Wafer cleaving method and apparatus

Abstract

The application provides a wafer cleaving method and device, the method comprising: determining a cutting edge corresponding to the target wafer; in a double-edge cutting mode, determining the thickness, hardness and photosensitivity of a protective film grown in different cleaving regions according to the material of the target wafer, the substrate deflection angle and the relative position of the different cleaving regions to the cutting edge; determining the film coating parameters in the target wafer protection process; and completing the cleaving of the target wafer. The embodiment of the application not only improves the versatility of the wafer cleaving device, but also effectively reduces the risk of cracking and contamination in the wafer cleaving process, maximizes the yield of the wafer, and reduces the cost of wafer protection through customized protection process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor, in particular to a wafer cleaving method and device. BACKGROUND

[0002] Wafer cleaving is a key step in the semiconductor manufacturing process, which refers to the process of separating the whole wafer after the front-end process into individual independent chips through physical or chemical methods, thereby providing a basis for subsequent packaging, testing and final application.

[0003] When positioning in the wafer cleaving process, some wafer devices only need to cut a vertical edge for positioning to arrange the wafers correctly, and some wafers need to cut a horizontal edge for positioning the device arrangement on the wafer, that is, a total of one vertical edge and one horizontal edge are cut. The former is suitable for the case where the device arrangement has one-way symmetry or the chip size is large, and reducing one cutting edge can save cutting time and material loss, and reduce the cost of a single chip. The latter is suitable for the case where the alignment accuracy of the lithography pattern is relatively high, and the yield is reduced due to positioning error, and the two cutting edges form an asymmetric structure, so that the wafer can only be loaded to the lithography machine stage in a unique direction, which can avoid positive and negative mistakes.

[0004] No matter which wafer cleaving method is used, small particles or sheet-shaped debris will be generated due to material fracture or peeling during the wafer cleaving process. The debris adsorbed on the wafer surface will cause contamination or damage to the wafer surface in the subsequent process, resulting in yield loss. In addition, stress concentration or material defect propagation during the cleaving process will cause macro or micro fracture and generate cracks, thereby causing the wafer to crack and resulting in product scrap. In the face of this problem, the prior art will pretreat the wafer surface before the wafer edge is cleaved, then grow a protective film to pre-protect the wafer surface, remove the protective film after the cleaving operation, and finally physically and / or chemically clean the wafer surface to obtain a clean wafer surface, thereby solving the debris and crack problem through the protection process.

[0005] In summary: (1) When positioning in the wafer cleaving process, there are two cases of cutting one edge and two edges; (2) For the cut horizontal edge, there is a substrate deflection angle due to non-crystalline cutting. Due to the different materials of the wafer (such as gallium arsenide, indium phosphide, etc.), the same material wafer also has different substrate deflection angles (such as 2°, 15°, etc.). Since the wafer cleaving cracking situation corresponding to the above various situations is different, different wafer protection processes need to be considered when the wafer is pre-protected to improve the quality of the wafer. The prior art does not discuss the above complex situations, resulting in reduced universality of the wafer cleaving method. SUMMARY

[0006] The embodiments of the present application aim to provide a wafer cleaving method and device, comprising:

[0007] In the first aspect, the embodiments of the present application provide a wafer cleaving method, comprising:

[0008] determining a cutting edge corresponding to the target wafer according to an edge cutting mode corresponding to the target wafer;

[0009] when the edge cutting mode is a double-edge cutting mode, determining thickness, hardness and photosensitivity of a protective film grown in different cleaving regions according to material of the target wafer, substrate deflection angle and relative positions of the different cleaving regions and the cutting edge;

[0010] determining film coating parameters in a protective process of the target wafer based on the thickness, hardness and photosensitivity of the protective film grown in the different cleaving regions;

[0011] generating a protective film on the surface of the target wafer based on the film coating parameters in the protective process of the target wafer, and then completing cleaving of the target wafer along the cutting edge.

[0012] Optionally, when the edge cutting mode is the double-edge cutting mode, the cutting edge comprises a vertical cutting edge and a horizontal cutting edge.

[0013] The determination of the thickness, hardness and photosensitivity of the protective film grown in the different cleaving regions according to the material of the target wafer, the substrate deflection angle and the relative positions of the different cleaving regions and the cutting edge specifically comprises:

[0014] determining initial parameters of thickness, hardness and photosensitivity of the protective film grown in the target wafer according to the material of the target wafer and the substrate deflection angle;

[0015] determining granularity parameters of the different cleaving regions according to the relative positions of the different cleaving regions and the vertical cutting edge and the horizontal cutting edge, and determining a sorting result of the granularity parameters of the different cleaving regions;

[0016] determining the thickness, hardness and photosensitivity of the protective film grown in the different cleaving regions according to the sorting result and the initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer.

[0017] Optionally, the determination of the thickness, hardness and photosensitivity of the protective film grown in the different cleaving regions according to the sorting result and the initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer specifically comprises:

[0018] The thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions are respectively based on the initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer as the numerical center points, and are evenly distributed in equal intervals.

[0019] Optionally, the specific calculation method of the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions is as follows:

[0020] The equal interval of the thickness, hardness and photosensitivity of the preset protective film is determined.

[0021] According to the order of the different cleavage regions in the sorting result, the equal interval value of the preset multiple is added or subtracted from the numerical center point in turn to determine the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions, so that the numerical values of the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions are respectively evenly distributed based on the equal interval.

[0022] Optionally, the initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer are determined according to the material and substrate deflection angle of the target wafer, and specifically include:

[0023] A distribution function of granularity parameters on wafers is established according to the historical data of wafer cleavage corresponding to the material and substrate deflection angle of the target wafer.

[0024] The initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer are determined according to the mathematical expectation value of the distribution function.

[0025] Optionally, the greater the substrate deflection angle, the smaller the initial parameter of the thickness of the protective film; the lower the initial parameter of the hardness of the protective film, the lower the initial parameter of the photosensitivity of the protective film.

[0026] Optionally, the method further includes:

[0027] When the edge cutting mode is a single edge cutting mode, the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions are determined according to the material and substrate deflection angle of the target wafer.

[0028] Optionally, the growth time in the film coating parameters of the different cleavage regions is determined by the thickness of the protective film grown in the corresponding cleavage region.

[0029] Optionally, the film hardening temperature in the film coating parameters of the different cleavage regions is determined by the hardness of the protective film grown in the corresponding cleavage region.

[0030] In a second aspect, an embodiment of the present application provides a wafer cleaving device, which comprises:

[0031] a cutting mode determination module configured to determine a cutting edge corresponding to a target wafer according to an edge cutting mode corresponding to the target wafer;

[0032] a protective film parameter determination module configured to determine thickness, hardness and photosensitivity of a protective film grown on different cleavage regions of the target wafer according to a material of the target wafer, a substrate deflection angle and relative positions of the different cleavage regions and the cutting edge when the edge cutting mode is a double-edge cutting mode;

[0033] a process parameter determination module configured to determine a film coating parameter in a protective process of the target wafer based on the thickness, hardness and photosensitivity of the protective film grown on the different cleavage regions;

[0034] a wafer cleaving module configured to complete cleaving of the target wafer based on the film coating parameter in the protective process of the target wafer.

[0035] The wafer cleaving method and device provided by the embodiments of the present application provide a double-edge cutting mode and a single-edge cutting mode according to whether the front and back surfaces of a wafer can be distinguished, and provide customized protective processes for different cleavage regions of a wafer according to different wafer materials, substrate deflection angles and relative position relationships between the different cleavage regions of the wafer and a cutting edge, which not only improves the versatility of a wafer cleaving device, but also effectively reduces the risk of cracking and contamination in the wafer cleaving process, maximizes the yield of wafers, and reduces the cost of wafer protection through the customized protective processes. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced.

[0037] Figure 1 a flowchart of a wafer cleaving method provided by the embodiments of the present application;

[0038] Figure 2 a schematic diagram of wafer debris generated by cutting provided by the embodiments of the present application;

[0039] Figure 3 a schematic diagram of wafer double-edge cutting mode provided by the embodiments of the present application;

[0040] Figure 4 a schematic diagram of a 4x4 cleavage region division mode provided by the embodiments of the present application;

[0041] Figure 5 an analysis schematic diagram of debris and cracking of different numbered cleavage regions of a GaAs wafer under a 4x4 cleavage mode provided by the embodiments of the present application;

[0042] Figure 6 A flowchart of a calculation method of the thickness, hardness and photosensitivity of the protective film in different cleavage regions in a double-side cutting mode provided for an embodiment of the present application is shown in FIG. 1.

[0043] Figure 7 A structural diagram of a wafer cleaving device provided for an embodiment of the present application is shown in FIG. 2.

[0044] Figure 8 A structural diagram of an electronic device provided for an embodiment of the present application is shown in FIG. 3. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

[0046] Similar reference numerals and letters refer to like items in the drawings below, and thus, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing description, and cannot be understood as indicating or implying relative importance.

[0047] An embodiment of the present application provides a wafer cleaving method. Figure 1 A flowchart of a wafer cleaving method provided by an embodiment of the present application is shown in FIG. 1, which comprises the following specific steps.

[0048] In step S110, a cutting edge corresponding to a target wafer is determined according to an edge cutting mode corresponding to the target wafer.

[0049] Wafer cleaving (also referred to as "cutting" or "dicing") is a key step in the semiconductor manufacturing process, which refers to the process of dividing a whole wafer that has completed the previous process (such as photolithography, doping, metallization, etc.) into individual independent chips through physical or chemical methods. The core purpose is to convert the wafer from "batch manufacturing" to "single functional unit", providing a basis for subsequent packaging, testing and final application.

[0050] In the process of using a cleaving machine to perform wafer cleaving operation, in order to ensure the accuracy of photolithography, the wafer needs to be edge-removed before photolithography in order to position the device on the wafer. Specifically, one or more smooth flat edges are cleaved for photolithography alignment. The steps of wafer edge removal are as follows: first, place the wafer on the cleaving machine, align it, and then perform scribing and cracking by the diamond knife on the device to produce a flat small edge, as shown in FIG. 2. Figure 2As shown. During this process, due to the scribing and cracking, a large number of debris are generated and adhere to the wafer surface. This debris can cause contamination or damage to the wafer surface in subsequent processes, resulting in yield loss. Furthermore, since the wafer surface is unprotected during the scribing process, it is prone to cracking, leading to product scrap. Therefore, before edge cleaving, a protective pretreatment process can be performed on the wafer surface to grow a protective film, providing pre-protection. After the wafer cleaving operation, the protective film is removed, and finally, the wafer surface is cleaned using physical and chemical methods to remove any remaining protective film, resulting in a cleaner wafer surface.

[0051] During wafer dicing, some wafers only require a vertical edge to be cut for positioning to ensure correct wafer placement; others require an additional horizontal edge for device placement, resulting in a total of one vertical and one horizontal edge being cut. The former is suitable for wafers with unidirectional device symmetry or large chip sizes, reducing the cutting edge saves cutting time and material waste, thus lowering per-wafer costs. The latter is suitable for wafers requiring high alignment accuracy of the photolithography pattern, preventing yield reduction due to positioning errors. Furthermore, the asymmetrical structure formed by the two cutting edges ensures that the wafer can only be loaded onto the photolithography stage in one orientation, preventing misalignment.

[0052] It is understandable from the above two schemes that cutting only one vertical edge and cutting one vertical edge plus one horizontal edge will result in different amounts of debris, different distribution of debris in different areas of the wafer, and different possibilities of wafer cracking in different areas, which will directly affect the execution of subsequent protection processes.

[0053] Therefore, the embodiments of the present invention first need to determine the cutting edge corresponding to the target wafer based on the edge cutting mode corresponding to the target wafer. The edge cutting mode can be divided into two categories: single-sided cutting mode and double-sided cutting mode, which represent cutting only one vertical edge or cutting one vertical edge plus one horizontal edge when used for photolithography alignment and wafer positioning.

[0054] In cleaving a batch of wafers, different wafers can correspond to different cutting modes, for the following reasons: a wafer includes a front side of the wafer, i.e., a front side of a chip, which is used for device and photolithography; and a back side of the wafer, i.e., a back side of a chip, which is often used for thinning / grinding / back side metal / back side marking, etc., and sometimes is coated with a colored film or a laser two-dimensional code, to facilitate distinguishing the front side and the back side or subsequent packaging and conduction. Since wafers to be cleaved in the same batch are from different sources, the edge cutting mode of the wafers needs to be confirmed. In a possible implementation, the edge cutting mode of a target wafer can be confirmed according to a back side mark of the wafer: for example, when the back side of the wafer is coated with gold / dyed film or a laser two-dimensional code, the target wafer is easy to distinguish the front side and the back side, and this type of wafer only needs to be cut vertically, i.e., belongs to a single-edge cutting mode; if the back side of the wafer is bare, it is difficult to distinguish the front side and the back side, and therefore the wafer needs to be cut both vertically and horizontally, i.e., belongs to a double-edge cutting mode.

[0055] In this step, after the edge cutting mode corresponding to the target wafer and the cutting edge are determined, different protection processes can be adaptively performed according to different cutting edges.

[0056] In step S120, when the edge cutting mode is the double-edge cutting mode, the thickness, hardness, and photosensitivity of the protection film grown on the different cleaving regions are determined according to the material of the target wafer, the substrate deflection angle, and the relative positions of the different cleaving regions and the cutting edge.

[0057] The foregoing steps describe that the edge cutting mode in the embodiments of the present application includes two modes, i.e., a single-edge cutting mode and a double-edge cutting mode. In this step, the double-edge cutting mode is discussed first. As shown in FIG. 1, a target wafer is cut with one vertical edge and one horizontal edge, the vertical cutting edge is generally a crystal direction cutting edge, and the horizontal cutting edge is generally a non-crystal direction cutting edge. The specific position of cutting is performed according to the general edge cutting position of wafer cleaving positioning, and does not affect the wafer cleaving of the middle region, which is not limited in the embodiments of the present application. Figure 3 The present application is applicable to common division modes of wafer cleaving, such as 2x2, 3x3, 4x4, and 5x5 division modes, which depend on the demand of a user to divide the target wafer into how many chips. For example, FIG. 2 shows a 4x4 division mode.

[0058] For example, FIG. 2 shows a 4x4 division mode, and subsequent embodiments are described according to the division mode. Embodiments of other division modes are also obtained according to similar principles, which are not described herein again. Figure 4 When the target wafer is divided into 16 cleaving regions in the 4x4 division mode, the debris and cracks caused by the edge cutting in the embodiments of the present application are affected by the following factors, resulting in the diversity of the protection processes for different cleaving regions on the wafer.

[0059]

[0060] ​(1) When the materials of wafers are different, the distribution of the chippings and cracks on the wafers caused by edge cutting is different. For example, for the chippings, the cleavage plane of GaAs wafer is easy to peel off due to its anisotropy, the cutting stress is concentrated on a specific crystal direction, and a large amount of layered chippings are caused to fall off; Si wafer has isotropy but high thermal expansion coefficient, and uniform chippings are caused by the combined action of mechanical grinding and thermal stress, but the particles are fine; InP wafer is mainly melted by laser cutting, the vaporization ratio of the material is low, the slag is solidified on both sides of the cut after cooling, and the amount of chippings is the least. For the cracks, the activation threshold of the cleavage plane of GaAs wafer is relatively low, the cracks quickly expand along the weak crystal plane, and the depth is significant; the cracks of Si wafer are mainly caused by thermal stress, but the isotropy disperses the stress, the crack depth is relatively shallow but the range is wide; the laser heat input of InP wafer is concentrated in the center of the cut, the edge tensile stress zone is narrow, and the cracks only expand along the shallow layer.

[0061] (2) For wafers of the same material, the distribution of chippings and cracks on the wafers caused by edge cutting is different for wafers with different substrate deflection angles. Taking GaAs 2° and GaAs 15° as examples, the cracking degree of GaAs 2° is that the cracks are located at 1 / 3-1 / 2 of the cutting edge, and the cracking degree of GaAs 15° is that the cracks are located at less than 1 / 4 of the cutting edge. Therefore, for GaAs wafers of the same material, the cracks of GaAs 2° and GaAs 15° with different substrate deflection angles are different, and the protective layer and subsequent removal process also need to be designed differently. In fact, the substrate deflection angle refers to the small angle deviation between the substrate surface and the cracking crystal plane. The substrate surface is the cleavage line working surface, and the cracking crystal plane is the natural cleavage plane. The substrate deflection angle usually refers to the angle of the substrate surface towards the cracking crystal plane. For example, for GaAs, the common ones are 0°, 2°, 6°, 9°, 10°, 15°, etc. Among them, 2° and 15° are commonly used in the high-power laser chip industry. Among them, 2° is that the cleavage line surface is deflected by 2° towards the cracking crystal plane, and 15° is that the cleavage line surface is deflected by 15° towards the cracking crystal plane. The larger the 15° angle deflection, the more preferentially the cleavage cracking approaches the cleavage cracking plane, the cracks quickly and continuously expand towards the cleavage plane, the energy dissipation is reduced, the external force required is smaller, and the chippings generated during cracking are relatively less. For the 2° substrate, the deflection angle is small, the distance of the cracks towards the cleavage plane is small, and the cracks easily move back and forth between the cleavage plane and the non-cleavage plane, resulting in a larger acting force required for the cleavage plane and more chippings generated. Figure 4The diagram illustrates the principle of debris and cracking analysis using GaAs with 2° and 15° angles as examples. In the diagram, A represents the substrate surface, and B represents the actual cleavage plane. The entire cracking process involves applying scribing and external force to A, causing the crack to move from A to B and eventually crack along B. C1 represents a 2° deflection from A to B, and C2 represents a 15° deflection from A to B. Because the deflection angle of C2 is larger, the crack easily reaches the direction of B. However, because the deflection angle of C1 is smaller, the crack may be affected by the direction of A or other crystal planes, requiring a larger external force to easily reach the direction of B, making it more difficult to crack and resulting in a larger external force and more debris. Generally, for wafers of the same material, a larger substrate deflection angle results in a smaller initial parameter for the thickness of the protective film, a lower initial parameter for the hardness of the protective film, and a lower initial parameter for the photosensitivity of the protective film.

[0062] (3) For wafers of the same material and substrate deflection angle, the distribution of debris and cracks formed after edge cutting varies in different cleavage regions. Specifically, factors such as the distance between different cleavage regions and the cutting edge, and the direction of wafer cracking at the cutting edge, all affect the debris and cracking situation in different cleavage regions. (See Appendix) Figure 5 This diagram illustrates the analysis of debris and cracking in different cleavage regions of a GaAs wafer under a 4×4 cleavage method. As shown, the wafer is divided into 16 4×4 cleavage regions according to the requirements of the cleavage operation, and each region is labeled 1-1 to 4-4. In this embodiment, different film thicknesses T, photosensitivity A, and hardening times t are set for different cleavage regions in the protection process based on their relative positions to the cutting edges. Region 1-1, being the boundary between two cutting edges and the location of the cleavage edge, generates more and larger debris, requiring the highest possible film thickness T(1-1). Specifically, a photosensitizing material is selected for the protective film preparation in the protection process, and after preparing a protective film of thickness T(1-1), a baking hardening process is performed. The hardness of the protective film, t(1-1), should also be the highest to ensure that no damage occurs when particles contact the surface. Removing the protective film from region (1-1) requires a relatively longer light exposure time and solution treatment time. For region 1-2, which is the direction of natural cracking of the cleavage edge, the size and number of debris particles are less than those in region 1-1. Therefore, the required protective film thickness T(1-2) and hardening time t(1-2) are less. At the same time, the light exposure time and solution treatment time during the subsequent film removal step will also be reduced.

[0063] Similarly, compared to cleavage region 4-4, cleavage region 4-4 is located at the edge of the wafer, making it more prone to breakage and subject to more contamination. Therefore, the film thickness T(4-4) and hardening temperature t(4-4) required for region 4-4 are greater than those required for region 4-1. On the other hand, region 2-1 is located in the scribing crack area, generating more and larger debris. Therefore, it requires a greater film thickness T(2-2) and hardening time t(2-2), and the protective film needs to be set with higher photosensitivity to facilitate subsequent removal.

[0064] After analyzing all cleavage regions in this manner, the thickness, hardness, and photosensitivity of the grown protective film can be set according to the different relative positions of the cleavage regions and the cutting edge. The different cleavage regions are ordered according to the size and number of debris particles as follows: (1-1) >(2-2) > (2-1) > (1-2) > (1-4) > (4-1) > (4-4) > (1-3) > (2-4) > (4-2) > (2-3) > (4-3) > (3-1) > (3-2) > (3-4) >(3-3). The thickness, hardness, and photosensitivity of the protective film grown on the target wafer will vary depending on the different cleavage regions. The specific order of these parameters is also related to the order of the debris particles. The order of film thickness T in different cleavage regions is the same as the order of debris particles, the order of hardening temperature t is the same as the order of debris particles, and the order of photosensitivity A is the opposite of the order of debris particles.

[0065] The above embodiments only illustrate the relationship between parameters such as the thickness, hardness, and photosensitivity of the protective film in different cleavage regions under the bilateral cutting mode. (Appendix) Figure 6 The specific calculation method for the thickness, hardness and photosensitivity of the protective film in different cleavage regions under the bilateral cutting mode is shown. Specifically, step S120 can be implemented through the following steps.

[0066] Step S121: Determine the initial parameters of the thickness, hardness, and photosensitivity of the protective film grown on the target wafer based on the material of the target wafer and the substrate deflection angle.

[0067] In this embodiment of the invention, when cleaving the target wafer, information such as the wafer material and substrate deflection angle, such as GaAs2° or GaAs15°, can first be obtained. This is basic information about any target wafer in the batch to be cleaved that can be obtained before wafer cleaving. This information is recorded in the system when the wafer is stored in the warehouse before entering the process pipeline. For a wafer with a determined material and substrate deflection angle, regardless of how the cleaving region is divided internally, the general situation of the debris and cracks generated in the double-sided dicing mode can be determined through historical data statistics. The initial parameters in this step can be understood as the average value of the parameters in the protective process over the entire wafer. In one possible implementation, a distribution function of debris particles on the wafer can be established based on historical data. The expected value of this function is the average value of the debris particles on the wafer. In addition, by establishing the correspondence between debris particles and parameters such as the thickness, hardness, and photosensitivity of the protective film in advance, the initial parameters of the thickness, hardness, and photosensitivity of the protective film grown on the wafer can be further obtained.

[0068] Step S122: Based on the relative positions of different cleavage regions with the vertical and horizontal cutting edges, determine the grain size parameters of the different cleavage regions, and determine the sorting result of the grain size parameters of the different cleavage regions.

[0069] The preceding embodiments have exemplarily described how, when a wafer is divided into 4×4 cleavage regions, the parameters of grain size are ordered according to the relative positions of different cleavage regions with the vertical and horizontal cutting edges, and the underlying principle. For other cleavage region division methods such as 2×2, 3×3, and 5×5, the ordering of protective film thickness, hardness, and photosensitivity in each cleavage region can also be pre-analyzed. This embodiment of the invention does not impose specific limitations; the ordering of coating parameters for different cleavage regions under commonly used cleavage region division methods can be pre-analyzed and saved.

[0070] Step S123: Based on the sorting results and the initial parameters of the thickness, hardness, and photosensitivity of the protective film grown on the target wafer, determine the thickness, hardness, and photosensitivity of the protective film grown in the different cleavage regions.

[0071] After determining the sorting results of the grain size parameters of different cleavage regions and the initial parameters of the thickness, hardness, and photosensitivity of the protective film grown on the target wafer, in one possible embodiment of the present invention, the values ​​of the thickness, hardness, and photosensitivity of the protective film grown in the different cleavage regions are respectively distributed discretely and uniformly at equal intervals, with the initial parameters of the protective film grown on the target wafer as the numerical center point. Other distribution methods with the initial parameters as the numerical center point can also be used as other feasible solutions, depending on user requirements. Specifically, the calculation method for the thickness, hardness, and photosensitivity of the protective film grown in different cleavage regions is as follows: determine the preset equal intervals for the thickness, hardness, and photosensitivity of the protective film; based on the order of the different cleavage regions in the sorting result, add or subtract the preset multiple of the equal interval value from the numerical center point to determine the thickness, hardness, and photosensitivity of the protective film grown in different cleavage regions, so as to achieve a discrete and uniform distribution of the thickness, hardness, and photosensitivity of the protective film grown in different cleavage regions based on the equal intervals.

[0072] For example, when using a 2×2 cleavage region division method in the double-sided dicing mode for GaAs2° wafers, this embodiment of the invention first determines the initial parameters of the thickness, hardness, and photosensitivity of the protective film grown on the target wafer based on two conditions: the wafer material GaAs and the substrate deflection angle of 2°. Specifically, the average value of the debris particles on the wafer can be obtained by using the mathematical expectation value of the distribution function of debris particles on the wafer established from historical data related to GaAs2° wafers. Then, by using the pre-established correspondence between debris particles and parameters such as the thickness, hardness, and photosensitivity of the protective film in the double-sided dicing mode of GaAs2° wafers, the initial parameters T0, t0, and A0 of the thickness, hardness, and photosensitivity of the protective film grown on the wafer can be further obtained.

[0073] Then, based on the relative positions of different cleavage regions with the vertical and horizontal cutting edges under the 2×2 cleavage region division method, the particle size parameters of different cleavage regions are sorted. Assuming that the upper left, upper right, lower right, and lower left regions of the four cleavage regions are O, P, Q, and R respectively, by calling the pre-analyzed and saved coating parameter sorting, from the pre-analyzed debris particle size parameter sorting O > P > Q > R, it can be seen that the protective film thickness sorting is O > P > Q > R, the hardness sorting is O > P > Q > R, and the photosensitivity sorting is R > Q > P > O.

[0074] Finally, after obtaining the sorting results of the particle size parameters of the four cleavage regions and the initial parameters of the thickness, hardness, and photosensitivity of the protective film grown on the target wafer, based on the principle of equally spaced discrete uniform distribution, the parameters of the thickness T, hardness t, and photosensitivity A of the protective film grown in the four cleavage regions can be obtained as follows: Cleavage region O: T0+1.5μ1, t0+1.5μ2, A0-1.5μ3; Cleavage region P: T0+0.5μ1, t0+0.5μ2, A0-0.5μ3; Cleavage region Q: T0-0.5μ1, t0-0.5μ2, A0+0.5μ3; Cleavage region R: T0-1.5μ1, t0-1.5μ2, A0+1.5μ3. Here, μ1, μ2, and μ3 are fixed interval constants when the thickness, hardness, and photosensitivity are evenly spaced discrete uniformly distributed, and these constants can be set according to the user's experience.

[0075] Step S130: Determine the coating parameters in the target wafer protection process based on the thickness, hardness, and photosensitivity of the protective films grown in the different cleavage regions.

[0076] After calculating the thickness, hardness, and photosensitivity of the protective film in different cleavage regions under the bilateral dicing mode, the coating parameters in the target wafer protection process can be determined. It is understood that, as explained above, the coating parameters in the target wafer protection process are different in different cleavage regions. The coating parameters in this step refer to the relevant process parameters involved in growing the protective film on the wafer during the protection process, including the growth time of the protective film and the hardening temperature. Specifically, the growth time in the coating parameters for different cleavage regions is determined by the thickness of the protective film grown in the corresponding cleavage region; the hardening temperature in the coating parameters for different cleavage regions is determined by the hardness of the protective film grown in the corresponding cleavage region. The numerical correspondence between the above protective film parameter values ​​and coating parameter values ​​can be pre-established using empirical values ​​to establish a lookup table, and then the corresponding coating parameter values ​​can be determined according to the required protective film parameters.

[0077] Step S140: After generating a protective film on the surface of the target wafer based on the coating parameters in the target wafer protection process, the target wafer is cleaved along the cutting edge.

[0078] After determining the coating parameters on different cleavage regions in the target wafer protection process, the wafer cleavage process in this embodiment of the invention can be performed. Since the wafer cleavage process in this embodiment of the invention includes a wafer protection process, the wafer cleavage process will be described below.

[0079] First, before cleaving the substrate wafer, a plasma treatment is performed on the wafer surface to increase the adhesion of the subsequent protective film layer. After pretreatment, a protective film can be grown on the wafer surface using vapor deposition or drop casting. At this stage, the edges of each cleaved region need to be shielded to prevent the protective film from growing on them. This ensures that the subsequent cleaving of the regions is not affected while still protecting the wafer surface. Different protective films with calculated coating parameters are grown for different cleaved regions. This reduces production costs compared to preparing a thicker protective film overall and also facilitates targeted treatment of the protective film in different regions.

[0080] After the protective film is prepared, the wafer can undergo a scribing and cracking process. This process involves creating pre-existing cracks on the substrate wafer surface using diamond scribing tools, following the direction of two flat edges. In this step, the diamond scribing tools are quite hard, while the wafer substrate is relatively brittle. Therefore, during scribing, the contact motion between the two generates debris. During cracking, a roller presses down on the scribing area, causing surface debris to embed into the substrate wafer surface and cause damage. For different flat edge lengths and substrate angles, the scribing pressure, length, and roller pressure during cracking are adjusted to meet the requirements for flat edge preparation. Therefore, surface protection is necessary before the process. This ensures that the debris particles generated in this step fall onto the protective layer, preventing direct contact with the wafer surface and reducing surface damage. Furthermore, the protective film on the wafer surface buffers the force extension during the scribing and cracking process, reducing the wafer cracking rate.

[0081] After the two flat edges of the wafer are prepared, the protective film can be removed. First, an organic solution with a specific ratio is used to react the protective film with organic matter. A commonly used organic solution is NMP (N-methylpyrrolidone), mainly because NMP is a polar organic solvent with good solubility and volatility. When the NMP remover comes into contact with the organic layer, NMP molecules interact with the molecules in the organic layer, breaking the chemical bonds between them, thus dissolving several layers in the NMP and achieving the removal effect. The processing time can be set according to the thickest cleavage region of the protective film, ensuring that other areas are relatively clean with minimal residue. Compared to direct plasma cleaning, wet cleaning has a higher rate, can treat thicker films, and is less expensive, while plasma treatment treats thinner films and is more expensive. Therefore, wet cleaning is used to remove most of the protective film first, with a small amount subsequently cleaned by plasma.

[0082] After the wet cleaning process, residual organic and etching solutions are washed and dried. Then, plasma cleaning is performed on the wafer surface to remove the remaining organic protective layer. First, oxygen plasma is used to treat the wafer surface with an oxide layer (the treatment time is short, only a thin oxide layer is needed), which protects the substrate surface when removing the residual protective film. Then, Ar plasma is used to treat the remaining protective film on the surface. For cleavage areas with more residual film, the treatment time is longer; for cleavage areas with less residual film, the treatment time is shorter. In addition, a wafer surface planarization process can be performed using an etching solution with a specific ratio (usually hydrochloric acid: hydrogen peroxide: water) to remove nanoscale imperfections caused by surface plasma cleaning and to remove the surface oxide layer. Finally, a cleaning, baking, and drying process is performed to form a dry and clean wafer, completing the wafer cleavage process. Therefore, in this embodiment of the invention, based on the thickness, hardness, and photosensitivity of the protective film grown in the different cleavage regions, the film removal parameters in the target wafer protection process are also determined. For example, the time parameters for plasma cleaning and chemical planarization can be finely adjusted according to the cleavage region.

[0083] Based on the above embodiments, the embodiments of the present invention can be applied not only to the double-sided dicing mode of wafers, but also to the single-sided dicing mode, that is, to wafers where only one vertical edge needs to be diced for alignment without dicing the front and back sides. The processing in this case is simpler: when the edge dicing mode is single-sided, it is only necessary to determine the thickness, hardness, and photosensitivity of the protective film grown in the different cleavage regions based on the material of the target wafer and the substrate deflection angle. In other words, the thickness, hardness, and photosensitivity of the protective film grown in different cleavage regions are the same. Once the material of the target wafer and the substrate deflection angle are determined, the initial parameters of the calculated thickness, hardness, and photosensitivity are the thickness, hardness, and photosensitivity of each cleavage region. Specifically, a preset wafer protection process parameter lookup table is consulted to determine the thickness, hardness, and photosensitivity of the protective film grown in the different cleavage regions. This lookup table contains the correspondence between the wafer material, substrate deflection angle, and the thickness, hardness, and photosensitivity of the grown protective film, and the process parameters for the protective films grown in the different cleavage regions are identical. The single-sided dicing mode corresponds to a simple protection mode in the protection process, distinct from the multi-region precision protection mode under the double-sided dicing mode.

[0084] The wafer cleaving method provided in this invention is applied to a cleaving device capable of cleaving wafers under different conditions. It offers both double-sided and single-sided cleaving modes depending on whether the front and back sides of the wafer can be distinguished. Furthermore, it provides customized protection processes for different cleaving regions of the wafer based on different wafer materials, substrate deflection angles, and the relative positions of different cleaving regions and cleaving edges. This not only improves the versatility of the wafer cleaving method but also effectively reduces the risk of wafer cracking and contamination during cleaving, maximizes wafer yield, and lowers the cost of wafer protection through customized protection processes.

[0085] Based on any of the above embodiments, the appendix Figure 7 A schematic diagram of the wafer cleaving apparatus provided in an embodiment of the present invention is shown, the details of which are as follows:

[0086] The cutting mode determination module 710 is used to determine the cutting edge corresponding to the target wafer according to the edge cutting mode corresponding to the target wafer;

[0087] The protective film parameter determination module 720 is used to determine the thickness, hardness and photosensitivity of the protective film grown in different cleavage regions based on the material of the target wafer, the substrate deflection angle and the relative position of different cleavage regions to the cutting edge when the edge cutting mode is a double-sided cutting mode.

[0088] The process parameter determination module 730 is used to determine the coating parameters in the target wafer protection process based on the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions.

[0089] The wafer cleaving module 740 completes the cleaving of the target wafer based on the coating parameters in the target wafer protection process.

[0090] The wafer cleaving apparatus provided in this invention provides both double-sided and single-sided cleaving modes depending on whether it can distinguish between the front and back sides of the wafer. It can also provide customized protection processes for different cleaving regions of the wafer based on different wafer materials, substrate deflection angles, and the relative positional relationship between different cleaving regions and the cleaving edge. This not only improves the versatility of the wafer cleaving apparatus but also effectively reduces the risk of wafer cracking and contamination during wafer cleaving, maximizes wafer yield, and reduces the cost of wafer protection through customized protection processes.

[0091] Based on any of the above embodiments, the appendix Figure 8The diagram illustrates the physical structure of an electronic device according to an embodiment of the present invention. This electronic device may include a processor 810, a communications interface 820, a memory 830, and a communication bus 840. The processor 810, communications interface 820, and memory 830 communicate with each other via the communication bus 840. The processor 810 can call logical instructions stored in the memory 830 to execute the following method:

[0092] The cutting edge corresponding to the target wafer is determined according to the edge cutting pattern corresponding to the target wafer;

[0093] When the edge cutting mode is a double-sided cutting mode, the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions are determined according to the material of the target wafer, the substrate deflection angle and the relative position of the different cleavage regions to the cutting edge.

[0094] The coating parameters in the target wafer protection process are determined based on the thickness, hardness, and photosensitivity of the protective films grown in the different cleavage regions.

[0095] Based on the coating parameters in the target wafer protection process, the cleavage of the target wafer is completed.

[0096] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention embodiment, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in this invention embodiment. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0097] On the other hand, embodiments of the present invention also provide a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, is implemented to perform the methods provided in the above embodiments, including, for example:

[0098] The cutting edge corresponding to the target wafer is determined according to the edge cutting pattern corresponding to the target wafer;

[0099] When the edge cutting mode is a double-sided cutting mode, the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions are determined according to the material of the target wafer, the substrate deflection angle and the relative position of the different cleavage regions to the cutting edge.

[0100] The coating parameters in the target wafer protection process are determined based on the thickness, hardness, and photosensitivity of the protective films grown in the different cleavage regions.

[0101] Based on the coating parameters in the target wafer protection process, the cleavage of the target wafer is completed.

[0102] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0103] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wafer cleaving method, characterized by, The method comprises: determining a cutting edge corresponding to the target wafer according to an edge cutting mode corresponding to the target wafer; when the edge cutting mode is a double-edge cutting mode, determining thickness, hardness and photosensitivity of a protective film grown in different cleavage regions according to material of the target wafer, substrate deflection angle and relative positions of the different cleavage regions and the cutting edge; determining film coating parameters in a protective process of the target wafer based on the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions; generating a protective film on the surface of the target wafer based on the film coating parameters in the protective process of the target wafer, and then completing cleavage of the target wafer along the cutting edge.

2. The wafer cleaving method according to claim 1, wherein when the edge cutting mode is a double-edge cutting mode, the cutting edge comprises a vertical cutting edge and a horizontal cutting edge; the determining of the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions according to the material of the target wafer, the substrate deflection angle and the relative positions of the different cleavage regions and the cutting edge specifically comprises: determining initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer according to the material of the target wafer and the substrate deflection angle; determining granularity parameters of the different cleavage regions and determining a sorting result of the granularity parameters of the different cleavage regions according to the relative positions of the different cleavage regions and the vertical cutting edge and the horizontal cutting edge; determining the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions according to the sorting result and the initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer.

3. The wafer cleaving method according to claim 2, wherein the determining of the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions according to the sorting result and the initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer specifically comprises: the values of the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions are respectively taken as numerical center points of the initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer, and are discretely and uniformly distributed at equal intervals.

4. The wafer cleaving method according to claim 3, wherein the specific calculation method of the values of the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions comprises: determining equal-interval intervals of the thickness, hardness and photosensitivity of the preset protective film; on the basis of the numerical center points, the equal-interval intervals of the preset multiples are sequentially added or subtracted according to the order of the granularity parameters corresponding to the different cleavage regions in the sorting result, so as to determine the values of the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions, so as to realize the discrete and uniform distribution of the values of the thickness, hardness and photosensitivity of the protective film grown in the different cleavage regions based on the equal-interval intervals.

5. The wafer cleaving method according to claim 2, wherein the determining of the initial parameters of the thickness, hardness and photosensitivity of the protective film grown in the target wafer according to the material of the target wafer and the substrate deflection angle specifically comprises: establishing a distribution function of the granularity parameters on wafers according to historical data of wafer cleavage corresponding to the material of the target wafer and the substrate deflection angle; The initial parameters of the thickness, hardness and photosensitivity of the protective film grown on the target wafer are determined according to the mathematical expectation of the distribution function.

6. The wafer cleaving method according to claim 2, wherein The greater the substrate deflection angle, the smaller the initial parameter of the thickness of the protective film; the lower the initial parameter of the hardness of the protective film, the lower the initial parameter of the photosensitivity of the protective film.

7. The wafer cleaving method of claim 1, wherein The method further comprises: When the edge cutting mode is a single-edge cutting mode, the thickness, hardness and photosensitivity of the protective film grown on the different cleavage regions are determined according to the material of the target wafer and the substrate deflection angle.

8. The wafer cleaving method of claim 1, wherein The growth time in the coating parameters of the different cleavage regions is determined by the thickness of the protective film grown on the corresponding cleavage region.

9. The wafer cleaving method of claim 1, wherein The hardening temperature in the coating parameters of the different cleavage regions is determined by the hardness of the protective film grown on the corresponding cleavage region.

10. A wafer cleaving apparatus, characterized in that, The device comprises: A cutting mode determination module configured to determine the cutting edge corresponding to the target wafer according to the edge cutting mode corresponding to the target wafer; A protective film parameter determination module configured to, when the edge cutting mode is a double-edge cutting mode, determine the thickness, hardness and photosensitivity of the protective film grown on the different cleavage regions according to the material of the target wafer, the substrate deflection angle and the relative position of the different cleavage regions to the cutting edge; A process parameter determination module configured to determine the coating parameters in the target wafer protection process based on the thickness, hardness and photosensitivity of the protective film grown on the different cleavage regions; A wafer cleaving module configured to complete the cleaving of the target wafer along the cutting edge after generating the protective film on the surface of the target wafer based on the coating parameters in the target wafer protection process.

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