CN211163459U

CN211163459U - Chemical mechanical polishing retaining ring and chemical mechanical polishing bearing head

Info

Publication number: CN211163459U
Application number: CN202020560952.XU
Authority: CN
Inventors: 孟松林; 赵德文; 李长坤; 倪孟骐
Original assignee: Huahaiqingke Co Ltd
Current assignee: Huahaiqingke Co Ltd
Priority date: 2020-04-16
Filing date: 2020-04-16
Publication date: 2020-08-04
Anticipated expiration: 2030-04-16

Abstract

The utility model discloses a chemical mechanical polishing retaining ring and chemical mechanical polishing bearing head, the chemical mechanical polishing retaining ring comprises an annular part, the annular part comprises a metal part and a non-metal part, the metal part is arranged on the upper side of the non-metal part and is combined to form a laminated structure through a bonding layer; the top surface and the outer side surface of the metal part are coated with protective layers so as to prevent metal ions and other pollutants from influencing the wafer manufacturing process.

Description

Chemical mechanical polishing retaining ring and chemical mechanical polishing bearing head

Technical Field

The utility model belongs to the technical field of the chemical mechanical polishing, particularly, relate to a chemical mechanical polishing retaining ring and chemical mechanical polishing bear head.

Background

Chemical Mechanical Polishing (CMP) is an ultra-precise surface processing technique for global Planarization. The polishing method generally attracts a substrate to a lower portion of a carrier head, the bottom surface of the substrate having a deposition layer abuts against a rotating polishing pad, and the carrier head is driven by a driving part to rotate in the same direction as the polishing pad and to apply a downward load to the substrate; meanwhile, the polishing solution is supplied between the polishing pad and the substrate, and the material removal of the substrate is realized under the combined action of chemistry and machinery.

The problems that the surface of the substrate is scratched by metal pollutants and/or the metal pollutants exceed the standard easily occur in the chemical mechanical polishing process, which are unacceptable in the field of chip manufacturing. Generally, once the surface of the substrate is scratched by or exceeds the metal contaminant level, all the related consumables may need to be replaced, thereby greatly increasing the production cost and reducing the production efficiency. Patent CN107301960A discloses that metal ion contaminants have strong mobility in semiconductor materials, and the metal ion contaminants cause oxide-polysilicon gate structure defects, PN junction leakage current increase, and threshold voltage change, which are serious hazards to device reliability.

The retaining ring may generally consist of a metallic part and a non-metallic part. In the chemical mechanical polishing process, the substrate may collide with the metal portion, and metal ion contamination is easily generated. In addition, since the polishing liquid has a strong corrosion and crystallization effect, the metal portion of the retaining ring is also easily contaminated with the polishing liquid and/or the cleaning liquid, which causes damage to the wafer surface due to crystal contaminants, corrosion debris, and the like.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art to at least a certain extent. To this end, the present invention provides in a first aspect a cmp retaining ring, comprising an annular portion including a metal portion and a non-metal portion, the metal portion being disposed on an upper side of the non-metal portion and bonded by an adhesive layer to form a laminated structure; wherein, the top surface and the lateral surface of metal portion coat the inoxidizing coating, the thickness of inoxidizing coating is 0.01 mu m-50 mu m.

As a preferred embodiment, the inner side of the metal part is also coated with a protective layer having a thickness of 0.1-5 μm.

In a preferred embodiment, the surface roughness Ra of the inner side surface, the top surface and the outer side surface of the metal part is 6.3 to 25 μm.

As a preferred embodiment, the protective layer covers the adhesive layer between the metal part and the non-metal part.

As a preferred embodiment, the top surface of the metal part is provided with a threaded sleeve, and the inner part and the top surface of the threaded sleeve are coated with a protective layer; the protective layer is made of parylene and the thickness of the protective layer is 0.01-0.1 μm.

In a preferred embodiment, the protective layer is a fluororesin hydrophobic coating.

In a preferred embodiment, the protective layer is parylene.

As a preferred embodiment, an adhesion enhancement layer is further coated between the metal part and the protective layer to enhance the adhesion between the protective layer and the metal part; the adhesion enhancement layer is a polymer adhesive with a thickness of 0.01-5 μm.

As a preferred embodiment, the protective layer is a thermoplastic polymer, which is Polytetrafluoroethylene (PTFE).

A second aspect of the present invention provides a cmp carrier head comprising a cmp retaining ring as defined in any one of the above.

The utility model discloses a chemical mechanical polishing retaining ring and chemical mechanical polishing bear head, top surface, medial surface and the lateral surface of the metal part of retaining ring are provided with resistant coating, and it can effectively protect the metal part of retaining ring, prevents that metal part from taking place to collide with and producing metal ion and polluting with other parts, avoids the influence of metal ion pollution to chemical mechanical polishing production.

Drawings

The advantages of the invention will become clearer and more easily understood from the detailed description given with reference to the following drawings, which are given by way of illustration only and do not limit the scope of protection of the invention, wherein:

FIG. 1 is a schematic view of a CMP retaining ring according to the present invention;

FIG. 2 is a schematic view of a first embodiment of the retaining ring of the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is a schematic structural view of a second embodiment of the retaining ring of the present invention;

fig. 5 is a schematic structural view of a third embodiment of the retaining ring of the present invention;

fig. 6 is a schematic structural view of a fourth embodiment of the retaining ring of the present invention;

fig. 7 is a schematic structural view of a fifth embodiment of the retaining ring of the present invention;

FIG. 8 is a schematic structural view of the carrier head for chemical mechanical polishing according to the present invention.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the following embodiments and accompanying drawings. The embodiments described herein are specific embodiments of the present invention and are provided to illustrate the concepts of the present invention; the description is intended to be illustrative and exemplary and should not be taken to limit the scope of the invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification thereof, and these technical solutions include technical solutions which make any obvious replacement or modification of the embodiments described herein.

The drawings in the present specification are schematic views to assist in explaining the concept of the present invention, and schematically show the shapes of the respective portions and the mutual relationships thereof. It should be understood that the drawings are not necessarily to scale, the same reference numerals being used to identify the same elements in the drawings in order to clearly illustrate the structure of the various elements of the embodiments of the invention.

In the present invention, "Chemical Mechanical Polishing" is also referred to as "Chemical Mechanical Planarization (CMP)" and "substrate" is also referred to as "wafer", and the meaning and the actual function are equivalent.

Fig. 1 is a schematic structural view of a cmp retainer ring 1 according to the present invention. A chemical mechanical polishing retaining ring 1 comprises an annular part 10, wherein the annular part 10 comprises a metal part 11 and a non-metal part 12, and the metal part 12 is arranged on the upper side of the non-metal part 12 and is combined into a laminated structure through an adhesive layer 14. In the embodiment shown in fig. 1, the top and inner side of the metal part 11 is provided with a protective layer 20, wherein the protective layer 20 has a thickness of 0.05 μm. The protective layer 20 is uniformly disposed on the top surface 11a and the inner side surface of the metal part 11 to prevent the metal part 11 of the retaining ring 1 from colliding with foreign objects to cause metal ion pollution.

As an embodiment of the present invention, the top surface 11a and the outer side surface 11b of the metal part 11 of the ring part 10 are provided with a protective layer 20, as shown in fig. 2. The illustration is for the sake of clarity of the position of the protective layer 20, and the actual thickness is in the order of micrometers. Fig. 3 shows a partial enlarged view at a in fig. 2, and in this embodiment, the top surface 11a and the outer side surface 11b of the metal portion 11 are equal in thickness, and have a thickness of 0.85 μm. As a variation of this embodiment, the thickness of the top surface 11a of the metal part 11 may be slightly smaller than the thickness of the outer side surface 11 b.

In the embodiment shown in fig. 2, the protective layer 20 on the outer side surface 11b of the metal part 11 needs to cover the adhesive layer 14 between the metal part 11 and the nonmetal part 12 to prevent the contaminants generated by polishing from gathering at the adhesive layer 14 to generate the crystallization of contaminant particles. In some embodiments, the length of protective layer 20 of outer side 11b is 1.1-1.3 times the height of metal portion 11. Preferably, the length of the protective layer 20 of the outer side 11b is 1.2 times the height of the metal part 11. Furthermore, the utility model discloses the mode of setting that inoxidizing coating 20 covers adhesive linkage 14 can also prevent effectively that adhesive linkage 14 from dropping between metal part 11 and the nonmetal portion 12, prevents the influence of dropping to the chemical mechanical polishing of adhesive linkage 14.

As another embodiment of the present invention, the thickness of the protective layer 20 is 0.01 μm to 50 μm. Preferably, the thickness of the protective layer 20 is 0.05 μm to 10 μm, so as to prevent foreign objects from colliding with the metal part 11 of the retaining ring 1 to generate metal ion contamination.

Fig. 4 shows a schematic view of another embodiment of the retaining ring, in which the inner side 11c of the metal part 11 is also provided with a protective layer 20, the thickness of the protective layer 20 being 0.1 μm to 5 μm. The thickness of the protective layer 20 on the inner side 11c is equal to the thickness of the protective layer 20 on the top side 11a and the outer side 11 b. In the embodiment shown in fig. 4, the protective layer 20 has a thickness of 0.5 μm.

In one embodiment of the present invention, the surface roughness Ra of the inner surface 11c, the top surface 11a, and the outer surface 11b of the metal part 11 is 6.3 μm to 25 μm. Preferably, the surface roughness Ra of the inner side surface 11c, the top surface 11a, and the outer side surface 11b of the metal part 11 is 12.5 μm. The surface roughness of metal portion 11 of the guard ring is set so as to improve the adhesion between protective layer 20 and metal portion 11, thereby improving the reliability of the adhesion and fixation of protective layer 20. In addition, the surface roughness of the metal portion is not easily set to be excessive, which may cause the accumulation of polishing contaminants.

In the embodiment shown in fig. 1, the top side of the metal part 11 of the retaining ring 1 is provided with a threaded sleeve 13, and a locking bolt secures the retaining ring 1 to the lower part of the carrier head by means of the threaded sleeve 13. In order to avoid metal ion contamination caused by the installation and removal of the retainer ring 1, a protective layer 20 is provided on the top surface and inside of the threaded sleeve 13. In the embodiment shown in fig. 1, the protective layer 20 is parylene and has a thickness of 0.01 μm to 0.1 μm. Parylene is a family of thermoplastic polymers synthesized from p-xylene. As an embodiment of the present invention, the thickness of the protective layer of the top surface of the thread bush 13 is 0.05 μm, which is verified to be increased to not more than 50 μm and not less than 0.01 μm in industrial practice, and the thickness of the protective layer inside the thread bush 13 is 0.08 μm. The protective layer has certain self-lubricity, and can ensure the assembly smoothness of the locking bolt and the threaded sleeve 13. The parylene can be obtained by vapor deposition at room temperature. Thin films of any thickness in the hundreds of microns can be produced using vapor deposition techniques. The vacuum deposited parylene has the excellent characteristics of uniformity, shape retention, no defect of micropores, inactive chemical property and the like, and can effectively prevent foreign objects from colliding with the metal part 11 of the retaining ring 1 to generate metal ion pollution. In addition, the protective layer 20 disposed on the metal part 11 has a surface defect capable of preventing particle contaminants generated during a polishing process from being attached to the retainer ring, so as to reduce scratching or scratching of the substrate caused by crystal falling of the upper portion of the retainer ring, thereby improving the yield of polishing of the substrate.

As an embodiment of the present invention, the protective layer 20 may be a fluorine resin type hydrophobic coating layer. The fluororesin hydrophobic coating is a coating taking fluororesin as a main film forming substance. Because fluorine element with large electronegativity is introduced into the fluororesin coating, the carbon-fluorine bond energy is strong, and the fluororesin hydrophobic coating has good weather resistance, heat resistance, low temperature resistance, chemical resistance, unique non-adhesiveness and low friction. Therefore, the fluororesin-based hydrophobic coating can effectively prevent the metal portion 11 of the retainer ring 1 from colliding with foreign objects to cause metal ion contamination.

As another embodiment of the present invention, the fluororesin-based hydrophobic coating layer is polyvinylidene fluoride (PVDF), which may be any one or more of tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-polychlorotrifluoroethylene copolymer (ECTFE), and polychlorotrifluoroethylene (CTFE).

As another embodiment of the present invention, in order to increase the adhesion of the protective layer 20 to the ring portion 10 of the retaining ring 1, an adhesion enhancing layer 30 may be provided between the protective layer 20 and the ring portion 10, as shown in fig. 5. The thickness of the adhesion enhancing layer 30 is between 1/5-1/2 of the thickness of the protective layer 20. In some embodiments, the adhesion enhancing layer 30 is a polymer adhesive disposed between the protective layer 20 and the ring portion 10 to increase the adhesion of the protective layer 20, so as to ensure that the protective layer 20 of the retaining ring 1 is reliably fixed to the inner side, the top side and the outer side of the metal portion 11. As a variation of this embodiment, the outer side surface of the metal part 11 is more likely to be collided with by a foreign object than the top surface and the inner side surface of the metal part 11, and therefore, an adhesion reinforcing layer 30 may be provided between the outer side surface of the metal part 11 and the protective layer 20. In some embodiments, the adhesion promotion layer 30 is a polymeric adhesive having a thickness of 0.01 μm to 5 μm. In some embodiments, the adhesion promotion layer 30 may also have a thickness of 5 μm to 15 μm. The utility model discloses in, the polymer binder who uses comprises synthetic emulsion, penetrant, protective agent, reinforcer and thickener, and its volume ratio is as follows, synthetic emulsion: penetrant: a protective agent: reinforcing agent: the thickening agent is 40: 30: 5: 15:10.

In order to increase the adhesion between the protective layer 20 and the metal part 11 of the ring part 10, before the protective layer 20 is coated, the surface of the metal part 11 needs to be subjected to sand blasting to change the roughness of the top surface, the inner side surface and/or the outer side surface of the metal part 11, so that the surface roughness of the metal part 11 is more suitable for the adhesive fixation of the protective layer 20. Preferably, the surface roughness Ra of the metal part 11 obtained by the blast treatment is 6.3 μm.

As another embodiment of the present invention, the protective layer 20 may be a thermoplastic polymer. In some embodiments, protective layer 20 may be Polytetrafluoroethylene (PTFE) with a thickness of 0.2 μm. The polytetrafluoroethylene has good chemical stability and corrosion resistance, and can effectively protect the metal part 11. The teflon may be sprayed on the top, inner, and outer sides of the metal part 11. Specifically, the protective layer 20 is made of ultra-fine polytetrafluoroethylene powder, and is sprayed on the top surface, the inner side surface, and the outer side surface of the metal part 11. In some implementations, the ultrafine polytetrafluoroethylene powder is nano-sized and has an average particle size of 5nm to 50 nm. As a variation of this embodiment, the protective layer 20 may be Polyethylene (PE), polymethyl methacrylate (PMMA), Polycarbonate (PC), Polyurethane (PU), polypropylene (PP), Polystyrene (PS), polyvinyl chloride (PVC), Nylon (Nylon), polyethylene terephthalate (PET), and/or Polyoxymethylene (POM), etc.

Fig. 6 is a schematic view of another embodiment of the cmp retaining ring of the present invention, in which the top and inner surfaces of the metal part 11 are provided with a protective layer 20a made of a thermoplastic polymer, such as polyethylene; and the outer side of the metal part 11 is provided with a protective layer 20b composed of a fluororesin hydrophobic coating, such as parylene (parylene), so that the metal part 11 of the retaining ring 1 is effectively protected, and the retaining ring is prevented from colliding with a foreign object to generate metal ion pollution.

As an embodiment of the present invention, since the protective layer 20 needs to cover the adhesive layer 14 between the metal part 11 and the nonmetal part 12, i.e. the protective layer 20 needs to go over the adhesive layer 14 and partially coat the nonmetal part 12. In order to enhance the adhesive strength between the protective layer 20 and the nonmetal part 12, an adhesion enhancing layer 30 may be provided between the protective layer 20 and the nonmetal part 12, as shown in fig. 7, and in this embodiment, the thickness of the adhesion enhancing layer 30 is 0.1 μm. In some embodiments, the non-metallic portion 12 is made of polyphenylene sulfide (PPS). The thickness of the protective layer 20 arranged on the inner side surface and the outer side surface corresponding to the non-metal part 12 is slightly smaller than that of the protective layer 20 corresponding to the metal part 11. The protective layers at the two positions are in smooth transition so as to prevent edges and corners or salient points from occurring and increase the probability of collision.

Use chemical mechanical polishing retaining ring and the retaining ring of current no inoxidizing coating produce and compare the experiment, it is easy to understand, except that the retaining ring has or not the inoxidizing coating, other hardware of the chemical mechanical polishing of use and its configuration of software are all unanimous. The experimental results obtained are shown in table 1.

TABLE 1 Hold Loop alignment Experimental results

Guard ring type	Metal ion contamination (%)	Wafer scratch (%)
			Protective-layer-free retaining ring	5‰	0.3‰
Retaining ring with protective layer	0.04‰	0.1‰

As can be seen from the data in table 1, the probability of metal ion contamination using a protective-layer-free retaining ring is 5%, and the probability of wafer surface scratching is 0.3%; after the retaining ring with the protective layer is used, the probability of metal ion pollution is reduced to 0.04 per thousand, and the probability of scratching the surface of the wafer is also reduced. To sum up, chemical mechanical polishing retaining ring can effectively reduce the emergence that metal ion pollutes, simultaneously, it also can solve to a certain extent that the crystallization of polishing process particle pollutant drops and fish tail or fish tail wafer surface's problem.

The second aspect of the present invention provides a chemical mechanical polishing carrier head, a structural schematic diagram of a chemical mechanical polishing carrier head 2, as shown in fig. 8, which includes the above-mentioned retaining ring 1. The top surface, the inner side surface and the outer side surface of the metal part 11 of the retaining ring 1 are provided with the protective layers 20, so that the anti-collision performance of the retaining ring is improved, and metal ion pollution caused by collision between a foreign object and the metal part of the retaining ring is effectively prevented.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A chemical mechanical polishing retaining ring, comprising an annular part, wherein the annular part comprises a metal part and a non-metal part, the metal part is arranged on the upper side of the non-metal part and is combined to form a laminated structure through an adhesive layer, the surface roughness Ra of the inner side surface, the top surface and the outer side surface of the metal part is between 6.3 μm and 25 μm, the top surface and the outer side surface of the metal part are coated with protective layers, the thickness of each protective layer is between 0.01 μm and 50 μm, and the protective layers cover the adhesive layer between the metal part and the non-metal part.

2. The cmp retaining ring of claim 1, wherein the top surface of the metal portion is provided with a threaded sleeve, the interior and top surface of the threaded sleeve being coated with a protective layer; the protective layer is made of parylene, and the thickness of the protective layer is 0.1-10 mu m.

3. The cmp retaining ring of claim 1, wherein the protective layer is a hydrophobic coating of a fluorocarbon resin type.

4. The cmp retaining ring of claim 1, wherein an adhesion enhancing layer is further coated between the metal portion and the protective layer to enhance adhesion of the protective layer to the metal portion; the adhesion enhancement layer is a polymer adhesive with a thickness of 0.01-10 μm.

5. The chemical mechanical polishing retaining ring of claim 1, wherein the protective layer is a thermoplastic polymer that is Polytetrafluoroethylene (PTFE).

6. A chemical mechanical polishing carrier head, comprising: comprising the chemical mechanical polishing retaining ring of any one of claims 1-5.