KR20130037192A - Preparation method of poly-urethane mounting pad - Google Patents

Abstract

PURPOSE: A method for manufacturing a polyurethane support pad is provided to uniformly perform a polishing process with high efficiency and to uniformize a thickness, pressure, or tension in a pad region. CONSTITUTION: A resin composition with polyurethane resins and DMF solvents is wet-congealed. A wet congelation is cleaned and dried. The surface of the wet congelation is polished. An adhesive layer is formed on the surface of the polished wet congelation. The wet congelation with an adhesive layer is thermally treated.

Description

Manufacturing method of polyurethane support pad {PREPARATION METHOD OF POLY-URETHANE MOUNTING PAD}

The present invention relates to a method for manufacturing a polyurethane support pad, and more particularly, to minimize product defects that may occur in the manufacturing process, and to provide a more uniform thickness, pressure distribution, or tension distribution in the entire pad to be manufactured. The present invention relates to a method for producing a polyurethane support pad, which can be shown, and which can realize more uniform and high efficiency polishing.

Since a substrate used in a semiconductor device or a display device requiring high integration requires a fine and precise surface, various planarization methods have been applied. In particular, according to a trend toward higher integration and higher performance of semiconductor devices or display devices, a method of relatively moving the polishing pad and the polished body while supplying a slurry composition including the abrasive particles and various chemical components between the polishing pad and the polished body is performed. This is commonly used. In such a polishing method, the polished body is fixed on a constant support pad so as to maintain a constant position and posture during polishing or processing for more accurate polishing.

In particular, in order to be used as a glass substrate for a display, the roughness of the surface of the glass substrate and the difference in position difference (TTV) are the main management factors, and they must be adjustable within a range of sub-microns to several tens of microns. . In addition, the waviness must be managed at the level of 40 nm, and in particular, the waviness management of about 20 nm is required to be applied as a glass substrate for TFT.

In order to achieve such fine grinding, in addition to adjusting the conditions and apparatus of the polishing process, the support pad used must have a high compression ratio and a recovery rate, and a more uniform thickness, pressure distribution, and tension distribution over the entire support pad area. do.

However, the previously known support pads have a uniform size and distribution of bubbles formed therein, resulting in poor physical properties such as compression rate and compression recovery rate, as well as no uniform physical properties over the entire support pad area. It has not been sufficient for applications where finer polishing is required, for example polishing of glass substrates for displays.

The present invention can minimize product defects that may occur in the manufacturing process, can exhibit a more uniform thickness, pressure distribution or tension distribution in the entire area of the pad to be manufactured, and can realize more uniform and high efficiency polishing. It is to provide a method for producing a polyurethane support pad that can be.

The present invention comprises the steps of wet solidifying a resin composition comprising a polyurethane resin and a DMF solvent; Washing and drying the wet coagulum; Polishing the surface of the wet coagulum; Forming an adhesive layer on a surface of the polished wet coagulated product; And it provides a method for producing a polyurethane support pad comprising the step of heat-treating the wet coagulation formed on the adhesive layer.

Hereinafter, a method of manufacturing a polyurethane support pad and a polyurethane support pad according to a specific embodiment of the present invention will be described in detail.

In the present specification, the 'support pad' refers to a pad which serves to closely adhere or fix the polishing target film to a carrier in a polishing process during a substrate manufacturing process used in a semiconductor or a display device.

According to one embodiment of the invention, the step of wet solidifying a resin composition comprising a polyurethane resin and a DMF solvent; Washing and drying the wet coagulum; Polishing the surface of the wet coagulum; Forming an adhesive layer on a surface of the polished wet coagulated product; And it may be provided a method for producing a polyurethane support pad comprising the step of heat-treating the wet coagulation formed on the adhesive layer.

If long and large pores are uniformly formed in the polyurethane support pad, the hardness of the pad can be lowered to produce a soft pad having a high compressibility, and easily trap the air trapped between the support pad and the film to be polished. The pressure applied in the polishing step can be evenly distributed to the entire support pad and the entire abrasive body, thereby minimizing the defects that may occur during polishing.

However, if the polyurethane support pad is too hard or too soft, the cause of product defects that may occur in the manufacturing process-for example, the uneven pressure distribution of the roll, or the gap between the rolls ( The overall uniformity of the polyurethane support pads manufactured by pad entanglement due to poor control, etc. may be affected. In addition, when such a polyurethane support pad is used, a defect such as a pad mark can be caused to be polished, for example, a glass substrate of a display device.

Accordingly, the inventors have found that the thickness, pressure distribution or tension distribution of the support pad is uneven after the polishing of one surface (eg, the back surface) of the polyurethane support pad or the formation of an adhesive layer on one surface of the support pad. Proceeding the research to solve the problem, by applying a constant heat treatment step after the surface polishing step and the adhesive layer forming step, it is possible to minimize the product defects that can occur in the manufacturing process, the entire area of the polyurethane support pad to be manufactured More uniform thickness, pressure distribution or tension distribution can be exhibited, and the experiment confirmed that the glass substrate and the like can be polished more uniformly and with high efficiency, and completed the invention.

In particular, in the manufacturing process of the polyurethane support pad, it may be possible to recognize or difficult to recognize, the resulting support pad may have a non-uniform thickness, pressure distribution or tension distribution, such as the heat treatment step Depending on the application, a stress or the like that is partially or locally distributed or accumulated on the polyurethane support pad can be spread evenly.

The heat treatment may be carried out at a temperature of 60 ℃ to 180 ℃, preferably at a temperature of 70 ℃ to 150 ℃, For a time between 1 and 100 minutes, preferably for a time between 10 and 60 minutes. If the heat treatment is performed at a temperature that is too low, the heat treatment effect is not properly exhibited, and thus, it is difficult for the polyurethane support pad to have a uniform thickness, pressure distribution or tension distribution. Product defects may occur. When the heat treatment is performed at a temperature that is too high, the polyurethane resin layer may be modified, and an adhesive layer which may be further used may also be volatilized or modified.

The heat treatment may be any conventionally known oven or heater, such as a continuous oven or batch oven, without particular limitation.

By heat-treating the wet solidified product on which the adhesive layer is formed, the thickness of the support pad to be manufactured may be locally uneven or pressure or tension may be concentrated on a part of the support pad. Accordingly, the polyurethane support pad according to the above production method not only has a more uniform thickness, pressure distribution or tension distribution, but also can polish the glass substrate, which is the film to be polished, at a uniform and high efficiency in actual polishing.

Meanwhile, the method of manufacturing the polyurethane support pad may include grinding (or buffing) the surface of the wet coagulated product. The polishing step is a step of cutting a surface of a polyurethane film (100% modulus 1 to 10) having low hardness by using a roll of sand paper wound at a high speed, and is a step of applying high energy.

In this polishing (or buffing) process, the polished finish may be cut several hundred um at a time, or several times several tens of um. In the case of polishing a low hardness film at a time, a difference in thickness or a level of polishing (buffing) may occur in the machine direction (MD) direction, and the energy unevenly accumulated on the support pad may cause a polishing film, For example, non-uniformly transferred to the glass substrate of the display may cause lines or stripes in the TD (Transverse Direction) direction.

The method of manufacturing the polyurethane support pad may include forming an adhesive layer on a surface of the polished wet coagulated product. This adhesive layer can be formed using any method and configuration known to be used to manufacture the final product of the support pad without any particular limitation. For example, the adhesive layer may be formed by coating a certain adhesive, such as a pressure-sensitive adhesive (PSA), on the surface of the wet coagulated product or the surface polished wet coagulated product, or the surface of the wet coagulated product or It may be formed by laminating a pressure-sensitive double-sided adhesive film on the surface of the surface polished wet coagulated product.

On the other hand, when a composition comprising an organic solvent, such as a polyurethane resin and a DMF solvent, is solidified in a coagulation bath containing an organic solvent and water, phase separation of the resin composition component, for example, phase separation of a polyurethane resin, water, and an organic solvent A phenomenon occurs, and by this phase separation, a polyurethane resin having a plurality of pores formed therein can be obtained.

Specifically, wet-solidifying the resin composition comprising the polyurethane resin and the DMF solvent may include forming the polyurethane resin composition; Forming a coating layer by applying or applying the polyurethane resin composition to a predetermined substrate or frame; And solidifying the coating layer.

In addition, after wet solidifying the resin composition including the polyurethane resin and the DMF solvent, washing, dehydrating and drying the coagulated product of the composition may be continuously performed. In the step of washing, dehydrating and drying the coagulated product of such a resin composition, a method and an apparatus known to be usable in the method for producing a support pad can be used without great limitation.

In the step of solidifying the coating layer may be made by putting the substrate or the frame on which the coating layer is formed into a dimethylformamide aqueous solution or a coagulation tank filled with water. In the solidification process, as the dimethylformamide inside the polyurethane resin is replaced with water, the polyurethane resin is gradually solidified and thus a plurality of pores may be formed. The concentration of the aqueous solution filled in the coagulation bath and the amount of the aqueous solution or water are not particularly limited, and may be appropriately adjusted according to the reaction conditions and the physical properties of the support pad to be produced. After the solidification process, water and DMF may remain in the polishing pad properly, and the solidified product may be washed and dried in an oven to remove water, DMF solvent, and other components from the polishing pad.

The polyurethane resin may have a weight average molecular weight of 30,000 to 1,000,000. In addition, the polyurethane resin may have a viscosity of 100,000 to 2,000,000 cps in a DMF Solution state of 30% at room temperature. In the manufacturing process of the polyurethane support pad, pores may be formed while dimethylformamide in the polyurethane resin is dissolved in water and escapes, and when using a polyurethane resin having a molecular weight or viscosity in the above range, It can be formed in a uniform size and a uniform distribution. When the viscosity of the polyurethane resin is less than 100,000 cps, it may not have proper physical properties as a support pad, and it may be difficult to manufacture a support pad. When the viscosity is more than 3,000,000 cps, it may be difficult to form pores in the support pad. Hardness can be significantly higher.

The resin composition may include 1 to 70 wt% of the polyurethane resin, preferably 3 to 50 wt%. When the content of the polyurethane resin in the resin composition is too small, it is difficult to properly form the body of the support pad, the viscosity of the composition is too low may not be easy to apply to the coating process for manufacturing the support pad. In addition, if the content of the polyurethane resin in the resin composition is too large, the density of the obtained polyurethane support pad becomes larger than necessary or the viscosity of the composition becomes so large that it is not easy to apply to the coating process for producing the support pad. Can be.

The resin composition may include a dimethylformamide (DMF) solvent, the dimethylformamide (DMF) means N, N'- dimethylformamide (N, N'-dimethylmethanamide). When the polyurethane resin composition is solidified, a polyurethane support pad having pores therein may be formed by phase separation of a resin composition component, for example, a polyurethane resin, water, and a DMF solvent. That is, in the solidification process of the resin composition, the DMF solvent present in the polyurethane resin is replaced with water in the coagulation bath, and when the solidification process is completed, a polyurethane resin for a support pad having pores formed therein is formed.

The resin composition may include 30 to 99 wt% of the DMF solvent, preferably 40 to 90 wt%. If the content of the DMF solvent on the resin composition is too small may not form pores in the resin during the solidification process, if the content is too large, the ratio of the polyurethane resin is greatly reduced to prepare a polyurethane support pad having proper properties It can be difficult to do.

The resin composition may further include an anionic surfactant. The anionic surfactants allow the water to penetrate uniformly over the entire area of the composition to be solidified, and to prevent the phase separation of the respective components of the polyurethane resin composition from being concentrated in a certain portion, so that pores are formed in the support pad. It can be made very uniform. Such anionic surfactants may be used by appropriately adjusting the content in consideration of physical properties and process conditions of the support pad to be manufactured, for example, may be included in 0.01 to 5 wt% of the polyurethane resin composition for the support pad. . Examples of the anionic surfactant include dodecylbenzenesulfonic acid, dodecylbenzenesulfonic acid derivatives, succinic acid, succinic acid derivatives, dodecylsulfate, dodecylsulfate derivatives, or mixtures of one or more thereof.

The resin composition may further include a nonionic surfactant to increase the adsorption force of the support pad or to planarize the surface of the pad. Examples of such nonionic surfactants include silicone-based polymers, silicone oils, glycerol-based polymers, or hydrocarbon-based polymers. Such a nonionic surfactant may be used by appropriately adjusting the content in consideration of physical properties and process conditions of the support pad to be manufactured, for example, may be included in 0.01 to 5 wt% of the polyurethane resin composition for the support pad. .

In addition, the resin composition may further include at least one additive selected from the group consisting of colorants, water repellents, fillers, pore size regulators and pigments. Such additives may be used by appropriately adjusting the content in consideration of physical properties or process conditions of the support pad to be manufactured, for example, each additive may be included in the resin composition in an amount of 0.01 to 10 wt%.

Polyurethane support pad manufactured by the above-described manufacturing method has a long and large pores uniformly formed therein to lower the hardness of the pad to implement a high compression rate and compression recovery rate, locally non-uniform thickness or a part of the support pad The phenomenon of concentration of pressure or tension can be eliminated to have a more uniform thickness, pressure distribution, or tension distribution.

The polyurethane support pad may have a density of 0.10 to 0.35 g / cm 3. In addition, the polyurethane support pad may have a compression ratio of 30% or more and a compression recovery rate of 95% or more according to JIS L1021-16.

According to the present invention, it is possible to minimize product defects that may occur in the manufacturing process, to show a more uniform thickness, pressure distribution or tension distribution in the entire area of the pad to be manufactured, and to achieve a more uniform and high efficiency polishing Methods of making polyurethane support pads that can be implemented and polyurethane support pads obtained therefrom can be provided.

1 shows a glass substrate polished using the polyurethane support pad of the embodiment.
2 shows a glass substrate polished using the polyurethane support pad of the comparative example.

The invention is explained in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

< Example : Polishing with Polyurethane Support Pads>

After coating the resin composition comprising the components shown in Table 1 on the PET film, the coating layer was wet coagulated, washed with water, dehydrated and dried to obtain a polyurethane resin film layer having pores therein.

Ingredients Polyurethane
Resin SW-80LM
Mw. 380K] Nonionic
Surfactant SD-7 SD-11 coloring agent DMF Water repellent Filler PEG usage
(weight%) ７９．３４ １．０６ ２．１２ ３．７ 10．６ 1.06 1.06 1.06

* Polyurethane Resin SW-80LM: 20 wt% Polyurethane Resin DMF Solution

And the buffing process was carried out using the roll wound by the sand paper which rotates at high speed so that the obtained polyurethane resin film layer may have more uniform thickness and high uniformity. Then, a pressure-sensitive double-sided adhesive tape was laminated on one surface of the buffed polyurethane resin film layer to obtain a polyurethane support pad of the finished product. [Polyurethane layer: 1200 mu m, adhesion layer: 250 mu m, release film: 80 mu m]

The obtained polyurethane support pad was heat-treated at 80 ° C. for 30 minutes, and then mounted on a polishing equipment to polish the glass substrate for 10 minutes. And, the polishing results were observed in the transmission mode in the Xenon Lamp, which is shown in FIG.

< Comparative example : Polishing with Polyurethane Support Pads>

A polyurethane support pad was obtained in the same manner as in Example 1, except that the obtained polyurethane support pad was heat-treated at 80 ° C. for 30 minutes. [Polyurethane layer: 1200 mu m, adhesion layer: 250 mu m, release film: 80 mu m]

Then, the polyurethane support pad was attached to the polishing equipment to polish the glass substrate for 10 minutes. And, the polishing results were observed in the transmission mode in the Xenon Lamp, which is shown in FIG.

< Example  And Comparative Example  Comparison>

The polyurethane support pad of the embodiment not only has a more uniform thickness, pressure distribution or tension distribution, but also, as shown in Fig. 1, it is possible to polish the glass substrate, which is the film to be polished, in a uniform and high efficiency in actual polishing.

On the other hand, the polyurethane support pad of the comparative example is not only uniform in thickness, pressure distribution or tension distribution, but also a defective line is observed in a polished glass substrate as shown in Fig. 2 in the TD direction. It can be confirmed that.

Claims (11)

Wet solidifying a resin composition comprising a polyurethane resin and a DMF solvent;
Washing and drying the wet coagulum;
Polishing the surface of the wet coagulum;
Forming an adhesive layer on a surface of the polished wet coagulated product; And
Method of producing a polyurethane support pad comprising the step of heat-treating the wet coagulation formed on the adhesive layer.
The method of claim 1,
A method for producing a polyurethane support pad, wherein the compression ratio according to IS L1021-16 of the polyurethane support pad to be produced is 30% or more and the compression recovery rate is 95% or more.
The method of claim 1,
Heat-treating the wet solidified product on which the adhesive layer is formed is a method of manufacturing a polyurethane support pad at 60 ° C to 300 ° C.
The method of claim 1,
The heat treatment is a method for producing a polyurethane support pad made 1 minute to 100 minutes.
The method of claim 1,
The polyurethane resin is a polyurethane resin composition for a support pad having a weight average molecular weight of 30,000 to 1,000,000.
The method of claim 1,
The polyurethane resin is a polyurethane resin composition for a support pad having a viscosity of 30,000 to 1,000,000 cps in a 30% DMF Solution at room temperature.
The method of claim 1,
The resin composition is a method for producing a polyurethane support pad further comprises at least one surfactant selected from the group consisting of anionic surfactants and nonionic surfactants.
The method of claim 7, wherein
The anionic surfactant is a polyurethane support pad comprising at least one compound selected from the group consisting of dodecylbenzenesulfonic acid, dodecylbenzenesulfonic acid derivatives, succinic acid, succinic acid derivatives, dodecyl sulfate and dodecyl sulfate derivatives Way.
The method of claim 7, wherein
The nonionic surfactant is a method for producing a polyurethane support pad comprising at least one compound selected from the group consisting of silicone-based polymers, silicone oils, glycerol-based polymers and hydrocarbon-based polymers.
The method of claim 7, wherein
The resin composition is 1 to 70 wt% polyurethane resin
30 to 99 wt% of the DMF solvent; And
A method for producing a polyurethane support pad comprising at least one surfactant selected from the group consisting of residual anionic surfactants and nonionic surfactants.
The method of claim 1,
The resin composition is a method for producing a polyurethane support pad further comprises at least one additive selected from the group consisting of colorants, water repellents, fillers, pore size regulators and pigments.

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