TWI539509B - Method for cutting ingot, brick and wafer - Google Patents

Description

Wafer rod cutting method, crystal tile and wafer

The invention relates to a cutting method of a wafer rod, a crystal brick and a wafer, in particular to a cutting method of a silicon wafer rod, and a twin crystal brick and a crucible cut by the cutting method. Wafer.

Referring to FIG. 1, a single crystal germanium wafer used in the semiconductor industry is known, mainly for cutting a single crystal rod 1 formed by a crystal pulling process (the cutting line 10 is illustrated) to a predetermined size of a crystal block (Brick). 11. The ingot 11 is then cut into a plurality of sheet-like germanium wafers 111. On the other hand, the mainstream specification of the single crystal rod 1 on the market is a single crystal rod 1 having a diameter of 8 inches, and is cut into a tantalum wafer 111 having a side length of about 6 吋 6 吋. The upper and lower left and right corners of the ingot 11 formed by the known cutting method are arc angles, so that the cut crucible wafer 111 exhibits a quadrangular shape in which the four corners are curved, and not the quadrangles in which the four corners are right angles.

After the single crystal rod 1 is cut into the ingots 11 of a predetermined size, the remaining portion of the single crystal rod 1 becomes the remaining side material, and can no longer be cut into the ingot 11 and the crucible wafer 111, so that the known cut is performed. The cutting method causes the edge material utilization ratio of the single crystal rod 1 to be poor, and the manufacturing cost per wafer 111 is high, and the cutting method needs to be improved.

Accordingly, it is an object of the present invention to provide a method of cutting a wafer rod which is innovative in cutting method, which can reduce production cost, and a ceramic tile and a wafer which are cut by the cutting method.

Thus, the method of cutting a wafer rod of the present invention comprises: providing a wafer rod having a circular cross section. On the cross section of the wafer rod, along a direction parallel to the wafer rod, a square crystal brick and four edge bricks respectively located around the square crystal brick are cut out, wherein the square crystal brick The length of a diagonal line parallel to the surface of the cross section is the same as the diameter of the wafer rod, and the side length of the surface is mL x mL, where m is an integer greater than or equal to 2, and L is a length. The square crystal brick is cut out into m×m square first crystal bricks, and a side of each first crystal brick parallel to the surface of the cross section has a length L×L. The four edge bricks are respectively cut into a square second brick, and a side of each second brick perpendicular to the surface of the cross section has a length L×L.

Another method for cutting a wafer rod according to the present invention differs from the first method described above in that the method is to cut the square crystal brick into m square first crystal bricks, each of the first crystal bricks. The length of one side of the surface parallel to the cross section is L x mL.

The crystal brick of the present invention comprises: a square crystal brick body, the material of the crystal brick body containing oxygen, and the oxygen concentration of the highest and lowest oxygen concentration in the four corners of one surface of the crystal brick body The value is greater than 1.5 ppma.

The wafer of the present invention comprises: a square substrate having four Opposite corners and a central location intersected by two diagonal lines passing through the four corners. The material of the substrate contains oxygen, and the oxygen concentration in the four corners of the substrate has a difference in oxygen concentration between the highest and the lowest two corners greater than 1.5 ppma.

The effect of the invention: by the above innovative cutting method, the wafer rod is first cut out of the square crystal brick and the four edge material crystal bricks, and then a plurality of first crystal bricks of a predetermined size are respectively cut and A plurality of second crystal bricks are subsequently cut out of the wafer. Since the use of edge bricks can improve the utilization of the wafer rods, the production cost per wafer can be reduced, and wafers with right angles can be cut, so that the wafers of single crystal can be made. After the film is assembled into a solar module, the overall light receiving area is increased.

2, 2'‧‧ ‧ wafer stick

20‧‧‧ wafers

201‧‧‧Substrate

202‧‧‧ corner

203‧‧‧Central location

21‧‧‧square crystal brick

210‧‧‧crystal brick body

211‧‧‧First crystal brick

212, 213‧‧‧ surface

214, 215, 216, 217‧‧ corner

218‧‧‧ side

22‧‧‧ edge brick

220‧‧‧crystal brick body

221‧‧‧Second crystal brick

222, 223‧‧‧ surface

224, 225, 226, 227‧‧ corner

23‧‧‧ cross section

3‧‧‧Axial direction

41‧‧‧First direction

42‧‧‧second direction

5‧‧‧坩锅

51‧‧‧矽 molten soup

A‧‧‧diagonal length

B‧‧‧ arrow

X, Y‧‧‧ length

R‧‧‧diameter

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is a schematic illustration of a cutting process showing a method of previously cutting a single crystal rod to obtain a plurality of germanium wafers. 2 is a schematic flow chart of a first preferred embodiment of a method for cutting a wafer rod of the present invention; FIG. 3 is a schematic view of a device for fabricating a wafer rod; and FIG. 4 is a crystal produced by the device of FIG. FIG. 5 is a schematic view of the present invention for cutting a first wafer into a plurality of wafers; FIG. 6 is a schematic view of the present invention for cutting a second wafer into a plurality of wafers; Figure 7 is a schematic view of another second wafer cut out of a plurality of wafers according to the present invention; Figure 8 is a schematic view of the first crystal brick of the present invention for cutting a square crystal brick into 3 × 3 squares. And FIG. 9 is a schematic flow chart showing a part of steps of a second preferred embodiment of the wafer bar cutting method of the present invention.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 2, a first preferred embodiment of the method for cutting a wafer rod of the present invention comprises the following steps.

Step 1: providing a wafer rod 2 having a cylindrical shape and having a circular cross section 23, the plane of the cross section 23 being perpendicular to an axial direction of the wafer rod 2 . Specifically, the wafer rod 2 may be a single wafer rod, and a wafer rod 2 having a diameter of 5 inches, 8 inches, 9 inches, 18 inches, 27 inches, 36 inches, etc. may be used. The axial length of the wafer rod 2 in the axial direction 3 is X, and X is a natural number greater than zero, and X = 156 mm in this embodiment.

Step 2: A square crystal brick 21 and four edge bricks 22 respectively located around the square crystal brick 21 are cut along the axial direction 3 of the cross section 23 of the wafer rod 2. Wherein, the square crystal brick 21 is a square body, and the geometric center point of the square crystal brick 21 and the geometric center point of the wafer rod 2 are located in the axial direction 3 . The four upper and lower left of the square crystal brick 21 The sides 218 disposed to the right and extending along the axial direction 3 are correspondingly located on the circumference of the wafer rod 2. The diagonal length A of a surface 212 of the square tile 21 parallel to the cross section 23 of the wafer rod 2 is the same as the diameter R of the wafer rod 2. The side length of the surface 212 of the square tile 21 parallel to the cross section 23 is mL x mL, where m is an integer greater than or equal to 2, and L is a length and is a natural number greater than zero. In the present embodiment, m = 2, L = 156 mm (about equal to 6 吋), and L is equal to the axial length X of the wafer rod 2. However, in fact, L and X may not be equal. Generally speaking, in actual production, X is usually several times L. In summary, the axial length X of the wafer stick 2 of the present invention may be greater than or equal to nL, where n is a positive integer.

Specifically, the second step is to first take a square wire mesh for cutting, the square wire mesh is wound by the same cutting steel wire, and the square wire mesh circle has an area corresponding to the surface 212 of the square crystal brick 21 . the size of. The wafer rod 2 is then cut directly along the axial direction 3 by the square wire web, so that the wafer rod 2 can be cut out of the square crystal brick 21 and the four edge material bricks 22.

Step 3: The square crystal brick 21 is cut out into m×m square first crystal bricks 211, and a side of each first brick 211 parallel to a surface 213 of the cross section 23 is L×L. . In the present embodiment, the first crystal brick 211 of 2 × 2 = 4 squares can be cut. The length of each of the first bricks 211 in the axial direction 3 is the same as the length of the wafer rod 2 in the axial direction 3, which is also equal to L. The specific cutting manner of this step is as follows: firstly, a first direction 41 and a second direction 42 parallel to the cross section 23 of the wafer rod 2 and perpendicular to each other are defined, and the first direction 41 and the second direction 42 are also Minute Do not perpendicular to the axial direction 3. Taking a cross-shaped wire mesh for cutting, the cross-shaped wire mesh is formed by winding the same cutting steel wire, and the two wire segments of the cross-shaped wire mesh respectively extend along the first direction 41 and the second direction 42 and mutually cross. After the cross-shaped wire web is cut along the axial direction 3, the square crystal brick 21 is cut into four equal parts to obtain the four first crystal bricks 211.

The cutting method of the third step is merely an example and is not limited thereto. For example, other cutting tools can also be used. First, the extending direction of the cutting tool is parallel to the first direction 41 and the first knife is cut along the axial direction 3, and then the extending direction of the cutting tool is parallel. The second direction 42 and the second knife are cut along the axial direction 3, so that the four first bricks 211 can also be obtained.

It should be noted that, in this embodiment, 18 吋 wafer rod 2 is used, m=2, so 2×2=4 square first crystal bricks 211 are cut out; referring to FIG. 8, when 27 吋 wafer rods are used The first crystal brick 211 of 3×3=9 squares can be cut out; when the 36吋 wafer rod is used, the first crystal brick 211 of 4×4=16 squares can be cut out. When cutting out the first crystal brick 211 of 3×3 or 4×4 or more, the wire mesh for cutting must have a corresponding design, and the cutting wire mesh has a cutting line segment which is closely intersected, and the cutting wire mesh It is wound from the same cut steel wire.

Step 4: The four edge bricks 22 are respectively cut into a square second brick 221, and one of each second brick 221 is perpendicular to the side of the surface 222 of the cross section 23 of the wafer rod 2. The length is L×L, and one side of each second brick 221 parallel to the surface 223 of the cross section 23 has a length L. ×Y, Y of the present embodiment is a length smaller than L. This completes the cutting of the wafer rod 2.

In addition, the material of each of the first bricks 211 of the embodiment includes oxygen, and one surface of each of the first bricks 211 (specifically, the surface 213 parallel to the cross section 23) In the corner, the difference in oxygen concentration between the highest and lowest oxygen concentrations is greater than 2.5 ppma. The material of each of the second bricks 221 of the present embodiment includes oxygen, and oxygen is applied to each of the four corners of one surface of each of the second bricks 221 (specifically, the surface 222 perpendicular to the cross section 23). The difference in oxygen concentration between the two corners with the highest and lowest concentrations is greater than 1.5 ppma. The difference in oxygen concentration of the first crystal brick 211 and the second crystal brick 221 is related to the manufacturing process of the wafer rod 2.

Referring to Figures 3 and 4, when a wafer rod 2' is fabricated, the crucible 51 is mainly filled in a crucible 5, and the wafer rod 2' is obtained by pulling crystal. Wherein the crucible 5 is continuously heated to keep the crucible soup 51 in a molten state, and the material of the crucible 5 is mainly SiO ₂ , oxygen is generated at a high temperature, and during the crystal pulling process, the oxygen will be as shown by the arrow B in FIG. 3 . As shown in the upward direction of the wafer rod 2' which is gradually pulled up, since the wafer rod 2' is formed by upward pulling, the top of the wafer rod 2 is pointed, and when the wafer rod 2' is completed, The pointed top is cut off. While the wafer rod 2 'run-down direction, the closer the wafer stick 2' the top of the higher oxygen concentration (denoted schematically O _H), the more the lower the lower the oxygen concentration (denoted O _L In the radial direction, the closer to the center of the wafer rod 2', the higher the oxygen concentration, the closer to the circumference of the wafer rod 2', the lower the oxygen concentration.

Referring to FIG. 2, therefore, each of the first bricks 211 in the present case is in the Among the four corners on the surface 213, one of the corners 214 corresponding to the central portion of the wafer rod 2 has the highest oxygen concentration, and the other three corners 215, 216, 217 have a low oxygen concentration. Generally, The difference in oxygen concentration between the highest and lowest two corners of the first brick 211 can be more than 2.5 ppma. Each of the second bricks 221 is in the four corners of the surface 222 so that the oxygen concentration is higher toward the two corners 224, 225 which are originally the top of the wafer rod 2, and the other two are farther away from the wafer. The oxygen concentration of the corners 226, 227 at the top of the rod 2 is relatively low. Generally, the difference in oxygen concentration between the highest and lowest corners of the second brick 221 can be 1.5 ppm or more.

Based on the above description, the present invention can provide a crystal brick comprising a square crystal brick body 210, 220, the material of the crystal brick body 210, 220 containing oxygen, one surface of the crystal brick body 210, 220 In the four corners, the difference in oxygen concentration between the highest and lowest oxygen concentrations is greater than 1.5 ppma.

Referring to Figures 5, 6, and 7, the present invention cuts the plurality of first crystal bricks 211 and the plurality of second crystal bricks 221, and then cuts the first crystal bricks 211 and the second by using a suitable cutting wire web. The tile 221 is used to obtain a plurality of wafers. The cutting direction of the first brick 211 (Fig. 5) is mainly to cut a plurality of wafer-like wafers 20 in the direction perpendicular to the axial direction 3. When two of the second bricks 221 are cut (Fig. 6), a plurality of wafer-like wafers 20 are cut in a direction parallel to the axial direction 3. When the other two second bricks 221 are cut (Fig. 7), a plurality of wafer-like wafers 20 are cut in a direction parallel to the axial direction 3. The wafers 20 cut by the first brick 211 or the second brick 221 are squares with square corners and the sides are L × L. The above cutting method and the setting direction and the cutting direction of each of the crystal blocks are merely examples, and the implementation is not limited thereto.

Since the wafer 20 of the embodiment is cut by the first brick 211 and the second brick 221, the oxygen concentration distribution of the wafer 20 is similar to that of the first brick 211 or the second crystal. The distribution of bricks 221 Each wafer 20 of the present embodiment includes a square substrate 201 having four opposite corners 202 and a central location 203 intersecting by two diagonal lines passing through the four corners 202. . The material of the substrate 201 contains oxygen, and the difference in oxygen concentration between the highest and lowest corners 202 of the four corners 202 of the substrate 201 is greater than 1.5 ppma.

Specifically, the oxygen concentration in the four corners of the square substrate of each wafer 20 cut out by the second ceramic tile 221 is the highest and the lowest oxygen concentration difference between the two corners is greater than 1.5 ppma; The oxygen concentration in the four corners of a square substrate of each wafer 20 cut out by a single brick 211 is the highest and the lowest oxygen concentration difference between the two corners is greater than 2.5 ppma. Further, as shown in FIG. 5, the corner 202 of the substrate 201 having the highest oxygen concentration is higher than the oxygen concentration at the center position 203. In addition, the first crystal brick 211 of FIG. 5 is exemplified by the first crystal brick 211 located in the upper left corner of the four first crystal bricks 211 of FIG. 2 , and the other three first crystal bricks of FIG. 2 . The difference in oxygen concentration between the corners and the center of the wafer cut out of 211 will also have a difference in oxygen concentration similar to that of the wafer 20 of FIG.

Referring to Figures 2 and 5, in summary, by the innovative cutting method of the present invention, the wafer rod 2 is first cut out of the square crystal brick 21 and the four edge bricks 22, and then cut to a predetermined size. First crystal brick 211 and second crystal brick 221. The plurality of wafers 20 are subsequently cut out. Since the use of the edge brick 22 can improve the overall utilization of the wafer rod 2, taking an 18-inch wafer rod as an example, the effective cutting area on the front side of the wafer rod can reach about 80.8%, which can reduce each The production cost of the wafer 20. Moreover, if it is necessary to cut the wafer 20 of the mainstream specifications and the corners are right angles, the present invention is very helpful for industrial utilization. Wherein, since the four corners of the conventional single crystal wafer are curved, after assembling the solar cell module, the cells in the module may have many vacant areas due to the arc angle of the wafer. These vacant areas are incapable of absorbing light; and the present invention can cut wafers having square corners at right angles, so that the single crystal wafers can be integrated into a battery module to increase the overall light receiving area of the module. Therefore, the module assembled by the wafer set of the present invention can improve the light absorption rate and the utilization ratio compared with the conventional module of the same size.

Referring to Fig. 9, a second preferred embodiment of the method for cutting a wafer rod of the present invention is substantially the same as the first preferred embodiment, and the following mainly describes different places.

In the third step of the embodiment, the square crystal bricks 21 having a side length of mL×mL are cut into m square first crystal bricks 211, and one of each of the first crystal bricks 211 is parallel to the wafer rod. The surface 213 of the cross section has a side length of L x mL. It should be noted that, in this embodiment, a wafer rod having a diameter of 18 , is used, and m=2, so that two square first crystal bricks 211 are cut out, which may be referred to as a rectangular body when viewed from the surface 213; When the wafer rod 2 is rubbed, three square first crystal bricks 211 can be cut out; when 36 wafer rods 2 are used, four square first crystal bricks 211 can be cut out.

The material of each of the first bricks 211 of the embodiment includes oxygen, and the oxygen concentration is the highest and the lowest of the four corners of one surface (specifically, the surface 213) of each of the first bricks 211. The difference in oxygen concentration in the corner is greater than 1.5 ppma; and further, the difference is greater than 2.5 ppma. Wherein each of the first crystal marked on tile 211 in FIG. 9 are O _H and O _L, a schematic of the overall oxygen concentration of each of the first crystal tile 211 the highest portion and the lowest.

Then, each of the first bricks 211 can be subsequently cut into a plurality of sheet-shaped wafers 20 each having an L×L side length. The difference in oxygen concentration between the highest and lowest corners of the four corners of a square substrate of each wafer 20 is greater than 1.5 ppma. Here, O _H and O _L are indicated on the wafer 20 of FIG. 9 for indicating the highest and lowest oxygen concentration of each wafer 20 itself.

It should be noted that the portions of the wafer 20 and the first crystal brick 211 marked with O _H and O _L are only used to represent the respective oxygen concentration distributions of the respective crystal bricks, and do not represent the O _H sites of the two. the same oxygen concentration, is not representative of both the labeled with the same oxygen concentration O _L site.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

2‧‧‧ wafer stick

21‧‧‧square crystal brick

210‧‧‧crystal brick body

211‧‧‧First crystal brick

212, 213‧‧‧ surface

214, 215, 216, 217‧‧ corner

218‧‧‧ side

22‧‧‧ edge brick

220‧‧‧crystal brick body

221‧‧‧Second crystal brick

222, 223‧‧‧ surface

224, 225, 226, 227‧‧ corner

23‧‧‧ cross section

3‧‧‧Axial direction

41‧‧‧First direction

42‧‧‧second direction

A‧‧‧diagonal length

X, Y‧‧‧ length

R‧‧‧diameter

Claims (13)

A method for cutting a wafer rod, comprising: providing a wafer rod having a circular cross section; and an axial direction parallel to the wafer rod on the cross section of the wafer rod Cutting a square crystal brick and four edge bricks respectively located around the square crystal brick, wherein a diagonal length of the surface of the square brick parallel to the cross section and a diameter of the wafer rod The same, and the side length of the surface is mL×mL, wherein m is an integer greater than or equal to 2, and L is a length; the square crystal brick is cut out into m×m square first crystal bricks, each first a side of the crystal tile parallel to the cross-section of the cross-section is L×L; and the four slabs are respectively cut into a square second crystal brick, one perpendicular to each of the second crystal bricks The side of the cross section has a side length of L x L. The method for cutting a wafer rod according to claim 1, wherein the material of each of the second crystal bricks comprises oxygen, and the oxygen concentration is the highest and lowest among the four corners of one surface of each of the second crystal bricks. The difference in oxygen concentration between the two corners is greater than 1.5 ppma. The method for cutting a wafer rod according to claim 1 or 2, wherein the material of each of the first crystal bricks contains oxygen, and the oxygen concentration is the highest among the four corners of one surface of each of the first crystal bricks. The difference in oxygen concentration between the two lowest corners is greater than 2.5 ppma. The method of cutting a wafer rod according to claim 1, wherein the diameter of the wafer rod is greater than or equal to 18 吋. The method of cutting a wafer rod according to claim 1, wherein the wafer rod has an axial length of X and X is greater than or equal to nL, wherein n is a positive integer. A method for cutting a wafer rod, comprising: providing a wafer rod having a circular cross section; and an axial direction parallel to the wafer rod on the cross section of the wafer rod Cutting a square crystal brick and four edge bricks respectively located around the square brick, the diagonal length of a surface of the square brick parallel to the cross section being the same as the diameter of the wafer rod And the side length of the surface is mL×mL, wherein m is an integer greater than or equal to 2, and L is a length; the square crystal brick is cut out into m square first crystal bricks, each of the first crystal bricks a side parallel to the surface of the cross section has a side length of L×mL; and the four side grain bricks are respectively cut out to form a square second crystal brick, one perpendicular to the cross section of each second crystal brick The side of the surface is L × L. The method for cutting a wafer rod according to claim 6, wherein the material of each of the second crystal bricks comprises oxygen, and the oxygen concentration is the highest and lowest among the four corners of one surface of each of the second crystal bricks. The difference in oxygen concentration between the two corners is greater than 1.5 ppma. A method of cutting a wafer rod according to claim 6 or 7, wherein each The material of the first crystal brick contains oxygen, and in the four corners of one surface of each of the first crystal bricks, the oxygen concentration difference between the highest and lowest two corners is greater than 2.5 ppma. The method of cutting a wafer rod according to claim 6, wherein the diameter of the wafer rod is greater than or equal to 18 吋. The method of cutting a wafer rod according to claim 6, wherein the wafer rod has an axial length of X and X is greater than or equal to nL, wherein n is a positive integer. A crystal brick obtained by the cutting method of the wafer rod according to claim 1 or 6, comprising: a square crystal brick body, the material of the crystal brick body containing oxygen, one surface of the crystal brick body In the four corners, the difference in oxygen concentration between the highest and lowest oxygen concentrations is greater than 1.5 ppma. A wafer obtained by cutting a tile according to claim 11 comprising: a square substrate having four opposite corners and one intersecting by two diagonal lines passing through the four corners The central location; the material of the substrate contains oxygen, and the oxygen concentration in the four corners of the substrate is the highest and the lowest oxygen concentration difference between the two corners is greater than 1.5 ppma. The wafer of claim 12, wherein the corner of the substrate having the highest oxygen concentration is higher than the concentration of oxygen at the central location.