TWM496842U - Protection sheet for laser cutting - Google Patents

Description

Laser cutting protection sheet

The present invention relates to a protective sheet for laser cutting, and more particularly to a protective sheet for laser cutting containing polyvinyl alcohol and glutaraldehyde.

The semiconductor wafer has a laminated structure including an interlayer insulating film and a functional film stacked on a semiconductor substrate (eg, germanium), and the wafer is implemented and formed on the substrate in a cutting process, and after being processed through the surface After cutting off (cutting) the semiconductor substrate, a component chip (for example, a semiconductor component or the like) is manufactured; wherein the cutting and separating process is performed by cutting the wafer along a boundary region of a street thereof to separately set the electrons The components are separated to achieve the process. However, as the integration degree of the semiconductor device increases and the width of the boundary is narrowed, the precision of the cutting increases, and the accompanying thermal effect problem (the cracking of the cutting path due to heat, fragmentation, etc.) becomes a bottleneck in the laser cutting process.

The wafer dicing process has evolved from a wafer-cut wafer to a typical laser-cutting process; it is first applied with laser light along the boundary to form a trench commensurate with the cutting edge width of the dicing blade. The blade cuts the wafer. However, when the laser light is irradiated along the boundary of the wafer, the generated thermal energy is absorbed by the wafer, causing thermal energy to accumulate on the wafer, which leads to an inevitable problem in the cutting process. However, the insulating film at the uppermost position in the laminated structure of the wafer; its main material is polyimide, which is easily broken or damaged in the wafer laser cutting process. Moreover, thermal energy is liable to cause melting or thermal decomposition of the wafer substrate, thereby causing problems such as vaporization, condensation, and deposition on the surface of the wafer. Therefore, when the wafer is diced, if the protective film of the wafer is not heat-resistant, the protective film is easily broken, and the splatter generated by the wafer dicing penetrates into the void of the rupture film, since these residues are not water-soluble. When it is attached to the surface of the wafer, it cannot be washed away by water to become a wafer defect.

In recent years, a process of cutting a wafer using only laser has been developed, and it has been attracting attention as a precision cutting method, which causes less thermal damage and can perform high-precision processing. However, even with this method, the thermal insulation of the laser light may cause poor delamination of the insulating film of the wafer. In addition, vapor fumes generated by heat may also accumulate between the insulating film in a layered state and the upper surface of the wafer. When the insulating film of the wafer is cleaned, the aerosol deposit cannot be removed, and the residue becomes a defect. The problem of surface contamination on the wafer.

A technique for solving this problem is known. For example, TW 200631086 A discloses a protective film for laser cutting comprising a solution having a water-soluble resin and at least one selected from the group consisting of water-soluble dyes and water-soluble colorants. And a water-soluble laser light absorber of a water-soluble ultraviolet absorber dissolved therein, which mainly applies a water-soluble resin such as polyvinyl alcohol, polyethylene glycol or cellulose to a surface of the wafer to form a protective film, and then Then the laser light cutting process is implemented. Therefore, the surface of the wafer is protected by the protective film, and even the residue such as the thermal decomposition product of the vapor or the substrate subjected to the laser irradiation is only scattered or coagulated and deposited on the surface of the protective film, and is not deposited on the wafer surface. Further, since the protective film is water-soluble, it can be easily removed by washing with water, that is, the protective film can be washed with water while removing the residue on the protective film.

In addition, the TW I399402 patent discloses a protective film composition for wafer dicing, comprising at least one resin selected from the group consisting of polyethyloxazoline and polyvinylpyrrolidone, at least one selected from the group consisting of water-soluble resins. And a component of the group consisting of alcoholic monomers, and a solvent such as water or a mixture of water and an organic solvent. Therefore, the protective film composition for wafer cutting has high thermal stability, prevents pyrolysis cross-linked materials due to laser irradiation in the cutting process, and exhibits high adhesion to the wafer, preventing laser wafer cutting The delamination of the protective film during the process. Further, the protective film composition can form a protective film having a suitable hardness, so that the protective film does not have a problem of cracking when the wafer is diced.

However, both of the above methods use a water-soluble resin, which generally has poor thermal stability. When the laser is irradiated in a laser laser cutting process, internal heat is generated. If the molecular weight of the water-soluble resin is not high enough, it may be It will be pyrolyzed by heat and will have limited protection for the substrate.

Therefore, how to develop a protective film composition which has high thermal stability and can prevent pyrolysis due to laser irradiation in a cutting process, and further uses the protective film composition to obtain a protective sheet for laser cutting, which is the current stage The wafer manufacturing industry is eager to solve the problem.

In view of the above-mentioned shortcomings of the prior art, the creator feels that he has not perfected it, exhausted his mind and researched and overcome it, and developed a laser protection sheet for his experience in the industry.

In order to achieve the above object, the present invention provides a protective sheet for laser cutting, comprising: a substrate; and a protective layer formed by the composition of the protective film for laser cutting coated on the substrate, the protective layer having a thickness of 100 to 5000 nm; wherein the protective film composition for laser cutting comprises: (A) a water-soluble polymer; and (B) a crosslinking agent; wherein the weight average molecular weight of the (A) water-soluble polymer (Mw) is 10,000 to 150,000.

In order to achieve the above protective film composition for laser cutting, the weight average molecular weight (Mw) of the (A) water-soluble polymer is from 5,000 to 150,000, particularly preferably from 12,500 to 125,000. This work enhances the cross-linking degree of the polymer by adding a crosslinking agent. When applied to a protective film for laser cutting, it has high thermal stability and can be coated with a lower molecular weight water-soluble resin, and the equipment machine is easier to clean. Moreover, the coating can be relatively uniform, and the effect of not reducing the strength of the protective film during laser cutting can be maintained.

The protective film composition described in the present application is coated on the surface of the wafer to be processed, and the thickness is usually about 100 to 5000 nm, especially 500 to 1500 nm, because the crosslinking agent is added to make the polymer. The degree of crosslinking is increased and the water-soluble polymer used has a weight average molecular weight of at least 5,000. In addition, when a high molecular weight polymer is used as a protective film for laser cutting, a relatively large amount of solvent must be used in the composition, and it is easy to cause uneven thickness of the coating film after the coating process is cured to evaporate the solvent.

The composition according to the above aspect, wherein the (A) water-soluble polymer has at least a hydrophilic group selected from the group consisting of a hydroxyl group, an oxiranyl group, a decylamino group, an amine group, and a sulfonic acid group. a group consisting of a sulfinic acid group, a carboxyl group, and a carbonyl group.

According to an embodiment of the present invention, the (A) water-soluble polymer is selected from the group consisting of polyethylene glycols, polypropylene glycols, polyethylene oxides, polypropylene oxides, polyether esters, and polyvinyl alcohols. A group consisting of alcohols, sodium polyacrylates, polyacrylamides, polyvinylpyrrolidone, carboxymethylcellulose, polytetramethylene glycols, and polyetheresters.

The above composition, wherein the (B) crosslinking agent is selected from the group consisting of an isocyanate crosslinking agent, a melamine crosslinking agent, an epoxy crosslinking agent, an acrylate crosslinking agent, an aldehyde or an isocyanate group ( A group consisting of methyl acrylates.

In the above composition, the (B) crosslinking agent is used in an amount of 1 to 10 parts by weight, preferably 1 to 5 parts by weight based on 100 parts by weight of the (A) water-soluble polymer, and the water solubility is not excessive when added. Good, you need to use a hot water cleaning device to remove the protective film.

The above composition further comprises an additive selected from the group consisting of a surfactant, an antifoaming agent, a leveling agent, and a solvent. The surfactant is selected from the group consisting of polyoxyethylene esters, polyoxyethylene ethers, sorbitol, sorbitol esters, polyethers, fatty alcohol alkoxys, stearic acids, sulfonic acids, carboxylic acids, phosphates. The nonionic or anionic surfactants are used alone or in combination. The defoaming agent is used in combination with a single or a plurality of methyl ethers, polyether esters, propylene glycols, ethylene oxide and propylene oxide polymers, lower alcohols, and higher alcohols. The leveling agent is used in an amount of 0.1 to 5 parts by weight, and is used alone or in combination of polyoxyethylene ethers, alcohol ethers, acetates, acrylics, acrylates, benzophenones, and hydroxyl groups. The solvent is selected from the group consisting of ethers, lower alcohols, propylene glycols, alcohol ethers, and hydroxy acids.

The protective film composition for laser cutting described in the present invention may be a liquid coating agent, or may be pre-coated on a surface of a substrate, further combined with an adhesive layer to be attached to the surface of the wafer, or used more The adhesive water-soluble polymer can be attached to the surface of the wafer without using an adhesive layer, and can be used as a protective sheet for laser cutting.

The protective film composition for laser cutting described in the present application is coated on the surface of a wafer to be processed, for example, a semiconductor wafer on which a plurality of lattice patterns are formed on the surface of the wafer, and then dried. Coating, thereby forming a protective film. The thickness of the protective film is usually about 100 to 5000 nm, especially 500 to 1500 nm, because the surface of the wafer to be processed has many recesses and protrusions, and the boundary is formed in the recesses. If the thickness is too small, Then, the thickness of the protective film at the convex portion is too small, so that the debris enters the protective film and deposits on the wafer surface; on the other hand, the unnecessary thickness does not have any advantage, and only causes the disadvantage of time-consuming cleaning with water after processing. .

In order to further disclose the present invention so that those skilled in the art can have a general knowledge, the present invention is further described in the following examples. It should be noted that the following examples are only for further explanation of the present invention, and are not intended to limit the scope of implementation of the present invention, and any person skilled in the art to which the present invention belongs can obtain the spirit of the present invention without violating the spirit of the present creation. The modifications and changes achieved are within the scope of this creation.

In order to fully understand the purpose, features and effects of this creation, a detailed description of the creation is given by the following specific examples, as follows:

The following is a description of the implementation of the protective film for laser cutting used in the protective sheet for laser cutting according to the present invention: <TABLE style="BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; BORDER- COLDER-TOP: medium none; mso-border-alt: double windowtext 1.5pt; mso-yfti-tbllook: 1184; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt; Mso-border-insideh: 1.5pt double windowtext; mso-border-insidev: 1.5pt double windowtext" class="MsoTableGrid" border="1" cellSpacing="0" cellPadding="0"><TBODY><tr>< Td> </td><td> Example 1 (parts by weight) </td><td> Example 2 (parts by weight) </td><td> Comparative Example 1 (parts by weight) </td><td > Comparative Example 2 (parts by weight) </td><td> Comparative Example 3 (parts by weight) </td></tr><tr><td> PVA molecular weight of about 13K </td><td> 20 </ Td><td> 0 </td><td> 20 </td><td> 20 </td><td> 0 </td></tr><tr><td> PVA molecular weight is about 119K </ Td><td> 0 </td><td> 20 </td><td> 0 </td><td> 0 </td><td> 0 </td></tr><tr>< Td> PVA molecular weight is about 250K </td><td> 0 </td><td> 0 </td><td> 0 </td><td> 0 < /td><td> 20 </td></tr><tr><td> glutaraldehyde</td><td> 1 </td><td> 1 </td><td> 0 </ Td><td> 15 </td><td> 1 </td></tr><tr><td> Test Results</td></tr><tr><td> Coating Appearance</td ><td> leveling</td><td> leveling</td><td> leveling</td><td> leveling</td><td> uneven wave pattern</td></tr><tr ><td> Water solubility (within 1 minute) </td><td> Water soluble</td><td> Water soluble</td><td> Water soluble</td><td> Not water soluble</td><td > 不水溶</td></tr><tr><td> sloping deposits</td><td> no </td><td> no </td><td> traces</td><td > None</td><td> Trace</td></tr></TBODY></TABLE>

Embodiment 1

The following composition of the protective film aqueous solution was obtained:

First, a water-soluble resin was dissolved in 100 ml of water (Polyvinyl alcohol, PVA) 20 g (molecular weight: about 13 K), and then 1 g of a crosslinking assistant Glutaraldehyde (Glutaraldehyde) was added. The aqueous solution of the protective film is applied to the germanium wafer by spin coating, dried on a germanium wafer to form a protective film having a thickness of 500 to 1300 nm, and the coated silicon wafer is placed on the laser. On the processing equipment, after laser processing, the protective film is washed with pure water and the surrounding conditions of the laser processing on the germanium wafer are observed, and there is no stain deposition, and the interface width after processing is similar to the diameter of the laser setting parameter, and the display is not It is affected by the protective film coating.

Embodiment 2

An aqueous solution of a protective film was prepared in the same manner as in the first embodiment and in parts by weight, but a polyvinyl alcohol having a molecular weight of about 119 K was alternatively used. The protective film was coated and evaluated in the same manner as in Example 1. The protective film was washed with pure water, free of smear deposits, and the interface width after processing was similar to the diameter of the laser setting parameter.

Comparative example one

An aqueous solution of the protective film was prepared in the same manner as in the first embodiment and in parts by weight, but no crosslinking agent was added. The protective film was coated and evaluated in the same manner as in the first example, and the protective film was washed with pure water, but it was easy to observe the smear deposition around the laser processing of the enamel wafer, and the dicing street was cauterized.

Comparative example two

An aqueous solution of the protective film was prepared in the same manner as in the first embodiment and in parts by weight, but the crosslinking agent was changed to 15 g. The protective film is coated and evaluated in the same manner as in the first example, and the protective film is not easily washed away using pure water at normal temperature; hot water is used, but there is no obvious sinter and residual phenomenon in the laser processing.

Comparative example three

The aqueous solution of the protective film was prepared in the same manner as in the first embodiment, and the polyvinyl alcohol having a molecular weight of about 250 K was used. The protective film was coated and evaluated in the same manner as in the first example, and the protective film was not easily washed away by the pure water at normal temperature; Water, and due to uneven film thickness, the cutting path is uneven, and the sinter and smudging residue increase.

Embodiment 3

An aqueous solution of a protective film was prepared in the same manner as in the first embodiment and the parts by weight, and the aqueous solution of the protective film was applied on a substrate to form a protective sheet for laser cutting.

The protective sheet for laser cutting according to the third embodiment is as shown in Fig. 1. The protective sheet for laser cutting 1 comprises: a substrate 10; and a protective film composition for laser cutting coated on the substrate The protective layer 20 is formed, and the protective layer 20 has a thickness of 500 to 1500 nm.

As mentioned above, this creation is fully in line with the three requirements of the patent: novelty, advancement and industrial applicability. In terms of novelty and advancement, the present invention provides a protective film composition for laser cutting by adding a crosslinking agent to increase the cross-linking degree between polymers, and is applied to a protective sheet for laser cutting. High thermal stability, and can make it less likely to contaminate the equipment machine during application, and can maintain the effect of not reducing the strength of the protective sheet during laser cutting; in terms of industrial availability, the products derived from the creation are utilized. When fully meet the needs of the current market.

The present invention has been disclosed in the above preferred embodiments, and it should be understood by those skilled in the art that the present invention is only intended to depict the present invention and should not be construed as limiting the scope of the present invention. It should be noted that variations and permutations equivalent to those of the embodiments are intended to be included within the scope of the present invention. Therefore, the scope of protection of this creation is subject to the definition of the scope of the patent application below.

1‧‧‧Protection film for laser cutting
10‧‧‧ substrates
20‧‧‧Protective layer

Figure 1 is a protective sheet for laser cutting according to the third embodiment of the present invention.

1‧‧‧Protection film for laser cutting

10‧‧‧ substrates

20‧‧‧Protective layer

Claims (11)

A protective sheet for laser cutting, comprising: a substrate; and a protective layer formed by the composition of the protective film for laser cutting coated on the substrate, the protective layer having a thickness of 100 to 5000 nm; wherein the The protective film composition for shot cutting, comprising: (A) a water-soluble polymer; and (B) a crosslinking agent; wherein the weight average molecular weight (Mw) of the (A) water-soluble polymer is 10,000 to 150,000 . The protective sheet for laser cutting according to claim 1, wherein the (A) water-soluble polymer has a weight average molecular weight (Mw) of 12,500 to 125,000. The protective sheet for laser cutting according to claim 1, wherein the (A) water-soluble polymer has at least one hydrophilic group in the structure, and the hydrophilic group is selected from the group consisting of a hydroxyl group and an epoxy group. A group consisting of an alkyl group, a decylamino group, an amine group, a sulfonic acid group, a sulfinic acid group, a carboxyl group, and a carbonyl group. The protective sheet for laser cutting according to claim 1, wherein the (B) crosslinking agent is glutaraldehyde. The protective sheet for laser cutting according to claim 1, wherein the (B) crosslinking agent is selected from the group consisting of an isocyanate crosslinking agent, a melamine crosslinking agent, an epoxy crosslinking agent, and an acrylate system. A group consisting of a crosslinking agent or a (meth) acrylate having an isocyanate group. The protective sheet for laser cutting according to any one of claims 1 to 4, wherein the (B) crosslinking agent is 0.1 to 10 based on 100 parts by weight of the (A) water-soluble polymer. Parts by weight. The protective sheet for laser cutting according to any one of claims 1 to 4, wherein the protective film composition for laser cutting further comprises a surfactant selected from a surfactant, an antifoaming agent, a leveling agent, and a solvent. Additions to the group formed. The protective sheet for laser cutting according to claim 7, wherein the surfactant is selected from the group consisting of polyoxyethylene esters, polyoxyethylene ethers, sorbitol, sorbitol esters, and polyethers. A group of nonionic or anionic surfactants such as fatty alcohol alkoxys, stearic acids, sulfonic acids, carboxylic acids, phosphates, and the like. The protective sheet for laser cutting according to claim 7, wherein the antifoaming agent is selected from the group consisting of methyl ethers, polyether esters, propylene glycols, ethylene oxide and propylene oxide polymers, and low A group consisting of carbon alcohols and higher alcohols. The protective sheet for laser cutting according to claim 7, wherein the leveling agent is 0.1 to 5 parts by weight, selected from the group consisting of polyoxyethylene ethers, alcohol ethers, acetates, acrylics, and acrylics. A group consisting of esters, benzophenones, and hydroxyls. The protective sheet for laser cutting according to claim 7, wherein the solvent is selected from the group consisting of ethers, lower alcohols, propylene glycols, alcohol ethers, and hydroxy acids.