TW527626B - Chemical mechanical polishing composition - Google Patents

Abstract

The invention provides chemical mechanical polishing (CMP) composition for semiconductor processing comprising an aqueous medium, abrasive particles, and an anionic surfactant, where the pH of the composition is less than or equal to 7.

Description

527626 V. Description of the invention (1) Field of the invention The present invention relates to a chemical mechanical polishing composition, in particular to a chemical mechanical polishing composition for polishing the surface of a dielectric layer in a semiconductor manufacturing process, and a chemical machinery using the polishing composition. Grinding method. BACKGROUND OF THE INVENTION Chemical mechanical polishing technology is a flattening technology developed to solve the difficulty of focusing on the lithography process due to the difference in coating height during IC manufacturing. Chemical mechanical polishing (CMP) technology was first applied in small quantities to the manufacture of 05-micron components. The size of the CMP technology is shrinking, and the number of chemical mechanical polishing applications is increasing. By the 0.25 micron generation, chemical mechanical polishing has become the mainstream and necessary planarization technology. In general, CMP is a polishing method used on semiconductors to produce metal connection lines and an intermediate metal dielectric layer (ILD) as an insulating layer. The method is to place the semiconductor wafer on a rotary grinding table equipped with a grinding head, and add a grinding slurry containing abrasive particles and certain specific chemicals during the contact friction process to improve the grinding efficiency. Therefore, in the process of CMP of the entire grinding paddle, two processes are involved: the electrochemical action of redox such as electron transfer between the chemical and the metal layer to be affected, or the physical adsorption between the chemical and the dielectric layer Function: First, the abrasive particles directly rub the mechanical force between the metal layer or the dielectric layer to destroy the crystal arrangement on the entire surface of the material and accelerate the grinding rate. For metal layers, the main chemical action involves the transfer of electrons in an aqueous solution. We can catalyze by adding some appropriate amount of oxidant. 4-This paper standard is applicable to the Zhongguanjia standard (CNS) A4 specification ⑵Q χ 297 meals]-'------ rt · pack ------ --Order --------- (Please read the notes on the back before filling this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 527626 A7 V. Description of the invention (agent, salt or mismatch Materials to accelerate the rate of electrons between metals and chemicals to promote the dissolution and oxidation of the metal layer. For dielectric or insulating layers, electron transfer will not occur, so we can adjust the pH value To change the electrical double-layer characteristics of the surface of the entire material, and then to protect or remove the material by the physical properties of electrical repulsion and attraction of the opposite sex. As for the friction of mechanical force, in addition to the machine The parameters and conditions are related to the nature of the abrasive particles, particle size, particle size, crystal structure, hardness, quilt, thermal expansion coefficient, thermal conductivity, compressive strength, tensile strength, etc. ^ Currently CMP The paddle material has been successfully applied in Ming Grinding of metal layers such as rhenium, steel, and polycrystalline silicon with a m or V group element, as well as dielectric layers or insulation of silicon dioxide, phosphate rock glass (BPSG), nitride stone, and thallium, please contact Shi Peng. At present, there are methods to increase the selectivity ratio between silicon dioxide and silicon nitride in the market. Some of them are achieved by using the special properties of abrasive particles. This method is shown in U.S. Patent No. 5,759,917 and No. 5 Patent No. 5,89u05. Hemei Patent No. 5,861,05. In addition, a surfactant containing fluorine or some compounds containing special organic salts or inorganic salts can be used as an additive to improve the selection ratio of silicon dioxide and silicon nitride in the insulating layer. As disclosed in U.S. Patent No. 5,738,800, U.S. Patent No. 5,863,838, WO 96/16436, U.S. Patent No. 5,352, and U.S. Patent No. 5,769,689. However, abrasive particles are used to achieve the promotion of silica and Revealed 277 for silicon nitride grinding. The paper size is in accordance with the Chinese National Standard (CNS) A4 specification (210 X 297 mm 527626 A7 B7. V. Description of the invention (comparative effect, easy to grind the pounds of grinding) It can cause problems such as scratches, poor dispersion, easy sinking, and cost problems .... If special organic or inorganic chemical additives are used on the right, the effect of Shishi is not good. The present invention is to make In the semiconductor manufacturing process, the ratio of the silicon dioxide to the silicon dioxide and the exhaustion of the grinding mill is reduced, and it can have a low cost, and can eliminate scratches, poor dispersion and easy sinking. The inventor of this case, after extensive research, found that chemical grinding compositions with certain special compositions can achieve the present invention: the purpose, and state the results obtained in the present invention. BRIEF SUMMARY OF THE INVENTION The main purpose of the present invention is to provide a chemical Mechanically grind the composition. It is yet another object of the present invention to provide a chemical mechanical polishing composition having a high polishing selection ratio of silicon dioxide and silicon nitride for use in a semiconductor process. Still another object of the present invention is to provide a chemical polishing composition which can eliminate the phenomenon of scratching, poor dispersion and easy precipitation. The present invention provides a chemical-mechanical polishing composition. The composition includes an aqueous medium, abrasive particles, and an anionic surfactant, and has a P Η value of 7 or less. J shows a brief explanation_ Figure 1 is a zeta potential diagram of monoxide and nitride zirconia. Detailed description of the invention i Research heavy The present invention provides a chemical mechanical polishing composition used in the semiconductor process' comprising 70- 99.5% by weight of an aqueous medium; 0.5-25% by weight of abrasive particles' are preferably 0.5-15% by weight. / ❶, more preferably 1_10% by weight; and 001_2 6 — This paper size applies the Chinese National Standard (CNS) A4 specification (21〇 χ 297mm) 527626

5. Description of the invention (4) The amount of the surfactant is preferably 003- 丨 weight. /. In a greater amount, the surfactant is an anionic surfactant including sulfate and dibasic acid. The aqueous medium used in the chemical mechanical polishing composition of the present invention may be water. In the preparation process, water may be used to make the chemical mechanical polishing composition into a slurry form. The preferred aqueous medium is deionized water. The abrasive particles used in the chemical mechanical polishing composition of the present invention I may be generally commercially available, such as S102, A12o3, Zr02, Ce02, Slc, Fe203, T102,

SlsN4 or a mixture thereof. These abrasive particles have the advantages of higher purity, bulk, and narrow particle size decoration, and are therefore suitable for use as abrasive particles in chemical mechanical polishing compositions. ≪ The anionic surfactant used in the chemical mechanical polishing composition of the present invention is an anionic surfactant having a hydrophilic group, and is preferably a surfactant containing sulfate and / or ~ fe root. This surfactant will form a protective layer on silicon nitride to reduce the impact of abrasive particles on its removal, but radon has no effect on the silicon monoxide layer, so it is completely safe for the mechanical force of abrasive particles. Thereby, the effect of improving the selection ratio of the crushing of the dioxide and the nitriding is achieved. According to the present invention, the chemical mechanical polishing composition may be added with nitric acid or ammonia water as needed. The pH value of the slurry is between the required range. In addition, a salt such as ammonium nitrate may be added to the polishing liquid as a pH buffering agent as needed. The content of ammonium nitrate is from 0.00 to 5.0% by weight, preferably from 0.03 to 0.5% by weight. As shown in Figure 1, the isoelectric point of silicon monoxide is near pH 2 and 3, and silicon nitride is at pH 5 so for silicon helium, when the pH is less than 5, the nitride is the band---^ paper rule Choi

527626 V. Description of the invention (Positive "raw" and the surface of the silicon oxide is either negatively charged or slightly positively charged. Therefore, we think of using anionic surfactant 1 for heterosexuality (please read the note on the back? Matters before filling (This page) Adsorbs an anionic hydrophilic group on the surface of silicon nitride, :: Qian Luan, forms a single-molecular absorption layer, and the nitrided surface becomes mechanical or chemical. This compound will follow Increasing the number of straight or branched carbons increases its interfacial activity, while reducing its solubility in water, and is a water-insoluble monomolecular film. The following examples will further illustrate the present invention, but not for use. In order to limit the scope of the present invention, modifications and changes that can be easily achieved by anyone skilled in the art are included in the scope of the present invention. The following examples demonstrate the preferred specific examples of the present invention and the use of the composition of the present invention. Examples of good methods] Six different concentrations of surfactants and nitrates were prepared as polishing fluids to evaluate the polishing rate of the CMP polishing fluids for the polishing rate of silicon dioxide (TEOS) and silicon nitride (siN) dielectric layers. The measured performance parameters include the grinding rate of silicon dioxide and nitrided sand. The test conditions are as follows: Printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs A · Instrument: iPEC / Westech 472 B · Conditions ·· Pressure ·· 2psi Back pressure: 0.5psi Temperature: 25 ° C Spindle speed: 90rpm One 8 One paper size applies to Chinese National Standard (CNS) A4 (210 X 297 mm) 527626 A7 B7 V. Description of the invention (6) Platen speed: 50rpm pedestal type: IC1000 Slurry flow rate: 150ml / min C. Chip: Silicon dioxide (TEOS) film and silicon nitride (SiN) film wafer, purchased from Silicon Valley Microelectonics. Inc., 6 inches by CVD technology A thin film of 8 ~ 9 microns ± 5% is deposited on the silicon wafer. Grinding test process: Before and after grinding, the thickness of the film must be measured with a Tencor SM-300 optical interferometer, and then the previously measured The thickness is subtracted by the thickness and then divided by the grinding time, which is the grinding rate. The grinding liquid is prepared as follows: at room temperature, first add ammonium nitrate in deionized water and stir, and make sure that the whole is completely dissolved, and then Add 10% colloidal silica abrasive particles, continue stirring for 20-30 minutes to make it uniformly dispersed in the entire solution. Add surfactant, continue stirring for 20 minutes. Finally, adjust the pH value to 4.0 with nitric acid. .You can test directly without adding any oxidant during grinding. The concentration of the whole additive is mainly based on the table. The grinding rate is shown in Table 1. (Please read the precautions on the back before filling this page) Wisdom of the Ministry of Economic Affairs Printed by the staff of the Property Bureau, Consumer Cooperatives. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 527626 A7 B7 V. Description of the invention (the effect of surfactants on the grinding rate of silicon and silicon nitride A ten Pit-based sulfate

SiN grinding selects the specific grinding rate of 1.8 257 4.5 -----, 13.2 where the grinding rate is in A / ^^ 7-di m 'with the added surfactant (ammonium dodecyl sulfate) Ά A plus 'The grinding rate of nitriding crushing gradually decreases, and the selection ratio of nitrogen cutting of the dioxide is gradually increasing. However, the addition of nitric acid as a salt, the inhibition of the grinding rate of rat fossils, and the improvement of the overall grinding selection ratio

:: Significant effect, so the effect of the force "ammonium succinate is purely a buffer for the pH value of the solution. The extraction can prove the dioxin to nitrogen cutting grinding selection ratio; the effect of surfactants, not nitrates. Example 2 /. The effect of the grinding results of ㈣ was measured, so we added the amount of additives and only changed the positive value to observe the change in the elimination rate.% Μ 乂 乂 The slurry composition was prepared in the same manner as described in Example 1 and ground Speed-10 — This paper is also suitable for Chinese specifications? X 297 mm 527626 A7 B7 i. Description of the invention (the rate is shown in Table II: 10% Shixi colloidal abrasive grains, ammonium acid 0 05% as a positive value Buffering agent, acidic falling solution is adjusted with nitric acid, alkaline solution is adjusted with ammonia water ------- A eleventh sulfuric acid according to pH value TEOS grinding rate SiN grinding rate selection ratio 1 0.5 9.0 226 220 1.0 2 0.5 8.5 178 105 1.7 3 0.5 8.0 238 170 1.4 4 0.5 7.0 178 36 4.9 5 0.5 4.0 514 39 13.2 6 0.5 2.5 614 23 26.7 "The main result is different. When the pH value changes from alkaline to acidic When you gradually adjust to 1, you will find that the The selection ratio is getting better and better, it is known that when the pH value is less than 3, you can get a selection ratio effect of more than 20. (Please read the precautions on the back before filling this page) Install i III II I Order · I I-Economic Printed by the Consumers' Cooperative of the Ministry of Intellectual Property Bureau I This example 3 In order to prove that anionic surfactants are suitable for the present invention, we will select a series of surfactants with different functional groups for comparison to prove that the printing does have its effect. The slurry was prepared in the same manner as described in Example 1 to evaluate the effects of different interfacial activities and agents. Each slurry included; K)% silica colloidal abrasive particles, 0.05% ammonium lithium phosphate, 0.5% of the same amount. Surfactant, pH is not adjusted, and its grinding speed is -11-Paper size applies Chinese National Standard (CNS) A4 (210x297 mm) 527626 A7 B7 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs as shown in Table III Table 3. Effect of different surfactants on the grinding rate of silicon dioxide and silicon nitride

^ The company's trade name. The surfactant is a long-slit molecular compound of sulfate and / or acid. V. Description of the invention

Hitenol HS-10

Rhone Poulenc DS_4 Some of the interface activities used in the above examples are 2 Example 3 ′ It can be proved that the anionic surfactants containing sulfate or transverse acid radicals have an excellent effect on the improvement of the silicon selectivity ratio of diazepam. Although specific examples have been used to describe the present invention, the invention is described, but it is known that the invention in the scope of the invention f, f & is not limited to the description and the embodiment without departing from the winter moon and the god < These restrictions are defined by the scope of the following patents. Applicable specifications of this button (⑽ · 7 ^ 1 · —----------- install -------- order --------- line t (please read the back first (Notes for filling in this page)

Claims (1)

I __i I am asking you to use the revised scope (March 91) A8 B8 C8 • A chemical mechanical polishing composition having a pH value of 7 or less, including: an aqueous medium; abrasive particles; and an anionic surfactant, wherein the content of the abrasive particles is 0.5-25% by weight, and the content of the anionic surfactant is The content is 0.01 to 2.0% by weight. 2. The composition according to item 1 of the scope of the patent application, wherein the abrasive particles are selected from the group consisting of Si02, Αα], Zr〇2, Ce02, SiC, Fe2 03, Ti02, Si3N4, or a mixture thereof 3. For example, the composition in the second item of the patent application scope, wherein the content of the abrasive particles is M0% by weight. 4. The composition according to item 1 of the patent application range, wherein the anionic surfactant is a surfactant containing sulfate and / or acid. 5. The composition according to item 4 of the scope of patent application, wherein the content of the anionic surfactant is 0.034 wt%. 6. The composition according to item 1 of the scope of patent application, which may further include a pH buffer 7. The composition according to item 6 of the scope of patent application, wherein the pH buffering agent is an inorganic salt. 8. The composition according to item 7 of the scope of patent application, wherein the inorganic salt is a nitrate. 9. The composition of item 8 in the patent application, wherein the nitrate is ammonium nitrate. 10. The composition according to item 8 of the scope of patent application, wherein the nitrate contains A B c D 527626 6. The scope of patent application f is 0.0-5.0% by weight. 11. The composition as claimed in claim 10 of the patent, wherein the content of the acid salts is 0.03-0.5 wt./0. 12. The composition according to item 4 of the application, wherein the surfactant containing sulfate and / or osmate is dodecyl ammonium sulfate. 13. The composition according to claims} to 2 of the patent application scope, which is used for chemical mechanical polishing in semiconductor manufacturing, including applying the polishing composition to the surface of a semiconductor wafer for chemical mechanical polishing. -2 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)