TWI773104B - Workpiece plate and method for slicing ingot - Google Patents

Abstract

The present invention provides an ingot workpiece plate and a method for slicing the ingot. When using the workpiece plate, a resin strip is fixed on the workpiece plate. The lengths of the workpiece plate and the resin strip match with the length of the ingot. The width of the workpiece plate is larger than that of the resin strip and smaller than the diameter of the ingot. Plural openings are disposed in the two sides along with the length direction of the workpiece plate. A cooling channel is disposed within the workpiece plate, extends along with the length direction of the workpiece plate, and connects to the plural openings. The diameter of the opening is smaller than that of the cooling channel. During the ingot slicing process, the slurry is fed into the cooling channel and flows downward and through the ingot surface from the openings. Accordingly, the slurry removes the heat of upper part of the ingot produced in the ingot slicing process. This invention can effectively reduce temperature difference between each of parts of the ingot, thereby reduces wafer wrap and improve the slicing quality

Description

Ingot workpiece plate and ingot cutting method

The invention relates to the field of silicon wafer manufacturing, in particular to a crystal rod workpiece plate and a crystal rod cutting method.

Wafer is one of the most basic and important raw materials in the manufacturing process of semiconductor chips. The crystal pulling step of the single crystal silicon rod, dividing the single crystal silicon rod into multi-segment single crystal silicon rods, grinding the outer diameter of the single crystal silicon rod and the rolling and segmenting step of processing the groove (notch), the single crystal silicon rod The rod is cut into silicon wafers, and the surface flatness of the wafers is improved by grinding.

At present, the mainstream cutting technology of 300mm silicon wafer is wire cutting. Wire cutting is a method of cutting crystal rods by cooperating with guide wheels, steel wires, mortar, temperature effects, etc. Mortar is a very important material in the wire cutting process. The density, viscosity and uniformity of the mortar will affect the cutting quality of the ingot. During the wire cutting process, the cutting position is cooled by the slurry to take away the heat generated during cutting. However, in the conventional technology, due to the structural defects of the workpiece plate, the distribution of the mortar on the crystal rod is unreasonable, so that the heat generated during the cutting of the crystal rod cannot be completely taken away by the mortar in time, and some heat will pass through the crystal rod to the crystal rod. The uncut part of the rod is transferred; and because the crystal rod is exposed in the air without cooling and other cooling measures, the temperature of the uncut part of the crystal rod can reach up to 70 °C, so the cut part and the uncut part have a large temperature deviation. Such temperature deviation will cause a large warp of the diced wafer, resulting in a decrease in the dicing yield.

In view of the shortcomings of the above-mentioned conventional techniques, the purpose of the present invention is to provide a crystal ingot workpiece plate and a crystal ingot cutting method, which are used to solve the conventional technology, due to the structural defects of the workpiece plate, resulting in the mortar on the crystal ingot. The distribution is unreasonable, so that the heat generated when the crystal rod is cut cannot be completely taken away by the mortar in time, and part of the heat will be transferred to the uncut part of the crystal rod through the crystal rod, and there will be a large temperature deviation between the cut part and the uncut part. Temperature deviation can cause large warpage of diced wafers, resulting in problems such as decreased dicing yield.

In order to achieve the above purpose, the present invention provides a crystal rod workpiece plate. When in use, the crystal rod to be cut is pasted on a resin strip, the resin strip is fixed on the crystal rod workpiece board, and the length direction of the crystal rod workpiece board and the resin strip is are consistent with the length direction of the crystal rod, the width of the crystal rod workpiece plate is larger than the width of the resin strip, and smaller than the diameter of the crystal rod, the two sides of the crystal rod workpiece plate are along the crystal rod workpiece plate A plurality of openings are arranged at intervals in the length direction of the ingot workpiece plate; a cooling channel is also arranged inside the crystal ingot workpiece plate, and the cooling channel extends along the length direction of the crystal ingot workpiece plate, and the plurality of opening holes are connected with the cooling channel. The channels are connected, and the diameter of the openings is smaller than the diameter of the cooling channels; in the process of wire cutting the crystal rod, mortar is introduced into the cooling channels, and the mortar flows through the plurality of openings and follows the crystals. The surface of the ingot flows down to remove heat from the upper part of the ingot through the mortar as the ingot is cut.

In one embodiment, the cooling channels are serpentinely distributed in the ingot workpiece plate.

In one embodiment, the difference between the width of the ingot workpiece plate and the width of the resin strip is 1-5 centimeters (cm).

In one embodiment, the ratio of the width of the ingot workpiece plate to the diameter of the ingot is 7/15˜1/2.

In another embodiment, the diameter of the ingot to be cut is 300 millimeters (mm), and the width of the ingot workpiece plate is 140-150 mm.

In one embodiment, the openings are evenly spaced, the distance between the openings is 8-20 mm, and the diameter of the openings is 1.5-3 mm.

In one embodiment, bosses are formed on the front and rear ends of the ingot workpiece plate, and the bosses face away from the surface of the ingot workpiece plate and the resin strip, wherein the front end and the rear end are Refers to the two ends perpendicular to the length direction of the ingot workpiece plate.

The present invention also provides a method for cutting a crystal rod, the method for cutting the crystal rod comprises attaching the crystal rod to be cut on the crystal rod workpiece plate as described in any of the above-mentioned solutions through a resin strip, and performing wire cutting on the crystal rod. During the cutting process, mortar is introduced into the cooling channel of the crystal ingot workpiece plate, and the mortar flows through the multiple openings of the crystal ingot workpiece plate and flows down the surface of the crystal ingot, so as to be taken away by the mortar in the process of completing the crystal ingot cutting process. Heat in the upper part of the ingot.

As mentioned above, the crystal ingot workpiece plate and the crystal ingot cutting method of the present invention have the following beneficial effects: the present invention re-optimizes the design of the width of the crystal ingot workpiece plate, and sets a plurality of openings on the crystal ingot workpiece plate. The hole is connected with the cooling channel. During the cutting process of the crystal rod, the mortar is introduced into the cooling channel. The mortar flows in the crystal rod workpiece plate through the opening and then flows to the crystal rod surface. When the crystal rod workpiece plate is cooled, the mortar is completely The wrapped crystal rod flows down the crystal rod, taking away the heat from the upper part of the crystal rod, and cooling the whole crystal rod, which can effectively reduce the temperature difference of each part of the crystal rod and help reduce the warpage generated during the cutting process. , which helps to improve the cutting quality.

11: Ingot workpiece plate

111: Opening

112: Cooling channel

12: Crystal rod

13: Resin strip

14: Nozzle

15: Drive device

16: Cutting Line

17: Line Roller

18: Mortar tank

19: Recycling device

Figure 1 shows a schematic diagram of the positional relationship between the ingot workpiece plate, the ingot and the resin strip

FIG. 2 is a schematic view of the structure of the ingot workpiece plate provided by the present invention.

FIG. 3 shows an exemplary structural schematic diagram of the cooling channel in the ingot workpiece plate provided by the present invention.

FIG. 4 is a diagram showing an example of ingot cutting using the ingot workpiece plate of the present invention.

FIG. 5 shows boxplots of the warpage of silicon wafers respectively cut by the conventional technology and the ingot workpiece plate provided by the present invention.

The embodiments of the present invention are described below by specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

It should be noted that the structures, proportions, sizes, etc. shown in the drawings in this specification are only used to cooperate with the contents disclosed in the specification, so as to be understood and read by those who are familiar with the technology, and are not used to limit the implementation of the present invention. Restricted conditions, it does not have technical substantive significance, any structural modification, proportional relationship change or size adjustment, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the present invention. The disclosed technical content must be within the scope of coverage. At the same time, terms such as "up", "down", "left", "right", "middle", etc. quoted in this specification are only for the convenience of description and clarity, and are not used to limit the implementation of the present invention. The change or adjustment of the scope and the relative relationship thereof shall also be regarded as the applicable scope of the present invention without substantially changing the technical content.

At present, the mainstream cutting technology of 300mm silicon wafer is wire cutting. During the wire cutting process, the cutting position is cooled by the slurry to take away the heat generated during cutting. However, in the prior art, due to the structural defects of the workpiece plate, the distribution of the mortar on the crystal rod is unreasonable, resulting in the production of The generated heat cannot be completely taken away by the mortar in time, so there is a large temperature difference between the cutting position and the uncut position of the ingot, which in turn leads to a large warpage of the cut wafer. Therefore, the present invention proposes an improvement countermeasure.

Specifically, as shown in FIGS. 1 to 3 , the present invention provides an ingot workpiece plate 11 . When in use, the ingot 12 to be cut is pasted on a resin strip 13 , and the resin strip 13 is fixed on the ingot workpiece plate 11 . On the other hand, the length direction of the crystal rod workpiece plate 11 and the resin strip 13 is consistent with the length direction of the crystal rod 12, and the length of the crystal rod workpiece plate 11 and the resin rod 13 is generally slightly larger than the length of the crystal rod 12 to be cut. The width of the rod workpiece plate 11 is larger than the width of the resin strip 13 and smaller than the diameter of the crystal rod 12 . a plurality of openings 111; the ingot workpiece plate 11 is also provided with a cooling channel 112, the cooling channel 112 extends along the length direction of the ingot workpiece plate 11, the plurality of openings 111 and the cooling channel 112 are connected, and the diameter of the opening 111 is smaller than the diameter of the cooling channel 112 to ensure that the mortar in the cooling channel 112 will not flow out through a single opening 111 but will flow through the next opening in sequence along the cooling channel 112. The hole 111 flows out; during the wire cutting process of the crystal rod 12, mortar is introduced into the cooling channel 112, and the mortar flows through the plurality of openings 111 and flows down the surface of the crystal rod 12 to complete the crystal rod 12. During the cutting process of the rod 12 , the heat of the upper part of the crystal rod 12 is taken away by the mortar, so as to reduce the temperature difference between the cut part and the uncut part of the crystal rod 12 . In the present invention, the width of the ingot workpiece plate 11 is optimized again, and a plurality of openings 111 are arranged on the ingot workpiece plate 11. The openings 111 are communicated with the cooling channel 112, and the openings 111 are opened in the process of cutting the ingot 12. Mortar is introduced into 111, and the mortar flows in the crystal rod workpiece plate 11 through the opening 111 and then flows to the surface of the crystal rod 12. While cooling the crystal rod workpiece plate 11, the mortar completely wraps the crystal rod 12 and flows down the crystal rod 12. , take away the heat of the upper part of the crystal rod 12, and play the role of cooling the crystal rod 12 as a whole, which can effectively reduce the temperature difference of each part of the crystal rod 12, help to reduce the warpage generated during the cutting process, and help to improve the cutting process. quality.

In order to make the flow of the mortar in the crystal rod workpiece plate 11 as uniform as possible, and to make the area through which the mortar flows as large as possible, in this embodiment, the cooling channel 112 is meandering and divided into the crystal rod workpiece plate 11 . cloth. In a further example, as shown in FIG. 3 , the cooling channels 112 are distributed along a bow-like structure, the arrows in FIG. 3 indicate the flow direction of the mortar, and the inlet and outlet of the cooling channels 112 are located on the same side, and are relatively close to each other. Preferably, it is located on the side adjacent to the side where the opening 111 is located, that is, the inlet and outlet of the cooling channel 112 are not on the same side as the opening 111 . Since the diameter of the cooling channel 112 is larger than the diameter of the opening 111, the mortar in the cooling channel 112 will flow through the openings 111 and flow out through the openings 111 in turn, thereby forming criss-crossing flow channels in the ingot workpiece plate 11. It is beneficial to increase the contact area between the mortar and the ingot workpiece plate 11, and the ingot workpiece plate 11 can be quickly cooled, and then the upper part of the ingot ingot 12 can be cooled through the ingot workpiece plate 11 to reduce the upper and lower parts of the ingot 12. In the process of the mortar flowing downstream with the surface of the crystal rod 12 , the heat on the upper part of the crystal rod 12 is removed, thereby cooling the crystal rod 12 .

The material of the ingot workpiece plate 11 includes but is not limited to stainless steel. The width difference between the ingot workpiece plate 11 and the resin strip 13 is carefully designed, and if it is too small or too large, it is difficult to evenly guide the mortar flowing out of the opening 111 to the surface of the ingot 12 . The inventor has found through a large number of experiments that the difference between the width of the crystal rod workpiece plate 11 and the width of the resin strip 13 is 1 to 5 cm (including the endpoint value. Including the endpoint value) is particularly preferred, such as 1 cm, 2 cm, 3 cm, 4 cm, 5 cm or any value within this interval. Considering that during installation, there should be left widths on both sides of the ingot workpiece plate 11 and the resin strip 13, and 2~3cm is recommended.

The specific size of the ingot workpiece plate 11 needs to be determined according to the diameter of the ingot 12 to be cut. Preferably, the ratio of the width of the ingot workpiece plate 11 to the diameter of the ingot 12 is 7/15˜1/2. More specifically, if the diameter of the ingot 12 to be cut is 300 mm, the width of the ingot workpiece plate 11 is 140-150 mm.

In order to ensure the uniform distribution of the mortar as much as possible, the openings 111 are preferably distributed at uniform intervals. In an example, the aperture d1 of the openings 111 is 1.5-3 mm, and the distance d2 between the openings 111 is 8-20 mm.

As an example, the front and rear ends of the ingot workpiece plate 11 are formed with bosses, and the bosses face away from the surface of the ingot workpiece plate 11 that is in contact with the resin strip 13 , wherein the front and rear ends are Yes Refers to the two ends perpendicular to the length direction of the ingot workpiece plate 11 . Forming the boss is beneficial to protect the crystal rod 12 and prevent the crystal rod 12 from being collided by foreign objects.

An exemplary process for cutting the ingot 12 by using the ingot workpiece plate 11 provided by the present invention is as follows: as shown in FIG. , juxtaposed above the cutting line 16, the crystal ingot workpiece plate 11 is connected with the driving device 15, the crystal ingot 12 moves downward toward the cutting line 16 under the driving of the driving device 15, and the cutting line 16 moves under the action of the wire roller 17, this During the process, the nozzle 14 injects the mortar into the crystal rod workpiece plate 11, and the mortar flows in the cooling channel 112 and flows through the openings 111, and then flows to the surface of the crystal rod 12 through the openings 111, and gradually wraps the crystal rod 12 without resin. The contact surface of the strip 13 flows to the cutting line 16, and finally flows down into the mortar tank 18 like a waterfall, and the mortar can be recycled through the recovery device 19.

Of course, the above process is only exemplary, for example, the ingot may also be fixed and the cutting line may be moved upward, which is not strictly limited in this embodiment. What is important is that the use of the ingot workpiece plate of the present invention can take away the heat on the surface of the ingot during the online cutting process, reduce the temperature difference between the cut part and the uncut part of the ingot, and help reduce the warpage caused by cutting. FIG. 5 shows the warpage of the silicon wafer cut out by using the ingot workpiece plate in the prior art for ingot cutting and the warpage of the silicon wafer cut out by using the ingot work plate provided by the present invention for ingot cutting. Comparison boxplot of curvature. As shown in FIG. 5 , using the conventional ingot workpiece plate, the warpage of the silicon wafer is as high as 10.99 micrometers (μm); while using the present invention, the maximum warpage of the silicon wafer is reduced to 4.8 μm, which is reduced by more than half. At present, the ingot workpiece plate has been put into use in the factory where the inventor is located, and it has been proved by practice that it can effectively reduce the warpage of the cut silicon wafer and improve the cutting quality.

The present invention also provides a method for cutting a crystal rod, the method for cutting the crystal rod comprises attaching the crystal rod to be cut on the crystal rod workpiece plate as described in any of the above-mentioned solutions through a resin strip, and performing wire cutting on the crystal rod. During the cutting process, mortar is introduced into the cooling channel of the crystal rod workpiece plate, and the mortar flows through the crystal rod The multiple openings of the workpiece plate flow down along the surface of the ingot, so as to remove the heat from the upper part of the ingot through the mortar during the cutting of the ingot. For the introduction of the ingot workpiece plate, please refer to the foregoing content, which will not be repeated for the sake of brevity. The crystal rod cutting method based on the crystal rod workpiece plate of the present invention can significantly reduce the warpage of the silicon wafer and improve the cutting quality.

In summary, the present invention provides a crystal ingot workpiece plate and a crystal ingot cutting method. When using the crystal rod workpiece board provided by the present invention, the resin strip is fixed on the crystal rod workpiece board, and the length directions of the crystal rod workpiece board and the resin strip are consistent with the length direction of the crystal rod, and the width of the crystal rod workpiece board is consistent with the length direction of the crystal rod workpiece board. larger than the width of the resin strip and smaller than the diameter of the crystal rod, the two sides of the crystal rod workpiece plate are provided with a plurality of openings at intervals along the length direction of the crystal rod workpiece plate; the crystal rod workpiece plate A cooling channel is also provided inside, the cooling channel extends along the length direction of the ingot workpiece plate, the plurality of openings communicate with the cooling channel, and the diameter of the openings is smaller than the diameter of the cooling channel ; In the process of wire cutting the crystal rod, the mortar is introduced into the cooling channel, and the mortar flows down the surface of the crystal rod after flowing through the plurality of openings, so as to be taken away by the mortar in the process of completing the crystal rod cutting Heat in the upper part of the ingot. The invention re-optimizes the design of the width of the crystal ingot workpiece plate, and sets a plurality of openings on the crystal ingot workpiece plate. After flowing in the crystal rod workpiece plate through the opening, it flows to the crystal rod surface. While cooling the crystal rod workpiece plate, the mortar completely wraps the crystal rod and flows down the crystal rod, taking away the heat from the upper part of the crystal rod, which acts as a countermeasure against the crystal rod. The effect of cooling the rod as a whole can effectively reduce the temperature difference of each part of the crystal rod, which helps to reduce the warpage generated during the cutting process and helps to improve the cutting quality. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments merely illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, any person with ordinary knowledge in the technical field is not departing from the All equivalent modifications or changes accomplished under the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (7)

A crystal rod workpiece board, when in use, the crystal rod to be cut is pasted on a resin strip, the resin strip is fixed on the crystal rod workpiece board, and the length directions of the crystal rod workpiece board and the resin strip are consistent with the length direction of the crystal rod , characterized in that the width of the ingot workpiece plate is greater than the width of the resin strip and smaller than the diameter of the ingot, and the two sides of the ingot workpiece plate are spaced along the length direction of the ingot workpiece plate A plurality of openings are provided; a cooling channel is also arranged inside the crystal ingot workpiece plate, the cooling channel extends along the length direction of the crystal ingot workpiece plate, and the plurality of openings are communicated with the cooling channel, The diameter of the openings is smaller than the diameter of the cooling channel; in the process of wire cutting the crystal rod, mortar is introduced into the cooling channel, and the mortar flows down the surface of the crystal rod after flowing through the plurality of openings. In the process of completing the cutting of the ingot, the heat of the upper part of the ingot is taken away through the mortar. The ingot workpiece plate of claim 1, wherein the cooling channels are meanderingly distributed in the ingot workpiece plate. The crystal ingot workpiece plate according to claim 1, wherein the difference between the width of the crystal ingot workpiece plate and the width of the resin strip is 1-5 cm. The ingot workpiece plate according to claim 1, wherein the ratio of the width of the ingot workpiece plate to the diameter of the ingot is 7/15˜1/2. The ingot workpiece plate according to claim 4, wherein the diameter of the ingot to be cut is 300 mm, and the width of the ingot workpiece plate is 140-150 mm. The ingot workpiece plate according to claim 1, wherein the openings are evenly spaced, the spacing between the openings is 8-20 mm, and the diameter of the openings is 1.5-3 mm. A method for cutting a crystal rod, comprising: attaching the crystal rod to be cut on the crystal rod workpiece board according to any one of claims 1-6 through a resin strip, and cutting the crystal rod to the crystal rod during the wire cutting process. crystal Mortar is introduced into the cooling channel of the ingot workpiece plate, and the mortar flows through the plurality of openings of the ingot workpiece plate and flows down the surface of the ingot, so as to remove the heat from the upper part of the ingot through the mortar during the cutting of the ingot.

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