KR200273586Y1 - A polishing pad using CMP having groove patterns - Google Patents

Abstract

The present invention relates to a polishing pad for CMP having a groove,

Macro grooves are formed on the upper surface of the polishing pad so that the grooves are orthogonal in the XY direction that grows at a predetermined interval from the center, and micro grooves formed in the XY direction are formed between the macro grooves. When the supplied slurry flows to the edge by the rotational force, the macro grooves become the main flow passages, and the micro grooves become the negative passages, thereby allowing the slurry to flow and distribute evenly over the entire surface of the polishing pad, resulting in uneven distribution of the slurry. It is possible to prevent the surface from becoming uneven and to increase the manufacturing cost due to the oversupply of the slurry.

Description

A polishing pad using CMP having groove patterns

The present invention relates to a polishing pad for chemical-mechanicalpolishing (hereinafter referred to as CMP) having grooves, and in particular, a predetermined distance in the XY axis direction on the surface of the polishing pad used for planarization of the surface in a semiconductor device manufacturing process. Macro grooves formed between the micro grooves formed therebetween and the slurry solution in the CMP process are uniformly distributed throughout the friction surface of the polishing pad and the wafer, and flows to increase the polishing efficiency, The present invention relates to a polishing pad capable of shaping flatness.

As the overall semiconductor industry develops, high integration of semiconductor devices is progressing. As such, the high integration technology for integrating more devices in a smaller area is attributable to the fine pattern technology of the circuit. Is reduced, and more wirings are stacked on one chip, thereby increasing the step height depending on the position inside the chip.

As described above, the step difference caused by the stacked wirings makes it difficult to evenly apply the conductive layer in the subsequent process, complicates the etching process when forming a contact for wiring connection, and is a photographic process that is a central element of the fine pattern technology. In addition, it is difficult to control the depth of focus, and the obstacles such as the reduction of the process margin due to the difference in thickness of each photosensitive layer, and the planarization technology is required.

As the planarization process in the semiconductor manufacturing process, a CMP method is used in which a step is filled using a material having excellent fluidity, or an upper portion of an artificially stepped laminated film is ground and planarized.

The CMP method is a method of grinding a surface of a wafer by rubbing a surface to be flattened on a polishing pad and rubbing the pad and the wafer while flowing a slurry having etching characteristics to the pressed surface. It is a technique to obtain a flat surface by simultaneously grinding the wafer surface by a mechanical method.

1 is a schematic diagram of a general CMP apparatus, and includes a circular table 10 that can be rotated at a high speed in a horizontal state by a lower driving motor (not shown), and a plate-shaped polishing pad attached to an upper portion of the table 10. (11), a slurry supply nozzle (12) for supplying a slurry (13) to the polishing pad (11) located at an upper center portion spaced from the center of the table (10), and an upper portion on one side of the table (10). And a carrier 14 mounted on the other side of the table 10 and a carrier 14 for rotating and mounting the wafer 15 on the lower surface to move the substrate 10 in close contact with the polishing pad 11. The dressing part 17 which grinds and removes the surface layer of (11) by predetermined thickness is provided.

The CMP apparatus having such a configuration is attracted by the carrier 14 so that the surface to be polished of the wafer 15 faces the polishing pad 11 and positioned on the polishing pad 11, and then the table 10 and the carrier 14. When a predetermined slurry 13 is supplied from the slurry supply nozzle 12 to the polishing pad 11 while rotating at a high speed in the same direction, the slurry 13 is uniformly applied to the upper surface by the rotational force, and the carrier 14 moves the surface to be polished of the wafer 15 from side to side with rotation while being in contact with or in close contact with the surface of the polishing pad 11, the opposite surface is polished and flattened.

When polishing is completed, the wafer 15 is unloaded to the outside of the apparatus, and the next wafer is loaded to repeat the same polishing step. After a certain period of time, the surface of the polishing pad 11 is worn, and the working surface is local. Since the polishing surface may be irregular because of the difference in the degree of wear in the region or the region, the dressing part 17 grinds the surface layer of the polishing pad 11 by a predetermined thickness to prepare subsequent polishing.

In the CMP apparatus as described above, the polishing rate, the planarization state, and the like are affected by the material or surface state of the polishing pad in contact with the surface to be polished of the wafer.

2 is a plan view of a polishing pad according to the related art, in which grooves 22 having concentric shapes of different sizes are formed on the surface of the polishing pad 20 at regular intervals, such that slurry is deposited on the polishing pad 20. When supplied, the slurry moves along the grooves 22 by the rotational force of the table and is supplied to the friction surface between the polishing surface of the wafer and the polishing pad to advance the CMP.

These grooves 22 are formed with a constant width and depth to affect the balanced supply, discharge and distribution of the slurry.

The polishing pad according to the prior art as described above has concentric grooves, but it is difficult to uniformly supply slurry during the polishing process using only the concentric grooves, and the edge portion of the polishing pad may be inertial due to rotation of the pad. The more slurry is supplied to the wafer, the more the edges of the wafer are polished than the center due to the difference in the flow distribution of each slurry, and this nonuniformity is intensified as the number of wafers to be polished increases. There is a problem of increasing the reliability of the process.

In addition, in order to correct the distribution imbalance of the slurry, there is another problem of increasing the manufacturing cost of the semiconductor device by supplying an excessive amount of the slurry.

The present invention is to solve the above problems, an object of the present invention, to provide a polishing pad having a groove that can control the balanced flow and distribution of the slurry to prevent the occurrence of defects due to uneven polishing of the wafer, slurry An object of the present invention is to provide a polishing pad for CMP having a groove that can prevent an increase in manufacturing cost due to excessive supply of the same.

1 is a schematic view of a typical semiconductor wafer CMP apparatus.

2 is a plan view of a polishing pad having grooves according to the prior art;

3 is a plan view of a polishing pad according to the present invention.

4 is a cross-sectional view taken along the line I-I of FIG. 3;

<Description of Symbols for Main Parts of Drawings>

10 table 11 polishing pad

12: slurry supply nozzle 13: slurry

14 carrier 15 wafer

17: dressing 20,30: polishing pad

22: groove 32: pad body

34: macro groove 36: micro groove

The characteristics of the polishing pad for CMP having a groove according to the present invention for achieving the above object,

Macro grooves formed in the X-Y axis orthogonal shape on the pad surface,

The micro groove is formed between the macro grooves in an X-Y orthogonal shape and is formed at a depth different from that of the spiral macro groove.

In addition, the micro grooves have a depth of 50 to 80% compared to the macro grooves, the macro grooves are 0.5 to 1.0 mm in depth, 0.5 to 0.8 mm in width, each spaced 5.0 to 8 mm in size, The macro grooves are formed to have a depth of 0.7 mm, a width of 0.6 to 0.65 mm, and an interval between grooves of 6.35 mm.

In addition, the micro grooves have a depth of 0.3 to 0.5 mm, a width of 0.1 to 0.3 mm, and each gap is formed to have a size of 1 to 3 mm. Preferably, the micro grooves have a depth of 0.4 mm and a width of 0.2. It is -0.25 mm, and the space | interval between grooves is formed in 2.1 mm.

In addition, the inside of the pad is uniformly impregnated with voids or microparticles formed therein, and the micro grooves are continuously connected to each other at the XY intersection points, and are also continuously connected to each other at the intersection points between the macro grooves and the micro grooves. The pad having the macro and micro grooves formed thereon is an upper pad, and at least one lower pad having a hardness different from the upper pad is further provided on a rear surface of the pad.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the CMP polishing pad having a groove according to the present invention.

3 is a plan view of the polishing pad according to the present invention.

First, in the polishing pad 30 according to the present invention, macro grooves 34 having a square cross section in the XY axis direction are formed on the upper surface of the disc-shaped main body 32 at regular intervals, and the macro grooves 34 are formed. The micro grooves 36 extending in the XY direction such as the macro grooves 34 are formed in a predetermined cross-sectional shape, for example, a rectangular cross-sectional shape.

The macro grooves 34 have a predetermined size, for example, a depth of 0.5 to 1.0 mm, a width of 0.5 to 0.8 mm, and a spacing of about 5.0 to 8 mm in consideration of polishing slurry or polishing surface. Preferably, the depth is 0.7 mm, the width is 0.6-0.65 mm, and the groove | channel spacing is formed in 6.35 mm, The size of the said micro groove 36 is 0.3-0.5 mm, for example, The width is 0.1-0.3 mm, and each space | interval is formed in the magnitude | size of about 1-3 mm, Preferably it is 0.4 mm in depth, 0.2-0.25 mm in width, and the space | interval between grooves is formed in 2.1 mm. .

When the slurry is supplied to the surface while the polishing pad 30 is rotated, the macro grooves 34 become the main flow passages of the slurry, and the micro grooves 36 having the relatively small sizes become the secondary passages. 30) The slurry is uniformly flowed through the surface, and the slurry is uniformly supplied during the polishing process by repeated intersections of the macro grooves 34 and the micro grooves 36, thereby improving the polishing uniformity and the uniformity. The improvement prevents oversupply and reduces manufacturing costs.

The polishing pad may obtain uniform slurry flow and supply effects by adjusting the width, depth, and spacing of the macro and micro grooves in consideration of the abrasive size of the slurry used.

In addition, the cross section of the groove may be formed in a U or V shape instead of a rectangular shape.

The grooves of FIG. 3 are formed to be continuously connected to each other at intersections of macro grooves or micro grooves, and the micro grooves are formed at different depths from the macro grooves, and have a depth of about 50 to 80% of the depth of the macro grooves. Is formed.

In addition, the polishing pads are uniformly impregnated with voids or microparticles formed therein, so that the slurry contains a slurry during polishing to maintain a uniform distribution of the slurry.

In addition, the above polishing pads may be used by using a polishing pad having grooves as an upper pad and a lower pad having a hardness different from that of the polishing pad.

The polishing pad 1 having only macro grooves and the polishing pad 2 having even microgrooves were tested under the same polishing conditions. As a result, the polishing pad 1 has a polishing rate of about 2700, a uniformity of about 1.5, and a polishing pad. 2 has a polishing rate of about 3000 and a uniformity of about 1.

As described above, the CMP polishing pad having grooves according to the present invention includes a macro groove formed on the upper surface of the polishing pad at regular intervals in the XY direction, and at a predetermined interval on the pad surface between the macro grooves. Since the micro grooves are formed, when the slurry supplied to the upper surface of the polishing pad flows to the edge by the rotational force during the wafer polishing process, the macro grooves become the main flow passages, and the micro grooves become the secondary passages to the entire surface of the polishing pad. By uniformly flowing and distributing the slurry, the non-uniform distribution of the slurry does not occur, thereby preventing the polishing surface from being uneven and there is an advantage of preventing the increase in manufacturing cost due to the over-supply of the slurry.

Claims (9)

Macro grooves formed in the X-Y axis orthogonal shape on the pad surface, A CMP polishing pad having microgrooves formed in an X-Y orthogonal shape between the macro grooves and having a different depth from the macro grooves. The method of claim 1, The micro groove has a depth of 50 to 80% compared to the macro groove, the polishing pad for CMP. The method of claim 1, The macro groove has a depth of 0.5 to 1.0 mm, a width of 0.5 to 0.8 mm, and a spacing of 5.0 to 8 mm in size for each CMP polishing pad. The method of claim 1, The macro groove has a depth of 0.7 mm, a width of 0.6 to 0.65 mm, and an intergroove spacing of 6.35 mm. The method of claim 1, The microgroove has a depth of 0.3 mm to 0.5 mm, a width of 0.1 mm to 0.3 mm, and each gap is formed to have a size of 1 to 3 mm. The method of claim 1, The microgroove has a depth of 0.4 mm, a width of 0.2 to 0.25 mm, and a groove-to-groove spacing of 2.1 mm. The method of claim 1, CMP polishing pad, characterized in that the inside of the pad is uniformly impregnated with voids or fine particles formed therein. The method of claim 1, And the micro grooves are continuously connected to each other at X-Y intersections, and the micro grooves are continuously connected to each other at intersections of the macro grooves and the micro grooves. The method of claim 1, And a pad having the macro and micro grooves formed thereon as an upper pad, and further including one or more lower pads having different hardness from the upper pad in the rear surface thereof.