carbide crystal ingot is subjected to a slower rotating speed, the rotating speed is gradually increased from low to high when the servo motor is started, and the laser head can scan from the outer side of the silicon carbide crystal ingot to the center of the silicon carbide crystal ingot along the radial direction at the fixed laser pulse frequency, and the rotating speed of the 6-inch silicon carbide crystal ingot changes from the outer side of the silicon carbide crystal ingot to the center of the silicon carbide crystal ingot when the fixed laser pulse frequency is 50KHz as shown in figure 5; when the rotation speed of the silicon carbide ingot is fixed, the system needs to wait for the rotation speed of the silicon carbide ingot to be stabilized at a preset value, then the laser head scans from the center of the silicon carbide ingot to the outer side of the silicon carbide ingot along the radius direction or scans from the outer side of the silicon carbide ingot to the center of the silicon carbide ingot along the radius direction, the pulse frequency of the laser is set to be low at a position close to the center, and the pulse frequency of the laser is set to be high at a position far from the center, as shown in fig. 6, when the rotation speed of the 6-inch silicon carbide ingot is fixed to be 200RPM, the change of the laser pulse frequency from the center of the silicon carbide ingot to the outer side of the silicon carbide ingot is realized.
When performing the linear feeding motion, the laser head is fed a certain distance from the outer side of the silicon carbide ingot to the center of the silicon carbide ingot every time the silicon carbide ingot rotates, until the laser head moves to the center of the silicon carbide ingot, or the laser head is fed a certain distance from the center of the silicon carbide ingot to the outer side of the silicon carbide ingot, until the laser head moves to the outer side of the silicon carbide ingot, the scanning of the whole end face is completed, the motion track of the laser head on the silicon carbide ingot is the motion track composed of a plurality of concentric circles with different radiuses as shown in fig. 3, and the distances between the adjacent concentric circles are the same.
When the laser head performs linear uniform motion, the rate of the uniform motion of the laser head is adjustable from 0.01-1.0 mm/sec, the rotating speed of the silicon carbide crystal ingot and the moving speed of the laser head are cooperated with each other, so that the distance between the scanned laser spots on the motion track is consistent, the laser motion can be performed in a mode of changing the rotating speed of the silicon carbide crystal ingot by fixing the laser pulse frequency, and can also be performed in a mode of changing the laser pulse frequency by fixing the rotating speed of the silicon carbide crystal ingot; and when the silicon carbide ingot rotates, the laser head makes uniform linear motion from the center of the silicon carbide ingot to the outer side of the silicon carbide ingot until the laser head moves to the outer side of the silicon carbide ingot, or the laser head makes uniform linear motion from the outer side of the silicon carbide ingot to the center of the silicon carbide ingot until the laser head moves to the center of the silicon carbide ingot to complete scanning of the whole end face, the motion track of the laser head on the silicon carbide ingot is a spiral line as shown in fig. 4, and the intervals between the adjacent spiral lines are the same.
As an improvement of the above embodiment, the laser unit includes at least two laser heads, the at least two laser heads are arranged at intervals along the radial direction of the silicon carbide ingot fixed on the fixing unit, the control unit controls the guide rail to drive the at least two laser heads to perform linear feeding motion or linear uniform motion along the radial direction of the silicon carbide ingot fixed on the fixing unit from the center of the silicon carbide ingot to the outer side of the silicon carbide ingot or from the outer side of the silicon carbide ingot to the center of the silicon carbide ingot at a predetermined rate, respectively scan different regions of the surface of the silicon carbide ingot to realize scanning of the entire surface of the silicon carbide ingot, wherein the at least two laser heads are set with corresponding focusing depths according to the corresponding light refractive indexes of the different regions during irradiation of the different regions of the surface of the silicon carbide ingot, so that the heights of the modified layers formed by irradiation in different areas inside and outside the silicon carbide crystal ingot are consistent.
Further, the method also comprises the following steps: the properties of the modified layers formed by irradiation of different areas inside and outside the silicon carbide ingot are consistent by adjusting the laser intensity, the laser irradiation frequency, the spot size, the pulse width and the like of at least two laser heads in different areas inside and outside the silicon carbide ingot.
For example, as shown in fig. 7, the laser unit comprises two laser heads, namely a first laser head 104a and a second laser head 104b, which are arranged in parallel along the radius direction of the silicon carbide ingot fixed on the fixing unit, wherein the first laser head 104a is responsible for scanning the annular area of the edge of the silicon carbide crystal, and the second laser head 104b is responsible for scanning the circular area inside the silicon carbide crystal, but in other embodiments, the two laser heads are not arranged in parallel but arranged in a staggered way, but when one laser head is aligned with the outer edge of the silicon carbide ingot, the other laser head is positioned inside the silicon carbide ingot, the first laser head and the second laser head are arranged in parallel along the radius direction, and scanning is carried out in regions, so that the whole end face of the silicon carbide ingot can be scanned, fig. 8 shows the scanning zones corresponding to the two laser heads, wherein the first laser head 104a scans correspondingly a first scanning zone a, that is, an annular zone at the edge of the silicon carbide crystal, and the second laser head 104b scans correspondingly a second scanning zone b, that is, a circular zone inside the silicon carbide crystal, wherein different focusing depths are set due to the different optical refractive indexes of the first scanning zone and the second scanning zone, so as to ensure that the obtained modified layers are consistent.
In particular, fig. 9a and 9b further illustrate the advantages of using two laser heads for processing. When only one laser head processes the whole silicon carbide ingot, in order to maintain the stability of the processing, the laser head 104 adopts the same focusing depth, and scans from the inner part to the outer periphery or from the outer periphery to the inner part, and as shown in fig. 9a, the problem that the heights of the edge modification layer and the inner modification layer are not consistent can occur; fig. 10 further illustrates the reason for the inconsistent height of the modified layer, because of the large refractive index difference between the inner region and the peripheral air of the silicon carbide crystal, the media around the laser focusing spot of the inner region are all silicon carbide, while one side of the laser focusing spot of the edge region is silicon carbide, the refractive index is n-2.654, the other side is air, and the refractive index is n-1, which results in different refraction effects of the optical path, causes the inconsistency of the focusing depth at the inner side and the edge of the crystal, and finally forms the modified regions with two different depths. When two laser heads are adopted, the second laser head 104b processes the second scanning area b, namely the inner circular area, and the first laser head 104a processes the second scanning area a, namely the peripheral annular area, as shown in fig. 9b, the height difference between the edge and the inner modified area caused by the refractive index difference can be compensated through the setting of different focusing depths of the two laser heads, so that the height of the inner modified layer and the edge is consistent, and the thickness uniformity in the processed wafer surface is ensured.
During processing, when the rotating speed of the silicon carbide crystal ingot reaches a preset rotating speed, the first laser heads and the second laser heads are arranged at intervals along the radial direction of the silicon carbide crystal ingot fixed on the fixing unit, and do linear feed motion or linear uniform motion integrally along the radial direction of the silicon carbide crystal ingot from the center of the silicon carbide crystal ingot to the outer side of the silicon carbide crystal ingot or from the outer side of the silicon carbide crystal ingot to the center of the silicon carbide crystal ingot at different laser pulse frequencies and different laser focusing depths respectively, one laser head is responsible for scanning the outer periphery, and the other laser head is responsible for a larger inner area, namely completing the scanning of the whole surface of the silicon carbide crystal ingot.
When the scanning of the whole end face is finished, namely the laser modification of one wafer is finished, a modification layer is formed, the wafer after the laser modification is stripped from the upper part of the silicon carbide ingot in a vacuum adsorption mode, and then the upper surface of the stripped silicon carbide ingot is ground, wherein the method specifically comprises the following steps: demagnetizing the rotary workbench, taking away the metal chuck, keeping the state that the silicon carbide ingot is adhered to the metal chuck, and grinding the upper surface of the silicon carbide ingot on a grinding workbench/working position to reduce the roughness of the upper surface of the silicon carbide ingot to be within 50 nm; then the metal chuck and the rest silicon carbide crystal ingot are electromagnetically adsorbed on the rotary worktable, so that the metal chuck and the rotary worktable are arranged in concentric circles, and the next silicon carbide crystal wafer is subjected to laser modification and stripping; when the thickness of the silicon carbide crystal ingot is not enough to peel one silicon carbide crystal ingot, demagnetizing the rotary worktable, taking away the metal chuck of the tool, carrying out off-line degumming removal on the residual part, and then placing the next metal chuck adhered with the silicon carbide crystal ingot to peel the next silicon carbide crystal wafer.
In this embodiment, the rotation scanning process and the linear scanning process are compared by setting specific laser parameters and motion parameters, see table 1, in which the processing efficiency of the two processing modes of the rotation scanning process and the linear scanning process is compared, and it is obvious that the time consumption of the rotation scanning process is much smaller than that of the linear scanning process no matter whether the wafer process is a wafer process with a diameter of 100mm (4 inches) or a wafer process with a diameter of 150mm (6 inches).
TABLE 1
The utility model provides a new processingequipment that is used for forming the modified layer inside the carborundum ingot, and the difference with traditional device be this device fix the ingot on a rotatory processing platform, the rotary motion is with certain rotational speed along with the workstation to the carborundum ingot, the laser head is linear feed motion or at the uniform velocity linear motion along the rectilinear direction of carborundum ingot, and both accomplish the scanning to the circular terminal surface of whole crystal in coordination.
The utility model discloses a rotary motion is done to the rotary worktable, the laser head is slow linear motion, and the motion is more stable, forms more level and smooth and even modified layer with the movement track of concentric circles or helix to do benefit to and obtain the wafer of more excellent face type, and the movement track of laser modification no longer is the reciprocal broken line in the crystal, has reduced the motor acceleration and deceleration waste time in the broken line motion process, improves machining efficiency; the motion state of the silicon carbide crystal ingot is more stable under the rotation motion, and the problems of unstable crystal fixation and non-uniform laser energy caused by acceleration and deceleration can be avoided; furthermore, two laser heads are adopted to work cooperatively, and different laser process conditions can be adopted on the periphery and the inside of the crystal ingot, so that the laser focusing position deviation caused by the edge effect of the crystal can be compensated, the modified layers in the inner part and the edge of the crystal ingot are ensured to be positioned on the same horizontal plane, and the in-chip consistency of the thickness of the wafer is ensured.
Although the present invention has been disclosed in the preferred embodiments, it is not intended to limit the present invention, and any person skilled in the art can use the above-mentioned method and technical contents to make possible changes and modifications to the technical solution of the present invention without departing from the spirit and scope of the present invention, and therefore, any simple modification, equivalent changes and modifications made to the above embodiments by the technical substance of the present invention all belong to the protection scope of the technical solution of the present invention.
Claims (7)
1. A processing apparatus for forming a modified layer inside a silicon carbide ingot, comprising: the device comprises a servo motor, a fixing unit, a laser unit and a control unit;
the fixing unit is used for fixing the silicon carbide crystal ingot;
the control unit controls the servo motor to drive the fixing unit to rotate according to a preset rotating speed, so that the silicon carbide crystal ingot fixed on the fixing unit is driven to rotate;
the control unit controls the laser unit to make a linear motion along a radius direction of the silicon carbide ingot at a predetermined rate during the rotation, and performs laser irradiation on the inside of the silicon carbide ingot during the linear motion to form a modified layer at a predetermined depth inside the silicon carbide ingot.
2. A processing apparatus as set forth in claim 1 wherein the scanning trajectory of the laser irradiation is a spiral or a plurality of concentric circles of different radii.
3. A processing apparatus as set forth in claim 1 wherein the holding unit comprises a rotary table and a metal chuck for holding the silicon carbide ingot, the rotary table being used for holding the metal chuck, wherein the rotary table, the metal chuck and the silicon carbide ingot are all held in concentric circles.
4. A processing apparatus as set forth in claim 3 wherein the rotary table is provided with an electromagnet and the metal chuck is fixed to the rotary table by way of electromagnetic attraction with the electromagnet.
5. The processing apparatus for forming a modified layer inside a silicon carbide ingot as set forth in claim 1, wherein the laser unit comprises at least one laser head, and the control unit controls the at least one laser head to make a straight feed motion or a straight uniform motion along a radius direction of the silicon carbide ingot from a center of the silicon carbide ingot to an outer side of the silicon carbide ingot or from the outer side of the silicon carbide ingot to the center of the silicon carbide ingot at a predetermined rate;
when the laser unit comprises two laser heads, the two laser heads are arranged at intervals along the radius direction of the silicon carbide crystal ingot and respectively irradiate different inner and outer areas on the surface of the silicon carbide crystal ingot so as to realize irradiation of the whole surface of the silicon carbide crystal ingot, wherein in the process that at least two laser heads irradiate different areas on the surface of the silicon carbide crystal ingot, corresponding focusing depths are set according to the light refractive indexes corresponding to the different areas, so that the heights of modified layers formed by irradiation of the different areas inside and outside the silicon carbide crystal ingot are consistent.
6. A processing apparatus as set forth in claim 1 wherein the diameter of a spot formed by laser irradiation inside the silicon carbide ingot is 10 to 50 μm, the pitch between adjacent scanning lines in a scanning track of the laser irradiation is the spot diameter or less, and the overlapping ratio of spots formed by the laser irradiation is 0 to 50%.
7. A processing apparatus for forming a modified layer inside a silicon carbide ingot as set forth in claim 1, further comprising a guide rail, wherein the control unit controls the laser unit to make a linear movement along the guide rail at a predetermined rate in a radial direction of the silicon carbide ingot.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220696717.4U CN217493055U (en) | 2022-03-28 | 2022-03-28 | Processing device for forming modified layer in silicon carbide crystal ingot |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114473188A (en) * | 2022-03-28 | 2022-05-13 | 杭州乾晶半导体有限公司 | Laser processing method and device for stripping wafer |
| CN115971642A (en) * | 2022-12-30 | 2023-04-18 | 山东天岳先进科技股份有限公司 | A kind of silicon carbide peeling sheet and processing method based on laser cracking |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114473188A (en) * | 2022-03-28 | 2022-05-13 | 杭州乾晶半导体有限公司 | Laser processing method and device for stripping wafer |
| CN115971642A (en) * | 2022-12-30 | 2023-04-18 | 山东天岳先进科技股份有限公司 | A kind of silicon carbide peeling sheet and processing method based on laser cracking |
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Assignee: Suzhou Heyu Finance Leasing Co.,Ltd. Assignor: Hangzhou Qianjing Semiconductor Co.,Ltd. Contract record no.: X2023980048824 Denomination of utility model: A processing device for forming a modified layer inside silicon carbide ingots Granted publication date: 20220927 License type: Exclusive License Record date: 20231201 |
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Denomination of utility model: A processing device for forming a modified layer inside silicon carbide ingots Effective date of registration: 20231206 Granted publication date: 20220927 Pledgee: Suzhou Heyu Finance Leasing Co.,Ltd. Pledgor: Hangzhou Qianjing Semiconductor Co.,Ltd. Registration number: Y2023980069375 |
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Address after: Building 1, No. 78 Donggang Eighth Road, Quzhou City, Zhejiang Province, China 324022 Patentee after: Zhejiang Caizi Technology Co.,Ltd. Country or region after: China Address before: 311200 room 205-2, building 1, Information Port Phase V, No. 733, Jianshe Third Road, Xiaoshan District, Hangzhou, Zhejiang Province Patentee before: Hangzhou Qianjing Semiconductor Co.,Ltd. Country or region before: China |