KR100424667B1 - The grind equipment and method manufacture ceramic pad retaining ring of grind for wafer - Google Patents

Abstract

The present invention relates to a ceramic retainer ring pad of a polishing apparatus for making a flat surface on a semiconductor wafer.

More specifically, the kneading process of mixing the composite zirconia ceramic powder with water; Spheroidizing the composite zirconia ceramic powder in a chamber at 80 ° C. by a spray method; Molding the ceramic into a press mold in the shape of an abrasive member of a pad; A sintering step of gradually cooling the molded abrasive member after firing; The sintered retainer ring polishing member is subjected to a process of polishing, cleaning, and inspecting the product, and then formed into a ceramic polishing member of the pad and attached to the stainless ring bottom groove forming the retainer ring, thereby protecting the polishing pad on the surface plate while polishing the wafer. Since no dust is generated, it is possible to provide a polishing device to prevent scratches and improve gloss, thereby improving product quality.

Description

The grind equipment and method manufacture ceramic pad retaining ring of grind for wafer

The present invention relates to a ceramic retainer ring of a polishing apparatus for making a flat surface on a semiconductor wafer. More specifically, the retainer ring pad, which is rotated in reverse according to the surface and the surface of the lower surface plate, is formed of ceramic material, but the retainer ring pad is formed of ceramic pieces of several pieces and fixed in stainless steel ring grooves. The present invention relates to a ceramic retainer ring polishing window and a manufacturing method for polishing a wafer, which prevents sticking, prevents scratches during polishing, and at the same time generates gloss on the surface of the wafer to produce high quality wafers.

Conventional wafer polishing apparatuses have a retainer ring surrounding the outer circumference of the wafer, and a polishing apparatus for polishing a wafer by pressing the retainer ring together with the wafer to a polishing plate is disclosed. When the fine powder is generated, scratches are generated on the surface of the wafer, resulting in product defects, as well as damage to the surface of the surface of the surface of the surface of the surface of the wafer.

In addition, as another wafer polishing apparatus, an annular tube is provided between the retainer ring and the wafer holding head, and the pressing force of the retainer ring is adjusted by adjusting the internal air pressure of the tube and the pressing force using a diaphragm. A method of adjusting is disclosed.

Such a wafer polishing apparatus has a drawback that when air is supplied to a tube, the weak portion expands more, and as a result, the retainer ring cannot be uniformly pressed over its entire circumference. In this way, if the pressing force is nonuniform, the polishing pressure applied to the wafer is also nonuniform, so that the wafer cannot be uniformly polished.

In addition, the method of adjusting the pressing force of the retainer ring with a diaphragm has a problem that the necessary pressing force cannot be obtained because the displacement amount of the retainer ring cannot be largely taken.

The present invention has been invented in view of the above problems, and a kneading process of mixing the composite zirconia ceramic powder with water; Spheroidizing the composite zirconia ceramic powder in a chamber at 80 DEG C by a spray method; Molding the composite zirconia ceramic into a press die in the shape of a retainer ring polishing member; A ceramic polishing member of a retainer ring formed by a sintering process of gradually cooling the molded pad piece after firing; In the process of polishing, cleaning, and inspecting the sintered retainer ring ceramic polishing member, the ceramic pad made of the ceramic polishing member is molded and attached to the stainless metal ring groove to protect the fusion pad on the surface plate during polishing. Since dust is not generated, it is invented to improve the quality of the product by preventing scratches and giving a good gloss.

1 is a block diagram of a retainer ring pad manufacturing method according to the present invention.

2 is a block diagram of a wafer polishing apparatus according to the present invention.

Figure 3 is a main part extraction configuration of the retainer ring and the surface plate according to the present invention.

Figure 4 is an illustration of the operating state of the retainer ring and the surface plate according to the present invention.

Figure 5 is a partially separated perspective view of the ceramic polishing members according to the present invention are molded and fitted to the stainless support ring, respectively.

Figure 6 is an illustration of the coupled state of the retainer ring bolted to the bottom fixing flange of the support tube according to the present invention.

7 is a configuration diagram of a retainer ring pad in a state where the ceramic polishing member of the present invention is fitted to a stainless support ring.

Figure 8 is a cross-sectional configuration of the stainless support ring is fixed to the ceramic polishing member forming the pad of the present invention.

<Code Description of Main Parts of Drawing>

1: Enclosure 2: Table Drive

3: drive shaft 4: surface plate

5: Control box 6: Retainer ring drive

7: support tube 8: retainer ring

9: ceramic pad 9 ': ceramic abrasive

10: Wafer 11: Pressure plate

11 ': Pressure bar 12: Melting pad

14: stainless steel ring 14 ': groove

15: drainage

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Kneading process of mixing the composite zirconia ceramic powder provided by selecting a ceramic material with water;

Spheroidizing the composite zirconia ceramic mixed with water in a chamber at 80 ° C. by spray;

Putting the mixed kneaded composite zirconia ceramic into a press mold shaped like a retainer ring polishing member, and molding at a pressure of 1ton / cm 2 to 2ton / cm 2;

A sintering process which is calcined for about 6 to 16 hours at a temperature of 1200 ° C. to 2000 ° C. in the sintering furnace after the press molding step, and then gradually cooled;

In the process of polishing, cleaning, and inspecting the ceramic polishing member of the sintered retainer ring, the ceramic retaining ring pad for wafer polishing is manufactured.

Composite zirconia ceramics used in the above process are zirconia (ZrO ₂ ) 89.16 to 99.1%, yttrium (Y ₂ O ₃ ) 4.95 to 5.35%, titanium nitride (TiN) 3.5 to 4.5%, alumina (Al ₂ O ₃ ) 0.15 0.35, 0.2% of silicon oxide (SiO ₂ ), 0.01% of iron oxide (Fe ₂ O ₃ ), and 0.04% of sodium oxide (Na ₂ O).

Referring to the wafer polishing apparatus made of the method for manufacturing a wafer retainer ceramic retainer ring pad is as follows.

A platen 4 which is rotated by a drive shaft 3 connected to the drive unit 2 inside the enclosure 1;

A retainer ring driver (6) provided with a control box (5) on the upper surface of the surface plate (4);

A circular retainer ring (8) installed at the lower end of the support tube (7) connected to the drive unit (6) so as to be rotated forward and backward;

Ceramic pads (9) attached to the lower surface of the retainer ring (8) in pieces to prevent wear and dust;

A configuration of the wafer polishing window with a pressure plate 11 fixed to a lower end of the pressure rod 11 'inserted through the support tube 7 to support the wafer 10;

The retainer ring 8 is joined by a stainless metal ring 14 having a plurality of grooves 14 'and a ceramic pad 9, and the ceramic pad 9 is made of a plurality of ceramic polishing members 9'. The ceramic polishing member 9 'and the ceramic polishing member 9' of the ceramic pad 9 fitted into the groove 14 'of the metal ring 14 and bonded and fixed to the groove 14' of the stainless metal ring 14, respectively. ) Is a configuration in which a plurality of drain holes 15 are formed.

The present invention thus obtained is zirconia (ZrO ₂ ) 89.16 to 99.1%, iturium (Y ₂ O ₃ ) 4.95 to 5.35%, titanium nitride (TiN) 3.5 to 4.5%, alumina (Al ₂ O ₃ ) 0.15 to 0.35, Zirconia ceramic powder mixed with 0.2% silicon oxide (SiO ₂ ), 0.01% iron oxide (Fe ₂ O ₃ ), and 0.04% sodium oxide (Na ₂ O) was ball milled (put a ball into the powder. Composite zirconia ceramic powder 1: mixed with water 6 and spherical ceramic powder obtained by spray drying at 80 ° C. in the shape of an abrasive member of a retainer ring pad. It is filled in a press die and compressed to a press pressure of 1ton / cm 2 to 2ton / cm 2.

The compressed retaining member of the retainer ring pad is calcined at 1,750 ° C. for 2 hours at 1,950 ° C. for 4 hours, and then subjected to a sintering process of gradually cooling.

In order to have strength, the ceramic polishing member compressed in the press is sintered in a sintering furnace, and then sintered at a temperature of 1,750 ° C. for 2 hours at 1,950 ° C. for 4 hours and then gradually cooled.

As can be seen from Table 1, the ceramic abrasive member of the retainer ring pad during the sintering in the sintering furnace gradually rises in temperature for the first 4 hours to form a annealed state for 2 hours at 1750 ° C, and then gradually rises for 2 hours at 1950 ° C. Hold the steel for about 4 hours and slowly cool it down.

At this time, the ceramic polishing member of the retainer ring pad is integrally formed from one side to the other side, and the strength of the inner surface and the strength of the outer surface are uniform.

Zirconia sintering used in the present invention is usually made at more than 1200 ℃ to change the firing temperature from 1,250 ℃ to 1,400 ℃ to investigate the characteristic changes such as density and shrinkage to derive the optimum manufacturing process conditions.

In addition, Table 2 below is a measurement of the outer diameter shrinkage according to the firing temperature and the molding pressure, Table 3 is the inner diameter shrinkage according to the firing temperature and the molding pressure, Table 4 is the thickness shrinkage according to the firing temperature and the molding pressure, Table 5 Shows the density characteristics according to the sintering temperature and uniaxial molding pressure, and Table 6 shows the density characteristics according to the sintering temperature and hydrostatic pressure (CIP).

As can be seen from the above table, as the sintering temperature was increased, the sintering density of the zirconia retainer ring ceramic abrasive member was increased, the firing temperature was 1,250-1,300 ° C, and the density was 5.92∼6.12 g / cm3.

The molding pressure greatly affected the shrinkage rate at low temperatures, and the firing temperature was an important factor at 1,250 ° C.

Referring to Tables 5 and 6, the difference between uniaxial molding and hydrostatic pressure molding was influenced only by the pressure in the low temperature sintering region of 1,250 ° C. In hydrostatic molding, the density was 5.91 to 6.07 g / cm 3, and the variation was smaller than that in uniaxial molding.

Although not used as various ceramic materials and retainer rings used in the present invention as described above, the physical and chemical properties of stainless materials are shown in Table 7 below.

As shown in Table 7, the ceramic retainer ring polishing member of the present invention is somewhat different in characteristics such as density, hardness, bending strength, Young's modulus, specific heat, thermal expansion rate, thermal shock, thermal conductivity, safety, corrosion resistance, use, etc. However, it can be seen that it has a superior effect compared to the existing stainless steel and plastic materials.

Briefly summarized the manufacturing process of the ceramic retainer ring pad of the present invention made as described above, the selected composite zirconia ceramics (Seramics) powder is prepared from raw material → raw material and water mixing → spheroidization → primary molding → sintering → polishing → inspection → The retainer ring polishing member is molded by the process of packaging the finished product.

The retainer ring ceramic abrasive member formed as described above is used in a plurality of retainer ring 8 ceramic pads 9 rotating in the same direction or in the opposite direction as the rotation of the surface plate 4 on the surface plate 4 of the polishing apparatus. The retainer ring 8 is formed of a retainer ring ceramic pad 9 by inserting and fixing the ceramic polishing member 9 'to the grooves 14' formed in the stainless metal ring 14, respectively. .

That is, in order to polish the wafer 10, the wafer 10 semi-finished on the surface plate 4, which is connected to the driving unit 2 inside the housing 1 corresponding to the retainer ring 8 and rotated by the drive shaft 3, is processed. ) And place it on the bottom of the retainer ring (8).

The wafer 10 placed on the surface plate lowers the upper cylinder of the pressure rod 11 ′ supporting the retainer ring 8 so that the wafer is positioned inside the retainer ring 8 and the silicon pad 9 at the bottom of the retainer ring 8 is placed. ) Is in close contact with the surface of the surface.

After the platen 4 and the retainer ring 8 correspond to each other as described above, the power supply is turned on by turning on the switch of the drive unit 2 and the upper retainer ring 8 drive unit 2 provided on one side of the housing 1. When applied, the platen 4 rotates to one side and the support tube 7 rotated by the drive unit 6 rotates the retainer ring 8 in the reverse direction, so that the wafer 10 located inside the retainer ring 8 is applied. Is polished by the surface plate 4.

The ceramic pad 9 attached to the bottom surface of the retainer ring 8 protects the molten pad 12 that is laid on the surface plate 4 when polishing the wafer 10, and does not cause scratches during polishing. Will not occur.

The life time of the retainer ring ceramic pad of the present invention is that it can be used for a long time without having to replace it as before, even after using 90 to 100 hours or more, and has a feature of reusing the ceramic pad.

The retainer ring 8 of the polishing apparatus as described above is made of a stainless metal ring 14 having a plurality of grooves 14 'and a ceramic pad 9.

The ceramic pad 9 is made of a ceramic polishing member 9 'formed of a plurality of pieces and fitted into the groove 14' of the stainless metal ring 14 to be adhesively fixed.

The fixing of the ceramic polishing member 9 'fitted into the groove 14' of the stainless ring 14 is made of an adhesive, and the adhesion is not particularly limited.

A plurality of drain holes 15 are formed between the ceramic polishing member 9 'and the ceramic polishing member 9' of the ceramic pad 9 fitted in the groove 14 'of the stainless metal ring 14.

The drain hole 15 of the ceramic pad 9 is for discharging the abrasive or the polishing liquid for polishing the wafer, and the drain hole 15 is formed in the shape of a saw to discharge the vortex.

In addition, as another embodiment of the present invention, the drain hole 15 of the ceramic pad 9 may be radially discharged to discharge the polishing liquid.

A plurality of discharge holes formed in the ceramic pad is not limited to a particular shape, but if the discharge hole is to discharge the liquid liquor will be within the scope of the present invention.

A plurality of bolt holes are formed on the stainless steel ring 14 of the retainer ring 8 to fix the bolt to the lower flange of the support tube.

In the present invention, when manufacturing the pad of the retainer ring, all the pads of the ring type are formed by the respective polishing portions without forming the ceramic material, and are attached to the stainless ring to form the pad so that the manufacturing process is simple and the material can be cut. It is.

According to the present invention, a ceramic pad made of a composite zirconia ceramic polishing member is attached to the bottom of the retainer ring to serve as a guide ring for the wafer when polishing the wafer, thereby preventing breakage of the melt pad on the surface plate, and at the same time, dust caused by wear. Since there is no occurrence of scratches during wafer polishing, the effect of gloss can be increased and the pads can be combined into several pieces, thereby reducing the cost.

Claims (7)

Kneading process by mixing the ceramic powder provided by selecting a ceramic material with water; Spheroidizing the composite silicon nitride ceramic mixed with water in a chamber at 80 ° C. by spray; Inserting the mixed kneaded ceramic into a ceramic abrasive-shaped press mold of a retainer ring pad and molding at a pressure of 1ton / cm 2 to 2ton / cm 2; A sintering process which is calcined for about 6 to 16 hours at a temperature of 1200 ° C. to 2000 ° C. in the sintering furnace after the press molding step, and then gradually cooled; A method of manufacturing a retainer ring ceramic pad for polishing a wafer, comprising the steps of polishing, washing and inspecting the sintered ceramic abrasive. The method of claim 1, The composite zirconia ceramics are zirconia (ZrO ₂ ) 89.16 to 99.1%, yttrium (Y ₂ O ₃ ) 4.95 to 5.35%, titanium nitride (TiN) 3.5 to 4.5%, alumina (Al ₂ O ₃ ) 0.15 to 0.35, oxidation Wafer polishing, characterized in that to form a composite zirconia ceramic retainer pad mixed with a composition of silicon (SiO ₂ ) 0.2%, iron oxide (Fe ₂ O ₃ ) 0.01%, sodium oxide (Na ₂ O) 0.04% Method for manufacturing retainer ring ceramic pads. A platen 4 which is rotated by a drive shaft 3 connected to the drive unit 2 inside the enclosure 1; A retainer ring driver (6) provided with a control box (5) on the upper surface of the surface plate (4); A circular retainer ring (8) installed at the lower end of the support tube (7) connected to the drive unit (6) so as to be rotated forward and backward; A ceramic pad 9 attached to the bottom of the stainless metal ring 14 forming the retainer ring 8 to prevent abrasion and dust; Wafer polishing device, characterized in that the wafer polishing window is composed of a pressure plate (11) fixed to the bottom of the pressure rod (11 ') so as to penetrate into the support tube (7) to support the wafer (10). The method of claim 3, The retainer ring 8 is joined by a stainless metal ring 14 having a plurality of grooves 14 'and a ceramic pad 9, and the ceramic pad 9 is made of a plurality of ceramic polishing members 9'. A polishing apparatus for a wafer polishing, characterized in that it is fitted into a groove (14 ') of the metal ring (14) to be adhesively fixed. The method of claim 3, The retainer ring 8 has a plurality of ceramic polishing members 9 'constituting the ceramic pad 9 and the ceramic polishing member 9' formed with drain holes 15 in the shape of a tuft so that the polishing liquid is vortex discharged. Wafer polishing polishing apparatus, characterized in that. The method of claim 3, And a plurality of discharge holes (15) formed between the ceramic polishing member (9 ') and the ceramic polishing member (9') forming the ceramic pad (9 ') radially. The method of claim 3, The ceramic pad (9) of the retainer ring (8) is a wafer polishing polishing device, characterized in that consisting of a plurality of pieces.