KR20160114558A - Cleaning solution for wafer and wafer process using the same - Google Patents

Abstract

Provided is a wafer cleaning solution, which comprises 0.01-30 wt% of a water-soluble polymer, 0.01-10 wt% of a surfactant, and the remaining amount of water. The wafer cleaning solution of the present invention is applied to a wafer dicing process or a wafer polishing process, thereby removing impurities remained on the surface of the wafer and improving the performance of the wafer product.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning solution for a wafer,

The present invention relates to a cleaning liquid, and more particularly, to a wafer cleaning liquid and a wafer processing method using the same.

Wafer dicing and wafer polishing are important steps in the wafer fabrication process. After the wafer dicing or polishing process, fragments and used reagents due to dicing or polishing may often remain on the surface, such impurities remaining on the wafer surface may affect subsequent processing. Therefore, it is necessary to clean the wafer surface with a cleaning liquid that can effectively remove such impurities.

This cleaning liquid, which is applied to cleaning wafers, has a good particle coating effect that prevents debris from aggregating by covering the debris generated by dicing, and easily removes the impurities remaining in the pores and holes, Should have a relatively low surface tension to avoid damage. In general, cleaning is carried out together with deionized water containing carbon dioxide in use. Since the cleaning liquid component is mixed with deionized water containing carbon dioxide, a dilution effect is generated. Therefore, the cleaning liquid penetrates into the diced position, By removing static electricity, it is extremely important to provide a stable surface tension to prevent short circuiting of the wafer line due to heat and static electricity generated.

In addition, if particles generated by dicing are not adequately covered, such particles can be deposited on the wafer surface, which, if deposited on a bump, can affect subsequent bumping efficiency and adhesion have.

At present, most of the cleaning agents used in the market are long chain carbon chain surfactants. Such a cleaning liquid is not sufficiently ideal for coating the particles, and the increase in surface tension after dilution is very large, so that the penetration ability of the cleaning liquid may deteriorate during use. Therefore, it is necessary to develop a new type of cleaning liquid, which is more convenient than a surfactant having a long carbon-chain-covering ability and an increase in surface tension after dilution, which is more convenient at the time of use.

The present invention provides a wafer cleaning solution having better particle coverage ability and less increase in surface tension after dilution.

The present invention further provides a wafer processing method which is more convenient in terms of use while having a better cleaning ability in removing impurities on the surface of a wafer by using a wafer cleaning liquid after a dicing process or a polishing process.

The present invention relates to a method for producing a water-soluble polymer by coagulating a water-soluble polymer on a dicing face by heat generated by dicing, thereby generating a more excellent coating effect and lubrication effect and reducing a diced particle size, Thereby preventing contamination of the wafer.

The present invention provides a wafer cleaning liquid containing a water-soluble polymer, a surfactant and a solvent in its composition. The weight percentage concentration of the water-soluble polymer in the whole wafer cleaning liquid is 0.01 wt% to 30 wt%, the weight percentage concentration of the surfactant in the whole wafer cleaning solution is 0.01 wt% to 10 wt%, and the balance is water.

The present invention provides a wafer cleaning liquid comprising a water-soluble polymer having a characteristic that the clouding point is between 30 and 80 degrees centigrade. When the cloud point is less than 25 degrees Celsius, the storage temperature is higher than the cloud point, so storage stability may be deteriorated and the layer separation phenomenon may occur. In actual polishing, the temperature does not exceed 80 degrees centigrade, but if the temperature is 80 degrees centigrade , There is a danger that the operator will suffer an image, so that when the cloud point of the water-soluble polymer exceeds 80 degrees, the lubrication effect can not be obtained.

According to one embodiment of the present invention, the water-soluble polymer is selected from the group consisting of a polyvinyl alcohol polymer and a copolymer thereof.

According to one embodiment of the present invention, the polymerization degree of the polyvinyl alcohol of the polyvinyl alcohol polymer is 300 to 3000. [

According to one embodiment of the present invention, the polyvinyl alcohol of the polyvinyl alcohol has a degree of saponification of 65 to 99. [

According to one embodiment of the present invention, the molecular weight of the water-soluble polymer is 13,200 to 176,000.

According to an embodiment of the present invention, the surface tension dilution ratio of the wafer cleaning liquid is 5,000 times or less and the surface tension thereof is 45.0 dynes / cm or less.

According to one embodiment of the present invention, the surfactant comprises a cationic surfactant, an anionic surfactant or a positive ion surfactant.

According to an embodiment of the present invention, the surfactant may be at least one selected from the group consisting of octyl alcohol, decyl alcohol, dodecyl alcohol, tridecyl alcohol, octadecyl alcohol, stearyl alcohol, oleyl alcohol, octylphenol, Compounds in which ethoxy and / or propoxy are added to the compound, or mixtures thereof.

The present invention further provides a wafer processing method using a wafer cleaning liquid, which comprises a step of performing a dicing process or a polishing process on the wafer, and then cleaning the wafer with the wafer cleaning liquid.

According to one embodiment of the present invention, the wafer polishing process includes a chemical mechanical polishing (CMP) process or a mechanical polishing process.

According to the above description, the wafer cleaning solution of the present invention can improve the particle impurity covering ability of the cleaning liquid by using a water-soluble polymer having a cloud point of 30 to 80 degrees as a main component and reduce the increase in surface tension after dilution. The present invention further provides a wafer processing method capable of removing impurities generated in a dicing or polishing process using such wafer cleaning liquid.

1 is an explanatory diagram of a semiconductor wafer of a wafer processing method using a wafer cleaning liquid of an embodiment of the present invention.
2A to 2C are process sectional views of a wafer processing method using a wafer cleaning liquid of an embodiment of the present invention.
Fig. 3 is a surface tension change curve after diluting the experimental example and the comparative example of the present invention.
4 is a particle size distribution diagram of the particles remaining on the wafer after cleaning with the cleaning liquid of the experimental example.
5 is a particle size distribution diagram of the particles remaining on the wafer after cleaning with the cleaning liquid of the comparative example.

In order that the features and advantages of the present invention will be more clearly understood, the present invention will be described in detail with reference to the accompanying drawings and the accompanying drawings.

The wafer cleaning liquid provided by the present invention includes a water-soluble polymer, a surfactant, and water. The wafer cleaning liquid of the present invention has a good ability to coat the small particles and a characteristic that the surface tension after dilution does not greatly increase so as to provide a better cleaning ability in removing impurities on the surface of the wafer, . Hereinafter, each component of the wafer cleaning liquid will be described in detail.

Water-soluble polymer

The water-soluble polymer includes a polyvinyl alcohol polymer having a clouding point of between 30 and 80 degrees Celsius. The polyvinyl alcohol polymer may be a polyvinyl alcohol and a polyvinyl alcohol copolymer. In one embodiment, the degree of polymerization of the polyvinyl alcohol of such a polyvinyl alcohol polymer is 300 or more. In another embodiment, the degree of polymerization of the polyvinyl alcohol of the polyvinyl alcohol polymer is from 300 to 3000. In another embodiment, the degree of polymerization of the polyvinyl alcohol of the polyvinyl alcohol polymer is 2000 to 2200. In one embodiment, the molecular weight of the water soluble polymer is 13,200 to 176,000. The degree of saponification of the polyvinyl alcohol of the polyvinyl alcohol polymer is 65 to 99. In addition, the weight percentage concentration of the water-soluble polymer in the whole wafer cleaning liquid is 0.01 wt% to 30 wt%. The water-soluble polymer of the embodiment of the present invention includes a polyvinyl alcohol polymer, and therefore the formed wafer cleaning liquid has a relatively good ability to coat the particles. This makes it possible to more effectively remove the impurities and the solvent remaining on the wafer surface when the wafer is cleaned.

The polyvinyl alcohol and the copolymer thereof of the embodiment of the present invention can be formed by various methods. In one embodiment, the polyvinyl alcohol and its copolymer are obtained by reacting a polyvinyl ester with a saponification catalyst. Among them, the polyvinyl ester can be formed by the polymerization reaction of the vinyl ester compound in the alcohol solvent by the action of the radical initiator. In one embodiment, the vinyl ester compounds include vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pentanoate, vinyl laurate, vinyl stearate, and vinyl benzoate. The copolymer monomer may be selected from the group consisting of ethylene, propylene, acrylic acid, acrylate, methacrylic acid, methacrylate, acrylamide, acrylamide derivatives, allyl alcohol, organic acid esters of allyl alcohol, Esters of citric acid and itaconic acid, and the like. The alcohol solvent includes methanol, ethanol, propanol or a combination thereof or a derivative thereof. The radical initiator includes azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), and the like. The polymerization reaction is not particularly limited, and generally, any reaction condition for producing a polyvinyl ester compound can be used. The degree of polymerization of the final polyvinyl ester compound is controlled by adjusting the addition amount of the reactant and the polymerization reaction time. The saponification catalyst may include a hydroxide or a carbonate compound of an alkali metal or an alkaline earth metal, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate or calcium carbonate. There is no particular limitation on the kind of the saponification catalyst, and any inorganic alkaline compound for producing polyvinyl alcohol by saponification reaction with polyvinyl ester can be generally used. The saponification catalyst may also comprise an organic amine alkaline compound, for example, an organic amine such as aqueous ammonia, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or a derivative thereof.

Surfactants

Surfactants include cationic surfactants, anionic surfactants or amphoteric surfactants. The surfactant may be a linear or branched surfactant. In one embodiment, the surfactant is selected from the group consisting of ethoxy and ethoxy, ethoxy, and propoxy, with a compound such as octyl alcohol, decyl alcohol, dodecyl alcohol, tridecyl alcohol, octadecyl alcohol, stearyl alcohol, oleyl alcohol, octylphenol, nonylphenol, / ≪ / RTI > propoxy, or mixtures thereof. The weight percent concentration of these surfactants in the entire wafer cleaning liquid is from 5 wt% to 10 wt%. When the concentration of the surfactant in the embodiment of the present invention is within the above range, the degree of surface tension dilution of the wafer cleaning liquid is such that when the dilution ratio of the surface tension at 1500 times dilution is? 31.25 dynes / cm and the dilution factor is 3000 times, The increase rate is? 40.63 dynes / cm. The wafer cleaning liquid of the embodiment of the present invention does not increase greatly so as to greatly increase the surface tension according to the dilution ratio and is therefore more convenient in application.

The present invention relates to a wafer processing method using a wafer cleaning liquid, in which a wafer is cut into a plurality of chips through a dicing process, or a wafer surface is planarized by a polishing process, and then impurities on a chip or a wafer surface are removed by the wafer cleaning liquid Lt; / RTI >

1 is an explanatory diagram of a semiconductor wafer of a wafer dicing method using a wafer cleaning liquid of an embodiment of the present invention. 2A to 2C are sectional views of a wafer dicing process using a wafer cleaning liquid of an embodiment of the present invention.

Wafer processing in the manufacturing process includes polishing the wafer to planarize the wafer surface and dicing the wafer to form a plurality of chips. When performing wafer polishing or wafer dicing, many dicing and polishing debris may occur. Such dicing polishing debris and the reagent used in the manufacturing process may adhere to the wafer surface and affect the performance of the wafer product. In an embodiment of the present invention, the use of the wafer cleaning liquid after wafer polishing or wafer dicing can improve the performance of the wafer product by removing impurities on the wafer surface.

Referring to FIGS. 1 and 2A, a wafer 100 having a plurality of dicing channels 14 is provided. The dicing channel 14 includes a plurality of horizontal dicing channels 14a extending in a first direction and a plurality of vertical dicing channels 14b extending in a second direction. The horizontal dicing channel 14a and the vertical dicing channel 14b are arranged in a lattice pattern to separate the plurality of chips 16.

More specifically, the wafer 100 includes at least a substrate 10 and a material layer 12. The substrate 10 is, for example, a semiconductor substrate, a semiconductor compound substrate, or a substrate (Semiconductor Over Insulator (SOI)) having a semiconductor on an insulating layer. The semiconductor may be an IVA group atom, for example, silicon or germanium. Semiconductor compounds are semiconductor compounds that are formed by atoms of Group IVA, such as silicon carbide or germanium silicide, or semiconductor compounds that are formed from Group IIIA atoms and Group VA atoms, for example, gallium arsenide have.

The dicing channel (14) is provided in the material layer (12). In one embodiment, the material layer 12 and some of the substrate 10 are removed in a laser dicing step prior to dicing with the dicing tool, so that the bottom of the dicing channel 14 is removed from the substrate 10, Exposed to the surface. In yet another embodiment, a material layer 12 is coated (not shown) on the substrate 10 at the bottom of the dicing channel 14.

The wafer 100 may be provided with various semiconductor elements, a metal interconnecting line, a solder pad, and a passivation layer, but it is not shown in the drawings for the sake of clarity.

2A through 2C, a dicing process is performed on a dicing tool 200 by first dicing a substrate 10 along a dicing channel 14 formed in a material layer 12, A groove 16 for dividing the chip 16a and a plurality of chips 16a is formed. In one embodiment, the dicing tool may be a diamond blade.

When the dicing process is performed, dicing debris may be generated. This dicing debris or a reagent (referred to as an impurity) used for dicing may be adhered to the surface of the wafer 100, And the cleaning process using the wafer cleaning liquid of the present invention can remove the impurities adhering to the surface of the wafer 100. [ In one embodiment, the cleaning process using the wafer cleaning liquid of the present invention is performed after the dicing process to remove impurities adhering to the surface of the wafer 100. [ In another embodiment, that is, when performing the dicing process, the cleaning process is performed at the same time to clean the surface of the wafer 100 with the wafer cleaning liquid of the present invention. In this case, dicing debris generated during dicing can be removed At the same time, the wafer cleaning liquid can also help lower the temperature of the dicing tool 200 during the dicing process.

The cleaning solution of the present invention may be applied to a chemical mechanical polishing process or a mechanical polishing process. In one embodiment, the surface of the wafer 100 is treated by chemical mechanical polishing (CMP) to planarize its surface. In another embodiment, the wafer 100 is thinned by chemical mechanical polishing (CMP) or mechanical polishing. Likewise, during the process of performing the polishing process or after the polishing process, the wafer cleaning solution of the present invention can be subjected to a cleaning process to remove impurities remaining on the surface of the wafer 100.

Hereinafter, the properties of commercially available products as experimental examples and comparative examples of the present invention, in particular, the changes in the surface tension after the dilution is compared with the capability of covering the small particle, and the results are described in detail below.

<Experimental Example 1>

50 g of polyvinyl alcohol having a degree of saponification of 80 mol% and a degree of polymerization of 2000 and 25 g of dodecyl polyethylene glycol propane diol copolymer ethers (surfactant) were dissolved in 925 g of water to adjust the detection pH value to 5.80 , And the detection blur point is 45 degrees Celsius. Table 1 shows the results of the measurements of the original washing liquid. The change in surface tension diluted with water is as shown in Fig. Dicing was performed with a commercial wafer dicing machine, and dilution magnification of the cleaning liquid was 2500 times. The surface of the wafer was observed with an optical microscope. As a result, there was no particle residue. The wastewater sample after dicing was analyzed and the particle size was analyzed with a MICROTRAC Nanotrac 150 particle size analyzer as shown in FIG.

<Experimental Example 2>

Polyvinyl alcohol having a saponification degree of 50 g of 84 mol% and a polymerization degree of 1400 and 25 g of dodecyl polyethylene glycol propane diol copolymer ethers (surfactant) were dissolved in 925 g of water to adjust the detection pH value to 5.91 , And the detection blur point is 75 degrees Celsius. Dicing was performed with a commercial wafer dicing machine, and dilution magnification of the cleaning liquid was 2500 times. Observation of the wafer surface with an optical microscope revealed no particles remaining.

<Experimental Example 3>

50 g of polyvinyl alcohol having a degree of saponification of 74 mol% and a degree of polymerization of 500 and 25 g of dodecyl polyethylene glycol propane diol copolymer ethers (surfactant) were dissolved in 925 g of water to adjust the detected pH value to 5.84 , And the detection blur point is 35 degrees Celsius. Dicing was performed with a commercial wafer dicing machine, and dilution magnification of the cleaning liquid was 2500 times. Observation of the wafer surface with an optical microscope revealed no particles remaining.

<Comparative Example>

The change in the surface tension of a commercially available product diluted with water is as shown in Fig. Dicing was performed with a commercial wafer dicing machine, and dilution magnification of the cleaning liquid was 2500 times. The surface of the wafer was observed with an optical microscope. As a result, the particles remained. The result of analysis of the particle diameter by a MICROTRAC Nanotrac 150 particle size analyzer after taking a sample of the wastewater after dicing is as shown in FIG.

Cleaning liquid pH value Surface tension
(Dyne / cm) Suspension particle size
(탆) Suspension particle size
percentage(%) Experimental Example 1
5.8
30.3
0.66 26.5 0.23 73.5 Comparative Example
6.7
30.8
0.91 44.7 0.27 55.3

As can be seen from the results of Table 1 and Fig. 4-5, the percentage of small particle suspension particle size in the experimental example is 73.5%, which is clearly higher than the small particle suspension particle size percentage of the comparative example of 55.3% and the particle size of the small particle particle is 0.23 탆. Lt; / RTI &gt; Further, according to the test results, the particle size of the large particles of the Example was 0.66 占 퐉, which was about 38% smaller than 0.91 占 퐉 in the comparative example and only about 26.5% in the large particle content ratio, 68.7%. In comparison with the comparative example, the experimental example shows relatively excellent covering ability and dispersing ability to the particles, and it is possible to coat and clean the impurities more effectively in this way, and the particles are agglomerated into lumps It is possible to prevent sedimentation.

3 is a graph showing changes in surface tension after diluting the example and the comparative example. As can be seen from FIG. 3, the examples are excellent in dilution stability and can maintain a similar surface tension even when diluted, and the difference in cleaning effect can be minimized even when there is a slight error in the dilution ratio in actual use.

In conclusion, the wafer cleaning solution of the present invention improves the coating ability of the fine particles by using a water-soluble polymer as a main component, thereby further improving the cleaning effect. In addition, such a wafer cleaning solution exhibits satisfactory dilution stability due to a small increase in surface tension after dilution It is more convenient when diluted. As described above, the wafer cleaning liquid and the wafer processing method using the same according to the embodiment of the present invention can effectively remove impurities on the surface of the wafer, and further improve the performance of the wafer product.

While the present invention has been described in connection with what is presently considered to be practical and preferred embodiments, it is not intended to limit the invention to those skilled in the art without departing from the spirit and scope of the invention. And therefore the scope of protection of the present invention is deemed to be based on the limitation of the scope of the attached patent application.

10: substrate
12: material layer
14: Dicing channel
14a: Horizontal dicing channel
14b: vertical dicing channel
16, 16a: chip
20: groove
100: wafer
200: Dicing tool

Claims (7)

From 0.01 wt% to 30 wt% of a water-soluble polymer having a cloud point of from 30 [deg.] C to 80 [deg.] C; And
More than 5 wt% to 10 wt% of a surfactant,
The other is a wafer cleaning liquid,
The water-soluble polymer is selected from the group consisting of a polyvinyl alcohol polymer and a copolymer thereof,
Wherein the polymerization degree of the polyvinyl alcohol polymer and the copolymer thereof is from 300 to 3,000. The wafer cleaning liquid according to claim 1, wherein the polyvinyl alcohol polymer and the copolymer thereof have a degree of saponification of 65 to 99 mol%. The wafer cleaning liquid according to claim 1, wherein the surface tension dilution ratio of the wafer cleaning liquid is 5,000 times or less and the surface tension thereof is 45.0 dynes / cm or less. The wafer cleaning liquid according to claim 1, wherein the surfactant comprises a nonionic surfactant, a cationic surfactant, an anionic surfactant or a positive ion surfactant. The non-ionic surfactant according to claim 4, wherein the nonionic surfactant is at least one selected from the group consisting of octyl alcohol, decyl alcohol, dodecyl alcohol, tridecyl alcohol, octadecyl alcohol, stearyl alcohol, oleyl alcohol, octylphenol, A compound to which an ethoxy group and / or a propoxy group is added, or a mixture thereof. Providing a wafer;
Performing a dicing process or a polishing process on the wafer; And
A method for processing a wafer, comprising the step of performing a cleaning process with the wafer cleaning liquid according to any one of claims 1 to 5. The method according to claim 6, wherein the polishing process includes a chemical mechanical polishing method or a mechanical polishing method.

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