CN114619364B

CN114619364B - Method for manufacturing retaining ring for chemical mechanical polishing process

Info

Publication number: CN114619364B
Application number: CN202110464132.XA
Authority: CN
Inventors: 相红旗; 陈浩聪; 姚力军; 潘杰
Original assignee: Ningbo Yingwei Taike New Material Co ltd; Ningbo Jiangfeng Electronic Material Co Ltd
Current assignee: Ningbo Yingwei Taike New Material Co ltd; Ningbo Jiangfeng Electronic Material Co Ltd
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2023-07-28
Anticipated expiration: 2041-04-26
Also published as: CN114619364A

Abstract

The invention relates to the technical field of metal plastic composite material processing, in particular to a manufacturing method of a retaining ring for a semiconductor chip chemical mechanical polishing process. Including corrosion of stainless steel rings, combination of stainless steel rings with plastic. The invention firstly carries out corrosion treatment on the stainless steel ring to form micro holes on the surface of the stainless steel ring, and the formed holes have special closing-in structures with small surface caliber and large internal aperture, thus forming holes with the aperture of 50-1000 mu m. Then plastic is molded on the surface of the stainless steel ring in an injection molding mode, and the plastic in a molten state is pressed into the micropore holes under the action of injection molding pressure, so that after the plastic is cooled and solidified, the plastic can be firmly attached to the surface of the stainless steel ring due to the existence of the micropore closing-in structure, and meanwhile, the high polymer can be directly injected into the shape structure of a final finished product through designing an injection mold structure, so that a large number of processing procedures and a large number of processing costs are saved.

Description

Method for manufacturing retaining ring for chemical mechanical polishing process

Technical Field

The invention relates to the technical field of metal plastic composite material processing, in particular to a manufacturing method of a retaining ring for a semiconductor chip chemical mechanical polishing process.

Background

In a Chemical Mechanical Polishing (CMP) process for semiconductor chip production, a carrier polishing head for a silicon wafer is mounted with a set of carrier assemblies. The polishing head holds a silicon wafer and grinds in contact with a polishing pad mounted on a platen in a CMP apparatus, and performs chemical mechanical planarization on the surface of the silicon wafer. The surface of the silicon wafer directly faces the polishing layer, the polishing pad and the silicon wafer rotate relative to each other, and the silicon wafer is easily separated from the holding of the polishing head in the process, so that the current polishing head carrier assembly is provided with a key component, and the retaining ring can limit the position of the silicon wafer, ensure that the silicon wafer stably rubs with the polishing pad, and play a role in stabilizing the surface flatness of the silicon wafer.

Currently in conventional CMP, the retaining ring used to limit the position of the silicon wafer is composed of plastic and stainless steel. The existing production process of the retaining ring needs to firstly machine plastic and stainless steel respectively, then bond the plastic and the stainless steel with each other by using an adhesive, and finally machine the plastic and the stainless steel again to obtain a finished product. The production process is very complex, the procedures are more, the time and the labor are wasted, the loss generated by material processing is large, and the production cost is high.

In the current bonding process by using the adhesive, the large performance and structural difference between the plastic and the stainless steel often cause poor bonding, and the plastic and the stainless steel are easy to fall off and separate in the processes of stress, heat or long-time storage and use, so that the use is greatly influenced. Therefore, the production cost is reduced, the binding force between the plastic and the stainless steel in the retaining ring is improved, and the stable binding effect is the key point of the current research.

Disclosure of Invention

In order to solve the above problems, the present invention provides a method for manufacturing a retaining ring, including:

corrosion of stainless steel ring: treating the surface to be injection-molded of the stainless steel ring with corrosive liquid to obtain the stainless steel ring with micropores with a closing-in structure on the surface to be injection-molded;

combination of stainless steel ring and plastic: and (3) placing the corroded stainless steel ring into a mold, and forming plastic on the surface to be injection molded of the stainless steel ring with micropores in an injection molding mode to obtain the retaining ring. Through adjusting injection pressure, the molten plastic is pressed into the microporous structure, so that the stainless steel ring and the plastic form firm combination, and meanwhile, the plastic is directly molded into a finished product appearance structure through a die, and subsequent machining is not needed.

As a preferable technical scheme of the invention, the shape of the micropore is round, the diameter is 50-1000 mu m, and the micropore depth is 10-500 mu m.

As a preferable technical scheme of the invention, the preparation raw materials of the corrosive liquid comprise one or more of inorganic acid and organic acid, one or more of inorganic acid salt and organic acid salt, an oxidant and water as a solvent.

As a preferable technical scheme of the invention, the mass concentration of the corrosive liquid is 0.01-100g/mL, and the corrosion temperature is 0-90 ℃.

As a preferred technical scheme of the invention, the inorganic acid is selected from one or more of sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid and boric acid, and the organic acid is selected from one or more of carboxylic acid, sulfonic acid, sulfinic acid and thiocarboxylic acid.

As a preferred embodiment of the present invention, the inorganic acid salt is selected from one or more of sulfate, nitrate, hydrochloride, phosphate and borate, and the organic acid salt is selected from one or more of carboxylate, sulfonate, sulfinate and thiocarboxylate.

As a preferred embodiment of the present invention, the oxidizing agent is selected from one or more of peroxides, permanganates, perchlorates, hypochlorites, dichromates, halogen oxides.

As a preferable technical scheme of the invention, the injection pressure of the injection molding is 10-150MPa.

The second aspect of the invention provides a retaining ring prepared by the method for manufacturing a retaining ring as described above.

A third aspect of the present invention provides the use of the method of manufacturing a retaining ring as described above for a chemical mechanical polishing process for semiconductor chip manufacturing. The retaining ring prepared by the manufacturing method provided by the invention is used for limiting the position of a silicon wafer in the Chemical Mechanical Polishing (CMP) process of a semiconductor chip.

Compared with the prior art, the invention has the following beneficial effects: the invention relates to a method for keeping the stainless steel ring and plastic firmly combined, which comprises the steps of firstly, carrying out corrosion treatment on the stainless steel ring to form micro holes on the surface of the stainless steel ring, wherein the formed holes have a special closing-in structure with small surface caliber and large internal aperture, and can form holes with the aperture of 50-1000 mu m and the depth of 10-500 mu m. Then the plastic is formed on the surface of the stainless steel ring with micropores in an injection molding mode, and the plastic in a molten state is pressed into the micropores under the action of injection molding pressure, so that after the plastic is cooled and solidified, the plastic can be firmly attached to the surface of the stainless steel ring due to the existence of a micropore closing-in structure, and the plastic has good stability and cannot generate serious quality problems such as deformation and falling off.

Drawings

FIG. 1 is a schematic structural view of a corroded stainless steel ring.

FIG. 2 is a graph showing the effect of the corroded stainless steel ring.

Fig. 3 is a photomicrograph of a cross section of a microwell.

Fig. 4 is a photomicrograph of the surface of the microwells.

Detailed Description

The contents of the present invention can be more easily understood by referring to the following detailed description of preferred embodiments of the present invention and examples included. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, definitions, will control.

The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprising," "including," "having," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

The conjunction "consisting of …" excludes any unspecified element, step or component. If used in a claim, such phrase will cause the claim to be closed, such that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of …" appears in a clause of the claim body, rather than immediately following the subject, it is limited to only the elements described in that clause; other elements are not excluded from the stated claims as a whole.

When an equivalent, concentration, or other value or parameter is expressed as a range, preferred range, or a range bounded by a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when ranges of "1 to 5" are disclosed, the described ranges should be construed to include ranges of "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a numerical range is described herein, unless otherwise indicated, the range is intended to include its endpoints and all integers and fractions within the range.

The singular forms include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or event may or may not occur, and that the description includes both cases where the event occurs and cases where the event does not.

Approximating language, in the specification and claims, may be applied to modify an amount that would not limit the invention to the specific amount, but would include an acceptable portion that would be close to the amount without resulting in a change in the basic function involved. Accordingly, the modification of a numerical value with "about", "about" or the like means that the present invention is not limited to the precise numerical value. In some examples, the approximating language may correspond to the precision of an instrument for measuring the value. In the present specification and claims, the range limitations may be combined and/or interchanged, such ranges including all the sub-ranges contained therein if not expressly stated.

Furthermore, the indefinite articles "a" and "an" preceding an element or component of the invention are not limited to the requirements of the number of elements or components (i.e. the number of occurrences). Thus, the use of "a" or "an" should be interpreted as including one or at least one, and the singular reference of an element or component also includes the plural reference unless the amount is obvious to the singular reference.

The present invention is illustrated by the following specific embodiments, but is not limited to the specific examples given below.

The invention provides a manufacturing method of a retaining ring, which comprises the following steps:

Corrosion of stainless steel ring

In one embodiment, the corrosive liquid of the invention is prepared from one or more of inorganic acid and organic acid, one or more of inorganic acid salt and organic acid salt, oxidant and water as solvent.

Preferably, the inorganic acid is selected from one or more of sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid and boric acid; more preferably hydrochloric acid; in one embodiment, the hydrochloric acid has a mass concentration of 0.02 to 0.10g/mL, and examples thereof include 0.02g/mL, 0.04g/mL, 0.06g/mL, 0.08g/mL, and 0.10g/mL.

The mass of a component in a unit volume of a mixture is referred to as the mass concentration of the component.

Preferably, the inorganic acid salt is selected from one or more of sulfate, nitrate, hydrochloride, phosphate and borate; examples thereof include sodium sulfate, sodium nitrate, sodium hydrochloride, sodium phosphate, potassium chloride, potassium nitrate, potassium sulfate, potassium hydrogen phosphate, sodium hydrogen phosphate, iron sulfate, iron nitrate, and iron trichloride; more preferably ferric chloride; in one embodiment, the concentration of the ferric trichloride is 0.06-0.30g/mL, and examples thereof include 0.06g/mL, 0.12g/mL, 0.18g/mL, 0.24g/mL and 0.30g/mL.

Preferably, the oxidizing agent of the present invention is selected from one or more of peroxides, permanganates, perchlorates, hypochlorites, dichromates, halogen oxides; examples include hydrogen peroxide, sodium peroxide, potassium permanganate, potassium perchlorate, sodium hypochlorite, potassium dichromate, and chlorine dioxide; more preferred is hydrogen peroxide; in one embodiment, the hydrogen peroxide concentration is 0.01 to 0.05g/mL, and examples thereof include 0.01g/mL, 0.02g/mL, 0.03g/mL, 0.04g/mL, and 0.05g/mL.

Further preferably, the hydrochloric acid of the present invention: ferric trichloride: the weight ratio of the hydrogen peroxide is (1-3): (5-7): 1, there may be mentioned 1:5: 1. 2:6:1. 3:7:1, a step of; preferably 2:6:1. the invention discovers that by controlling the types and weight ratio of each component of the corrosive liquid, a hole structure with uniform size is easy to obtain.

In a preferred embodiment, the mass concentration of the corrosive raw material in the corrosive liquid is 0.01-100g/mL, preferably 0.01-10g/mL, more preferably 0.01-2g/mL, and even more preferably 0.05-0.5g/mL; the temperature of the etching is 0 to 90 ℃, preferably 10 to 50 ℃, more preferably 15 to 40 ℃, still more preferably 20 to 30 ℃; the etching time is 0.5 to 5 hours, preferably 1 to 4 hours, more preferably 2 to 3 hours.

In a more preferred embodiment, the micropores of the present invention are circular in shape and have a diameter of 50 to 1000. Mu.m, and examples thereof include 50. Mu.m, 100. Mu.m, 150. Mu.m, 200. Mu.m, 250. Mu.m, 300. Mu.m, 400. Mu.m, 500. Mu.m, 600. Mu.m, 700. Mu.m, 800. Mu.m, 1000. Mu.m; as the depth of the micropores 10 to 500. Mu.m, there may be mentioned 10. Mu.m, 50. Mu.m, 100. Mu.m, 150. Mu.m, 200. Mu.m, 250. Mu.m, 300. Mu.m, 400. Mu.m, 500. Mu.m.

In a more preferred embodiment, the average diameter of the micropores of the present invention is 50 to 500. Mu.m, and examples thereof include 50. Mu.m, 100. Mu.m, 150. Mu.m, 200. Mu.m, 250. Mu.m, 300. Mu.m, 400. Mu.m, and 500. Mu.m; the standard deviation of the diameters of the micropores is less than 100, preferably less than 90, more preferably less than 80, and even more preferably less than 60.

Plastic injection molding

In one embodiment, the method for combining the stainless steel ring and the plastic comprises the steps of injection molding, wherein the injection pressure of injection molding is 10-150MPa; preferably, according to the method for combining the stainless steel ring and the plastic, the injection pressure of injection molding is 100MPa.

In one embodiment, the plastic of the present invention comprises a thermoplastic and/or a thermoset; preferred thermoplastics include one or more of polypropylene (PP), polyethylene (PE), nylon (PA 6), nylon (PA 66), nylon (PA 46), nylon (PA 11), nylon (PA 12), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyacetal (POM), polyphenylene Sulfide (PPs), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), and polyoxybenzyl ester (POB).

The invention discovers that after a stainless steel ring is corroded to form a structure with micropores on the surface, plastic is subjected to injection molding on the surface with the micropores, such as plastic melting injection molding, the plastic is injected to the surface of the stainless steel ring under larger pressure, so that the molten plastic is pressed into the micropores under the action of pressure, and good adhesion performance is obtained after molding. Because the retainer ring is applied to the Chemical Mechanical Polishing (CMP) process of a semiconductor chip, the part between the stainless steel and the plastic of the retainer ring is stressed for a long time when the retainer ring is used, and firm combination can be required to be formed between the stainless steel and the plastic so as not to deform and fall off to endanger production safety, the corrosive liquid needs to be arranged, and the purpose is to obtain micropores with a closing-in characteristic structure, so that the combination strength of the stainless steel and the plastic is improved. According to the invention, the corrosion liquid of hydrochloric acid, ferric trichloride and hydrogen peroxide is used for facilitating the inter-crystal corrosion of stainless steel, micropores with a closing-in characteristic structure are easy to form, the increase of residual stress is avoided, the adhesion performance is improved, and the long-time stability is improved. Wherein FIG. 1 is a schematic structural view of a corroded stainless steel ring, and the surface of the stainless steel ring is provided with a micropore structure. Fig. 2 is a photograph of the surface of a stainless steel ring after corrosion.

Examples

The present invention will be specifically described below by way of examples. It is noted herein that the following examples are given solely for the purpose of further illustration and are not to be construed as limitations on the scope of the invention, as will be apparent to those skilled in the art in light of the foregoing disclosure.

Example 1

The present example provides a method of manufacturing a retaining ring for a semiconductor chip Chemical Mechanical Polishing (CMP) process, comprising:

corrosion of stainless steel ring: treating the surface to be injection-molded of the stainless steel ring with corrosive liquid to obtain the stainless steel ring with micropores with a closing-in structure on the surface to be injection-molded; the preparation raw materials of the corrosive liquid comprise inorganic acid salt with the mass concentration of 0.18g/mL, inorganic acid with the mass concentration of 0.06g/mL, oxidant with the mass concentration of 0.03g/mL, solvent with the mass concentration of water, inorganic acid salt with the mass concentration of 0.27g/mL, and oxidant with the mass concentration of 0.27g/mL, wherein the temperature is 25 ℃ and the corrosion time is 2 hours;

injection molding of plastics; placing the corroded stainless steel into a mould, and forming plastic on the surface of the stainless steel ring with micropores in a melting injection molding mode, wherein the injection pressure of the plastic in the melting injection molding is 100MPa; the plastic comprises polyphenylene sulfide.

The retaining ring prepared by the method of combining the stainless steel ring and the plastic as described above is applied to the Chemical Mechanical Polishing (CMP) process of semiconductor chips to play a role in limiting the position of a silicon wafer.

Example 2

corrosion of stainless steel ring: treating the surface to be injection-molded of the stainless steel ring with corrosive liquid to obtain the stainless steel ring with micropores with a closing-in structure on the surface to be injection-molded; the preparation raw materials of the corrosive liquid comprise inorganic acid salt with the mass concentration of 0.18g/mL, inorganic acid with the mass concentration of 0.06g/mL, oxidant with the mass concentration of 0.03g/mL, solvent with the mass concentration of water, inorganic acid salt with the mass concentration of 0.27g/mL, and oxidant with the mass concentration of 0.27g/mL, wherein the solvent is ferric trichloride, the inorganic acid with the mass concentration of hydrochloric acid, the temperature of 50 ℃ and the corrosion time of 2h;

Example 3

corrosion of stainless steel ring: treating the surface to be injection-molded of the stainless steel ring with corrosive liquid to obtain the stainless steel ring with micropores with a closing-in structure on the surface to be injection-molded; the preparation raw materials of the corrosive liquid comprise inorganic acid salt with the mass concentration of 0.06g/mL, inorganic acid with the mass concentration of 0.02g/mL, oxidant with the mass concentration of 0.01g/mL, solvent with the mass concentration of water, inorganic acid salt with the mass concentration of 0.09g/mL, and oxidant with the mass concentration of 0.09g/mL, wherein the temperature is 25 ℃ and the corrosion time is 2 hours;

injection molding of plastics; placing the corroded stainless steel into a mould, and forming plastic on the surface of the stainless steel ring with micropores in a melting injection molding mode, wherein the injection pressure of the plastic in the melting injection molding is 100MPa; the plastic comprises polyetheretherketone.

Example 4

corrosion of stainless steel ring: treating the surface to be injection-molded of the stainless steel ring with corrosive liquid to obtain the stainless steel ring with micropores with a closing-in structure on the surface to be injection-molded; the preparation raw materials of the corrosive liquid comprise inorganic acid salt with the mass concentration of 0.30g/mL, inorganic acid with the mass concentration of 0.10g/mL, oxidant with the mass concentration of 0.05g/mL, solvent with the mass concentration of water, inorganic acid salt with the mass concentration of 0.45g/mL, and oxidant with the mass concentration of 0.45g/mL, wherein the temperature is 25 ℃ and the corrosion time is 2 hours;

Example 5

corrosion of stainless steel ring: treating the surface to be injection-molded of the stainless steel ring with corrosive liquid to obtain the stainless steel ring with micropores with a closing-in structure on the surface to be injection-molded; the preparation raw materials of the corrosive liquid comprise inorganic acid salt with the mass concentration of 0.24g/mL, water as a solvent, ferric trichloride as the inorganic acid salt, and the mass concentration of the corrosive liquid is 0.24g/mL, the temperature is 25 ℃, and the corrosion time is 2 hours.

Example 6

corrosion of stainless steel ring: treating the surface to be injection-molded of the stainless steel ring with corrosive liquid to obtain the stainless steel ring with micropores with a closing-in structure on the surface to be injection-molded; the preparation raw materials of the corrosive liquid comprise inorganic acid salt with the mass concentration of 0.18g/mL, inorganic acid with the mass concentration of 0.06g/mL, oxidant with the mass concentration of 0.03g/mL, solvent with the mass concentration of water, inorganic acid salt with the mass concentration of ferric trichloride, inorganic acid with the mass concentration of 0.29g/mL, oxidant with the mass concentration of potassium perchlorate, and the temperature of 25 ℃ and the corrosion time of 2h;

Evaluation of Performance

The following experiments were performed as an experimental group provided in the examples.

1. The number, size and standard deviation of micropores are observed by SEM scanning electron microscope to observe the corrosion surface structure of the formed stainless steel, and every 4mm is observed ² The number and size of micropores in the area are calculated by the formula(i=1 to N, xi is the diameter of a single microwell,/->For the average diameter of the micropores, N is the number of micropores), the standard deviation of the micropores was calculated, and the micropores were observed for the presence of a special closed structure, and the results are shown in table 1, wherein the structure of the micropores of example 1 is shown in fig. 3 and 4, and the micropores were observed to have a closed structure and be relatively uniform in size.

2. Tensile shear Strength test the stress of the stainless steel and plastic bonding surface is mainly shearing force in the Chemical Mechanical Polishing (CMP) process of the semiconductor chip, so the bonding strength of the stainless steel and plastic can be characterized by shearing strength, and the tensile shear strength is tested by a tensile tester according to the measuring method of the tensile shear strength of national standard GB/T7124-2008, and the result is shown in Table 1.

Table 1 performance characterization test

As shown in the test results of Table 1, the manufacturing method provided by the invention can obtain the stainless steel ring with the micropore with the special closing structure, and the stainless steel ring is combined with the plastic by an injection molding method, so that the obtained retaining ring can effectively improve the bonding force between the stainless steel and the plastic, and simultaneously reduce the residual stress, thereby improving the tensile shear strength, and having good stability and service life.

The foregoing examples are illustrative only and serve to explain some features of the method of the invention. The appended claims are intended to claim the broadest possible scope and the embodiments presented herein are merely illustrative of selected implementations based on combinations of all possible embodiments. It is therefore intended that the appended claims not be limited by the choice of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within which variations in these ranges should also be construed as being covered by the appended claims where possible.

Claims

1. A method of making a retaining ring, comprising:

combination of stainless steel ring and plastic: placing the corroded stainless steel ring into a mold, and forming plastic on the surface to be injection molded of the stainless steel ring with micropores in an injection molding mode to obtain a retaining ring;

the corrosive liquid is prepared from the following raw materials: inorganic acid salt with the mass concentration of 0.18g/mL, inorganic acid with the mass concentration of 0.06g/mL, oxidant with the mass concentration of 0.03g/mL, and water as solvent, wherein the inorganic acid salt is ferric trichloride, the inorganic acid is hydrochloric acid, and the oxidant is hydrogen peroxide; the mass concentration of the corrosive liquid is 0.01-0.45 g/mL, and the corrosion temperature is 25 ℃.

2. The method of claim 1, wherein the micropores have a circular shape, a diameter of 50-1000 μm and a micropore depth of 10-500 μm.

3. The method of manufacturing a retaining ring according to claim 1, wherein the injection pressure of the injection molding is 10-150MPa.

4. A retainer ring produced by the production method of the retainer ring according to any one of claims 1 to 3.