TWI556960B - Production Method of EVA Chemical Mechanical Grinding Pad - Google Patents

Description

EVA chemical mechanical polishing pad manufacturing method

The present invention relates to the field of chemical mechanical polishing techniques, and more particularly to a method of making an EVA chemical mechanical polishing pad.

In order to effectively increase production capacity and reduce costs, the flattening process for producing semiconductor components has become increasingly important. In the flattening process, a chemical mechanical polishing (CMP) process is often used to remove excess portions of the wafer surface film to achieve full planarization.

The chemical mechanical polishing process fixes the polishing pad on the rotating disk of the polishing machine, and then presses the wafer against the polishing pad by using the polishing head. The rotation of the rotating disk can drive the polishing pad to cause mutual mutual interaction between the wafer surface and the polishing pad. Friction, at the same time, an acidic or alkaline chemical slurry or slurry is continuously and uniformly injected between the wafer and the polishing pad to combine mechanical polishing and wet chemical reaction to remove the film deposited on the surface layer of the wafer. The surface is smooth and flat.

The polishing pad currently used in the CMP process is mainly a polishing pad based on a low-density material. For example, the polishing pad disclosed in the Republic of China Patent No. M443593 has a base layer made of low-density polyethylene or low. Made of a mixture of density polyethylene and ethylene vinyl acetate. However, such a low-density polishing pad is not sufficiently solid, and wear powder is likely to occur in the CMP process. Furthermore, since the polishing pad of the conventional low-density material is usually cut into several pieces according to different thicknesses after being poured, and then made into a finished product, the quality of the polishing pad is unstable. set.

In view of the above, the present invention provides a method for fabricating an EVA chemical mechanical polishing pad to effectively overcome the above-mentioned various deficiencies of the prior art.

The main object of the present invention is to provide a method for producing an EVA chemical mechanical polishing pad, which uses a high density EVA (ethylene-vinyl acetate copolymer) foaming material as a base layer to reduce the generation of abrasive powder.

Another object of the present invention is to provide a method for fabricating an EVA chemical mechanical polishing pad, which can make the CMP process more stable by injecting a base layer of an EVA foamed material into a single mold.

Another object of the present invention is to provide a method for manufacturing an EVA chemical mechanical polishing pad, which uses a base layer of a double-layer EVA foam material to achieve an ideal removal rate effect and easily control the shape of the polishing pad.

Therefore, in order to achieve the above object, an EVA chemical mechanical polishing pad disclosed in the present invention comprises a first substrate layer and a first adhesive layer, wherein the first substrate layer is an EVA (ethylene-vinyl acetate copolymer) foaming material. The first adhesive layer is disposed below the first base layer.

In addition, the method for manufacturing an EVA chemical mechanical polishing pad disclosed in the present invention comprises the steps of: firstly blending ethylene and vinyl acetate according to a foaming ratio of 1.35:1, and uniformly stirring the first base layer raw material; Grinding the pad mold, heating the polishing pad mold to a temperature of 25 to 100 ° C; then, injecting and molding, the first base layer material is injected into the polishing pad mold, so that the first base layer material is 70 to 200 bar (Bar) Mixing under pressure cycle and generating polymerization at a temperature of 40-120 ° C; after curing, forming an EVA foam material Forming the first substrate layer; finally, forming the first adhesive layer below the first substrate layer, thereby preparing the EVA chemical mechanical polishing pad of the present invention.

Thereby, the EVA chemical mechanical polishing pad of the invention can avoid the situation that the polishing pad of the general low-density material is easy to wear the powder during the CMP process. Further, the present invention can make the polyethylene chain of the base layer more tight and stable in the process by single-die perfusion. In addition, the second substrate layer can be adhered to the bottom of the first substrate layer through the first adhesive layer to form a structure of the double-layer substrate layer, so that the desired removal rate effect is obtained, and the surface of the polishing pad is controlled. Shape variable.

In order to further understand the purpose, features and functions of the present invention, the drawings are described in detail as follows:

10‧‧‧First basal layer

20‧‧‧First adhesive layer

30‧‧‧Second basal layer

40‧‧‧Second Adhesive Layer

50‧‧‧ Grinding platform

1 is a cross-sectional view of an EVA chemical mechanical polishing pad disclosed in a first embodiment of the present invention.

2 is a flow chart showing a method of fabricating an EVA chemical mechanical polishing pad disclosed in a first embodiment of the present invention.

Figure 3 is a cross-sectional view showing an EVA chemical mechanical polishing pad disclosed in a second embodiment of the present invention.

Please refer to FIG. 1 , which is a cross-sectional view of an EVA chemical mechanical polishing pad 100 according to a first embodiment of the present invention.

The EVA chemical mechanical polishing pad 100 disclosed in the first embodiment of the present invention, the main If the first base layer 10 and the first adhesive layer 20 are formed, the material of the first base layer 10 is an EVA (ethylene-vinyl acetate copolymer) foam material, and the surface thereof has a plurality of pores of 30 to 50 micrometers, and The first adhesive layer 20 is disposed on the back surface of the first substrate layer 10. The material of the first adhesive layer 20 may be a pressure sensitive adhesive for adhering the polishing pad to the polishing platform 50 of the chemical mechanical polishing apparatus.

The EVA chemical mechanical polishing pad 100 of the first embodiment of the present invention can be produced by the steps of stirring, pouring, demoulding, aging, baking, CNC grinding thickness, appearance processing, and adhesive bonding. Here, please refer to FIG. 2 to describe the manufacturing process of the first embodiment in more detail. The steps include: first, as in step S100, the composition formula of the EVA foaming material, that is, the chemical raw materials ethylene and vinyl acetate According to the estimated foaming ratio of 1.35:1, the required amount is adjusted according to the procedure, and the first base layer raw material is uniformly stirred, that is, poured into the stirring tank tank of the filling machine.

Then, in step S110, a polishing pad mold is provided. When the filling machine is in operation, the polishing pad mold needs to be heated to a temperature of 25 to 100 ° C by a heating circulation system, and the time required is about 1 hour.

Then, in step S120, the first base layer material is directly injected into the polishing pad mold by injection molding. Then, the first base material is mixed and mixed by a pressure of 70 to 200 bar (Bar) through a perfusion machine for 1 hour, and the EVA foam material is placed in the polishing pad mold at a temperature range of 40 ° C to 120 ° C. The polymerization of the copolymer is carried out.

In step S130, after the action of high temperature and high pressure, the air of the polishing pad mold is discharged from the vent hole, and the EVA foam material is foamed and expanded, and after 1 hour, the polishing pad mold is opened, and then baked by hot baking, and The first base layer 10 composed of the EVA foamed material is obtained by grinding to a suitable thickness by CNC.

Finally, in step S140, the adhesive bonding is performed, that is, the pressure sensitive adhesive is applied to the back surface of the first substrate layer 10, and after curing, the first adhesive layer 20 is formed, thereby obtaining the EVA chemistry of the first embodiment. The mechanical polishing pad 100 is finished.

In the present invention, since the first base layer 10 is composed of an EVA foam material, the material property is good toughness and flexibility, and high wafer removal rate uniformity can be achieved, so that a general low-density material can be avoided. The basal layer is susceptible to abrasion of the powder during the CMP process. Furthermore, the first substrate layer 10 can be formed by single-die infusion to make the polyethylene chain tighter, and the single-mode infusion product has the smallest difference, which makes the process more stable.

In addition, the EVA chemical mechanical polishing pad of the present invention can be a structure having a double-layered hard substrate layer, and it is easier to control a slight change in the removal rate in comparison with a polishing pad of a generally low-density material. Please refer to FIG. 3, which is a cross-sectional view of an EVA chemical mechanical polishing pad 200 according to a second embodiment of the present invention.

The EVA chemical mechanical polishing pad 200 disclosed in the second embodiment of the present invention sequentially includes a first substrate layer 10, a first adhesive layer 20, a second substrate layer 30, and a second adhesive layer 40 from top to bottom; The first base layer 10 and the second base layer 30 may be formed by injecting EVA foam material through a single mold, and each of them is processed to a suitable thickness by CNC, and the two layers are further laminated. The first adhesive layer 20 and the second layer The adhesive layer 40 may be made of a pressure sensitive adhesive, and the materials may be adhered together by pressure, respectively, for bonding the second base layer 30 to the back surface of the first base layer 10, and fixing the polishing pad to the chemical mechanical polishing device. Grinding platform 50.

In the EVA chemical mechanical polishing pad 200 of the second embodiment of the present invention, the first base layer 10 has a thickness of about 2.2 cm, and a plurality of pores of 30 to 50 micrometers are distributed at the picking position, and the slurry is polished in the CMP process. Can be impregnated in the first substrate layer 10 to effectively remove the wafer table The thickness of the second substrate layer 30 is about 1.3 cm, which increases the compression space and toughness of the polishing pad to meet the specifications of the client CMP removal rate; and the thickness of the first adhesive layer 20 is about 0.095 cm, which can The first substrate layer 10 and the second substrate layer 30 are closely adhered to increase the deformation of the polishing pad, so that the surface of the first substrate layer 10 can be uniformly ground and used as a medium for grinding the pressure; as for the second substrate layer 30 The thickness is also about 0.095 cm.

In summary, the EVA chemical mechanical polishing pad disclosed in the present invention is different from the polishing pad generally based on a low-density material, and is composed of an EVA (ethylene-vinyl acetate copolymer) foaming material. The base layer is formed by an adhesive layer disposed on the back of the base layer. Since the base layer of the EVA foam material has good toughness and flexibility, high wafer removal rate uniformity can be achieved, thereby preventing chemical mechanical It is easy to wear the powder during the grinding process.

Furthermore, the EVA chemical mechanical polishing pad disclosed in the present invention is manufactured by a higher density process of single-die infusion molding, so that the polyethylene chain of the base layer is tighter, and the single-mode infusion product has the smallest difference. Can make the process more stable.

In addition, the present invention can also use a two-layer base layer to achieve the desired removal rate effect, and the thickness of the adhesive layer adhered by the double-layer base layer will be advantageous for controlling the deformation of the surface of the polishing pad.

Although the present invention has been disclosed above in the foregoing embodiments, it is not intended to limit the invention. It is within the scope of the invention to be modified and modified without departing from the spirit and scope of the invention. Please refer to the attached patent application for the scope of protection defined by the present invention.

10‧‧‧First basal layer

20‧‧‧First adhesive layer

50‧‧‧ Grinding platform

Claims (8)

The invention relates to a method for preparing an EVA chemical mechanical polishing pad, which comprises the steps of: blending ethylene and vinyl acetate according to a foaming ratio of 1.35:1, uniformly stirring to obtain a first base layer raw material; providing a polishing pad mold, Heating the polishing pad mold to a temperature of 25 to 100 ° C; injecting the first substrate material into the polishing pad mold by injection molding, so that the first substrate material is 70 to 200 bar (Bar) Mixing under pressure circulation and generating a polymerization reaction at a temperature of 40 to 120 ° C; after solidification molding, forming a first base layer composed of an EVA foamed material; and forming a first adhesive layer on the first base layer Underneath, the EVA chemical mechanical polishing pad is produced. The method of fabricating an EVA chemical mechanical polishing pad according to claim 1, wherein the first substrate material is stirred and poured into the polishing pad mold by a filling machine. The method for fabricating an EVA chemical mechanical polishing pad according to claim 1, further comprising the step of opening the polishing pad mold, taking out the first substrate layer, and performing hot baking and aging. The method for fabricating an EVA chemical mechanical polishing pad according to claim 1, further comprising the steps of: forming a second substrate layer and bonding the second substrate layer to the underside of the first substrate layer through the first adhesive layer, The second substrate layer is composed of an EVA foam material. The method for fabricating an EVA chemical mechanical polishing pad according to claim 4, further comprising the step of forming a second adhesive layer under the second substrate layer. The method for fabricating an EVA chemical mechanical polishing pad according to claim 5, wherein the material of the second adhesive layer is a pressure sensitive adhesive. The method for fabricating an EVA chemical mechanical polishing pad according to claim 1, wherein the material of the first adhesive layer is a pressure sensitive adhesive. The method for fabricating an EVA chemical mechanical polishing pad according to claim 1, wherein the surface of the first substrate layer has a plurality of pores of 30 to 50 μm.