JP2000117618A - Abrasive pad and manufacturing of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a step resolving characteristic and the uniform polishability by providing an abrasive pad with an abrasive material layer having a groove formed by patterning a resist layer of a surface of a base layer being a base material to the desired shape by a lithographic process, and etching the surface of the base layer while using the resist layer as a mask. SOLUTION: A flattened layer 12 utilizing a resist layer is formed on a main surface side of a coarsened base layer 11, and dry etching the whole main surface of the base layer 11 from the flattened layer 12 side until the flattened layer 12 is completely removed, to obtain the base layer remarkably superior in the smoothness of the main surface (face 38). Then a resist mask pattern 13 for forming a groove is formed by a conventional semiconductor lithographic technique, and a groove 14 is formed by the dry etching by a plasma etching device with oxygen as a main component gas. The depth and inclination angle of the groove are adjusted by controlling the drying etching condition and time. Then the resist film is separated and removed to obtain an abrasive material layer having a desired shape of a groove pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing pad for polishing a member to be polished by interposing an abrasive between the member and a member to be polished and giving relative movement to the member to be polished.
More particularly, the present invention relates to a polishing pad for a semiconductor wafer having semiconductor devices formed thereon, which is particularly inexpensive and has excellent polishing characteristics, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As semiconductor integrated circuits become more highly integrated and finer, the steps of semiconductor manufacturing processes become more complicated. Along with this, the surface state of the semiconductor device is not necessarily flat. The presence of a step on the surface causes disconnection of the wiring, an increase in the local resistance value, and the like, resulting in disconnection, a reduction in current capacity, and the like. In addition, the insulating film also leads to deterioration of breakdown voltage and generation of leakage.

On the other hand, as the integration and miniaturization of semiconductor integrated circuits increase, the wavelength of the light source of the semiconductor exposure apparatus used for optical lithography becomes shorter and the numerical aperture (NA) becomes larger. Has become substantially shallower. In order to cope with the shallower depth of focus, the surface of the semiconductor device needs to be flatter than ever.

As a method for globally planarizing a semiconductor device surface, a chemical mechanical polishing (Chemical Mechanical Polishing) method is used.
cal Polishing or Chemical Mechanical Planarizatio
n, hereinafter referred to as CMP) technology is considered a promising method. CMP has been developed based on a mirror polishing method for a silicon wafer, and is performed using an apparatus shown in FIG.

As a configuration of a polishing apparatus, a polishing pad 32 is provided on a polishing platen 31 that is driven to rotate. On the other hand, a wafer 34 is held by the polishing head 33 and the wafer 3
4 is in contact with the polishing pad 32. In this state, the polishing platen 31 is driven to rotate, a load is applied to the polishing head 33 from above, and a swinging motion 37 is performed in the radial direction of the polishing platen 31 while rotating.

During this operation, the abrasive 36 is discharged from the abrasive supply nozzle 35 onto the polishing pad 32, and the abrasive 36 is supplied to the polishing surface of the wafer 34 to polish the outermost surface of the wafer flat. ing. That is, the abrasive 36 diffuses on the polishing pad 32 and the polishing pad 32 and the wafer 34
As a result of the relative movement of the two, they penetrate between the two and polish the surface of the wafer. At this time, the polishing pad 32 and the wafer 3
The mechanical polishing by the relative movement of No. 4 and the chemical action of the abrasive act synergistically to perform good polishing.

As the polishing pad 32, a sheet-like one made of foamed polyurethane has been used in many cases. However, when a wafer is polished using a sheet-like polishing pad made of foamed polyurethane, there is a problem that the edge of the wafer is large, and this polishing pad generally (1) is compressed when a load is applied. (2) When affixed to a polishing platen, a desired flatness cannot be obtained due to unevenness of an adhesive layer provided on a polishing pad (sheet). Specifically, λ (wavelength of light ) It is difficult to obtain the following surface accuracy, and (3) dressing is required because clogging is likely to occur.

In order to solve such a problem, in recent years,
A polishing pad mainly composed of an epoxy resin has been proposed (Japanese Patent Application No. 8-115794). On this type of polishing pad surface, in order to increase the parallelism and surface accuracy of the surface in order to perform uniform polishing, to facilitate the supply of the abrasive and improve the polishing rate of the surface of the object to be polished, further polishing chips are removed. In order to discharge, it is necessary to form a groove pattern.

[0009] By the way, there are two types of objects to be polished by CMP: an interlayer insulating film such as SiO ₂ and a wiring film such as Al and W (hereinafter referred to as an object to be polished). When the hardness of the polishing pad is smaller than the hardness of the object to be polished, the polishing pad wears more than the object to be polished, and the shape (accuracy) of the polished surface of the polishing pad cannot be maintained. On the other hand, when the hardness of the polishing pad is larger than that of the polishing object, the deformation of the pad is small, and if the parallelism and the surface accuracy of the pad are insufficient, the contact between the polishing object and the polishing pad may occur. Becomes uneven, so that uniform polishing cannot be performed, and even due to slight impurities mixed between the polishing object and the polishing pad,
There is a problem that scratches called scratches are likely to occur. In addition, when the groove pattern is non-uniform, too wide, or too deep, the polishing becomes non-uniform, easily scratches, and the step-elimination characteristics of the object to be polished are insufficient. There was a problem that.

[0010] Therefore, the polishing pad needs to have excellent parallelism and surface accuracy, and the grooves on the surface must be finely, accurately and uniformly formed in a desired shape. In particular, this requirement is important for a relatively hard polishing pad, and a hard pad having good surface accuracy and a good groove pattern has excellent step-elimination characteristics and excellent durability. There is an increasing demand for a manufacturing technique for forming the surface accuracy and the groove pattern inexpensively and favorably.

In response to the above requirements, conventionally, grinding (not shown) is performed by a mechanical method to increase surface accuracy, and a groove pattern is formed by a similar mechanical method. FIG. 4 shows a method of forming grooves after mechanically grinding a polishing pad. A desired spiral groove pattern 44 is formed on the entire surface of the polisher by rotating the stage 43 to which the polishing pad 42 is fixed while pressing the cutting needle 41 against the surface of the polishing pad and moving the position little by little. Was.

[0012]

However, in the above-mentioned conventional mechanical grinding method, it takes time to obtain surface accuracy, and it is difficult to reduce an in-plane flatness error to several μm or less. There was a problem. Furthermore, the method of forming a groove pattern by cutting requires a long time, and it is technically difficult to form a groove having a groove width of 0.4 mm or less and a depth of 0.2 mm or less, and has a high dimensional accuracy. There is a problem that it is difficult to form a groove. In addition, there is a problem that debris due to cutting remains, and it takes time to remove the debris.

The present invention solves the above-mentioned problems, and has a short processing time, a small flatness error, and a high precision of a groove pattern. An object of the present invention is to provide a polishing pad having good uniform polishing properties.

[0014]

In order to solve the above-mentioned problems, the present invention firstly discloses a method of interposing an abrasive between a member to be polished and imparting a relative motion between the member and the member to be polished. A polishing pad for polishing the member to be polished, wherein the polishing pad patterns a resist layer applied to the surface of a base material layer serving as a base material into a desired shape by lithography, and the resist layer A polishing pad (Claim 1), comprising a polishing material layer having a groove formed by etching the surface of the base material layer by an etching method as a mask.

Secondly, there is provided "a polishing pad according to claim 1, wherein the etching method is a dry etching method or a wet etching method." Thirdly, "the polishing pad according to any one of claims 1 to 2, wherein the lithography method includes a step of exposing a pattern having a desired shape to a resist surface using a stepper. I will provide a.

Fourth, the base material layer is coated with a flattening layer on the base material layer surface, and the flattening layer and the surface of the base material layer are etched at substantially the same etching rate by etch-back. 2. The structure according to claim 1, wherein the back is flattened.
A polishing pad according to any one of claims 1 to 3 (Claim 4). " Fifthly, there is provided "a polishing pad according to claim 4, wherein a resist layer is used as the flattening layer."

Sixth, the present invention provides "a polishing pad according to claim 4, wherein a polyimide layer is used as the planarizing layer." Seventh, the polishing pad according to any one of claims 1 to 3, wherein the surface of the base layer is planarized by polishing using a polishing apparatus. "I will provide a.

Eighth, "the flatness of the surface of the abrasive layer is
4. The method according to claim 4, wherein the pp is ± 2 μm or less.
7. A polishing pad according to any one of claims 7 to 8 (claim 8). Ninthly, there is provided “a polishing pad according to any one of claims 1 to 8, wherein the width of the groove is 100 μm or less”. Tenth, "a method of manufacturing a polishing pad having an abrasive layer, wherein an abrasive is interposed between a member to be polished and a relative movement is provided between the member and the member to be polished to polish the member to be polished. The manufacturing method, a step of patterning a resist layer applied to the surface of a base material layer serving as a base material of the abrasive layer into a desired shape by lithography, and the resist layer by etching Forming a groove in the surface of the base material layer by etching the base material layer using the mask as a mask (claim 10).

Eleventh, "before the step of patterning the resist layer applied to the surface of the base material layer into a desired shape by lithography, a flattening film is further applied to the surface of the base material layer. The method for manufacturing a polishing pad according to claim 10, further comprising a step of etching back the flattening film and the surface of the base material layer at substantially the same etching rate and flattening the flattening film and the surface of the base material layer. 11) ”.

Twelfth, before the step of patterning the resist layer applied to the surface of the base material layer into a desired shape by lithography, the surface of the base material layer is further polished by a polishing apparatus. And a method for manufacturing a polishing pad according to claim 10 (claim 12). A thirteenth feature is that the member to be polished is a semiconductor wafer.
The polishing pad according to any one of claims (Claim 13) "is provided.

Fourteenthly, there is provided "a method for manufacturing a polishing pad according to any one of claims 10 to 12, wherein the member to be polished is a semiconductor wafer (claim 14)."

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In manufacturing a polishing pad according to the present invention, first, a base layer is formed into a substantially flat main surface, and then a flattening film is applied to the base layer. Alternatively, the main plane of the base material layer is flattened by a polishing method. Thereafter, a resist layer is applied to the base material layer, a groove pattern is projected and exposed, and after development, a resist pattern corresponding to the groove pattern is formed. Thereafter, the base material layer is etched using the resist pattern as a mask, and as a result, an abrasive layer having a groove pattern is formed. The polishing material layer may be used as it is as a polishing pad, or the polishing material layer may be attached to an appropriate elastic sheet having a single-layer structure or a laminated structure to form a polishing pad having a multilayer structure.

Here, the material of the base layer is preferably one selected from an epoxy resin, a polyurethane resin, an acrylic resin, a fluororesin, and a polyester resin. The material of the flattening layer is selected so that the etching rate is the same as that of the base material layer.
This is one selected from a G (Spin On Glass) film, a novolak resin resist film, and a naphthoquinone resin resist film. Further, the baking conditions of the flattening film are adjusted so that the etching rates of the flattening film and the base material layer are the same.

The exposure of the resist film may be performed by a stepper (reduction projection exposure apparatus) or an aligner. The width of the groove pattern is preferably 100 μm or less. The width of the groove pattern refers to the width of the valley on the assumption that the groove pattern is a periodic pattern of valleys (concavities and convexities).

The etching of the substrate layer is performed by a dry method.
Alternatively, a wet method is preferable. Hereinafter, the present invention will be specifically described with reference to Examples 1 and 2. Embodiment 1 A polishing pad according to the present invention and a process for manufacturing the polishing pad will be described with reference to FIGS. 1 (a), 1 (b) and 1 (c). (1) First, as shown in FIG. 1 (a), the epoxy resin is formed into a sheet after polymerization, and the main surface side (surface side used for polishing) of the base material layer 11 on which rough surface treatment has been performed. To form a planarization layer 12. The flattening layer 12 is formed by applying by a spin coating type apparatus and baking. Polyimide resin is preferable as the material of the planarizing layer,
The thickness is preferably in the range of 2 to 20 μm. Here, the polyimide layer may be applied a plurality of times, and for example, if the polyimide layer is applied 5 times with a thickness of 2 μm, it can be formed to a thickness of 10 μm. The baking may be performed after each application, or every several applications, or all times, that is, after the application of the entire film thickness. The baking is preferably performed at 140 to 400 ° C. for 30 to 300 minutes. Then, the entire main surface of the base layer 11 is completely removed from the side of the flattening layer 12 by a dry etching apparatus containing oxygen as a main component until the flattening layer 12 completely disappears (indicated by 38 in FIG. 1A). Dry etching). At the stage where the planarizing layer 12 is applied, the surface of the planarizing layer 12 is flat, and the material of the planarizing film is selected so that the planarizing film and the base material layer have the same etching rate. Surface) can be obtained with a base layer having extremely good flatness. (2) Next, as shown in FIG. 1B, a resist mask pattern 13 for forming a groove is formed by a normal semiconductor photolithography technique, and dry etching is performed by a plasma etching apparatus using oxygen as a main component gas. (3) Although the groove 14 is formed by the etching of (2), a desired shape can be obtained by controlling the dry etching conditions and time for the depth of the groove and the inclination angle of the groove. Then, by removing and removing the resist film 13, an abrasive layer having a groove pattern of a desired shape can be obtained as shown in FIG.

The thus-prepared abrasive layer may be used as it is as a polishing pad by attaching it to a polishing platen,
A polishing pad may be prepared by attaching the abrasive layer to a sheet having an appropriate elastic single-layer structure or a laminated structure, and then may be used by attaching it to a polishing platen. [Embodiment 2] A polishing pad and a manufacturing process of the polishing pad according to the present invention will be described with reference to FIGS. 2 (a), 2 (b) and 2 (c). (1) First, as shown in FIG. 2 (a), a base material layer 2 is formed into a sheet after polymerization of an epoxy resin, and rough surface treatment is performed.
A flattening layer 22 is formed on the main surface side (surface side used for polishing) of the first. The flattening layer 22 is formed by applying by a spin coating type device and baking. A polyimide resin is preferable as the material of the flattening layer, and the thickness is 2 to 2
A range of 0 μm is preferred. Here, the polyimide layer may be applied a plurality of times, and for example, if the polyimide layer is applied 5 times with a thickness of 2 μm, it can be formed to a thickness of 10 μm. Bake is 1
It may be performed every application, every several applications, or all times, that is, after the application of the entire film thickness. The bake condition is 1
It is preferable to carry out at 40 to 400 ° C. for 30 to 300 minutes. Then, the base material layer 21 to which the flattening layer 22 is applied
Is polished by a polishing apparatus 40. That is, the base layer 21 on which the flattening layer 22 is applied is fixed to the polishing head 33, and the flattening layer 22 is pressed against the polishing pad 41. In this state, the polishing platen 23 to which the polishing pad 41 is fixed is given a rotational movement 50, and the polishing head 33 is given a swinging movement 37. An abrasive (not shown) is supplied between the polishing pad 41 and the flattening film 22 until the flattening film 22 is completely removed (up to the surface indicated by 39 in FIG. 2A). Polished.

Here, in the processing by the polishing apparatus, once the polishing apparatus is adjusted, many base material layers can be continuously flattened. However, when surface polishing is performed by grinding, skill and adjustment requiring a long time are required for each base material layer. The processing by the polishing apparatus can drastically reduce the production time of the polishing pad and drastically reduce the production cost.

In this embodiment, the flattening film is formed. However, the flattening film is not always necessary, and it may be polished and flattened without the flattening film. (2) Next, as shown in FIG. 2B, a resist mask pattern 24 for forming a groove is formed by a normal semiconductor photolithography technique, and dry etching is performed by a plasma etching apparatus using oxygen as a main component gas. (3) Although the groove 25 is formed by the etching of (2), a desired shape can be obtained for the depth of the groove and the inclination angle of the groove by controlling the dry etching conditions and time. Next, by removing and removing the resist film 24, an abrasive layer having a groove pattern of a desired shape can be obtained as shown in FIG.

The thus-prepared abrasive layer may be used as it is as a polishing pad by attaching it to a polishing platen,
A polishing pad may be prepared by attaching the abrasive layer to a sheet having an appropriate elastic single-layer structure or a laminated structure, and then may be used by attaching it to a polishing platen. When the polishing pad manufactured as in Examples 1 and 2 is used for polishing a semiconductor wafer on which a semiconductor element pattern is formed in the manufacture of a semiconductor device, polishing uniformity, a polishing speed, and a level difference can be eliminated. It was excellent.

[0030]

As described above, according to the present invention,
A polishing pad with extremely flatness, that is, a polishing pad with excellent polishing uniformity of a member to be polished, can be obtained by a method of applying a flattening film and etching back or a method of polishing with a polishing apparatus. Further, the processing time required for flattening the polishing pad is extremely short since the flattening is performed by etch back or polishing, so that an inexpensive polishing pad can be obtained. In addition, since grooving is performed using lithography technology and dry etching technology, grooving can be performed with extremely high precision and high throughput, and an inexpensive polishing pad excellent in polishing characteristics can be obtained. . The polishing pad manufactured in this manner has extremely good step-elimination characteristics and uniform polishing properties of the semiconductor device pattern to be polished by the polishing pad.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for manufacturing a polishing pad according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a method for manufacturing a polishing pad according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating polishing by CMP.

FIG. 4 is a view showing a conventional method for manufacturing a polishing pad.

[Explanation of symbols]

 11, 21 · base material layer 12, 22 · planarization film 13, 24 · resist mask for groove pattern formation 14, 25 · groove 23 ··· polishing table 31 ··· polishing table 32 ··· Polishing pad 33 ··· Polishing head 34 ··· Wafer 35 ··· Abrasive supply nozzle 36 ··· Abrasive 37 ··· Oscillating motion 41 ··· Cutting needle 43 ···・ ・ Stage 44 ・ ・ ・ ・ ・ ・ Groove pattern 36 ・ ・ ・ ・ Abrasives 38 and 39 ・ Planarized base material layer surface 40 ・ ・ ・ ・ Polishing device 41 ・ ・ ・ ・ Polishing pad

Claims (14)

[Claims] 1. A polishing pad for polishing a member to be polished by interposing an abrasive between the member and a member to be polished and giving relative movement to the member to be polished, wherein the polishing pad comprises: The resist layer applied to the surface of the base material layer serving as a base material is patterned by lithography into a desired shape, and is formed by etching the surface of the base material layer by an etching method using the resist layer as a mask. A polishing pad comprising an abrasive layer having a groove. 2. The polishing pad according to claim 1, wherein said etching method is a dry etching method or a wet etching method. 3. The polishing pad according to claim 1, wherein said lithography method includes a step of exposing a pattern having a desired shape to a resist surface by a stepper. 4. The base material layer, a flattening layer is applied on the base material layer surface, and the flattening layer and the surface of the base material layer are etched back at substantially the same etching rate by etch back. The polishing pad according to claim 1, wherein the polishing pad is planarized. 5. The polishing pad according to claim 4, wherein a resist layer is used as said flattening layer. 6. The polishing pad according to claim 4, wherein a polyimide layer is used as said flattening layer. 7. The polishing pad according to claim 1, wherein a surface of said base material layer is flattened by polishing using a polishing apparatus. 8. The polishing pad according to claim 4, wherein the flatness of the surface of the polishing material layer is ± 2 μm or less in pp. 9. The polishing pad according to claim 1, wherein the width of the groove is 100 μm or less. 10. A polishing agent is interposed between the polishing member and a member to be polished,
Polishing the member to be polished by giving relative movement between the member to be polished, a method for manufacturing a polishing pad comprising an abrasive layer, wherein the manufacturing method, the base material of the abrasive layer and Patterning the resist layer applied to the surface of the base material layer into a desired shape by lithography, and etching the base material layer using the resist layer as a mask by an etching method to form a surface on the base material layer. Forming a groove. 11. A step of applying a flattening film to the surface of the substrate layer before the step of patterning the resist layer applied to the surface of the substrate layer into a desired shape by lithography. 11. The method of manufacturing a polishing pad according to claim 10, further comprising a step of etching back the flattening film and the surface of the base material layer at substantially the same etching rate and flattening. 12. Before the step of patterning the resist layer applied to the surface of the base material layer into a desired shape by lithography, the surface of the base material layer is further polished by a polishing apparatus. The method for manufacturing a polishing pad according to claim 10, further comprising: 13. The polishing pad according to claim 1, wherein said member to be polished is a semiconductor wafer. 14. The method according to claim 10, wherein the member to be polished is a semiconductor wafer.