Chip cutting method

Abstract

The invention discloses a chip cutting method, which comprises the following steps of: adhering a wafer to a base material to obtain a sample to be cut; the to-be-cut sample is cut in the first direction, the wafer is cut into a plurality of wafer units, a first cut sample is obtained, and the cutting depth is larger than the thickness of the wafer and smaller than the thickness of the to-be-cut sample; the first cutting sample is cut in the second direction, a plurality of cutting grooves are formed in each wafer unit, a second cutting sample is obtained, the cutting depth is smaller than the thickness of the wafer, and the first direction intersects with the second direction; and carrying out splitting treatment on the second cutting sample, so that each wafer unit is broken at the cutting groove, and a plurality of chips are obtained. According to the chip cutting method, the problem that the chip and the base material are not firmly bonded when the wafer is cut into the chip with the ultra-small size can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor cutting, and in particular relates to a chip cutting method. Background Art

[0002] With the miniaturization and high performance of electronic devices, the demand for ultra-small chips is increasing. However, traditional chip cutting methods often face problems such as chip sticking, insufficient precision, low cutting efficiency, etc., which lead to loss of cutting yield when processing ultra-small chips.

[0003] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0004] The object of the present invention is to provide a chip cutting method, which can solve the problem of weak adhesion between the chip and the substrate (cutting film) when cutting a wafer into ultra-small chips.

[0005] In order to achieve the above object, a specific embodiment of the present invention provides a technical solution as follows: a chip cutting method, comprising the following steps:

[0006] Bonding the wafer to the substrate to obtain a sample to be cut;

[0007] Cutting the sample to be cut along a first direction to cut the wafer into a plurality of wafer units to obtain a first cut sample, wherein the cutting depth is greater than the thickness of the wafer and less than the thickness of the sample to be cut;

[0008] Cutting the first cutting sample along the second direction to form a plurality of cutting grooves on each of the wafer units to obtain a second cutting sample, wherein the cutting depth is less than the thickness of the wafer, and the first direction and the second direction intersect;

[0009] The second cut sample is split to break each wafer unit at the cutting groove to obtain a plurality of chips.

[0010] In one or more embodiments of the present invention, the first direction and the second direction are perpendicular to each other.

[0011] In one or more embodiments of the present invention, when the sample to be cut is cut along the first direction, the cutting depth exceeds the thickness of the wafer by at least 20 μm.

[0012] In one or more embodiments of the present invention, the minimum distance between the bottom surface of the cutting groove on the second cutting pattern and the surface of the substrate facing the wafer is 10-30 μm.

[0013] In one or more embodiments of the present invention, the substrate includes a cutting film, and the cutting film is a UV film or a non-UV film.

[0014] In one or more embodiments of the present invention, in the step of cutting the chip along the first direction, the rotation speed of the cutting blade in the cutting equipment is 35000-45000 rpm / min, the cutting speed is 35-45 mm / s, and the cutting water flow rate is 0.8-1.5 L / min.

[0015] In one or more embodiments of the present invention, in the step of cutting the chip along the second direction, the rotation speed of the cutting knife in the cutting equipment is 35000-45000 rpm / min, the cutting speed is 35-45 mm / s, and the cutting water flow rate is 0.8-1.5 L / min.

[0016] In one or more embodiments of the present invention, the contact area between each wafer unit on the first cutting sample and / or the second cutting sample and the substrate is greater than or equal to 0.09 mm 2 .

[0017] In one or more embodiments of the present invention, the cleaving process comprises:

[0018] A release film is used to cover one side of the wafer unit on the second cutting sample, and an elastic roller is used to roll the release film along the first direction to break the wafer unit at the cutting groove.

[0019] In one or more embodiments of the present invention, the chip cutting method further includes:

[0020] Performing film expansion processing on the plurality of wafer units and substrates after the cleavage processing, so that the distance between adjacent chips on the substrate is greater than or equal to 30 μm;

[0021] The chip and the substrate are separated to obtain a plurality of chips.

[0022] Compared with the prior art, the chip cutting method of the present invention divides the wafer into a plurality of strip-shaped wafer units by cutting through the wafer along a first direction, and cuts a plurality of cutting grooves on the wafer unit without cutting through the wafer unit along a second direction. Since the wafer unit is in the shape of strips, its bonding area with the substrate is large. Therefore, during the two cutting processes, the chip will not be separated and lost from the substrate due to the impact of the cutting fluid. The second cut sample is then split to break the wafer unit at the cutting groove, thereby obtaining individual chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A flowchart of a chip cutting method in an example of the present invention;

[0025] Figure 2 A schematic diagram of a sample to be cut being cut in an example of the present invention;

[0026] Figure 3 It is a schematic diagram of cutting a sample to be cut along a first direction in an example of the present invention;

[0027] Figure 4 It is a schematic diagram of cutting a sample to be cut along a second direction in an example of the present invention;

[0028] Figure 5 A schematic diagram of a splitting process in an example of the present invention;

[0029] Figure 6 FIG. 1 is a schematic diagram of separating a chip and a substrate in an example of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0031] As mentioned in the background technology, with the miniaturization and high performance of electronic devices, the demand for ultra-small chips is increasing. However, the traditional chip cutting method generally involves bonding a wafer to a substrate and then cutting the wafer in two directions to cut the wafer into several independent units, namely chips.

[0032] However, when ultra-small chips need to be cut and prepared, for example, ultra-small chips of 100*100μm, the wafer cutting process will use cutting fluid (such as water, etc.) to spray onto the contact point between the wafer and the cutting knife. The chip will be affected by the impact of the cutting fluid and the force of the cutting knife contacting the chip during cutting. If the traditional chip cutting method is still maintained, the bonding force between the wafer and the substrate, due to the small size of the chip, that is, the bonding area between each chip and the substrate is too small, during the cutting process, the chip will be separated from the substrate under the action of the above two forces, resulting in the loss of the chip.

[0033] For example, in order to ensure that the chip is not separated from the substrate under the action of the above two forces, the bonding force between the wafer and the substrate must be relatively large in the early stage. However, this will make it difficult to separate a single chip from the substrate after cutting, resulting in damage and scrapping of the chip during the process.

[0034] like Figure 1 As shown, a chip cutting method in an example of the present invention includes the following steps:

[0035] S1, bonding the wafer to the substrate to obtain a sample to be cut;

[0036] S2, cutting the sample to be cut along the first direction, cutting the wafer into a plurality of wafer units, and obtaining a first cut sample, wherein the cutting depth is greater than the thickness of the wafer and less than the thickness of the sample to be cut;

[0037] S3, cutting the first cutting sample along the second direction to form a plurality of cutting grooves on each of the wafer units to obtain a second cutting sample, wherein the cutting depth is less than the thickness of the wafer, and the first direction and the second direction intersect;

[0038] S4, performing a splitting process on the second cut sample, so that each of the wafer units is broken at the cutting groove to obtain a plurality of chips.

[0039] It can be understood that the chip cutting method of the present invention divides the wafer into a plurality of strip-shaped wafer units by cutting through the wafer along a first direction, and cuts a plurality of cutting grooves on the wafer unit without cutting through the wafer unit along a second direction. Since the wafer unit is in the shape of strips, its bonding area with the substrate is large. Therefore, during the two cutting processes, the chip will not be separated and lost from the substrate due to the impact of the cutting fluid. The second cut sample is then split to break the wafer unit at the cutting groove, thereby obtaining individual chips.

[0040] It should be noted that since wafers are generally round and chips are generally rectangular, some scraps whose shapes do not meet the requirements will be produced after cutting. Only the parts whose shapes meet the requirements after cutting are the required chips.

[0041] Step S1, bonding a wafer to a substrate to obtain a sample to be cut.

[0042] Specifically, the substrate may include a cutting film, and the cutting film may be a UV film or a non-UV film, such as D-485 (UV film) (whose peeling force is greater than or equal to 400 g / 25 mm) and SPV224 (non-UV film) (whose peeling force is greater than or equal to 100 g / 25 mm).

[0043] Specifically, the substrate may further include a fixing ring, and the outer periphery of the cutting film is fixed on the cutting ring to fix the cutting film.

[0044] Specifically, the wafer can be bonded to the substrate using an existing film bonding machine on the market, such as a fully automatic film bonding machine from Lintec of Japan, to complete the film bonding operation.

[0045] Specifically, there should be no bubbles between the dicing film and the wafer, and the size of particles between the dicing film and the wafer should be less than or equal to 100 μm.

[0046] like Figure 2 and 3 As shown, step S2, cutting the sample to be cut along the first direction, cutting the wafer into a plurality of wafer units, obtaining a first cut sample, the cutting depth is greater than the thickness of the wafer and less than the thickness of the sample to be cut.

[0047] Specifically, when cutting the sample to be cut along the first direction, the cutting depth exceeds the thickness of the wafer by at least 20 μm, thereby ensuring that the wafer can be cut through along the first direction. Preferably, the cutting depth exceeds the thickness of the wafer by 30 μm.

[0048] The first cut sample includes a substrate and a plurality of wafer units bonded to the substrate.

[0049] Specifically, in step S2, a common cutting machine on the market can be used to implement the above-mentioned cutting process; for example, a Japanese Disco cutting machine and a cutting blade are used, and the cutting accuracy is ±3 μm.

[0050] Specifically, in the step of cutting the chip along the first direction, the rotation speed of the cutting blade in the cutting equipment is 35000-45000 rpm / min, the cutting speed is 35-45 mm / s, and the cutting water flow rate is 0.8-1.5 L / min. Preferably, the rotation speed of the cutting blade is 40000 rpm, the cutting speed is 40 mm / s, and the cutting water flow rate is 1.2 L / min.

[0051] Specifically, the contact area between each wafer unit on the first cut sample and the substrate is greater than or equal to 0.09 mm 2 This ensures the bonding force between the wafer unit and the substrate, ensures that the wafer unit will not be separated from the substrate by the force of the cutting knife and cutting water, ensures cutting accuracy, and avoids wafer (chip) loss.

[0052] like Figure 2 and 4 As shown, step S3, cutting the first cutting sample along the second direction, forming a plurality of cutting grooves on each of the wafer units, and obtaining a second cutting sample, the cutting depth is less than the thickness of the wafer, and the first direction and the second direction intersect.

[0053] Specifically, the minimum distance between the bottom surface of the cutting groove on the second cutting pattern and the surface of the substrate facing the wafer is 10-30 μm. That is, along the depth direction of the cutting groove, the minimum distance between the inner surface of the cutting groove and the surface of the substrate facing the wafer is 10-30 μm; such a setting can ensure that the wafer unit will not be cut through and facilitate the subsequent splitting process.

[0054] The second cutting sample includes a substrate and a plurality of wafer units bonded to the substrate (the wafer units in the second cutting sample have a plurality of cutting grooves).

[0055] Specifically, in step S3, a common cutting machine on the market can be used to implement the above-mentioned cutting process; for example, a Japanese Disco cutting machine and a cutting blade are used, and the cutting accuracy is ±3 μm.

[0056] Specifically, in the step of cutting the chip along the first direction, the rotation speed of the cutting blade in the cutting equipment is 35000-45000 rpm / min, the cutting speed is 35-45 mm / s, and the cutting water flow rate is 0.8-1.5 L / min. Preferably, the rotation speed of the cutting blade is 40000 rpm, the cutting speed is 40 mm / s, and the cutting water flow rate is 1.2 L / min.

[0057] Specifically, the contact area between each wafer unit on the first cut sample and the substrate is greater than or equal to 0.09 mm 2 This ensures the bonding force between the wafer unit and the substrate, ensures that the wafer unit will not be separated from the substrate by the force of the cutting knife and cutting water, ensures cutting accuracy, and avoids wafer (chip) loss.

[0058] Preferably, the first direction and the second direction are perpendicular to each other, so that the chip formed after the subsequent splitting process is rectangular.

[0059] like Figure 5 As shown, step S4, the second cut sample is split to break each wafer unit at the cutting groove to obtain a plurality of chips.

[0060] Specifically, the splitting process comprises: using a release film to cover one side of the wafer unit on the second cutting sample, and rolling the release film with an elastic roller along a first direction to break the wafer unit at the cutting groove. The release film can be a common release film on the market, which also plays a role in protecting the wafer (chip).

[0061] Preferably, the elastic roller can be a rubber roller to protect the wafer (chip). Further, a 0.5 kg rubber roller can be used to roll back and forth twice along the first direction to ensure that all wafer units are broken to obtain a single chip.

[0062] Furthermore, the chip cutting method further comprises:

[0063] The wafer units and substrates after the splitting process are subjected to film expansion process, so that the distance between adjacent chips on the substrate is greater than or equal to 50 μm; and then the chips and the substrate are separated to obtain a plurality of chips.

[0064] Specifically, several wafer units and substrates after the splitting process can be placed on a mold expander for mold expansion. Thus, the distance between adjacent chips on the substrate is greater than or equal to 50 μm. This setting is to facilitate the separation of chips and substrates. The mold expander can be a common mold expander on the market.

[0065] For example, a film expander is used to stretch the cut film, with a stretching stroke of 5 to 10 cm, an expansion amount of about 1.2 times the chip size, and a chip spacing greater than or equal to 30 μm, meeting the process requirements for chip picking.

[0066] Specifically, the step of separating the chip and the substrate may include:

[0067] like Figure 6 As shown, the substrate is fixed, and a lifting device (such as an air cylinder, oil cylinder, etc.) is used to lift the cutting film on the side of the substrate away from the chip to increase the spacing between multiple chips, and then a vacuum plunger is used to adsorb the chips one by one to separate the chip from the substrate (cutting film). During the picking process, the chip is not damaged by collision, the chip position is normal and not skewed, and the equipment can successfully complete the picking work.

[0068] The full-chip chip cutting method of the present invention is described in detail below in conjunction with specific embodiments and comparative examples.

[0069] Example 1

[0070] The cutting material is 8-inch silicon wafer with a thickness of 120μmm, and the purpose is to cut it into single chips of 100*100μm.

[0071] The specific cutting steps are:

[0072] The fully automatic film laminating machine from Japan Lintec is used to complete the laminating operation of wafers and dicing films. The working environment is in a Class 100 clean room. The dicing film is D-485 (UV film), and the particle size between the dicing film and the wafer is less than or equal to 100μm.

[0073] The wafer is cut along the first direction using a Japanese Disco cutting machine and cutting blade. The spindle speed of the cutting machine is 40000rpm, the cutting speed is 40mm / s, the cutting depth is 150±10μm, and the cutting water flow is 1.2L / min. The cutting blade is a Disco ZH-05 series blade (4800 mesh diamond blade). The cutting effect is: the chipping size of the front side of the wafer is less than or equal to 15μm (meets the requirement of less than or equal to 25μm), the chipping size of the back side of the wafer is less than or equal to 30μm (meets the requirement of less than or equal to 50μm), and the wafer is completely cut through, so that the wafer is divided into several strip-shaped wafer units.

[0074] The wafer was cut along the second direction (perpendicular to the first direction) using a Japanese Disco cutter and a cutting blade. The spindle speed of the cutter was 40,000 rpm, the cutting speed was 20 mm / s, the cutting depth was 100 ± 10 μm, and the cutting water flow rate was 1.2 L / min. The cutting blade was a Disco ZH-05 series blade (4800 mesh diamond blade). The wafer unit was not cut through, resulting in multiple cutting grooves on each wafer unit.

[0075] Cover the wafer unit with a release film, then use a 0.5kg rubber roller to roll back and forth twice along the cutting direction, and finally observe the chip fracture under a high-power microscope. At this time, all the chips that have not been cut through are broken, and the chip is turned from a whole sheet into a single chip.

[0076] Place the above chips and substrate on the expansion machine, set the expansion stroke to 5cm, the chip spacing before expansion is less than or equal to 20μm (the thickness of the cutting blade), and the chip spacing after expansion is greater than or equal to 35um measured under a microscope. Then pick up the chip to separate the chip from the substrate.

[0077] There was no chip loss during the whole process.

[0078] Example 2

[0079] The cutting material is 8-inch silicon wafer with a thickness of 120μmm, and the purpose is to cut it into single chips of 100*100μm.

[0080] The specific cutting steps are:

[0081] The fully automatic film laminating machine from Japan Lintec is used to complete the film laminating operation of wafers and cutting films. The working environment is in a Class 100 clean room. The cutting film is SPV224 (non-UV film), and the particle size between the cutting film and the wafer is less than or equal to 100μm.

[0082] The wafer is cut along the first direction using a Japanese Disco cutting machine and cutting blade. The spindle speed of the cutting machine is 40000rpm, the cutting speed is 40mm / s, the cutting depth is 150±10μm, and the cutting water flow is 1.2L / min. The cutting blade is a Disco ZH-05 series blade (4800 mesh diamond blade). The cutting effect is: the chipping size of the front side of the wafer is less than or equal to 15μm (meets the requirement of less than or equal to 25μm), the chipping size of the back side of the wafer is less than or equal to 30μm (meets the requirement of less than or equal to 50μm), and the wafer is completely cut through, so that the wafer is divided into several strip-shaped wafer units.

[0083] The wafer was cut along the second direction (perpendicular to the first direction) using a Japanese Disco cutter and a cutting blade. The spindle speed of the cutter was 40,000 rpm, the cutting speed was 20 mm / s, the cutting depth was 100 ± 10 μm, and the cutting water flow rate was 1.2 L / min. The cutting blade was a Disco ZH-05 series blade (4800 mesh diamond blade). The wafer unit was not cut through, resulting in multiple cutting grooves on each wafer unit.

[0084] Cover the wafer unit with a release film, then use a 0.5kg rubber roller to roll back and forth twice along the cutting direction, and finally observe the chip fracture under a high-power microscope. At this time, all the chips that have not been cut through are broken, and the chip is turned from a whole sheet into a single chip.

[0085] The chips and substrates are placed on a mold expansion machine, and the expansion stroke is set to 5 cm. The chip spacing before expansion is less than or equal to 20 μm (the thickness of the cutting blade), and the chip spacing after expansion is measured under a microscope to be greater than or equal to 50 μm. Then pick up the chip to separate the chip from the substrate.

[0086] There was no chip loss during the whole process.

[0087] Comparative Example 1

[0088] The cutting material is 8-inch silicon wafer with a thickness of 120μmm, and the purpose is to cut it into single chips of 100*100μm.

[0089] The specific cutting steps are:

[0090] The fully automatic film laminating machine from Japan Lintec is used to complete the film laminating operation of wafers and cutting films. The working environment is in a Class 100 clean room. The cutting film is SPV224 (non-UV film), and the particle size between the cutting film and the wafer is less than or equal to 100μm.

[0091] The wafer is cut along the first direction (perpendicular to the first direction) using a Japanese Disco cutting machine and a cutting blade. The spindle speed of the cutting machine is 40000rpm, the cutting speed is 40mm / s, the cutting depth is 150±10μm, and the cutting water flow is 1.2L / min. The cutting blade is a Disco ZH-05 series blade (4800 mesh diamond blade). The cutting effect is: the chipping size of the front side of the wafer is less than or equal to 15μm (meets the requirement of less than or equal to 25μm), the chipping size of the back side of the wafer is less than or equal to 30μm (meets the requirement of less than or equal to 50μm), and the wafer is completely cut through, so that the wafer is divided into several strip-shaped wafer units.

[0092] The wafer is cut along the second direction using a Japanese Disco cutter and a cutting blade. The spindle speed of the cutter is 40,000 rpm, the cutting speed is 40 mm / s, the cutting depth is 150 ± 10 μm, and the cutting water flow is 1.2 L / min. The cutting blade is a Disco ZH-05 series blade (4800 mesh diamond blade). Along the second direction, the wafer unit is completely cut through to obtain individual chips.

[0093] Place the above chips and substrate on the expansion machine, set the expansion stroke to 5cm, the chip spacing before expansion is less than or equal to 20μm (the thickness of the cutting blade), and the chip spacing after expansion is greater than or equal to 35um measured under a microscope. Then pick up the chip to separate the chip from the substrate.

[0094] During the cutting process along the second direction, chips are lost.

[0095] Comparative Example 2

[0096] The cutting material is 8-inch silicon wafer with a thickness of 120μmm, and the purpose is to cut it into single chips of 100*100μm.

[0097] The specific cutting steps are:

[0098] The fully automatic film laminating machine from Japan Lintec is used to complete the laminating operation of wafers and dicing films. The working environment is in a Class 100 clean room. The dicing film is D-485 (UV film), and the particle size between the dicing film and the wafer is less than or equal to 100μm.

[0099] The wafer is cut along the first direction (perpendicular to the first direction) using a Japanese Disco cutting machine and a cutting blade. The spindle speed of the cutting machine is 40000rpm, the cutting speed is 40mm / s, the cutting depth is 150±10μm, and the cutting water flow is 1.2L / min. The cutting blade is a Disco ZH-05 series blade (4800 mesh diamond blade). The cutting effect is: the chipping size of the front side of the wafer is less than or equal to 15μm (meets the requirement of less than or equal to 25μm), the chipping size of the back side of the wafer is less than or equal to 30μm (meets the requirement of less than or equal to 50μm), and the wafer is completely cut through, so that the wafer is divided into several strip-shaped wafer units.

[0100] The wafer is cut along the second direction using a Japanese Disco cutter and a cutting blade. The spindle speed of the cutter is 40,000 rpm, the cutting speed is 40 mm / s, the cutting depth is 150 ± 10 μm, and the cutting water flow is 1.2 L / min. The cutting blade is a Disco ZH-05 series blade (4800 mesh diamond blade). Along the second direction, the wafer unit is completely cut through to obtain individual chips.

[0101] Place the above chips and substrate on the expansion machine, set the expansion stroke to 5cm, the chip spacing before expansion is less than or equal to 20μm (the thickness of the cutting blade), and the chip spacing after expansion is greater than or equal to 35um measured under a microscope. Then pick up the chip to separate the chip from the substrate.

[0102] During the cutting process along the second direction, chips are lost.

[0103] Comparative Example 3

[0104] The cutting material is 8-inch silicon wafer with a thickness of 120μmm, and the purpose is to cut it into single chips of 100*100μm.

[0105] The specific cutting steps are:

[0106] The fully automatic film laminating machine from Japan Lintec is used to complete the film laminating operation of wafers and cutting films. The working environment is in a Class 100 clean room. The cutting film is SPV224 (non-UV film), and the particle size between the cutting film and the wafer is less than or equal to 100μm.

[0107] The wafer is cut along the first direction (perpendicular to the first direction) using a Japanese Disco cutting machine and a cutting blade. The spindle speed of the cutting machine is 40000rpm, the cutting speed is 40mm / s, the cutting depth is 150±10μm, and the cutting water flow is 1.2L / min. The cutting blade is a Disco ZH-05 series blade (4800 mesh diamond blade). The cutting effect is: the chipping size of the front side of the wafer is less than or equal to 15μm (meets the requirement of less than or equal to 25μm), the chipping size of the back side of the wafer is less than or equal to 30μm (meets the requirement of less than or equal to 50μm), and the wafer is completely cut through, so that the wafer is divided into several strip-shaped wafer units.

[0108] The wafer is cut along the second direction using a Japanese Disco cutter and a cutting blade. The spindle speed of the cutter is 40,000 rpm, the cutting speed is 20 mm / s, the cutting depth is 150 ± 10 μm, and the cutting water flow is 1.2 L / min. The cutting blade is a Disco ZH-05 series blade (4800 mesh diamond blade). Along the second direction, the wafer unit is completely cut through to obtain individual chips.

[0109] Place the above chips and substrate on the expansion machine, set the expansion stroke to 5cm, the chip spacing before expansion is less than or equal to 20μm (the thickness of the cutting blade), and the chip spacing after expansion is greater than or equal to 35um measured under a microscope. Then pick up the chip to separate the chip from the substrate.

[0110] During the cutting process along the second direction, chips are lost.

[0111] It can be seen from the chip cutting methods of Examples 1 and 2 and Comparative Examples 1 to 3 that the chip cutting method of the present invention is targeted at small-sized chips and can avoid chip loss during the process of cutting wafers into chips, thereby cutting out more chips, improving chip integration, reducing material waste, and reducing production costs.

[0112] Compared with the prior art, the chip cutting method of the present invention divides the wafer into a plurality of strip-shaped wafer units by cutting through the wafer along a first direction, and cuts a plurality of cutting grooves on the wafer unit without cutting through the wafer unit along a second direction. Since the wafer unit is in the shape of strips, its bonding area with the substrate is large. Therefore, during the two cutting processes, the chip will not be separated and lost from the substrate due to the impact of the cutting fluid. The second cut sample is then split to break the wafer unit at the cutting groove, thereby obtaining individual chips.

[0113] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0114] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A chip cutting method, characterized in that: The following steps are involved: Bonding the wafer to the substrate to obtain a sample to be cut; Cutting the sample to be cut along a first direction to cut the wafer into a plurality of wafer units to obtain a first cut sample, wherein the cutting depth is greater than the thickness of the wafer and less than the thickness of the sample to be cut; Cutting the first cutting sample along the second direction to form a plurality of cutting grooves on each of the wafer units to obtain a second cutting sample, wherein the cutting depth is less than the thickness of the wafer, and the first direction and the second direction intersect; The second cut sample is split to break each wafer unit at the cutting groove to obtain a plurality of chips.

2. The chip cutting method according to claim 1, characterized in that: The first direction and the second direction are perpendicular to each other.

3. The chip cutting method according to claim 1, characterized in that: When the sample to be cut is cut along the first direction, the cutting depth exceeds the thickness of the wafer by at least 20 μm.

4. The chip cutting method according to claim 1, characterized in that: The minimum distance between the bottom surface of the cutting groove on the second cutting sample and the surface of the substrate facing the wafer is 10 to 30 μm.

5. The chip cutting method according to claim 1, characterized in that: The substrate includes a cutting film, and the cutting film is a UV film or a non-UV film.

6. The chip cutting method according to claim 5, characterized in that: In the step of cutting the chip along the first direction, the rotation speed of the cutting blade in the cutting equipment is 35000-45000 rpm / min, the cutting speed is 35-45 mm / s, and the cutting water flow rate is 0.8-1.5 L / min.

7. The chip cutting method according to claim 5, characterized in that: In the step of cutting the chip along the second direction, the rotation speed of the cutting blade in the cutting equipment is 35000-45000 rpm / min, the cutting speed is 35-45 mm / s, and the cutting water flow rate is 0.8-1.5 L / min.

8. The chip cutting method according to claim 6 or 7, characterized in that: The contact area between each wafer unit on the first cut sample and the second cut sample and the substrate is greater than or equal to 0.09 mm 2 .

9. The chip cutting method according to claim 1, characterized in that: The steps of the cleavage process include: A release film is used to cover one side of the wafer unit on the second cutting sample, and an elastic roller is used to roll the release film along the first direction to break the wafer unit at the cutting groove.

10. The chip cutting method according to claim 1, characterized in that: The chip cutting method further comprises: Performing film expansion processing on the plurality of wafer units and substrates after the cleavage processing, so that the distance between adjacent chips on the substrate is greater than or equal to 30 μm; The chip and the substrate are separated to obtain a plurality of chips.

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