A method for reducing post-cut wafer orientation deviation

Abstract

The application provides a method for reducing wafer orientation deviation after cutting, which comprises the following steps: dividing a wire cutting machine into multiple groups, obtaining a wire cutting deviation rule of the wire cutting machine in different horizontal zero target ranges, and cutting a to-be-cut wafer rod by matching the corresponding wire cutting machine according to the wire cutting deviation rule, so as to reduce the wafer orientation deviation after cutting. For products with a wafer specification of ≤±0.1°, the defective rate is reduced from 3.5% to below 0.5%. For ultra-high specification products with a wafer specification of ≤±0.05°, the yield rate is above 98.5%.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology and relates to a method for reducing crystal orientation deviation of wafers after dicing. Background Technology

[0002] With the gradual promotion of domestic production of large-size semiconductor silicon wafers, the technical requirements for silicon wafer substrates in China are becoming increasingly stringent, gradually aligning with international standards. As a crucial technical parameter in silicon wafer control, the improvement of silicon wafer crystal orientation in terms of yield and capability is becoming increasingly important.

[0003] Crystal orientation is mainly controlled by ingot bonding and wire cutting. Currently, the mainstream technology mainly controls the bonding crystal orientation of the ingot bonding machine and makes certain adjustments to the cutting level of the wire cutting machine to achieve the purpose of controlling the crystal orientation of silicon wafers. However, it can only process products with wafer specifications ≥ ±0.15°. For products with wafer specifications ≤ ±0.1°, the defect rate remains high.

[0004] Therefore, how to provide a method to reduce the crystal orientation deviation of wafers after dicing, so as to improve the processing yield of high-specification wafers and reduce costs, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for reducing the crystal orientation deviation of wafers after dicing, in order to solve the problem of high crystal orientation defect rate in the prior art when dicing high-specification wafers.

[0006] To achieve the above and other related objectives, the present invention provides a method for reducing crystal orientation deviation of a wafer after dicing, comprising the following steps:

[0007] S1: Divide the wire EDM machine into multiple groups, at least one group of wire EDM machines has a horizontal zero-position target range greater than zero degrees, at least one group of wire EDM machines has a horizontal zero-position target range less than zero degrees, and at least one group of wire EDM machines has a horizontal zero-position target range including zero degrees.

[0008] S2: Data collection. After the crystal rod is bonded to the bonding machine, the rotation angle of the crystal rod cutting angle relative to the initial positioning is Φ. The collected data includes cutting data corresponding to different rotation angle ranges within the range of -90°≤Φ≤90°. Among them, the cutting data includes the X-axis cutting deviation and Y-axis cutting deviation of each wire cutting machine.

[0009] S3: Using Φ as the abscissa and the X-axis cutting deviation and Y-axis cutting deviation of each group of wire EDM machines as the ordinates, establish the X-axis cutting deviation diagram and Y-axis cutting deviation table for each group of wire EDM machines.

[0010] S4: Provide the crystal rod to be cut, obtain the rotation angle Φ' of the crystal rod cutting angle relative to the initial positioning after the crystal rod is bonded to the bonding machine, the X-axis re-inspection deviation and the Y-axis re-inspection deviation, determine whether the X-axis re-inspection deviation and the Y-axis re-inspection deviation of the crystal rod to be cut are within the preset range. If they are within the preset range, proceed to the next step. If they are not within the preset range, remove the crystal rod to be cut from the bonding machine and re-bond it.

[0011] S5: Based on the X-axis cutting deviation diagram and the Y-axis cutting deviation diagram, select the wire EDM machine that matches the sum of the X-axis cutting deviation and the X-axis re-inspection deviation of the crystal rod to be cut at Φ' within the qualified range of the X-axis target crystal orientation, and the sum of the Y-axis cutting deviation and the Y-axis re-inspection deviation of the wafer to be cut within the qualified range of the Y-axis target crystal orientation as the target wire EDM machine.

[0012] Optionally, in step S1, the horizontal zero point is the X-axis cutting deviation of the wire EDM machine when -5°≤Φ≤5°. The wire EDM machines are divided into five groups. The target range of the horizontal zero point for the first group of wire EDM machines is 0.04°~0.05°, the target range of the horizontal zero point for the second group of wire EDM machines is 0.02°~0.04°, the target range of the horizontal zero point for the third group of wire EDM machines is -0.02°~0.02°, the target range of the horizontal zero point for the fourth group of wire EDM machines is -0.04°~-0.02°, and the target range of the horizontal zero point for the fifth group of wire EDM machines is -0.05°~-0.04°.

[0013] Optionally, in step S2, the different rotation angle ranges include -90° to -80°, -80° to -70°, ..., 70° to 80°, and 80° to 90°.

[0014] Optionally, in step S2, the X-axis cutting deviation is the difference between the X-axis cutting crystal orientation and the X-axis re-inspection crystal orientation, wherein the X-axis cutting crystal orientation is the actual X-axis crystal orientation of the wafer detected after cutting, and the X-axis re-inspection crystal orientation is the actual X-axis crystal orientation obtained after the crystal rod is bonded to the bonding machine; the Y-axis cutting deviation is the difference between the Y-axis cutting crystal orientation and the Y-axis re-inspection crystal orientation, wherein the Y-axis cutting crystal orientation is the actual Y-axis crystal orientation of the wafer detected after cutting, and the Y-axis re-inspection crystal orientation is the actual Y-axis crystal orientation obtained after the crystal rod is bonded to the bonding machine.

[0015] Optionally, in step S4, the X-axis re-inspection deviation is the difference between the X-axis re-inspection crystal direction and the X-axis target crystal direction, wherein the X-axis re-inspection crystal direction is the actual X-axis crystal direction obtained after the crystal rod is bonded to the bonding machine, and the X-axis target crystal direction is the target value of the X-axis crystal direction of the wafer after cutting; the Y-axis re-inspection deviation is the difference between the Y-axis re-inspection crystal direction and the Y-axis target crystal direction, wherein the Y-axis re-inspection crystal direction is the actual Y-axis crystal direction obtained after the crystal rod is bonded to the bonding machine, and the Y-axis target crystal direction is the target value of the Y-axis crystal direction of the wafer after cutting.

[0016] Optionally, in step S4, the difference between the X-axis crystal orientation after cutting and the target X-axis crystal orientation is within the range of -0.1° to 0.1°, and the difference between the Y-axis crystal orientation after cutting and the target Y-axis crystal orientation is within the range of -0.1° to 0.01°, which is the crystal orientation qualification standard for the wafer. The preset range is -0.065° to 0.065°. Here, the X-axis crystal orientation after cutting is the actual X-axis crystal orientation of the wafer detected after cutting, the target X-axis crystal orientation is the target value of the X-axis crystal orientation of the wafer after cutting, the Y-axis crystal orientation after cutting is the actual Y-axis crystal orientation of the wafer detected after cutting, and the target Y-axis crystal orientation is the target value of the Y-axis crystal orientation of the wafer after cutting.

[0017] Optionally, in step S5, at Φ', one of the X-axis cutting deviation of the target wire EDM machine and the X-axis re-inspection deviation of the crystal rod to be cut is positive and the other is negative; and / or one of the Y-axis cutting deviation of the target wire EDM machine and the Y-axis re-inspection deviation of the crystal rod to be cut is positive and the other is negative.

[0018] Optionally, in step S4, the difference between the X-axis crystal orientation after cutting and the target X-axis crystal orientation is within the range of -0.05° to 0.05°, and the difference between the Y-axis crystal orientation after cutting and the target Y-axis crystal orientation is within the range of -0.05° to 0.05°, which is the crystal orientation qualification standard for the wafer. The preset range is -0.045° to 0.045°. Here, the X-axis crystal orientation after cutting is the actual X-axis crystal orientation of the wafer detected after cutting, the target X-axis crystal orientation is the target value of the X-axis crystal orientation of the wafer after cutting, the Y-axis crystal orientation after cutting is the actual Y-axis crystal orientation of the wafer detected after cutting, and the target Y-axis crystal orientation is the target value of the Y-axis crystal orientation of the wafer after cutting.

[0019] Optionally, in step S5, at Φ', one of the X-axis cutting deviation of the target wire EDM machine and the X-axis re-inspection deviation of the crystal rod to be cut is positive and the other is negative, and one of the Y-axis cutting deviation of the target wire EDM machine and the Y-axis re-inspection deviation of the crystal rod to be cut is positive and the other is negative.

[0020] Optionally, in step S5, if no wire cutting machine can be matched where the sum of the X-axis cutting deviation and the X-axis re-inspection deviation of the crystal rod to be cut is within the acceptable range of the X-axis target crystal orientation, and the sum of the Y-axis cutting deviation and the Y-axis re-inspection deviation of the wafer to be cut is within the acceptable range of the Y-axis target crystal orientation, then the crystal rod to be cut is removed from the rod gluing machine and re-glued.

[0021] As described above, in the method for reducing the crystal orientation deviation of wafers after dicing according to the present invention, the wire dicing machine is divided into multiple groups, and the dicing deviation law of the wire dicing machine with different horizontal zero-position target ranges is obtained. The corresponding wire dicing machine is matched according to the dicing deviation law to cut the crystal rod to be diced, thereby reducing the crystal orientation deviation of the wafer after dicing. For products with wafer specifications ≤ ±0.1°, the defect rate is reduced from 3.5% to below 0.5%. For ultra-high specification products with wafer specifications ≤ ±0.05°, the yield rate reaches more than 98.5%. Attached Figure Description

[0022] Figure 1 The diagram shows a method for reducing crystal orientation deviation of wafers after dicing, as described in an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram showing the initial positioning of the crystal rod in an embodiment of the present invention.

[0024] Figure 3 This diagram illustrates the rotation of the crystal rod's cutting angle by Φ degrees relative to its initial positioning after the crystal rod is bonded to the bonding machine, as shown in an embodiment of the present invention.

[0025] Component designation explanation

[0026] 1 crystal rod

[0027] 10 crystal rod chamfer

[0028] 2 adhesive layers

[0029] 3 Sticker Machine Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0031] Please see Figures 1 to 3 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] This embodiment provides a method for reducing crystal orientation deviation of wafers after dicing. Please refer to [link to relevant documentation]. Figure 1 This includes the following steps:

[0033] S1: Divide the wire EDM machine into multiple groups, at least one group of wire EDM machines has a horizontal zero-position target range greater than zero degrees, at least one group of wire EDM machines has a horizontal zero-position target range less than zero degrees, and at least one group of wire EDM machines has a horizontal zero-position target range including zero degrees.

[0034] S2: Data collection. After the crystal rod is bonded to the bonding machine, the rotation angle of the crystal rod cutting angle relative to the initial positioning is Φ. The collected data includes cutting data corresponding to different rotation angle ranges within the range of -90°≤Φ≤90°. Among them, the cutting data includes the X-axis cutting deviation and Y-axis cutting deviation of each wire cutting machine.

[0035] S3: Using Φ as the abscissa and the X-axis cutting deviation and Y-axis cutting deviation of each group of wire EDM machines as the ordinates, establish the X-axis cutting deviation diagram and Y-axis cutting deviation table for each group of wire EDM machines.

[0036] S4: Provide the crystal rod to be cut, obtain the rotation angle Φ' of the crystal rod cutting angle relative to the initial positioning after the crystal rod is bonded to the bonding machine, the X-axis re-inspection deviation and the Y-axis re-inspection deviation, determine whether the X-axis re-inspection deviation and the Y-axis re-inspection deviation of the crystal rod to be cut are within the preset range. If they are within the preset range, proceed to the next step. If they are not within the preset range, remove the crystal rod to be cut from the bonding machine and re-bond it.

[0037] S5: Based on the X-axis cutting deviation diagram and the Y-axis cutting deviation diagram, select the wire EDM machine that matches the sum of the X-axis cutting deviation and the X-axis re-inspection deviation of the crystal rod to be cut at Φ' within the qualified range of the X-axis target crystal orientation, and the sum of the Y-axis cutting deviation and the Y-axis re-inspection deviation of the wafer to be cut within the qualified range of the Y-axis target crystal orientation as the target wire EDM machine.

[0038] The method for reducing the crystal orientation deviation of the wafer after cutting in this embodiment will be described in detail below with reference to the specific accompanying drawings.

[0039] As an example, such as Figure 2 As shown, this illustrates the initial positioning of the crystal rod. In this embodiment, the notch angle 10 of crystal rod 1 faces upwards in the vertical direction as the initial positioning; as shown... Figure 3 As shown, after the crystal rod 1 is bonded to the rod bonding machine 3 through the adhesive layer 2, the crystal rod cutting angle 10 will rotate relative to the initial positioning, and the rotation angle is recorded as Φ. In step S1, the horizontal zero position of the wire cutting machine is the X-axis cutting deviation when Φ = 0°. However, in actual processing, it is difficult to get Φ to 0 after the crystal rod 1 is bonded to the rod bonding machine 3. Therefore, in this embodiment, the X-axis cutting deviation when -5°≤Φ≤5° is taken as the horizontal zero position. Here, the X-axis is defined as being along the horizontal direction and the Y-axis as being along the vertical direction.

[0040] As an example, in step S1, the wire EDM machines are divided into five groups, and the horizontal zero position of the wire EDM machines is adjusted as shown in Table 1 below. The target range of the horizontal zero position of the first group of wire EDM machines is 0.04° to 0.05°, the target range of the horizontal zero position of the second group of wire EDM machines is 0.02° to 0.04°, the target range of the horizontal zero position of the third group of wire EDM machines is -0.02° to 0.02°, the target range of the horizontal zero position of the fourth group of wire EDM machines is -0.04° to -0.02°, and the target range of the horizontal zero position of the fifth group of wire EDM machines is -0.05° to -0.04°.

[0041] Table 1:

[0042]

[0043]

[0044] As an example, in step S2, the data collection example is shown in Table 2 below, including X-axis re-inspection crystal orientation, Y-axis re-inspection crystal orientation, X-axis target crystal orientation, Y-axis target crystal orientation, X-axis re-inspection deviation, Y-axis re-inspection deviation, Φ angle, X-axis crystal orientation after cutting, Y-axis crystal orientation after cutting, X-axis cutting deviation, Y-axis cutting deviation, and cutting machine. Among them, the X-axis re-inspection crystal orientation is the actual X-axis crystal orientation obtained after the crystal rod is bonded to the bonding machine, and the Y-axis re-inspection crystal orientation is the actual Y-axis crystal orientation obtained after the crystal rod is bonded to the bonding machine; the X-axis target crystal orientation and the Y-axis target crystal orientation can be provided by a third party, which are the target values ​​of the X-axis and Y-axis crystal orientations of the wafer after dicing as required by the customer; the X-axis re-inspection deviation is the difference between the X-axis re-inspection crystal orientation and the X-axis target crystal orientation, and the Y-axis re-inspection deviation is the difference between the Y-axis re-inspection crystal orientation and the Y-axis target crystal orientation; the X-axis post-dicing crystal orientation is the actual X-axis crystal orientation of the wafer after dicing, and the Y-axis post-dicing crystal orientation is the actual Y-axis crystal orientation of the wafer after dicing, and the X-axis dicing deviation is the difference between the X-axis post-dicing crystal orientation and the X-axis re-inspection crystal orientation, and the Y-axis dicing deviation is the difference between the Y-axis post-dicing crystal orientation and the Y-axis re-inspection crystal orientation.

[0045] Table 2

[0046]

[0047] As an example, step S2 requires collecting sticking and cutting data corresponding to different rotation angle intervals within the range of -90°≤Φ≤90°. Specifically, in this embodiment, sticking and cutting data corresponding to every 10° Φ interval are collected. For example, for the first group of wire EDM machines, sticking and cutting data are collected for Φ values ​​of -90°~-80°, -80°~-70°, ..., 70°~80°, and 80°~90°. For the second group of wire EDM machines, sticking and cutting data are collected for Φ values ​​of -90°~-80°, -80°~-70°, ... For the third group of wire EDM machines, data on stick adhesion and cutting at Φ ranges of -90° to -80°, -80° to -70°, ..., 70° to 80°, and 80° to 90° are collected. For the fourth group of wire EDM machines, data on stick adhesion and cutting at Φ ranges of -90° to -80°, -80° to -70°, ..., 70° to 80°, and 80° to 90° are collected. For the fifth group of wire EDM machines, data on stick adhesion and cutting at Φ ranges of -90° to -80°, -80° to -70°, ..., 70° to 80°, and 80° to 90° are collected. For each Φ range in each group of wire EDM machines, at least three data points are collected to improve the accuracy of the collected data.

[0048] As an example, in step S3, through data modeling and analysis, the corresponding X-axis cutting deviation patterns and Y-axis cutting deviation patterns can be obtained from the X-axis cutting deviation diagram and Y-axis cutting deviation diagram of each group of wire EDM machines. In this embodiment, for the first and second groups of wire EDM machines, the Y-axis cutting deviation has a positive slope within the range of Φ = -90° to 90°, and the X-axis cutting deviation value is generally positive; within the range of Φ = -90° to 0°, the Y-axis cutting deviation is generally negative; and within the range of Φ = 0° to 90°, the Y-axis cutting deviation is generally positive. For the third group of wire EDM machines, the Y-axis cutting deviation fluctuates within the range of -0.03° to 0.03°, with a slope close to zero, and the X-axis cutting deviation fluctuates within the range of -0.03° to 0.03°. The slope is close to zero; for the fourth and fifth group wire EDM machines, within the range of Φ from -90° to 90°, the Y-axis cutting deviation has a negative slope, and the X-axis cutting deviation is generally negative. Within the range of Φ from -90° to 0°, the Y-axis cutting deviation is generally positive, and within the range of Φ from 0° to 90°, the Y-axis cutting deviation is generally negative. That is, by adjusting the horizontal zero position of the wire EDM machine, the X-axis and Y-axis cutting deviation patterns can be changed.

[0049] As an example, in step S4, if the wafer's processing specification is ≤ ±0.1°, that is, the difference between the crystal orientation after X-axis cutting and the target crystal orientation on the X-axis is within -0.1° to 0.1°, and the difference between the crystal orientation after Y-axis cutting and the target crystal orientation on the Y-axis is within -0.1° to 0.01°, which is the acceptable crystal orientation standard for the wafer, then the preset range is -0.065° to 0.065°. When the X-axis re-inspection deviation and the Y-axis re-inspection deviation after the crystal rod to be cut is bonded to the bonding machine are both within -0.065° to 0.065°, the next step of target wire cutting machine matching is performed. When at least one of the X-axis re-inspection deviation and the Y-axis re-inspection deviation after the crystal rod to be cut is bonded to the bonding machine is not within -0.065° to 0.065°, the crystal rod to be cut is removed from the bonding machine and re-bonded until the X-axis re-inspection deviation and the Y-axis re-inspection deviation are both within the range of -0.065° to 0.065°, the next step of target wire cutting machine matching is performed.

[0050] As an example, taking a wafer processing specification of ≤±0.1°, with a target crystal orientation of 0° on both the X and Y axes, the acceptable range for both the X and Y axes is -0.1° to 0.1°, as shown in Table 3 below. For instance, if the Φ' of the crystal rod to be cut is 35° after being bonded to the bonding machine, the X-axis re-inspection deviation is negative (-0.045°) and the Y-axis re-inspection deviation is negative (-0.055°). When the target cutting machine has a Φ' of 35°, the X-axis cutting deviation is positive (0.035°) and the Y-axis cutting deviation is positive (0.025°). By complementing the X-axis cutting deviation and the X-axis re-inspection deviation, and by complementing the Y-axis cutting deviation and the Y-axis re-inspection deviation, the expected crystal orientation after X-axis cutting is -0.01° and the expected crystal orientation after Y-axis cutting is -0.03°, which meets the qualification requirements and allows processing to continue.

[0051] Table 3

[0052]

[0053] As examples, the above examples illustrate cases where the X-axis / Y-axis re-inspection deviation and cutting deviation are complementary. In some examples, if one of the X-axis / Y-axis re-inspection deviation and cutting deviation is not complementary, but the sum of the corresponding re-inspection deviation and cutting deviation still meets the acceptable crystal orientation range, processing and cutting can continue. As shown in Table 4 below, for example, if the wafer to be cut has a Φ' of 35° after being bonded to the bonding machine, the X-axis re-inspection deviation is negative (-0.045°), and the Y-axis re-inspection deviation is positive (0.04°), and the target cutting machine has a positive X-axis cutting deviation (0.035°) and a positive Y-axis cutting deviation (0.025°) when Φ' is 35°, then the X-axis re-inspection deviation and X-axis cutting deviation are complementary, and the expected crystal orientation after X-axis cutting is -0.01°. The Y-axis re-inspection deviation and Y-axis cutting deviation are not complementary, and the expected crystal orientation after Y-axis cutting is 0.065°, which meets the acceptable requirements, and processing can continue. Preferably, when the inspection deviation and cutting deviation of the X-axis / Y-axis can be complementary on one axis but not on the other, for the non-complementary axis, the matching wire EDM machine is required to ensure that the sum of the inspection deviation and cutting deviation within Φ'±10° is within the acceptable range of the crystal orientation, so as to improve the cutting yield.

[0054] Table 4

[0055]

[0056] As an example, the above examples illustrate situations where the X-axis / Y-axis re-inspection deviation and cutting deviation cannot complement each other. In some examples, neither the X-axis / Y-axis re-inspection deviation nor the cutting deviation can complement each other, but the sum of the corresponding re-inspection deviation and cutting deviation still meets the acceptable crystal orientation range, and processing can continue. As shown in Table 5 below, for example, if the Φ' of the crystal rod to be cut is 35° after being bonded to the rod bonding machine, the X-axis re-inspection deviation is positive (0.045°), the Y-axis re-inspection deviation is positive (0.05°), and the target cutting machine, when Φ' is 35°, has a positive X-axis cutting deviation (0.025°) and a positive Y-axis cutting deviation (0.025°). In this case, the X-axis re-inspection deviation and the X-axis cutting deviation cannot complement each other, and the expected crystal orientation after X-axis cutting is 0.07°; the Y-axis re-inspection deviation and the Y-axis cutting deviation cannot complement each other, and the expected crystal orientation after Y-axis cutting is 0.075°, which meets the acceptable requirements, and processing can continue. It should be noted that when the re-inspection deviation and cutting deviation of the X-axis and Y-axis cannot complement each other, although the crystal orientation after X-axis cutting and the crystal orientation after Y-axis cutting are expected to meet the qualification requirements, the yield will be reduced during mass production. When the re-inspection deviation and cutting deviation after X-axis / Y-axis matching cannot complement each other, it is generally recommended to perform the "unmatched product reset method", that is, to remove the crystal rod to be cut from the rod gluing machine and re-glu it.

[0057] Table 5

[0058]

[0059] Specifically, in this embodiment, when cutting products with wafer specifications ≤ ±0.1°, if both the X-axis and Y-axis re-inspection deviations of the crystal rod to be cut are within -0.035° to 0.035°, it is designated to be processed arbitrarily in the third group of wire cutting machines, and the wafer orientation defect rate after cutting is <0.1%; if one of the X-axis and Y-axis re-inspection deviations of the crystal rod to be cut is within -0.065° to -0.035° or 0.035° to 0.065°, and the other is within -0.065° to 0.065°, priority is given to matching the X-axis / Y-axis re-inspection deviations. If a wire EDM machine with complementary inspection and cutting deviations cannot be matched with a machine that also has complementary X-axis / Y-axis inspection and cutting deviations, and one of these deviations is not complementary, then the ingot must be re-glued. After cutting, the wafer orientation defect rate will be <0.5%. If either the X-axis or Y-axis inspection deviation of the ingot to be cut is outside the range of -0.065° to 0.065°, it indicates that the ingot re-inspection after gluing by the ingot gluing machine is unqualified, and the ingot must be re-glued.

[0060] As an example, in step S4, if the wafer's processing specification is ≤ ±0.05°, that is, the difference between the crystal orientation after X-axis cutting and the target crystal orientation on the X-axis is within -0.05° to 0.05°, and the difference between the crystal orientation after Y-axis cutting and the target crystal orientation on the Y-axis is within -0.05° to 0.05°, then the wafer's crystal orientation is considered acceptable. The preset range is -0.045° to 0.045°. When the X-axis re-inspection deviation and the Y-axis re-inspection deviation are both within -0.045° to 0.045° after the crystal rod to be cut is bonded to the bonding machine, the next step, target wire cutting machine matching, is performed. If, after the crystal rod to be cut is bonded to the bonding machine, at least one of the X-axis re-inspection deviation and the Y-axis re-inspection deviation is not within the range of -0.045° to 0.045°, then the crystal rod to be cut is removed from the bonding machine and re-bonded until both the X-axis re-inspection deviation and the Y-axis re-inspection deviation are within the range of -0.045° to 0.045°, then the next step of matching the target wire cutting machine is performed. In step S5, a wire cutting machine with complementary X-axis / Y-axis re-inspection deviations and cutting deviations is matched, so that the crystal orientation of the cut wafer is reduced, meeting the crystal orientation qualification requirements, and the crystal orientation defect rate of the cut wafer is <1.5%.

[0061] As an example, in step S5, if a wire cutting machine cannot be matched at Φ' where the sum of the X-axis cutting deviation and the X-axis re-inspection deviation is within the acceptable range of the X-axis target crystal direction and the sum of the Y-axis cutting deviation and the Y-axis re-inspection deviation is within the acceptable range of the Y-axis target crystal direction, the "Unmatchable Product Reset Method" is executed, and the crystal rod to be cut is removed from the rod gluing machine and re-glued.

[0062] In summary, the method for reducing wafer orientation deviation after dicing in this invention involves dividing the wire dicing machine into multiple groups, obtaining the cutting deviation patterns of the wire dicing machine within different target zero-position ranges, and matching the corresponding wire dicing machine to the crystal rod to be diced based on the cutting deviation patterns, thereby reducing the wafer orientation deviation after dicing. For products with wafer specifications ≤ ±0.1°, the defect rate is reduced from 3.5% to below 0.5%, and for ultra-high specification products with wafer specifications ≤ ±0.05°, the yield reaches over 98.5%. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial applicability.

[0063] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for reducing crystal orientation deviation of wafers after dicing, characterized in that, Includes the following steps: S1: Divide the wire cutting machine into multiple groups. At least one group of wire cutting machines has a horizontal zero-position target range greater than zero degrees, at least one group of wire cutting machines has a horizontal zero-position target range less than zero degrees, and at least one group of wire cutting machines has a horizontal zero-position target range including zero degrees. The rotation angle of the crystal rod cutting angle relative to the initial positioning after the crystal rod is bonded to the bonding machine is Φ. The horizontal zero position is the X-axis cutting deviation of the wire cutting machine when -5°≤Φ≤5°. The X-axis cutting deviation is the difference between the crystal orientation after X-axis cutting and the X-axis re-inspection crystal orientation. The X-axis cutting orientation is the actual X-axis crystal orientation of the wafer detected after cutting. The X-axis re-inspection crystal orientation is the actual X-axis crystal orientation obtained after the crystal rod is bonded to the bonding machine. S2: Collect data. The collected data includes cutting data corresponding to different rotation angle ranges within the range of -90°≤Φ≤90°. The cutting data includes the X-axis cutting deviation and Y-axis cutting deviation of each wire cutting machine. The Y-axis cutting deviation is the difference between the crystal orientation after Y-axis cutting and the Y-axis re-inspection crystal orientation. The crystal orientation after Y-axis cutting is the actual Y-axis crystal orientation of the wafer detected after cutting. The Y-axis re-inspection crystal orientation is the actual Y-axis crystal orientation obtained after the crystal rod is bonded to the bonding machine. S3: Using Φ as the abscissa and the X-axis cutting deviation and Y-axis cutting deviation of each group of wire EDM machines as the ordinates, establish the X-axis cutting deviation diagram and Y-axis cutting deviation diagram for each group of wire EDM machines. S4: Provide the crystal ingot to be cut, obtain the rotation angle Φ' of the ingot's cutting angle relative to the initial positioning after it is bonded to the bonding machine, the X-axis re-inspection deviation, and the Y-axis re-inspection deviation, and determine whether the X-axis re-inspection deviation and Y-axis re-inspection deviation of the crystal ingot to be cut are within the preset range. If they are within the preset range, proceed to the next step; if they are not within the preset range, remove the crystal ingot to be cut from the bonding machine and re-bond it. The X-axis re-inspection deviation is the difference between the X-axis re-inspected crystal direction and the X-axis target crystal direction, and the X-axis target crystal direction is the target value of the X-axis crystal direction of the wafer after cutting; the Y-axis re-inspection deviation is the difference between the Y-axis re-inspected crystal direction and the Y-axis target crystal direction, and the Y-axis target crystal direction is the target value of the Y-axis crystal direction of the wafer after cutting. S5: Based on the X-axis cutting deviation diagram and the Y-axis cutting deviation diagram, select the wire EDM machine that matches the sum of the X-axis cutting deviation and the X-axis re-inspection deviation of the crystal rod to be cut at Φ' within the qualified range of the X-axis target crystal orientation, and the sum of the Y-axis cutting deviation and the Y-axis re-inspection deviation of the crystal rod to be cut within the qualified range of the Y-axis target crystal orientation as the target wire EDM machine.

2. The method for reducing crystal orientation deviation of wafers after dicing according to claim 1, characterized in that: In step S1, the wire EDM machines are divided into five groups. The horizontal zero-position target range of the first group of wire EDM machines is 0.04°~0.05°, the horizontal zero-position target range of the second group of wire EDM machines is 0.02°~0.04°, the horizontal zero-position target range of the third group of wire EDM machines is -0.02°~0.02°, the horizontal zero-position target range of the fourth group of wire EDM machines is -0.04°~-0.02°, and the horizontal zero-position target range of the fifth group of wire EDM machines is -0.05°~-0.04°.

3. The method for reducing crystal orientation deviation of wafers after dicing according to claim 1, characterized in that: In step S2, the cutting data corresponding to each 10° Φ interval is collected. Different rotation angle intervals include -90°~-80°, -80°~-70°, ..., 70°~80°, and 80°~90°.

4. The method for reducing crystal orientation deviation of wafers after dicing according to claim 1, characterized in that: In step S4, the difference between the X-axis crystal orientation after cutting and the target X-axis crystal orientation is within the range of -0.1° to 0.1°, and the difference between the Y-axis crystal orientation after cutting and the target Y-axis crystal orientation is within the range of -0.1° to 0.01°, which is the qualified standard for wafer crystal orientation. The preset range is -0.065° to 0.065°. Here, the X-axis crystal orientation after cutting is the actual X-axis crystal orientation of the wafer detected after cutting, the target X-axis crystal orientation is the target value of the X-axis crystal orientation of the wafer after cutting, the Y-axis crystal orientation after cutting is the actual Y-axis crystal orientation of the wafer detected after cutting, and the target Y-axis crystal orientation is the target value of the Y-axis crystal orientation of the wafer after cutting.

5. The method for reducing crystal orientation deviation of wafers after dicing according to claim 4, characterized in that: In step S5, at Φ', one of the X-axis cutting deviation of the target wire EDM machine and the X-axis re-inspection deviation of the crystal rod to be cut is positive and the other is negative; and / or one of the Y-axis cutting deviation of the target wire EDM machine and the Y-axis re-inspection deviation of the crystal rod to be cut is positive and the other is negative.

6. The method for reducing crystal orientation deviation of a wafer after dicing according to claim 1, characterized in that: In step S4, the difference between the X-axis crystal orientation after cutting and the target X-axis crystal orientation is within the range of -0.05° to 0.05°, and the difference between the Y-axis crystal orientation after cutting and the target Y-axis crystal orientation is within the range of -0.05° to 0.05°, which is the qualified standard for wafer crystal orientation. The preset range is -0.045° to 0.045°. Here, the X-axis crystal orientation after cutting is the actual X-axis crystal orientation of the wafer detected after cutting, the target X-axis crystal orientation is the target value of the X-axis crystal orientation of the wafer after cutting, the Y-axis crystal orientation after cutting is the actual Y-axis crystal orientation of the wafer detected after cutting, and the target Y-axis crystal orientation is the target value of the Y-axis crystal orientation of the wafer after cutting.

7. The method for reducing crystal orientation deviation of a wafer after dicing according to claim 6, characterized in that: In step S5, at Φ', one of the X-axis cutting deviation of the target wire EDM machine and the X-axis re-inspection deviation of the crystal rod to be cut is positive and the other is negative, and one of the Y-axis cutting deviation of the target wire EDM machine and the Y-axis re-inspection deviation of the crystal rod to be cut is positive and the other is negative.

8. The method for reducing crystal orientation deviation of a wafer after dicing according to claim 1, characterized in that: In step S5, if no wire cutting machine can be matched where the sum of the X-axis cutting deviation and the X-axis re-inspection deviation of the crystal rod to be cut is within the acceptable range of the X-axis target crystal direction, and the sum of the Y-axis cutting deviation and the Y-axis re-inspection deviation of the wafer to be cut is within the acceptable range of the Y-axis target crystal direction, then the crystal rod to be cut will be removed from the rod gluing machine and re-glued.

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