CN216759447U - Chemical mechanical polishing pad - Google Patents

Abstract

The utility model discloses a chemical mechanical polishing pad. The chemical mechanical polishing pad of the present invention comprises an upper polishing layer and a lower polishing layer; the upper polishing layer is arranged on the surface of the lower polishing layer in a sticking mode, and a buffer layer is eliminated, so that the chemical mechanical polishing pad can be directly used; the upper polishing layer is a prism array layer, and grooves are formed between adjacent prisms. Therefore, the grooving is not required to be processed in a milling mode, the waste of raw materials is reduced, the manufacturing cost of the polishing pad is reduced, meanwhile, the residues of chips in the groove caused by milling are avoided, and the quality of the produced wafer is improved. Moreover, the prism of the upper polishing layer is a polygonal prism, so that the distribution uniformity of polishing solution can be improved, the polishing outflow time can be effectively delayed, and the utilization rate of the polishing pad can be improved.

Description

Chemical mechanical polishing pad

Technical Field

The utility model relates to the technical field of chemical mechanical polishing, in particular to a chemical mechanical polishing pad.

Background

In recent years, in order to reduce the production cost of silicon integrated circuits, the size of silicon wafers is gradually increased, the integration degree of electronic components thereon is higher, and the specific size of devices is also continuously reduced. In the processing process, in order to ensure the photoetching quality, the surface flatness of the silicon wafer is required to reach the nanometer level. Chemical mechanical polishing is currently the only method that achieves this goal. The polishing pad plays a role in physical polishing, carrying polishing solution and the like in the chemical mechanical polishing process, and the product quality of the polishing pad is very important to the processing quality.

The surface of the traditional polishing pad is a smooth surface, the smooth polishing pad has uneven surface pressure distribution in the chemical mechanical polishing process, and the mobility of polishing liquid is poor, so that the problems of over-polishing, scratching and the like of the surface of a silicon wafer are caused, and the problem is mainly solved by a mode of slotting the surface of the polishing pad at present. Researches show that the radial grooves on the surface of the polishing pad can improve the polishing liquid capacity, take away chips generated in the polishing process and reduce the surface scratch of a silicon wafer, and the circumferential grooves are beneficial to storing liquid and improving the utilization rate of the polishing liquid. At present, the common groove shapes include an involute type along the radial direction, a radial type, a concentric circular ring type along the circumferential direction, a logarithmic spiral type, and a grid type in which the directions of the X and the Y are mutually perpendicular, for example, patent CN106564004B discloses a polishing pad with a radial groove and a circumferential groove, which utilizes a circumferential central symmetrical groove and a radial linear groove to improve the uniformity of the flow of polishing solution and improve the product yield.

However, in the current polishing pad surface grooving method, grooves are formed directly and integrally on the surface of the overall polishing layer by surface milling, which needs to sacrifice a large part of raw materials, resulting in a high polishing pad preparation cost; moreover, the precision of the milling technology and the protection of the polishing layer are limited, the grooves are narrow, and scraps are easy to remain in the grooves during processing, so that the surface of the wafer is scratched during chemical mechanical polishing; meanwhile, the grooves are prone to have the condition that the surfaces are uneven and cannot be trimmed, and the quality of the produced wafers is further influenced in the chemical mechanical polishing production process.

SUMMERY OF THE UTILITY MODEL

The utility model provides a chemical mechanical polishing pad, aiming at solving the problems that the smooth surface of the existing polishing pad can cause poor mobility of polishing liquid, and the preparation cost of the polishing pad is higher and the quality of a produced wafer is influenced due to the improvement of the mobility of the polishing liquid by slotting the surface. The chemical mechanical polishing pad is composed of an upper polishing layer and a lower polishing layer, wherein the upper polishing layer is composed of a prism array, the prism array of the upper polishing layer is additionally arranged on the lower polishing layer, and grooves allowing a polishing solution to flow are formed between the prisms.

The purpose of the utility model is realized by the following technical scheme.

A chemical mechanical polishing pad includes a lower polishing layer and an upper polishing layer; the upper polishing layer is arranged on the lower polishing layer; the upper polishing layer is a prism array layer and comprises a plurality of prisms arranged in an array, and a groove is formed between every two adjacent prisms; the lower polishing layer and the upper polishing layer may be the same or different materials.

In a preferred embodiment, an adhesive layer is provided between the upper polishing layer and the lower polishing layer; the upper polishing layer is adhered to the surface of the lower polishing layer through the adhesive layer.

In a more preferred embodiment, the adhesive layer is a double-sided adhesive tape, and the double-sided adhesive tape comprises a PET (polyethylene terephthalate) support layer as a middle layer and pressure-sensitive glues positioned on two sides of the PET support layer.

More preferably, the thickness of the double-sided adhesive tape is more than or equal to 50 mu m and less than or equal to 150 mu m.

In a preferred embodiment, the lower polishing layer is the same material as the upper polishing layer and is polyurethane.

In the preferred embodimentIn the examples, the lower polishing layer was circular, had an area Sa, and was 280000mm²≤Sa≤2100000mm²。

In a more preferred embodiment, the area Sa of the lower polishing layer is 2009600mm²。

In preferred embodiments, the lower polishing layer has a thickness H1 and 0.5H 1 3mm, more preferably 1mm, 1.2mm, or 3 mm.

In preferred embodiments, the lower polishing layer has a hardness of R1 and 20D R1 40D, more preferably 20D, 25D, or 40D.

Further preferably, the hardness of the upper polishing layer is R2, and R1 ≦ R2 ≦ 41D.

In a preferred embodiment, the total area of the upper polishing layer is Sb, and 0.70 Sb/Sa is 0.95.

In a preferred embodiment, the upper polishing layer has a thickness H2 and 0.5H 2 2mm, more preferably 0.5mm or 1.5 mm.

In a preferred embodiment, the width of the groove is W, and W is more than or equal to 0.2mm and less than or equal to 1.5 mm.

In a preferred embodiment, the chemical mechanical polishing pad of any of the above, the prism is a polygonal prism.

Further preferably, the prism is a hexagonal prism or an octagonal prism.

In a more preferred embodiment, the prisms are hexagonal prisms.

Compared with the prior art, the utility model has the following advantages and beneficial effects:

the chemical mechanical polishing pad comprises an upper polishing layer and a lower polishing layer, wherein the upper polishing layer is arranged on the surface of the lower polishing layer in a prism structure mode in a sticking mode, so that grooves do not need to be machined on the surface of the polishing layer in a milling mode, waste of raw materials is reduced, and the manufacturing cost of the polishing pad is reduced; meanwhile, the mode of additional arrangement is adopted, the technical limit of arrangement of the groove is reduced, the size and the surface finish degree of the groove can be accurately designed, the residue of chips caused by milling in the groove is avoided, the scratch rate of the surface of the wafer in the chemical mechanical polishing production process is effectively reduced, the surface finish degree of the produced product is high, and the quality of the produced wafer is improved.

In the chemical mechanical polishing pad, the prism of the upper polishing layer is a polygonal prism, particularly preferably a hexagonal prism, and compared with the traditional groove in the types of involute type, radial type or concentric circular ring type, logarithmic spiral type and the like along the circumferential direction, the chemical mechanical polishing pad has the advantages that the splitting effect of polishing liquid is better, the distribution uniformity of the polishing liquid can be improved, the polishing outflow time is effectively delayed, and the utilization rate of the polishing pad is improved.

In addition, hardness, area ratio and the like of the upper polishing layer and the lower polishing layer are preferably adjusted, and a buffer layer is abandoned, so that the chemical mechanical polishing pad can be directly used, the manufacturing cost of the polishing pad is further reduced, and the use efficiency is improved.

Drawings

FIG. 1 is a top view of a chemical mechanical polishing pad of the present invention in an exemplary embodiment;

FIG. 2 is a schematic sectional view taken along the line A-A in FIG. 1;

FIG. 3 is an enlarged partial top view of a chemical mechanical polishing pad of the present invention in an exemplary embodiment;

FIG. 4 is a schematic view of a stamped cut configuration of the lower polishing pad;

FIG. 5 is a schematic view of the flow structure of a polishing solution on a chemical mechanical polishing pad of the present invention;

the attached drawings are marked as follows: 1-lower polishing layer, 2-upper polishing layer, 201-prism, 202-groove, 3-blank.

Detailed Description

The technical solutions of the present invention are further described in detail below with reference to specific examples and drawings, but the scope and implementation of the present invention are not limited thereto.

In the description of the specific embodiments, it should be noted that the terms "upper", "lower", "bottom", "top", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships where the products of the utility model are usually placed when the products of the utility model are used, and the terms "first", "second", and the like are used for convenience of distinction and are only used for convenience of description and simplification of description, but do not indicate or imply that the structures or elements referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore are not to be construed as limiting the utility model, and are not intended to indicate or imply relative importance.

Unless expressly stated or limited otherwise, the terms "mounted," "disposed," "connected," "secured," and the like are to be construed broadly and encompass, for example, both fixed and removable connections or integral parts thereof; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

Example one

The chemical mechanical polishing pad can be used as a polishing pad of a wafer silicon chip, and can be directly used in the production of the wafer silicon chip to carry out chemical mechanical polishing on the surface of the silicon chip and produce and obtain the wafer silicon chip with high surface flatness.

Referring to fig. 1 and 2, the chemical mechanical polishing pad has a polishing layer, and the polishing layer is specifically composed of an upper polishing layer and a lower polishing layer, and specifically includes a lower polishing layer 1 and an upper polishing layer 2. Wherein, the lower polishing layer 1 is a basic layer and has a supporting function; the upper polishing layer 2 is arranged in particular in an applied manner on the lower polishing layer 1 and forms together with the upper polishing layer 1 a polishing layer having functional utility.

The shape and size of the lower polishing layer 1 are not particularly limited, and may be designed according to practical requirements, for example, in the illustrated preferred embodiment, the lower polishing layer 1 is circular. Further, the area of the lower polishing layer 1 was defined as Sa, and 280000mm²≤Sa≤2100000mm²。

Further, in another preferred embodiment, the thickness of the lower polishing layer 1 is defined as H1, and 0.5 ≦ H1 ≦ 3 mm. In more preferred embodiments, the thickness H1 of the lower polishing layer 1 can be 1mm, 1.2mm, or 3 mm.

The materials of the lower polishing layer 1 and the upper polishing layer 2 are selected from conventional polishing layer materials, such as polyurethane, non-woven fabric or a composite material of the polyurethane and the non-woven fabric. Moreover, the materials of the lower polishing layer 1 and the upper polishing layer 2 are independently selected, i.e., the materials of the lower polishing layer 1 and the upper polishing layer 2 can be the same or different; as in the preferred embodiment shown, the material of the lower polishing layer 1 and the material of the upper polishing layer 2 are both selected to be the same material, in particular, polyurethane.

Referring to fig. 2 and 3, in the chemical mechanical polishing pad, the upper polishing layer 2 is embodied as a prism array layer, that is, the upper polishing layer 2 includes a plurality of prisms 201, specifically, a plurality of prisms 201 arranged according to actual sizes, and the plurality of prisms 201 jointly constitute the upper polishing layer 2. Specifically, the plurality of prisms 201 may be arranged in a regular array or randomly according to actual production requirements; in the preferred embodiment shown, a plurality of prisms 201 are arranged in a regular array.

Moreover, in some prisms 201, two adjacent prisms 201 are not disposed next to each other, but have a distance therebetween, so that a groove 202 is formed between the adjacent prisms 201. In the production of wafer silicon wafers, the polishing solution carried by the chemical mechanical polishing pad can flow in the grooves 202, so that the fluidity of the polishing solution is improved. The pitch of the prisms 201 can be designed according to practical requirements, for example, in a preferred embodiment, please refer to fig. 3, the width of the groove 202 is defined as W, and W is greater than or equal to 0.2mm and less than or equal to 1.5 mm.

Further, the shape and size of the prisms 201 are not particularly limited, and may be designed according to practical requirements, for example, the shape of the prisms 201 may be preferably polygonal prisms, so that the grooves 202 between adjacent prisms 201 have uniform size and shape, and the flow uniformity of the polishing liquid on the entire polishing pad is good. In addition, on the circumference of the polygonal prism 201, based on the fixed included angle between each edge of the polygon, a plurality of grooves 202 with different flow directions can be formed between the single prism 201 and the plurality of prisms 201 around the single prism 201, so that the flow dividing effect of the polishing solution is better, the distribution uniformity of the polishing solution can be improved, the polishing outflow time is effectively delayed, and the utilization rate of the polishing pad is improved.

Go up polishing layer 2 plus the form that sets up on last polishing layer 1 and be unlimited, can adjust according to the reality, go up polishing layer 2 and can install after the shaping alone earlier and put on last polishing layer 1 again, need not directly to mill by whole polishing layer, can adopt including embedded or the mode of pasting like the mode that polishing layer 2 specifically set up on lower polishing layer 1. For example, in an embedded mode, an embedded slot hole corresponding to the prism 201 can be formed in the upper surface of the lower polishing layer 1, then the prism 201 is embedded and assembled to the upper surface of the lower polishing layer 1, and the embedded slot hole and the prism 201 can be sealed by glue and the like; in the adhering mode, the bottom of the prism 201 and the upper surface of the lower polishing layer 1 may be adhered by adhesion, so that the prism 201 is adhered to the lower polishing layer 1, for example, the bottom of the prism 201 may be directly adhered to the upper surface of the lower polishing layer 1 by adhesive or glue.

Similarly, the shape and size of the prisms 201 of the upper polishing layer 2 are not particularly limited, and may be designed according to practical requirements. As shown in the preferred embodiment, the total area of the upper polishing layer 2 is defined as Sb, and 0.70. ltoreq. Sb/Sa. ltoreq.0.95. In another preferred embodiment, the upper polishing layer 2 is defined to have a thickness H2 and 0.5H 2 2mm, more preferably 0.5mm or 1.5 mm.

Further, the hardness of each of the lower polishing layer 1 and the upper polishing layer 2 is not particularly limited, and may be determined according to actual requirements and by the selected material. In a preferred embodiment, the lower polishing layer 1 and the upper polishing layer 2 are both made of polyurethane, and the hardness of the lower polishing layer 1 is defined as R1, and 20D R1D 40D, more preferably 20D, 25D or 40D; the hardness of the upper polishing layer 2 is R2, and R1 is not less than R2 is not less than 41D.

In a preferred embodiment, the upper polishing layer 2 is attached to the surface of the lower polishing layer 1 by means of a double-sided adhesive tape. In the manufacturing process of the polishing pad formed by adopting the sticking mode, specifically, the lower polishing layer 1 can be prepared and formed into a layer structure with a smooth surface by adopting a die; in the manufacturing of the upper polishing layer 2, please refer to fig. 4, the blank 3 is taken, the double-sided adhesive tape and the substrate are adhered to the bottom of the blank 3, the blank is cut into a plurality of prisms 201 by a punching and cutting method, and then the upper polishing layer 2 is obtained, and the substrate is removed; then, the prism 201 is adhered to the lower polishing layer 1 with a clean upper surface by a double-sided adhesive tape, so as to form the chemical mechanical polishing pad.

The double-sided adhesive tape has good adhesive force and is thin, the prism 201 and the lower polishing layer 1 are well adhered through the thin double-sided adhesive tape, and meanwhile the space occupancy rate of the whole polishing pad structure by the adhesive layer formed by the double-sided adhesive tape is small, so that the use effect of the whole polishing pad is prevented from being affected. In a preferred embodiment, the adopted double-sided adhesive has a PET support layer with a middle layer, and pressure-sensitive adhesives positioned on two sides of the PET support layer have good adhesion to the upper polishing layer 2 and the lower polishing layer 1; furthermore, the overall thickness of the double-sided adhesive tape is not less than 50 μm and not more than 150 μm.

Example two

The present embodiment is the same as the first embodiment. Further, referring to fig. 1 to 4, in the chemical mechanical polishing pad of the present embodiment, the prisms 201 are hexagonal prisms and octagonal prisms. In a more preferred embodiment, the prisms 201 are hexagonal prisms.

As shown in fig. 5, the prism 201 is designed as a hexagonal prism structure. When the chemical mechanical polishing pad is used for carrying out fine machining on a wafer silicon wafer, the polishing pad rotates anticlockwise, polishing liquid is shunted outwards along the grooves 202 between the prisms 201 and is uniformly distributed on the polishing layer, the distribution uniformity of the polishing liquid is improved, and the outflow time of the polishing liquid is effectively delayed.

EXAMPLE III

The present embodiment is the same as the first embodiment. Further, in the chemical mechanical polishing pad of the present embodiment, the materials of the lower polishing layer 1 and the upper polishing layer 2 are polyurethane, and specifically: the lower polishing layer 1 is round and has a hardness of R1, preferablyOptionally, R1 ═ 25D; the thickness of the lower polishing layer 1 is H1, preferably, H1 ═ 1.8 mm; the area of the lower polishing layer 1 is Sa, preferably, Sa is 2009600mm². The prisms 201 of the upper polishing layer 2 are hexagonal prisms with a hardness of R2, preferably, R2 ═ 32D; the upper polishing layer 2 has a thickness of H2, preferably, H2 ═ 0.8 mm; the area of the upper polishing layer 2 is Sb, preferably Sb/Sa ═ 0.85; the width W of the groove 202 is 0.7 mm.

The chemical mechanical polishing pad can be directly used in the production of wafer silicon chips, and can produce the wafer silicon chips with low surface scratch rate and high polishing precision.

The above embodiments are merely preferred embodiments of the present invention, and the technical solutions of the present invention are described in further detail, but the above descriptions are exemplary, not exhaustive, and are not limited to the disclosed embodiments, the scope and implementation of the present invention are not limited thereto, and any changes, combinations, deletions, substitutions or modifications that do not depart from the spirit and principle of the present invention are included in the scope of the present invention.

Claims (10)

1. A chemical mechanical polishing pad comprising a first polishing layer and a second polishing layer; the second polishing layer is disposed on the first polishing layer; the second polishing layer is a prism array layer and comprises a plurality of prisms arranged in an array, and a groove is formed between every two adjacent prisms; the first polishing layer and the second polishing layer may be the same or different materials.

2. The chemical mechanical polishing pad of claim 1, wherein an adhesive layer is disposed between the second polishing layer and the first polishing layer; the second polishing layer is adhered to the surface of the first polishing layer through the adhesive layer.

3. The chemical mechanical polishing pad of claim 1, wherein the first polishing layer and the second polishing layer are the same material and are polyurethane.

4. The chemical mechanical polishing pad of claim 1, wherein the first polishing layer has a circular shape, an area Sa, and a thickness of 280000mm²≤Sa≤2100000mm²。

5. The chemical mechanical polishing pad according to claim 1, wherein the first polishing layer has a thickness of H1 and 0.5. ltoreq. H1. ltoreq.3 mm.

6. The chemical mechanical polishing pad according to claim 1, wherein the first polishing layer has a hardness of R1, and 20D ≦ R1 ≦ 40D; the hardness of the second polishing layer is R2, and R1 is not less than R2 is not less than 41D.

7. The chemical mechanical polishing pad of claim 1, wherein the total area of the second polishing layer is Sb, the area of the first polishing layer is Sa, and 0.70 ≦ Sb/Sa ≦ 0.95.

8. The chemical mechanical polishing pad according to claim 1, wherein the second polishing layer has a thickness of H2 and 0.5. ltoreq. H2. ltoreq.2 mm.

9. The chemical mechanical polishing pad according to claim 1, wherein the width of the groove is W, and 0.2 mm. ltoreq. W.ltoreq.1.5 mm.

10. The chemical mechanical polishing pad according to any one of claims 1 to 9, wherein the prism is a polygonal prism.

Images