KR20050031752A - A polishing-head for wafer polisher - Google Patents

Abstract

A polishing head of a wafer polishing apparatus is provided to improve the flatness of a wafer and to obtain an aiming thickness from the wafer by controlling the pressure applied to the wafer according to corresponding portions. A polishing head(20) of a wafer polishing apparatus includes a head body, pressurizing parts, an air pressure correcting part, a contact plate, and a support part. The head body(21) includes a plurality of air pressure supply ports(31,35). The air pressure supply ports are capable of controlling discretely the pressure of each portion of the polishing head by supplying compressed air. The pressurizing parts(25,27) are installed under the head body corresponding to the air pressure supply ports in order to press a wafer(W). The air pressure correcting part is installed under each pressurizing part to control the pressure discrepancy between the pressurizing parts. The contact plate(23) is installed under the air pressure correcting part to contact and press the wafer, directly. The support part is used for connecting and supporting the head body, the pressurizing parts, the air pressure correcting part and the contact plate.

Description

Polishing head of wafer polishing machine {A Polishing-Head For Wafer Polisher}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for a wafer, and more particularly, to a polishing head of a wafer polishing apparatus capable of adjusting the pressure applied to each portion of a wafer at the time of polishing a single wafer.

1A and 1B are sectional views illustrating a conventional sheet polishing apparatus of a wafer. As shown in the drawing, the conventional wafer polishing apparatus 1 is provided with a polishing pad 11 disposed on an upper surface and a lower platen 10 that rotates in one direction, and a wafer that is movable on an upper side of the lower platen 10. and a polishing head 13 for rotating (w) to the polishing pad 11 of the lower plate 10.

And the lower surface of the polishing head 13 is provided with a wafer adhesive plate 15 for bonding the wafer (w), the upper side is provided with a rotating shaft 17 for transmitting the rotational power of the polishing head (13).

In the state where the wafer w is adsorbed on the lower surface of the polishing head 13 of the polishing apparatus 1, the wafer w is pressed against the polishing pad 11 to rotate about the rotating shaft 17, and the lower plate ( 10 rotates in the opposite direction with respect to the polishing head 13.

The polishing liquid is supplied between the polishing head 13 and the lower plate 10 over the entire process of polishing, and the wafer w is subjected to friction and polishing liquid caused by the rotation of the polishing head 13 and the lower plate 10. Polished by the fine particles have a mirror surface with high flatness.

However, the conventional wafer polishing apparatus having the above structure has the following problems.

In the case of using the conventional wafer polishing apparatus 1, the operator can define the rotational speed and the polishing head of the polishing head 13 and the lower plate 10 to control the flatness of the wafer w. 13 was only an average pressure applied to the wafer w.

In recent years, as the specification level of the wafer w is increased and the specification of the wafer w is increased, a polishing process must be performed to maintain a high flatness over the entire surface of the wafer w.

In the polishing of a wafer w having a large size, only by adjusting the average polishing pressure, there is a difference in the pressure applied to each part in the radial direction and the rotational speed of the surface plate, and thus the degree of polishing is changed. There has been a problem that acts as a factor to deteriorate the flatness of.

An object of the present invention is to implement a polishing head of a wafer polishing apparatus capable of improving the flatness of a wafer by finely adjusting the pressure applied to the entire surface of the wafer in the wafer polishing apparatus.

Another object of the present invention is to implement a polishing head of a wafer polishing apparatus which can adjust the pressure applied to the entire surface of the wafer for each part and thus can produce a wafer having a desired thickness.

The polishing head of the wafer polishing apparatus according to the present invention for achieving the above object is, in the polishing head of the polishing apparatus for polishing a wafer sheet to supply compressed air so as to enable separate pressure control to each part of the polishing head. A head body having a plurality of pneumatic supply ports; Pressurizing means installed at a lower end of the head main body at a position corresponding to the pneumatic supply port to apply pressure for polishing the wafer by compressed air supplied by each pneumatic supply port; Pneumatic correction means is provided on the lower surface of each pressing means for adjusting the pressure deviation between the plurality of pressing means; An adhesive plate installed to be in contact with the lower side of the pneumatic correction means, the lower surface of which pressurizes the wafer to allow polishing of the wafer; And it characterized in that it comprises a coupling support means for supporting the head body, the pressing means, the pneumatic control means, the bonding plate.

The plurality of pressing means is provided in a concentric circle shape in the radial direction from the center of the head, wherein each of the pressing means is characterized in that the pneumatic supply port is connected to supply compressed air.

The upper end of the pressurizing means in the center of the polishing head is formed with a cylindrical air flow groove into which compressed air can be introduced, and the lower end forms a wide disk shape with respect to the upper end. Air flow grooves are formed along the circumference to be inserted, and the lower end forms a wide concentric disc shape with respect to the upper end, and the lower end of the head body has a concave-convex shape corresponding to the pressing means so that the upper end of each pressing means can be inserted. Concentric circles are formed, characterized in that the lower end of each pressing means is placed in close proximity to each other.

The upper outer surface of each pressing means is provided with a sealing means for preventing the leakage of compressed air, characterized in that for preventing the outflow of the compressed air through the contact portion between the uneven portion of the head body and the upper end of the pressing means. .

The sealing means is characterized in that the rubber ring.

Pneumatic correction means and the elastic sheet is in close contact with the lower surface of each pressing means formed of an elastic material; It is characterized in that it comprises a pneumatic balloon is installed in close contact with the lower side of each elastic sheet to cover each elastic sheet to correct the pressure deviation between each part.

An air flow hole is formed below each groove to enable the supply of compressed air to the pneumatic balloon.

Between the pneumatic balloon and the adhesive plate is provided with a separate pneumatic supply port capable of pressure control to supply compressed air to prevent the inflow of foreign matter into the interior space of the polishing head.

The elastic sheet is characterized in that it is formed of a polyurethane material.

The coupling support means is characterized in that the circular frame is formed with a step on the inner peripheral surface to enable the installation of the adhesive plate.

Adhesive plate is characterized in that the stepped flange is formed on the edge so as to span the stepped portion of the circular frame.

On the lower side of the cylindrical frame is characterized in that the separation prevention ring is attached to prevent the wafer from being adhered to the adhesive plate to be separated from the polishing head in the process of polishing.

The lower surface of the release preventing ring is positioned below the thickness corresponding to half of the wafer thickness than the lower surface of the adhesive plate.

According to the present invention, the pressure applied to each part of the wafer during the wafer polishing process can be controlled for each part.

Hereinafter, a configuration of a preferred embodiment of a polishing head of a wafer polishing apparatus according to the present invention having the above configuration will be described in detail with reference to the accompanying drawings.

Fig. 2 is an exploded perspective view illustrating the polishing head configuration of the wafer polishing apparatus of this embodiment, Fig. 3 is an exemplary side cross-sectional view of the polishing head of this embodiment, and Fig. 4 is a front sectional view thereof. 5 and 6 are partial cross-sectional views of the polishing head of this embodiment, respectively.

As shown, the polishing apparatus of this embodiment is a polishing apparatus for polishing a wafer sheet, and the polishing head 20 is provided with a configuration that allows the pressure applied to the wafer W to be adjusted for each part. .

In the polishing head 20 of the present embodiment, the polishing head 20 is divided into a plurality of parts so that pressure adjustment is separately performed on each part. The polishing head 20 of the present embodiment has a thick disc shape as a whole. The head body 21 of the upper half, and pressurizing means that is addressed thereto and pressurizes the wafer W, the lower side of the polishing head 20 is provided with an adhesive plate 23 to which the wafer W is bonded.

Since the polishing head 20 of the present embodiment should be capable of adjusting pressure for each part, the polishing head 20 includes a plurality of pressing blocks 25, 27, and 29 as pressing means, and the head body 21 has each pressing block 25, Pneumatic supply ports 31, 33 and 35 are installed as pneumatic supply means for supplying compressed air to the 27 and 29.

The pneumatic supply ports 31, 33 and 35 of this embodiment are provided with separate pressure control means so that the measurement and control of the pressing force can be made separately for each of the pressure blocks 25, 27 and 29.

The pressing means of this embodiment consists of three pressing blocks 25, 27, 29 which are concentric in the radial direction at the center of the polishing head 20.

The first press block 25 located at the center of the polishing head 20 has a cylindrical groove 25a formed thereon to receive compressed air from the pneumatic supply port 31 to form a cylinder shape, and a press plate at the lower end thereof. 25b forms a wide disk shape compared to the upper end to press the large area flat.

A pneumatic supply port is provided on the upper surface of the upper end of the second press block 27 having a concentric shape surrounding the first press block 25 from the radial direction and the third press block 29 surrounding the second press block 27. Air flow grooves 27a and 29a are formed along the circumferential direction of each pressurizing block so as to receive compressed air from 27 and 29 to form an air flow path.

In addition, the upper end portions of the second and third pressing blocks 27 and 29 form a cylindrical cross section, and the pressing plates 27b and 29b at the lower portions form a wide concentric disc shape.

In this embodiment, the pressure plates 25b, 27b, and 29b of the plurality of pressure blocks are placed in close proximity to each other, so that gaps are formed between the pressure blocks 25, 27, and 29, resulting in a pressure deviation applied to the wafer W. It is preventing.

In addition, concentric irregularities are formed at the lower end of the head body 21 so that upper ends of the first, second, and third pressing blocks 25, 27, and 29 may be inserted.

In order to prevent the compressed air from leaking through the contact portions of the head body 21 and the pressure blocks 25, 27 and 29, both sides of the upper ends of the first, second and third pressure blocks 25, 27 and 29 and the head body Between the 21 is provided with a sealing means 37 to prevent leakage of compressed air introduced from the pneumatic supply ports (31, 33, 35).

In this embodiment, the sealing means (37) is provided in close contact with the circumferential surface of the rubber ring-like sealing, such as O-ring or quad-ring contact the upper end of the pressure block (25, 27, 29) and the head body 21 have.

On the other hand, the lower side of each pressure plate (25b, 27b, 29b) is provided with a pneumatic correction means for reducing the pressure deviation applied to the pressure block (25, 27, 29), the pneumatic correction means of the present embodiment It includes an elastic sheet 40 attached to the lower side of the pneumatic balloon 41, which is installed in close contact with the lower side of the elastic sheet 40.

The pneumatic balloon 40 of the present embodiment is inflated by the compressed air to press the adhesive plate 23 at the bottom and to correct the pressure difference at the boundary of the pressure blocks 25, 27, 29 to be linear. To this end, an air flow hole 43 communicating with the pneumatic balloon 41 is formed downward from the air flow grooves 25a, 27a, 29a of the pressure blocks 25, 27, 29, and the pressure blocks 25, 27. A part of the air to pressurize 29, forms a structure that can be used to inflate the pneumatic balloon 41.

The elastic sheet 41 of the present embodiment is installed in close contact with the lower side of the pneumatic balloon, and should be a material that maintains a certain strength to support the pressure applied from the pressure blocks 25, 27, 29, and the pressure between the blocks It is preferable that the material is made of an elastic material to correct the difference. Therefore, the elastic sheet 41 of the present embodiment is made of a resin material which is an elastic material.

In addition, according to the embodiment, the lower side of the elastic sheet 41 is further provided with an additional sheet 57 covering each elastic sheet mode to further reduce the pressure deviation applied by each pressing means at the boundary to be linear In some cases.

The adhesive plate 23, which is a flat plate installed on the lower side of the polishing head 20 and adhered to the wafer W, is formed of a metal disc having a predetermined thickness to maintain desired high degree of flatness.

In the present embodiment, the pressing means, the pneumatic correction means, the bonding support means is provided to be coupled to the head body 21 is supported. Coupling support means of the present embodiment is characterized in that the cylindrical frame 50 is formed on the inner circumferential surface 51 to support the pressing means and the pneumatic correction means from the outside, so that the adhesive plate 23 can span.

In addition, the adhesive plate 23 of the present embodiment has a stepped flange 23a formed at an edge portion thereof so as to span the stepped portion 51 of the cylindrical frame 50. When the adhesive plate 23 is placed to span the cylindrical frame 50, the lower surface of the adhesive plate 23 and the lower surface of the cylindrical frame 50 are placed on the same plane.

In addition, the lower end of the cylindrical frame 50 of the present embodiment as a means for preventing the wafer W adhered to the adhesive plate 23 from being removed from the polishing head 20 during the polishing process 53. ) Is provided.

The separation prevention ring 53 is preferably manufactured to cover about half of the thickness of the wafer W, and the bottom surface of the separation prevention ring 53 of the present embodiment has a thickness corresponding to half the thickness of the wafer W. As much as the lower side of the adhesive plate 23 is lowered.

In addition, in this embodiment, in order to prevent penetration of the polishing liquid or contaminants through the edge of the adhesive plate 23, compressed air is directly supplied to the adhesive plate 23 to purify by air pressure. Possible structure. To this end, the head body 21 of the present embodiment is formed with a separate pneumatic supply port 55 to allow the compressed air to reach the adhesive plate 23 directly.

The following describes the operation of the polishing head of the wafer polishing apparatus of the embodiment according to the present invention having the configuration as described above.

When the wafer is polished using the polishing apparatus having the polishing head 20 having the above-described configuration, the polishing head 20 is a polishing pad of the lower plate in a state in which the wafer W is brought into close contact with the adhesive plate 23. The wafer W is pressed and rotated so that the mirror surface is polished.

In this case, when the polishing process is started, each pneumatic supply port supplies compressed air in different states to the respective pressure blocks 25, 27 and 29, which are pressurizing means, through separate control means, and pressurized block ( 25, 27 and 29 press the adhesive plate 23 by the pressure of the compressed air supplied to press the wafer (W).

In addition, the pneumatic balloons are inflated through the air flow holes to press the lower adhesive plate. Even in the case where there is a pneumatic difference between each pneumatic balloon, the elastic sheet 41 provided on the lower side of the pneumatic balloon 40 corrects the step, and each elastic sheet 41 is a pressure block (25, 27, 29) and pneumatic The pressure step at the balloon boundary is corrected and controlled to be linear.

In addition, the thin film additionally installed at the bottom of the elastic sheet 41 corrects the pressure difference at each boundary to be more linear.

Since the pressing force of each pressing means is controlled separately throughout the entire process of polishing, it is possible to change the degree of polishing for each part of the wafer W according to the user's intention or to manufacture the wafer W having a high flatness during the polishing process. It becomes possible.

Then, since compressed air is directly supplied to the adhesive plate 23 through the pneumatic supply port 55, the polishing liquid flows into the polishing head 20 through the edge of the adhesive plate 23 by the injection pressure of the compressed air. Can be prevented.

The scope of the present invention is not limited to the above embodiments, but is determined by the matters described in the claims, and it is obvious that the present invention includes various modifications and adaptations made by those skilled in the art in the same range as the matters described in the claims.

The present invention enables fine adjustment of the polishing pressure of the wafer because the pressure applied to each part of the wafer in the wafer polishing process can be separately controlled by the above configuration.

This not only enables the manufacture of wafers with excellent flatness during polishing, but also enables the production of wafers with various types of surfaces to meet the user's use. It is possible to be polished by the method.

1A and 1B are cross-sectional views illustrating a conventional wafer sheet polishing apparatus.

2 is an exploded perspective view illustrating the configuration of a preferred embodiment of a polishing head of a wafer polishing apparatus according to the present invention;

3 is an exemplary side cross-sectional view of a polishing head of the wafer polishing apparatus according to the present invention.

4 is an exemplary front sectional view of a polishing head of the wafer polishing apparatus according to the present invention.

5 and 6 are exemplary partial sectional views of the polishing head according to the present invention.

* Description of the symbols for the main parts of the drawings *

10 ............ top plate 20 ............. grinding head

21 ............ Head body 23 ............. Adhesive plate

25,27,29 ...... Pressure block 25a, 27a, 29a .... Air flow groove

31,33,35,55 ... Pneumatic supply port 37 ............

40 ............ Pneumatic balloon 41 ............. Elastic sheet

43 ............ Air flow hole 50 ............. Cylindrical frame

53 ............ Release prevention ring

Claims (10)

In the polishing head of the polishing apparatus for polishing a wafer sheet, A head body having a plurality of pneumatic supply ports for supplying compressed air to enable separate pressure control of each part of the polishing head; Pressurizing means installed at a lower end of the head main body at a position corresponding to the pneumatic supply port to apply pressure for polishing to the wafer by compressed air supplied by each pneumatic supply port; Pneumatic correction means is provided on the lower surface of each pressing means for adjusting the pressure deviation between the plurality of pressing means; An adhesive plate installed to be in contact with the lower surface of the pneumatic correction means, the lower surface of which is in direct contact and pressurization with the wafer to polish the wafer; And And a head support, a pressurizing means, a pneumatic correction means, and a joining support means for holding and bonding the adhesive plate. The method according to claim 1, wherein the pressing means is arranged in a concentric circle shape in the radial direction from the center of the polishing head, And each pneumatic supply port is connected to each of the pressing means to supply compressed air. The method of claim 2, wherein the upper end of the pressing means in the center of the head is formed in the center of the cylindrical groove into which compressed air can be injected, the lower end forms a wide circular plate shape with respect to the upper end, The upper surface of the upper end of the pressure means is formed with an air flow groove is formed along the circumference so that compressed air can be injected, the lower end forms a wide disk shape for the upper end, The head body is formed with a concentric concave-convex in which an upper end of each pressing means is inserted, and a lower end of each pressing means is placed in close proximity to each other. The method of claim 3, wherein the outer surface of the upper end of each pressurizing means is provided with a sealing means for preventing the leakage of compressed air, the outflow of the compressed air through the contact portion between the uneven portion of the head body and the upper end of the pressurizing means A polishing head of a wafer, characterized in that for preventing. The polishing head of claim 4, wherein the sealing means is rubber packing. The pneumatic balloon according to any one of claims 1 to 5, wherein the pneumatic correction means includes a pneumatic balloon which is installed in close contact with a lower surface of each pressurizing means and corrects a pressure deviation between the parts; The polishing head of the wafer, characterized in that it comprises an elastic sheet in close contact with each elastic sheet formed of an elastic material. 7. The polishing head of claim 6, wherein an air flow hole is formed below an air flow groove formed at an upper end of each pressurizing means to supply compressed air to the pneumatic balloon. The wafer polishing method according to claim 6, wherein a separate pneumatic supply port is provided between the pneumatic balloon and the adhesive plate to control pressure, thereby supplying compressed air to prevent foreign substances from entering the inner space of the polishing head. head. The wafer polishing head according to claim 1, wherein the coupling support means is a cylindrical frame having a step formed on an inner circumferential surface thereof to allow the adhesive plate to be installed.  The wafer polishing head according to claim 9, wherein the adhesive plate has a stepped flange formed at an edge thereof so as to span the stepped portion of the circular frame.