KR20210099808A - Wafer polishing pad, apparatus and manufacturing method thereof - Google Patents

Abstract

An object of the present invention is to provide a polishing pad for a wafer polishing apparatus, capable of improving the flatness quality of a wafer by preventing glazing occurring in a wafer polishing process, an apparatus for manufacturing the same, and a method for manufacturing the same. The present invention provides a polishing pad manufacturing method comprising a step of manufacturing a non-woven pad, a polyurethane impregnation step for impregnating the non-woven pad with polyurethane, and a surface polishing step for polishing the surface of the non-woven pad impregnated with polyurethane, wherein the polyurethane impregnation step and the surface polishing step are configured to obtain a uniform density ratio between the surface layer and the inside of a polishing pad.

Description

BACKGROUND ART A polishing pad for a wafer polishing apparatus, an apparatus for manufacturing the same, and a manufacturing method thereof

The present invention relates to a wafer polishing apparatus, and more particularly, to a polishing pad used in the wafer polishing apparatus.

A single crystal silicon ingot is generally grown and manufactured according to the Czochralski method. In this method, polycrystalline silicon is melted in a crucible in a chamber, a single-crystal seed crystal is immersed in the molten silicon, and the single-crystal silicon ingot (hereinafter, ingot) of a desired diameter is grown while gradually rising.

The manufacturing process of a single crystal silicon wafer (Single Silicon Wafer) includes a single crystal growing process for making an ingot using the above-described method, a slicing process for obtaining a thin disk-shaped wafer by slicing the ingot, and , an edge polishing process that processes the outer periphery to prevent cracking and distortion of the wafer obtained by the slicing process, and improves the flatness of the wafer by removing damage caused by mechanical processing remaining on the wafer It consists of a lapping process to make the wafer mirror-finished, a polishing process to mirror-finish the wafer, and a cleaning process to remove abrasives or foreign substances attached to the polished wafer.

Among them, in the wafer polishing process, both sides of the wafer can be simultaneously polished by using a double-side polishing apparatus (DSP, Double Side Polishing Apparatus).

1 is a perspective view of a general wafer polishing apparatus, and FIG. 2 is a plan view of the polishing pad of FIG. 1 .

As shown in FIG. 1 , a typical wafer polishing apparatus 100 includes an upper surface plate 110 , a lower surface plate 120 , an upper pad (or an upper polishing pad) 130 , and a lower pad (or lower surface). polishing pad) 140 , a carrier 150 , a sun gear 160 , an internal gear 170 and a central shaft 180 .

The upper plate 110 and the lower plate 120 face each other and are rotatably disposed.

The upper pad 130 is disposed under the upper plate 110 , and the lower pad 140 is disposed above the lower plate 120 . The wafer W is polished while the upper and lower pads 130 and 140 face each other inside the upper plate 110 and the lower plate 120 .

Each of the upper plate 110 and the lower plate 120 may have a disc shape, and the upper and lower pads 130 and 140 attached to the upper plate 110 and the lower plate 120, respectively, may also have a disc shape. there is.

The sun gear 160 is installed on the outer periphery of the central shaft 180 , and the internal gear 170 is installed on the outer periphery of the lower plate 120 . The internal gear 170 may rotate in a direction opposite to that of the sun gear 160 .

The carrier 150 is disposed between the upper pad 130 and the lower pad 140 , and may be rotated by rotation of the sun gear 160 and the internal gear 170 . In addition, the carrier 150 has an insertion hole into which the wafer W can be inserted and a slurry hole into which the slurry can be introduced. The carrier 150 may have a disk shape in which a screw is formed on an outer circumferential surface.

The gear portion formed on the outer peripheral surface of the sun gear 160 and the gear portion formed on the inner surface of the internal gear 170 mesh with the gear 152 formed on the outer peripheral surface of the carrier 150 . Accordingly, as the upper plate 110 and the lower plate 120 rotate about the driving shaft 180 by a driving source (not shown), the carrier 150 rotates and revolves.

Although not shown, a plurality of slurry supply holes 190 through which nozzles for supplying the slurry are installed may be formed in the upper portion of the upper plate 110 .

In the general wafer polishing apparatus 100 having the above configuration, when the wafer W is inserted and seated in the insertion hole of the carrier 150 installed between the upper platen 110 and the lower platen 120, the wafer (W) is rubbed against the upper and lower pads 130 and 140 respectively attached to the upper plate 110 and the lower plate 120 . At this time, both surfaces of the plurality of wafers W mounted on the carrier 140 are friction-polished in a batch form by the slurry and polishing pads 130 and 140 supplied from the top of the upper plate 110 to the inside. . That is, the wafer W is rubbed and polished as the upper pad 130 of the upper plate 110 and the lower pad 140 of the lower plate 120 rotate in opposite directions.

However, the polishing pads 130 and 140 cause glazing in which the porous surfaces of the polishing pads 130 and 140 are changed due to frequent friction with the wafer W and the surface layers are clogged by the slurry or polishing by-products. Such glazing lowers the friction coefficient of the polishing pads 130 and 140, thereby deteriorating the polishing quality of the wafer.

Accordingly, an object of the present invention is to provide a polishing pad for a wafer polishing apparatus capable of improving flatness quality of a wafer by preventing glazing occurring in a wafer polishing process, an apparatus for manufacturing the same, and a method for manufacturing the same.

The present invention comprises the steps of preparing a non-woven pad; a polyurethane impregnation step of impregnating the nonwoven pad with polyurethane; and a surface polishing step of polishing the surface of the nonwoven pad impregnated with polyurethane, wherein the polyurethane impregnating step and the surface polishing step include a polishing pad having a uniform density ratio between the surface layer and the inside of the polishing pad provide a way

The polyurethane impregnation step is a pretreatment step of pretreatment of the nonwoven pad; a primary drying step of drying the moisture of the nonwoven pad; an impregnation step of immersing the nonwoven pad in polyurethane; a secondary drying step of drying the polyurethane impregnated in the nonwoven pad; And it may include a compression process of compressing the polyurethane-impregnated nonwoven pad.

The impregnation step may be performed at least two times of polyurethane impregnation process.

The impregnation step is a first impregnation process of impregnating the hydrophilic polyurethane; And it may include a secondary impregnation process of impregnating the hydrophobic polyurethane.

In the surface polishing step, a buffing process is performed so that the density ratio of the polyurethane-containing porous layer and the non-containing porous layer in the surface layer of the polishing pad is 1:1.

The thickness of the nonwoven pad may be 4 mm to 6 mm, and the thickness of the nonwoven pad removed during the buffing may be 2.5 mm to 3.5 mm.

The overall density of the polishing pad may be ^{0.44 to 0.55 g/cm 3 .}

On the other hand, the present invention is a non-woven pad manufacturing unit for manufacturing a non-woven pad; a polyurethane impregnated portion impregnating the nonwoven pad with polyurethane; and a surface polishing unit for polishing the surface of the polyurethane-impregnated nonwoven pad, wherein the polyurethane-impregnated unit includes: a primary polyurethane tank accommodating a hydrophilic polyurethane; and a secondary polyurethane water bath impregnated with hydrophobic polyurethane.

The buffing process may be performed so that the density ratio of the porous layer containing the polyurethane and the porous layer not containing the polyurethane in the surface layer of the polishing pad is 1:1.

The thickness of the nonwoven pad may be 4 mm to 6 mm, and the thickness of the nonwoven pad removed during the buffing may be 2.5 mm to 3.5 mm.

The present invention provides a polishing pad for a wafer polishing apparatus manufactured by any one of the manufacturing methods or manufacturing apparatuses described above.

According to the polishing pad for a wafer polishing apparatus of the present invention, the manufacturing apparatus and the manufacturing method thereof, glazing occurring in the polishing process of the wafer is prevented by equalizing the density of polyurethane impregnated in the surface layer of the polishing pad, thereby improving the flatness quality of the wafer. can be improved

In addition, the polishing pad of the present invention maintains a high roughness of the pad surface layer, thereby suppressing a decrease in the removal rate due to an increase in the use time of the conventional pad, thereby increasing the lifespan.

1 is a perspective view of a general wafer polishing apparatus.
2 is a schematic configuration diagram of an apparatus for manufacturing a wafer polishing pad according to an embodiment of the present invention.
3 is a flowchart illustrating a method of manufacturing a wafer polishing pad according to an embodiment of the present invention.
4 and 5 are process diagrams illustrating a process of manufacturing a polishing pad according to the manufacturing method of FIG. 3 .
6 is a cross-sectional view of a polishing pad containing polyurethane (a) before buffing (b) and after buffing.
7 is a graph showing the density state according to the thickness of the polishing pad of one embodiment of the present invention and the polishing pad of a comparative example.
FIG. 8 is a front view CT taken showing the tomographic state of the polishing pads of FIG. 7 at a thickness of 100 μm.

Hereinafter, the embodiments will be clearly revealed through the accompanying drawings and the description of the embodiments. In the description of an embodiment, each layer (film), region, pattern or structure is “on” or “under” the substrate, each layer (film), region, pad or pattern. In the case of being described as being formed on, "on" and "under" include both "directly" or "indirectly" formed through another layer. do. In addition, the criteria for the upper / upper or lower / lower of each layer will be described with reference to the drawings.

In the drawings, sizes are exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not fully reflect the actual size. Also, like reference numerals denote like elements throughout the description of the drawings. Hereinafter, an embodiment will be described with reference to the accompanying drawings.

2 is a schematic configuration diagram of an apparatus for manufacturing a wafer polishing pad according to an embodiment of the present invention, FIG. 3 is a flowchart of a method for manufacturing a wafer polishing pad according to an embodiment of the present invention, and FIGS. 4 and FIG. 5 is a process diagram showing a process of manufacturing a polishing pad according to the manufacturing method of FIG. 3 , and FIG. 6 is a cross-sectional view of a polishing pad containing polyurethane (a) before (b) buffing, and after (b) buffing.

As shown in FIG. 2 , the apparatus for manufacturing a wafer polishing pad according to an embodiment of the present invention includes a nonwoven pad manufacturing unit 1 , a polyurethane impregnated unit 2 , a surface polishing unit 3 , and a tape attachment and cut unit. (4) may be included.

Here, each of the units 1, 2, 3, and 4 may be a combination of a series of devices, and each of the units 1, 2, 3, and 4 may constitute a connected manufacturing route.

The nonwoven pad manufacturing unit 1 includes a series of apparatuses for manufacturing nonwoven pads, which are the main materials used for polishing pads. For example, as shown in FIG. 4 , the nonwoven pad manufacturing unit 1 includes a supply unit 10 for supplying a bundle of fibers (C), a pressing unit 20 for pressing the bundle of fibers (C), and a needle. It may include a pressing unit 30 and a punching unit 40 for performing a punching process.

The polyurethane impregnated portion 2 includes a series of devices for impregnating and coating the nonwoven pad with polyurethane. For example, the polyurethane impregnated part 2 is, as shown in FIG. 4, a pretreatment water tank 50, a primary drying unit 60, a primary polyurethane water tank 70, a secondary polyurethane water tank ( 80), the secondary drying unit 100 and the compression roller 110 may be included.

The surface abrasive part 3 includes a series of devices for removing the surface layer part of the polyurethane-impregnated nonwoven pad. For example, the surface abrasive part 3 may include sandpaper 120 for buffing processing, as shown in FIG. 5 .

The tape attaching and cutting unit 4 includes a series of devices for attaching the double-sided tape T to one surface of the polishing pad subjected to the buffing process and cutting the tape in the form of a circular pad.

For example, the tape attachment and cut part 4 is, as shown in FIG. 5 , a cutter part 130 , a tape attachment part 140 , a compression part 150 , a shape cutting part 160 , and a packaging inspection part ( 170) may be included.

Hereinafter, a polishing pad using the apparatus for manufacturing a wafer polishing pad according to an embodiment of the present invention including the above-described configuration and a method for manufacturing the same will be described in detail.

As shown in Figure 3, the polishing pad for a wafer polishing apparatus of an embodiment of the present invention (hereinafter, polishing pad) is a non-woven pad manufacturing step (S100), polyurethane impregnation step (S200), surface polishing step (S300) and It may be manufactured by a method of manufacturing a polishing pad including the step of attaching and cutting the tape ( S400 ) and the step of mounting the polishing pad ( S500 ).

1) Non-woven Pad Manufacturing Step (Non-woven Fabric Manufacturing, S100)

The polishing pad of this embodiment starts to be made in the form of a pad while performing the nonwoven fabric manufacturing step. Non-Woven Fabric refers to a non-woven pad using a loom. It is also called bonded fabric as it is made to form a fabric directly by binding fibers. Here, as the fiber, a material such as polyester, viscose rayon, nylon, polypropylene, cotton, hemp, wool, asbestos, glass fiber, or acetate may be selected.

The nonwoven fabric is classified into two types: a dry-laid non-woven fabric manufacturing method that does not use water, and a wet-laid non-woven fabric manufacturing method that uses water according to a manufacturing method. In the nonwoven pad manufacturing step (S100) of this embodiment, a dry nonwoven fabric manufacturing method may be used.

In more detail, the nonwoven pad manufacturing step (S100) is, as shown in (1) of FIG. 4, i) the supply unit 10 supplies a bundle of fibers (C) to the compression unit 20, ii) the pressing unit 20 presses the supplied fiber (C) to make a web (W, web, a thinly spread fiber), iii) the bonding unit 30 and the punching unit 40 are the web (W) By punching (Punching) the fiber of the state with a needle (needle) to prepare a non-woven pad (F). The manufactured nonwoven pad (F) is subjected to a polyurethane impregnation step (S200) in order to have physical properties that the polishing pad (Pad) should have.

2) polyurethane impregnating step (polyurethane impregnating, S200)

The polyurethane impregnation step (S200) includes the process of impregnating the nonwoven fabric pad (F) produced in the step (S100) in 1) in the polyurethane water bath 70 for a predetermined time. The nonwoven pad F has a plurality of pores, that is, a porous layer, not only on the surface but also on the inside. Polyurethane (PU) may provide necessary physical properties to the polishing pad (Pad) while penetrating into the porous layer of the nonwoven pad (F).

Polyurethane (PU) is a compound produced by the combination of a polyol and an isocine salt. That is, it is a polymer compound in which a urethane bond is repeatedly contained in a polymer chain, and epoxy, polyester, phenol, and the like correspond to this compound.

Polyurethane impregnation step (S200), as shown in (2) of Figure 4, i) pretreatment (pretreatment), ii) primary drying (1st drying), iii) impregnating (impregnating), iv) secondary drying (2nd drying), v) may include a pressing process.

The pretreatment and drying process are steps performed before the polyurethane (PU) impregnation, so that the polyurethane (PU) impregnation process is performed smoothly. The pretreatment process may include a process of immersing the nonwoven pad F in the pretreatment water tank 50 containing a cleaning solution or a chemical. 1) The nonwoven pad (F) manufactured in step (S100) may be moved into the pretreatment tank 50 by rollers (R). The nonwoven pad (F) that has undergone the pretreatment process may be moved to the primary drying process by the roller (R).

The primary drying process may be a process of drying the moisture of the nonwoven pad (F) dipped by a cleaning solution or a chemical. For example, the primary drying process may be performed through the primary drying unit 60 capable of evaporating a cleaning solution or a chemical using a heater, a fan, or the like.

The impregnation process is a process of immersing the nonwoven pad (F) in the polyurethane water tank 70 containing the polyurethane (PU). Polyurethane (PU) is manufactured by mixing two or more liquids, and its properties depend on the type of isocine salt and polyol, which are reactants. The long bonds contained in the polyol make it a soft elastomer, and the enormous amount of linkage helps it become a hard polymer. Maintaining an intermediate length between the two bonds allows for very flexible and moderate rigidity. That is, by adjusting the ratio of the soft segment and the hard segment, which are constituent materials, when manufacturing polyurethane (PU), elasticity and ductility can be adjusted according to use. The higher the soft segment ratio, the lower the hardness and elasticity.

If the conditions of the polyurethane (PU) impregnation process are controlled, the mass, volume, thickness, etc. of the polyurethane (PU) contained in the nonwoven pad (F) may be changed. Here, the conditions may be the impregnation time, the concentration of the polyurethane (PU), the number of impregnations, the moving speed of the nonwoven pad (F), and the like.

In this embodiment, the glazing can be improved through the improvement of air permeability by equalizing the density of the polyurethane (PU) on the surface and the inside of the polishing pad (Pad). To this end, in the polyurethane impregnation process, at least one of the following homogenization conditions may be included.

First, in the polyurethane impregnation process, the nonwoven pad (F) containing polyurethane (PU) primarily may be immersed in the secondary polyurethane water tank (80). That is, the polyurethane impregnation process may be performed at least twice. In addition, the nonwoven pad (F) containing the polyurethane (PU) may be further immersed in the tertiary polyurethane water bath 90 or the cleaning bath 90 for additional polyurethane impregnation or cleaning, if necessary.

Here, both the polyurethane of the primary polyurethane tank 70 and the secondary polyurethane tank 80 may have hydrophobic properties. That is, it may have properties that are not compatible with water.

In addition, the primary polyurethane tank 70 may be filled with water-friendly hydrophilic polyurethane, and the secondary polyurethane tank 80 may be filled with hydrophobic polyurethane. Here, when the primary polyurethane tank 70 has hydrophilicity, the polyurethane can be impregnated while moving more smoothly compared to the hydrophobicity from the surface to the inside of the nonwoven pad F when the polyurethane is impregnated.

Second, the thickness of the nonwoven pad used for polyurethane impregnation can be made thick. For example, the polyurethane impregnation step (S200) may be performed by applying the nonwoven fabric pad having a thickness of 5 mm prepared in the nonwoven fabric manufacturing step (S100) described above (the conventional nonwoven pad has a thickness of 2.3 mm). In this case, in the surface polishing step ( S300 ) to be described later, the buffing thickness may be further increased to 2.7 mm or more compared to the prior art.

That is, in the embodiment, the thickness of the nonwoven pad may be 4 mm to 6 mm, and the thickness of the nonwoven pad removed during buffing may be 2.5 mm to 3.5 mm.

After that, a secondary drying process may be performed. For example, the secondary drying process may be performed through the secondary drying unit 100 capable of drying the polyurethane (PU) with a heater, a fan, or the like.

Then, the nonwoven pad (UF) containing the polyurethane (PU) is passed through the compression roller 110 to perform a compression process so that the polyurethane (PU) is deeply contained to the inside of the nonwoven pad (UF).

3) Surface Finishing (S300)

After the polyurethane impregnation step (S200) described above, the nonwoven pad (UF) is subjected to a surface polishing step (S300). In the surface polishing step (S300), sanding or buffing is performed using sand paper to remove foreign substances from the surface and the bottom of the nonwoven pad UF. In addition, through the surface polishing step ( S300 ), the thickness of the polishing pad and the porosity ratio of the surface may be adjusted.

As shown in (a) of FIG. 6, the polyurethane (PU) impregnation density in the polishing pad (Pad) is high in the surface layer portion (High), and decreases toward the inside (Low). Therefore, due to the high density of polyurethane (PU) on the surface of the polishing pad, the slurry flowing into the surface of the polishing pad does not move to the inside during wafer polishing, so that the glazing occurs in the form of being adhered to the surface.

In order to improve this problem, in the surface polishing step (S300), as shown in FIGS. It can be removed to further expose the pores (P) inside the surface layer. Accordingly, the polishing pad can increase the ratio of the polyurethane (PU) impregnated portion and the non-impregnated inner portion in the surface layer portion so that the slurry does not adhere to the surface while moving to the inside of the polishing pad (pad). can do.

In addition, the overall density of the ^{polishing pad may be 0.44 to 0.55 g/cm 3} , the compressibility of the polishing pad may be 1.9 to 2.0%, and the hardness of the polishing pad may be 88 Asker C. That is, even if the density of polyurethane (PU) impregnation with respect to the surface layer portion of the polishing pad is adjusted, the basic physical properties required for the polishing pad may be observed.

4) Tape pasting and cutting (S400)

The tape attachment and cutting step ( S400 ) is a step in which a double-sided tape (T) is attached to one surface of a polishing pad (UF) impregnated with polyurethane (PU) and cut in the form of a circular pad.

In more detail, the tape attachment and cutting step (S400) is, as shown in FIG. and ii) the tape attachment part 140 attaches the double-sided tape T to one surface of the polishing pad US (PSA prepasting), iii) the pressing part 150 is a double-sided tape (T) and (PAS pasting, Press), iv) the shape cutting unit 160 cuts the polishing pad UF, on which the double-sided tape T is pressed, into a predetermined shape (eg, a circle of the size of a surface plate), v ) The packaging inspection unit 170 inspects the product and packs it with packaging paper (Inspection, Shipping).

5) Mounting of the Polishing Pad (S500)

In the fourth step (S400), the packaged polishing pad UF is subjected to a wafer polishing process together with the slurry after one side of the double-sided tape T is attached to the surface of the wafer polishing apparatus.

7 is a graph showing the density according to the thickness of the polishing pad of one embodiment of the present invention and the polishing pad of a comparative example.

As shown in FIG. 7 , the polishing pad of the embodiment was manufactured with a uniform polyurethane impregnation ratio using the above-described manufacturing apparatus and manufacturing method, and regardless of the thickness (from the front part to the bottom part) of the polishing pad, the average It can be seen that the density value is shown. On the other hand, the polishing pad of the comparative example has a higher density in the surface layer forming the front part and the bottom part.

As such, in the conventional (comparative example) polishing pad, due to the high density of the surface, the slurry flowing into the pad surface during the polishing process does not move to the inside of the pad, thereby causing glazing in the form of adhering to the pad surface.

In the polishing pad of the present invention, the density of the surface and the inside of the pad is uniform, and the flow of the slurry to the inside of the polishing pad can be improved.

FIG. 8 is a front view CT taken showing the tomographic state of the polishing pads of FIG. 7 at a thickness of 100 μm.

In general, it was observed that the glazing generated on the polishing pad in Comparative Example was formed to a depth of 300 μm from the surface of the polishing pad to the inside. That is, the layer thickness of the glazing can be formed up to 300 μm below the front surface of the polishing pad.

As shown in FIG. 8 , as can be seen from the results of photographing the 100 μm-thick layer of the present example and the comparative example, it can be seen that the glazing area (white spot, glazing area) is more in the case of the comparative example.

As described above, the polishing pad of this embodiment makes the density of the pad surface and the inside uniform, so that the slurry flows smoothly into the pad interior, so that the glazing area can be controlled to 100 μm from the pad surface layer.

However, according to the polishing pad for a wafer polishing apparatus of the present invention and a manufacturing method thereof, glazing occurring in the polishing process of the wafer can be prevented by equalizing the density of the polyurethane exposed on the polishing pad surface, thereby improving the flatness quality of the wafer. there is.

In addition, the polishing pad of the present invention maintains a high roughness of the pad surface layer, thereby suppressing a decrease in the removal rate due to an increase in the use time of the conventional pad. That is, the life of the polishing pad can be extended.

Features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by a person skilled in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

10: supply unit 20: crimping unit
30: adhesive part 40: punching part
50: pretreatment water tank 60: primary drying unit
70: primary polyurethane tank 80: secondary polyurethane tank
100: drying unit 110: pressing roller
130: cutter part 140: tape attachment part
150: crimping unit 160: shape cutting unit
170: packaging inspection department
S100: Non-woven pad manufacturing step S200: Polyurethane impregnation step
S300: surface polishing step S400: tape attaching and cutting step
S500 : Polishing Pad Mounting Step

Claims (11)

manufacturing a non-woven pad;
a polyurethane impregnation step of impregnating the nonwoven pad with polyurethane; and
Including; surface polishing step of polishing the surface of the nonwoven pad impregnated with polyurethane;
The polyurethane impregnation step and the surface polishing step,
A method of manufacturing a polishing pad for a wafer polishing apparatus, wherein the density ratio between the surface layer and the inside of the polishing pad becomes uniform. According to claim 1,
The polyurethane impregnation step
a pretreatment step of pretreating the nonwoven pad;
a primary drying step of drying the moisture of the nonwoven pad;
an impregnation step of immersing the nonwoven pad in polyurethane;
a secondary drying step of drying the polyurethane impregnated in the nonwoven pad; and
A method of manufacturing a polishing pad for a wafer polishing apparatus comprising a compression step of compressing the polyurethane-impregnated nonwoven pad. 3. The method of claim 2,
The impregnation step is a method of manufacturing a polishing pad for a wafer polishing apparatus to perform at least two times of polyurethane impregnation process. 4. The method of claim 3,
The impregnation step
The first impregnation process of impregnating the hydrophilic polyurethane; and
A method of manufacturing a polishing pad for a wafer polishing apparatus comprising a secondary impregnation process of impregnating the hydrophobic polyurethane. 5. The method of claim 4,
A method of manufacturing a polishing pad for a wafer polishing apparatus in which a density ratio of the porous layer containing the polyurethane and the porous layer not containing the polyurethane in the surface layer of the polishing pad is buffed to be 1:1. 6. The method of claim 5,
The thickness of the nonwoven pad is 4 mm to 6 mm,
A method of manufacturing a polishing pad for a wafer polishing apparatus, wherein the thickness of the nonwoven pad removed during the buffing is 2.5 mm to 3.5 mm. 7. The method of claim 6,
The total density of the polishing pad is 0.44 to 0.55 g/cm ^{3 A} method of manufacturing a polishing pad for a wafer polishing apparatus. a non-woven pad manufacturing unit for manufacturing a non-woven pad;
a polyurethane impregnated portion impregnating the nonwoven pad with polyurethane; and
Including; a surface polishing unit for polishing the surface of the nonwoven pad impregnated with polyurethane;
The polyurethane impregnated part
a primary polyurethane bath containing hydrophilic polyurethane; and
An apparatus for manufacturing a polishing pad for a wafer polishing apparatus comprising a secondary polyurethane water bath impregnated with hydrophobic polyurethane. 9. The method of claim 8,
The surface polishing unit is an apparatus for manufacturing a polishing pad for a wafer polishing apparatus for buffing so that the density ratio of the polyurethane-containing porous layer and the non-containing porous layer in the surface layer of the polishing pad is 1:1. 10. The method of claim 9,
The thickness of the nonwoven pad is 4 mm to 6 mm,
A thickness of the nonwoven pad removed during the buffing is 2.5 mm to 3.5 mm. The polishing pad for a wafer polishing apparatus manufactured by the manufacturing method or manufacturing apparatus of any one of Claims 1-10.

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