JP6578985B2 - Substrate, substrate cutting method - Google Patents

Description

  The present invention relates to a substrate diced by a blade and a method for cutting the substrate.

  As a technique for dividing a substrate such as a wafer into chips, there is a blade dicing method using a blade. In this method, first, a substrate as a workpiece is attached to the surface of a dicing tape. Then, the substrate is cut by rotating a dicing blade (hereinafter referred to as a blade) while adsorbing and holding the back surface of the dicing tape.

  The blade is a cutting tool mainly composed of abrasive grains and a binder between the abrasive grains. Rotate the blade at high speed to scrape the substrate with countless sharp abrasive corners. Depending on the material of the substrate to be cut, the abrasive grain type, grain size, concentration, and binder are selected. For example, gallium arsenide, which is a compound semiconductor, is brittle compared to silicon, which is a single semiconductor, and therefore it is necessary to use abrasive grains having a small particle size.

  Abrasive grains are evenly mixed in the binder of the blade. As the substrate is diced, the bonding material wears, new abrasive grains appear on the surface, and the new abrasive particles scrape the workpiece to maintain the sharpness. This is called self-generated blade action.

  For the base material of the dicing tape, polyvinyl chloride (PVC), polyolefin (PO), polyethylene terephthalate (PET) or the like is used, and an adhesive layer is formed on the surface thereof.

  In order to maintain the sharpness of the blade, the blade is exposed using a plate called a dressing board. The dressing board is a plate in which an abrasive such as silicon carbide is mixed in a binder made of resin.

  Patent Document 1 discloses that a wafer sticking pressure-sensitive adhesive sheet formed by applying a pressure-sensitive adhesive layer on a substrate surface is used as a dicing tape. This adhesive sheet for sticking a wafer is obtained by dispersing abrasive grains having a particle size of 0.5 to 100 μm and a Mohs hardness of 6 to 10 in a base material.

JP 63-205382 A

  There are three blade dicing methods: half-cut, semi-full cut, and full-cut. Currently, the full-cut method that completely cuts the substrate is the mainstream. The blade at full cut cuts not only into the substrate but also into the dicing tape. For this reason, the blade tip may be covered with cutting waste such as dicing tape or metal, resulting in a blade clogged state where abrasive grains do not protrude. As a result, the sharpness of the blade was lowered, leading to chip chipping or cracking.

  In recent years, the substrate has been made thinner in order to improve heat dissipation. When the substrate is made thinner, the blade cutting resistance at the time of blade dicing is reduced by that amount, so that the self-generated blade action due to the wear of the binder is reduced. As a result, the sharpness of the blade may be reduced, chipping or cracking may occur due to crushing or clogging that causes the abrasive grains of the blade to wear smoothly.

  The types of blades include electroformed blades, metal blades, and resin blades. Since the resin blade uses a resin as the binder, the binder is easily worn, and clogging and crushing are unlikely to occur. However, the resin blade needs to be thick because the strength of the binder is small. For this reason, there is a problem that the kerf width, which is a cutting allowance during blade dicing, becomes as wide as 100 μm or more. Even for metal blades, the kerf width becomes wide for the same reason.

  Since the electroformed blade uses a high-strength material such as nickel for the binder, the blade thickness can be reduced. However, nickel is hard to wear and is easily clogged and crushed. This can shorten the life of the blade. It is required to maintain the self-generated blade action of the electroformed blade for a long period of time.

  In the technique disclosed in Patent Document 1, abrasive grains are provided in the base material of the dicing tape. Thereby, the self-generated blade action of the blade can be maintained. However, the substrate of the dicing tape is required to have properties such as water resistance, heat resistance, transparency when irradiated with UV, and stretchability when expanded. If abrasive grains are provided in the substrate, such properties may be impaired. In addition, the blade's spontaneous blade action cannot be obtained unless the substrate is cut with the blade.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a substrate that can maintain the self-generated blade action of the blade for a long time without any adverse effects and a method for cutting the substrate. To do.

The substrate according to the invention of the present application is provided with polishing layers on the upper and lower surfaces of the main part of the dicing street , and polishing using silicon oxide, aluminum oxide, silicon carbide, titanium alloy or tungsten alloy provided on the polishing layer as a material. An agent is provided.

The substrate cutting method according to the invention of the present application is a blade having abrasive grains and a binder for bonding the abrasive grains, and dicing a dicing street provided with an abrasive having a Mohs hardness equal to or greater than the Mohs hardness of the binder. A dicing street having a first portion provided with an abrasive along the dicing street, and a first portion provided with an abrasive located on the left and right of the first portion. And the density of the abrasive in the first part is greater than the density of the abrasive in the second part, and the side part including the side surface of the blade is in contact with the second part and sandwiched between the side parts of the blade The central portion is in contact with the first portion .

  According to the present invention, since the abrasive is provided on the dicing street of the substrate, the self-generated blade action of the blade can be maintained for a long time without any harmful effects.

2 is a perspective view of a substrate according to Embodiment 1. FIG. It is sectional drawing of a dicing street. It is a figure which shows the cutting method of a board | substrate. It is sectional drawing of the dicing street which concerns on Embodiment 2. FIG. It is sectional drawing of the dicing street which concerns on Embodiment 3. FIG. It is sectional drawing of the dicing street which concerns on Embodiment 4. FIG.

  A substrate and a substrate cutting method according to an embodiment of the present invention will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repeated description may be omitted.

Embodiment 1 FIG.
FIG. 1 is a perspective view of a substrate according to the first embodiment. A plurality of chips 12 are formed on the substrate 10. In order to divide the plurality of chips 12 into individual pieces, dicing streets 14 and 16 are formed between the plurality of chips 12. The dicing street 14 is a dicing street that extends long in the y direction. The dicing street 16 is a dicing street extending long in the x direction.

  FIG. 2 is a cross-sectional view of the dicing street 14. The dicing street 14 includes a main body 20 made of a substrate material such as silicon, a polishing layer 22 provided on the upper surface of the main body 20, and a polishing layer 24 provided on the lower surface of the main body 20. . The polishing layers 22 and 24 are provided with an abrasive. The abrasive is, for example, silicon oxide, aluminum oxide, silicon carbide, titanium alloy, or tungsten alloy. The polishing layers 22 and 24 are formed on all dicing streets.

  The polishing layers 22 and 24 can be formed by, for example, a method in which the above-described abrasive is mixed into a resin for molding, and then poured into the dicing street 14 and baked and hardened at about 150 degrees. In this case, polishing layers 22 and 24 in which an abrasive and a resin are mixed can be obtained. The polishing layer in which the abrasive and the resin are mixed has a structure similar to a known dressing board. However, the polishing layers 22 and 24 may be formed by another method. For example, the polishing layers 22 and 24 may be formed by directly forming an abrasive on the dicing street using a sputtering method.

  FIG. 3 is a diagram illustrating a substrate cutting method according to the first embodiment. The blade 30 is an electroformed blade that rotates in the direction of the arrow. The blade 30 includes an infinite number of abrasive grains 32 and a binding material 34 that bonds the abrasive grains 32. The abrasive grains 32 can be appropriately selected according to the material of the substrate to be cut. For example, green carborundum, artificial corundum, optical emery, white alundum, boron carbide, chromium oxide (III), cerium oxide or diamond. It is a powder. The main component of the binder 34 is, for example, nickel. Innumerable abrasive grains 32 are mixed in the binder 34.

  The substrate 30 is cut along the dicing street 14 by sending the blade 30 rotated at high speed in the positive y direction of FIG. At this time, the main body 20 and the polishing layers 22 and 24 are cut by the blade 30. By cutting the polishing layers 22 and 24, the cutting resistance of the blade 30 is increased as compared with the case where the polishing layers 22 and 24 are not provided. Since the bonding agent 34 of the blade 30 is worn by the abrasive in the polishing layers 22 and 24, a self-generated blade action is obtained. It is important to promote the wear of the binder 34 with an abrasive. In order to promote wear of the binder 34 with the abrasive, the Mohs hardness of the abrasive needs to be equal to or greater than the Mohs hardness of the binder 34. When the material of the binder 34 is nickel, the Mohs hardness of the binder 34 is about 5. In this case, the Mohs hardness of the abrasive contained in the polishing layers 22 and 24 needs to be 5 or more.

  By dicing all the dicing streets with the blade 30, the cutting of the substrate 10 is completed, and the chips are separated into individual pieces. During cutting of the substrate 10, the bonding agent 34 continues to be worn by the abrasive contained in the polishing layers 22, 24, so that the self-generated blade is promoted, and the blade 30 can be prevented from being clogged and crushed. Accordingly, the life of the blade 30 is extended and the frequency of blade replacement is reduced, so that productivity is improved and the cost of the blade can be reduced. In addition, the sharpness of the blade can be maintained, and chipping and cracking are less likely to occur.

  At the time of dicing, a dicing tape having a base material and an adhesive layer applied to the base material surface is attached to a substrate which is an object to be cut. In the substrate cutting method according to Embodiment 1 of the present invention, the self-generated blade action of the blade can be maintained for a long time without cutting the dicing tape. Since it is not necessary to provide abrasive grains in the base material of the dicing tape, the function of the dicing tape can be maintained.

  The substrate and the substrate cutting method according to Embodiment 1 of the present invention can be variously modified without losing the characteristics. For example, the position where the polishing layer is provided is arbitrary. The polishing layer may be provided on at least a part of the dicing street. The polishing layer only needs to have an abrasive, and the presence or absence of other configurations is not important. A polishing layer may be formed on the dicing street on the back electrode of the substrate 10.

  These modifications can also be applied as appropriate to the substrates and substrate cutting methods according to the following embodiments. Since the substrate and the substrate cutting method according to the following embodiment have many similarities to the first embodiment, differences from the first embodiment will be mainly described.

Embodiment 2. FIG.
FIG. 4 is a cross-sectional view of a dicing street according to the second embodiment. The dicing street 14 includes a first portion 40 provided along the dicing street 14 and a second portion 42 located on the left and right of the first portion 40. The first portion 40 and the second portion 42 are provided with an abrasive. The density of the abrasive in the first portion 40 is greater than the density of the abrasive in the second portion 42. Therefore, a strong spontaneous blade action is exerted on the portion of the blade 30 that cuts the first portion 40, and a weak spontaneous blade action is exerted on the portion of the blade 30 that cuts the second portion 42.

  In FIG. 4, the blade 30 is shown two-dimensionally to show the width of the blade 30. The width x2 of the blade 30 is larger than the width x1 of the first portion 40. As a result, the side portions 30 a and 30 b including the side surface of the blade 30 are in contact with the second portion 42, and the central portion 30 c sandwiched between the side portions 30 a and 30 b of the blade 30 is in contact with the first portion 40.

  If the uniform dicing street is continuously cut with the blade, the side surface portion of the blade is easily worn compared to the center portion of the blade. Wear on the side surface is not preferable because it causes chipping. Therefore, in Embodiment 2 of the present invention, the density of the abrasive in the dicing street is made non-uniform so that the blade is easily worn at the central portion 30c of the blade 30 and the central portion at the side surface portions 30a and 30b of the blade 30. The blade was made harder to wear than 30c. Thereby, even if the cutting of the substrate is continued, the shape of the blade can be kept uniform.

Embodiment 3 FIG.
FIG. 5 is a cross-sectional view of a dicing street according to the third embodiment. The dicing street 14 is formed with a non-polishing portion 52 on which no abrasive is provided and a polishing portion 50 having an abrasive. In the non-polished part 52, a shallow groove 52a and a groove 52b deeper than the groove 52a are formed. The polishing unit 50 fills the grooves 52a and 52b. An anchor effect is produced when the polishing unit 50 fills the grooves 52a and 52b. Therefore, it is possible to prevent the polishing unit 50 from peeling from the non-polishing unit 52 in the dicing street. The shape of the groove provided in the non-polishing part 52 can be changed as appropriate as long as the anchor effect is obtained.

Embodiment 4 FIG.
FIG. 6 is a cross-sectional view of a dicing street according to the fourth embodiment. An abrasive 60 is embedded in the dicing street 14. After forming the polishing slurry 60, the film formation is continued without covering the mask, so that the configuration of FIG. 6 can be obtained while streamlining production. Similar to the polishing unit 50 in FIG. 5, the abrasive in FIG. 6 is a plate-like solid. Advancing the cutting of the substrate while cutting the abrasive 60 with the blade 30 can promote the self-generated blade action. Note that the features according to the embodiments and the substrate cutting method according to each embodiment described so far may be combined as appropriate.

  10 substrate, 12 chips, 14,16 dicing street, 20 main body, 22,24 polishing layer, 30 blades, 32 abrasive grains, 34 binder

Claims (6)

Characterized comprising an abrasive layer on the upper surface and the lower surface of the main body portion of the dicing streets, provided in the polishing layer, a silicon oxide, aluminum oxide, silicon carbide, further comprising a polishing agent to the material a titanium alloy or a tungsten alloy A substrate. Provided with abrasives made of silicon oxide, aluminum oxide, silicon carbide, titanium alloy or tungsten alloy provided on dicing street,
The dicing street is formed with a first portion provided with the abrasive along the dicing street, and a second portion provided on the left and right of the first portion and provided with the abrasive,
The density of the abrasive of the first portion, the second portion the abrasive board it is greater than the density of the. Substrate according to claim 1 or 2, further comprising a resin mixed with the abrasive. In the dicing street, there is a non-polishing portion where grooves are formed and the abrasive is not provided, and a polishing portion having the abrasive provided so as to fill the grooves,
The substrate according to any one of claims 1 to 3, wherein an anchor effect is generated when the polishing portion fills the groove. The abrasive substrate according to any one of claims 1 to 3, characterized in that embedded in the dicing street. A substrate cutting method characterized by dicing a dicing street provided with an abrasive having a Mohs hardness equal to or greater than the Mohs hardness of the binding material with a blade having abrasive grains and a binding material for binding the abrasive grains. There,
The dicing street is formed with a first portion provided with the abrasive along the dicing street, and a second portion provided on the left and right of the first portion and provided with the abrasive.
The density of the abrasive in the first part is greater than the density of the abrasive in the second part,
Side portion including a side surface of the blade is in contact with the second portion, the central portion of the sandwiched on the side surface of the blade cutting method of board you being in contact with the first portion.

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