CN101302403B - Polishing solution for ultra-precise low-damage polish of large size diamond wafer and preparation thereof - Google Patents

Abstract

The invention belongs to the superhard material polishing technical field and discloses polishing solution used for ultraprecise and low-damage polishing of a large-scale diamond wafer and a method for preparing the same. The method is characterized in that: oxidants with strong oxidbillity including chromium trioxide, ammonium persulphate, potassium permanganate, potassium dichromate, oxydol, potassium ferrate, potassium perchlorate and so on are adopted as main compositions; a proper amount of abrasive material is added for preparing the polishing solution; and micro-removal of surface material of the diamond wafer can be realized by means of chemical and mechanical composite action at normal temperature or low temperature. Moreover, the polishing effect of the polishing solution can beimproved by addition of proper amount of catalyst, stabilizer, dispersant and so on as well. The polishing solution and the method have the advantages that: the polishing solution prepared has the advantages of high polishing efficiency, good polishing quality, good stability and so on; and the ultraprecise and low-damage polishing of the large-scale diamond wafer can be realized at the normal temperature or the low temperature.

Description

For ultra-precision large-size diamond wafer polishing liquid low-damage polishing and preparation

method

FIELD

[0001] The present invention belongs to the technical field of polishing a superhard material, and particularly relates to a polishing liquid and a method for preparing a large-sized ultra precision diamond wafer for polishing low damage.

Background technique

[0002] diamond wafer not only has high hardness and wear resistance, and excellent electrical insulation, thermal conductivity, light transmittance and acoustic and mechanical properties of new materials is considered the most promising in the 21st century, defense and high-tech fields cutting-edge technology has a wide range of applications. However, due to the constraints of the crystal growth mechanism phase, with increasing thickness of the wafer, the surface roughness and grain size will increase to several tens of microns or even microns, precision machining method must be used to surface roughness down to the nanometer level, and to a certain type of surface accuracy can be put into use. When a particular application in the field of high-tech, not only requires a very small diamond wafer having a surface roughness, but also its surface integrity Surface Accuracy and high demands made. Currently polished diamond wafer planarization is lagging behind technology, especially the ultra-precision polishing large size without injury CVD diamond wafer planarization technology has become the bottleneck of diamond wafers are widely used in high-tech fields.

[0003] Since diamond is the highest known hardness and high chemical inertness of the material, such that the prior art polishing is difficult to achieve a large-sized diamond wafer without damaging the surface of the ultra-precision machining. For example, polishing the laser beam, an ion beam polishing polishing, mainly for small size (Φ <1 inch) diamond wafer, and complex equipment, and high cost, it is difficult for industrial production; electrical and thermal chemical polishing techniques spark polishing technology, although now possible to realize a large-sized diamond wafer planarizing polishing, but the polishing surface roughness Ra can only reach the level of several hundred nanometers, but also brings damage and contamination of the machined surface; although the conventional mechanical polishing technique capable of achieve nano polishing, but the polishing efficiency is very low, but also easy to leave damage such as scratches in the machined surface. Chemical mechanical polishing (CMP) as an ultra-precision machining technology is based on the principle of mechanical and chemical action of the composite, the processing is the best way to implement a large-sized wafer without damage to ultra-smooth surface finish, it is widely used in IC manufacturing.

[0004] Although there are a method for chemical mechanical polishing of the diamond film, but due ΚΝ03 + Κ0Η NaN03 + KN03 + LiN03 or the like as the oxidant mixture melts, the desired temperature of the polishing 324~360 ° C, the presence of energy consumption, the polishing liquid evaporation loss is large, the problem is difficult to ensure stability of the polishing liquid ingredients, etc., especially with the diamond wafer size increases, the deformation due to high temperatures and polishing diamond wafer warpage problem is more prominent. Further, since the conventional polishing solution containing no added catalyst, a stabilizer, a dispersing agent was used a polishing composition, there is a low polishing rate, poor stability of the polishing liquid. The polishing process with the existing equipment can not meet the requirements of ultra-precision machining cost-efficient large-size diamond wafer.

SUMMARY

[0005] The present invention is to solve the technical problem of providing a low damage ultraprecision diamond wafer polishing of large size and preparation method thereof adapted to solve the chemical mechanical polishing using diamond wafer due to melt mixing height polishing liquid oxidant exists polishing temperature, high equipment cost, low processing efficiency, poor quality polishing. [0006] To achieve the above object, the technical solution of the present invention is:

[0007] - large size diamond wafer types for ultra-precision polishing of low damage solution, characterized in that it comprises an abrasive, an oxidizing agent, a catalyst, a dispersing agent, a stabilizing agent, and deionized water, as a percentage by mass of the raw materials :

[0008] Abrasive: 4 ~ 20%;

[0009] Antioxidant: 5~30%;

[0010] Stabilizer: 1 ~ 5%;

[0011] Dispersant: 0.1 ~ 10%;

[0012] Catalyst: 1 ~ 5%;

[0013] Deionized water: 42~65%; mass percentage of the raw materials is 100%;

The abrasive purity [0014] The 98% ~ 100%; particle size distribution 50nm~14 μ m.

Preparation [0015] The method of the above-described polishing liquid, comprising the steps of:

[0016] 1) Select an abrasive, an oxidizing agent, a stabilizer, a dispersant, deionized water, and the catalyst feed standby, the percentage by mass of the raw materials as follows: Abrasive: 4~20%; oxidant: 5~30%; Stabilizer: 1 ~ 5%; dispersant: 0 1~10%; catalyst: 1 ~ 5%; deionized water: 42~65%; mass percentage of the raw materials is 100%;

[0017] 2) above was added to the abrasive mass percentage of deionized water, ultrasonic agitation 10~30min, sufficiently so that the abrasive dispersed in deionized water to prepare a suspension;

While [0018] 3) adding an oxidizing agent and a catalyst as described above mass percentage in suspension, heating ultrasonic agitation 10~15min, so that various solvents and thoroughly dissolving and dispersing.

[0019] 4) In the above-described percentage by mass was added stabilizers and dispersing agents, ultrasonic agitation 10~15min, the polishing liquid can be prepared.

[0020] The titanium oxide abrasive, when any of the above mixing an abrasive silica, boron carbide, silicon carbide, cubic boron nitride, diamond or a mixture of two, any two or more, as with any ratio.

Oxidant [0021] The chromium trioxide is, any one or more of ammonium persulfate, potassium permanganate, potassium dichromate, hydrogen peroxide, potassium ferrate, potassium perchlorate and the like or a mixture of two, any two when the above mixing ratio is arbitrary.

[0022] The catalyst is one or two or more, phosphoric, nitric, sulfuric any ferrous sulfate, ferric nitrate mixing arbitrary two or more kinds, arbitrary ratio.

Stabilizer [0023], wherein one or two or more of tartaric acid, potassium dihydrogen phosphate, citric acid, maleic acid arbitrary, mixing sodium silicate, arbitrary two or more kinds, arbitrary ratio.

Dispersant [0024] The silica sol of sodium hexametaphosphate, calcium activity, any one or two or more of sodium silicate mixture, mixing any two or more arbitrary ratio.

[0025] The effects and benefits of the present invention are: the present invention reagents may be employed with a strong oxidizing agent at low temperature as a main component of the diamond wafer, the polishing allows the desired temperature was lowered to 50~150 ° C, effectively due to the high temperature of the polishing solution resulting from energy consumption, large evaporation loss of the polishing liquid, the polishing liquid is difficult to ensure stability problems and other components, especially for large size diamond wafer processing, it can effectively solve the large size of polishing due to high temperatures diamond wafer warpage and deformation and other problems, to improve the surface accuracy and surface quality type diamond wafer, the surface roughness of the diamond wafer after polishing can reach nanometer level. Further, by using a dispersant and a strong adsorption stabilizer additives to improve dispersion stability of the polishing liquid.

BRIEF DESCRIPTION [0026] FIG. 1 is a scanning electron micrograph of 500-fold diamond wafer front surface polishing.

[0027] FIG. 2 is a 500 times after polishing SEM photograph of the diamond wafer surface.

Detailed ways

[0028] below with reference to the accompanying drawings and the technical solutions described in detail specific embodiments of the present invention.

[0029] oxidants, stabilizing agents, dispersing agents, catalysts and other drugs in methods of the invention are used in common drugs. The method of the present invention are used in conventional apparatus known devices.

[0030] Example 1:

[0031] A method for preparing a large-sized low damage ultra-precision diamond wafer polishing liquid for polishing, comprising the steps of:

[0032] 1) the percentage by mass of the raw materials is occupied: Abrasive: 18% Antioxidant: 25%, stabilizer: 3%; Dispersant:; catalyst: 25%; Deionized water: 50 5%;. select an abrasive, an oxidizing agent, stabilizing agents, dispersing agents, catalysts, and deionized

Alternate water feed;

[0033] The boron carbide abrasive, 98% purity, particle size of 2μπι; the oxidizing agent is potassium permanganate; said stabilizer is tartaric acid; said dispersant is sodium silicate; the the catalyst is phosphoric acid.

[0034] 2) above was added to the abrasive mass percentage of deionized water, ultrasonic stirring 15min, the abrasive dispersed in deionized water sufficient to prepare a suspension;

[0035] 3) In the above-described suspension was added the aforementioned oxidant mass percent, the catalyst was heated with stirring while ultrasonic lOmin, promote dissolution and dispersion of various solvents.

[0036] 4) In the above solution, the mass percentage addition of stabilizers and dispersing agents, ultrasonic agitation lOmin, the polishing liquid can be prepared.

[0037] Example 2:

[0038] A method for preparing a large-sized low damage ultra-precision diamond wafer polishing liquid for polishing, comprising the steps of:

[0039] 1) the percentage by mass of the raw materials is occupied: Abrasive: 10% Antioxidant: 30%, stabilizer: 3%; Dispersant:; catalyst: 45%; Deionized water: 51 5%;. select an abrasive, an oxidizing agent, stabilizing agents, dispersing agents, catalysts, and deionized

Alternate water feed;

[0040] The abrasive material is titanium dioxide having a purity of 99%, a particle size of 10 μ m; the oxidizing agent is ammonium persulfate and hydrogen peroxide; said stabilizer is tartaric acid and sodium tartrate, sodium silicate representing each accounted for 1.5% percent by mass; dispersing agent is the sodium hexametaphosphate; the catalyst is sulfuric acid and ferrous sulfate, ferrous sulfate share each accounted for 2.25% by mass percentage.

[0041] 2) above was added to the abrasive mass percentage of deionized water, ultrasonic stirring 30min, sufficiently so that the abrasive dispersed in deionized water to prepare a suspension;

[0042] 3) In the above-described suspension was added the aforementioned oxidant mass percent, the catalyst was heated with stirring while ultrasonic lOmin, promote dissolution and dispersion of various solvents.

[0043] 4) In the above-described percentage by mass was added stabilizers and dispersing agents, ultrasonic agitation lOmin, the polishing liquid can be prepared.

[0044] Example 3:

[0045] A method for preparing a large-sized low damage ultra-precision diamond wafer polishing liquid for polishing, comprising the steps of:

[0046] 1) the percentage by mass of the raw materials is occupied: Abrasive: 15% Antioxidant: 23%, stabilizers: 5%; dispersant:; Catalyst: 3 5%; Deionized water: 52 5%;. select an abrasive, an oxidizing agent, stabilizing agents, dispersing agents, catalysts, and deionized

Alternate water feed;

[0047] The abrasive is silicon carbide with a purity of 99%, a particle size of 2 μ m; the oxidizing agent is potassium dichromate; said stabilizer is citric acid; the dispersing agent is hexametaphosphoric acid sodium; phosphoric acid and the catalyst is ferric nitrate.

[0048] 2) above was added to the abrasive mass percentage of deionized water, ultrasonic stirring 15min, sufficiently so that the abrasive dispersed in deionized water to prepare a suspension;

[0049] 3) In the above-described suspension was added the aforementioned oxidant mass percent, the catalyst was heated with stirring while ultrasonic lOmin, promote dissolution and dispersion of various solvents.

[0050] 4) In the above-described percentage by mass was added stabilizers and dispersing agents, ultrasonic agitation lOmin, the polishing liquid can be prepared.

[0051] Example 4:

[0052] A method for preparing a large-sized low damage ultra-precision diamond wafer polishing liquid for polishing, comprising the steps of:

[0053] 1) the percentage by mass of the raw materials is occupied: Abrasive: 20% Antioxidant: 10%, stabilizer: 3%; Dispersant: 10%; Catalyst: 5%; Deionized water: 52%; selecting abrasive , oxidizing agents, stabilizing agents, dispersing agents, catalysts and deionized water feed standby;

[0054] The boron carbide abrasive, 98% purity, particle size of 2μπι; the oxidizing agent is chromium trioxide; said stabilizer is citric acid, citric acid mass percentage share of each accounted for 1.5% ; said dispersant is sodium silicate; the catalyst is sulfuric acid.

[0055] 2) above was added to the abrasive mass percentage of deionized water, ultrasonic stirring 30min, sufficiently so that the abrasive dispersed in deionized water to prepare a suspension;

[0056] 3) In the above-described suspension was added the aforementioned oxidant mass percent, the catalyst was heated with stirring while ultrasonic lOmin, promote dissolution and dispersion of various solvents.

[0057] 4) In the above-described percentage by mass was added stabilizers and dispersing agents, ultrasonic agitation lOmin, the polishing liquid can be prepared.

[0058] Example 5:

[0059] A method for preparing a large-sized low damage ultra-precision diamond wafer polishing liquid for polishing, comprising the steps of:

[0060] 1) the percentage by mass of the raw materials is occupied: Abrasive: 6%, the oxidizing agent: 30%, stabilizers: 2%; dispersant: 8%; Catalyst: 20%; Deionized water: 34%; selecting abrasive , oxidizing agents, stabilizing agents, dispersing agents, catalysts and deionized water feed standby;

[0061] The diamond abrasive particles, a purity of 99% particle size of 0. 5μπι; the oxidizing agent is potassium permanganate; said stabilizer is citric acid; the catalyst is phosphoric acid.

[0062] 2) above was added to the abrasive mass percentage of deionized water, ultrasonic stirring 20min, sufficiently so that the abrasive dispersed in deionized water to prepare a suspension;

[0063] 3) In the above-described suspension was added the aforementioned oxidant mass percent, the catalyst was heated with stirring while ultrasonic lOmin, promote dissolution and dispersion of various solvents. [0064] 4) In the above-described percentage by mass was added stabilizers and dispersing agents, ultrasonic stirring 15min, the polishing liquid can be prepared.

[0065] Example 6:

[0066] A method for preparing a large-sized low damage ultra-precision diamond wafer polishing liquid for polishing, comprising the steps of:

[0067] 1) the percentage by mass of the raw materials is occupied: Abrasive: 10% Antioxidant: 28%, stabilizers: 1.4% • 'Dispersant: 3%; Catalyst: 2 7%; Deionized water: 54. 9%; selecting an abrasive, an oxidizing agent, a stabilizer, a dispersant, a catalyst material and deionized water reserve;

[0068] The boron carbide abrasive, 98% purity, particle size of 2μπι; the oxidizing agent is potassium ferrate; potassium dihydrogen phosphate as the stabilizer; the dispersing agent is sodium hexametaphosphate ; said catalyst is phosphoric acid.

[0069] 2) above was added to the abrasive mass percentage of deionized water, ultrasonic stirring 20min, sufficiently so that the abrasive dispersed in deionized water to prepare a suspension;

[0070] 3) In the above-described suspension was added the aforementioned oxidant mass percent, the catalyst was heated with stirring while ultrasonic lOmin, promote dissolution and dispersion of various solvents.

[0071] 4) In the above-described percentage by mass was added stabilizers and dispersing agents, ultrasonic stirring 15min, the polishing liquid can be prepared.

[0072] Example 7:

[0073] - preparation of ultra-precision large diamond wafer polishing of low damage species for liquid, comprising the steps of:

[0074] 1) the percentage by mass of the raw materials is occupied: Abrasive: 7%, the oxidizing agent: 15%, stabilizers: 3.5%; dispersant: 8%; Catalyst: 4%; Deionized water: 625.%; select an abrasive, an oxidizing agent, a stabilizer, a dispersant, deionized water, and the catalyst feed standby;

[0075] The diamond abrasive, 99% purity, a particle size of 10 μ m; the oxidizing agent is potassium permanganate; Whetstone said stabilizer is an acid; said dispersant is sodium hexametaphosphate ; said catalyst is phosphoric acid.

[0076] 2) above was added to the abrasive mass percentage of deionized water, ultrasonic stirring 20min, sufficiently so that the abrasive dispersed in deionized water to prepare a suspension;

[0077] 3) In the above-described suspension was added the aforementioned oxidant mass percent, the catalyst was heated with stirring while ultrasonic lOmin, promote dissolution and dispersion of various solvents.

[0078] 4) In the above-described percentage by mass was added stabilizers and dispersing agents, ultrasonic stirring 15min, the polishing liquid can be prepared.

[0079] In the polishing temperature conditions of 60 ° C, using a polishing liquid prepared according to Example 1, the polishing tests carried out on a precision polishing machine. FIG 2 is a diamond wafer after polishing the surface obtained by scanning electron microscope photograph (magnification 500 times), a small amount of black dots in FIG. 2 CVD diamond wafer is inherent growth defects. FIG 1 is a non-polished diamond wafer surface SEM photograph of 500 times.

Claims (5)

A large ultra-precision diamond wafer polishing of low damage solution, characterized in that it comprises an abrasive, an oxidizing agent, stabilizing agents, dispersing agents, catalysts and deionized water, the percentage proportion by mass of the raw materials is: abrasive: 4~20%; oxidant: 5~30%; stabilizer: 1 ~ 5%; dispersant: 1 ~ · 0 ·; catalyst: 1 ~ 5%; deionized water:% 42~65; the quality of the raw materials total percentage is 100%; the abrasive ~ 100%, a purity of 98%; grain size distribution 50nm~14μπι; said dispersant is silica sol, sodium hexametaphosphate, calcium activity, any sodium silicate one or a mixture of two or more, the mixing of any two or more thereof, any ratio; stabilizer according to any one of tartaric acid, potassium dihydrogen phosphate, citric acid, maleic acid, sodium silicate, or mixing two or more kinds, the mixing of any two or more thereof, of any ratio; the catalyst is nitric acid, ferrous sulfate, ferric nitrate in any mixing two or more kinds of sulfuric acid, or; any two when the above mixing ratio is arbitrary.

2. A method according to claim 1 for a large-sized ultra-precision diamond wafer polishing of low damage solution, characterized in that: the use of reagents having a strong oxidizing effect on the diamond wafer at a low temperature, so that the The polishing required temperature was reduced to 50 ~150 ° C.

The method of preparing the polishing liquid according to claim 1, characterized by comprising the following steps: 1) Select an abrasive, an oxidizing agent, a stabilizer, a dispersant, deionized water, and the catalyst feed standby, as a percentage by mass of the raw materials: abrasive : 4~20%; oxidant: 5~30%; stabilizer: 1 ~ 5%; dispersant: 0 1~10%; catalyst: 1 ~ 5%; deionized water: 42~65%; the quality of the raw materials total percentage is 100%; 2) above was added to the abrasive mass percentage of deionized water, ultrasonic agitation 10~30min, sufficiently so that the abrasive dispersed in deionized water to prepare a suspension; 3) in the above-described mass suspension while the percentage adding an oxidizing agent and a catalyst, heating ultrasonic agitation 10~15min, so that various solvents and thoroughly dissolving and dispersing; 4) in the solution described above mass percentage addition of stabilizers and dispersing agents, ultrasonic agitation 10~15min, Ltd. I was polishing liquid.

4. The method of preparation according to claim 3, wherein: said oxidant is chromium trioxide, any ammonium persulfate, potassium permanganate, potassium dichromate, hydrogen peroxide, potassium ferrate, potassium perchlorate in or a mixture of two or more; mixing any two or more arbitrary ratio.

The production method according to claim 3, wherein: said abrasive is titania, any one of silica, boron carbide, silicon carbide, cubic boron nitride, diamond or a mixture of two or more ; mixing any two or more arbitrary ratio.