TW439208B - Post process of self-aligned contact - Google Patents

Abstract

The self-aligned contact (SAC) of the present invention is fabricated by the well-known technology, the polymer and the C-containing residuals will be remained on the SAC structure and do a certain degree of damage to the substrate. Then the SAC postprocessing procedure is performed by using the down-stream mode of etching machine to generate plasma, the reactive gas to generate the plasma contains O2 and fluorine-containing gas to eliminate the remained polymer and carbon-containing residual, and to repair the damage caused by etching. Furthermore, the photoresist can be removed together. The gas pressure of the postprocessing chamber is about 500 to 3000 mT, the power of plasma is about 300 to 1000 W, the flow rate of oxygen is about 1000 to 2000 sccm, the flow rate of fluorine-containing gas is about 25 to 400 sccm, the processing temperature is about 50 to 120 DEG C.

Description

14 3 9 2 0 8 A7 B7 V. Description of invention () Field of invention: Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs This invention is related to the process of manufacturing semiconductor components, especially a method for forming self-aligned contact windows * and more special After finishing the self-aligning contact window, a post-processing process is performed. Background of the Invention: The development of semiconductor components in new application fields is constantly driving the development of semiconductor components in the computer and communication related industries. For example, the interface of computers will develop in the area of audiovisual control in the future. The above-mentioned control interface will require a large number of memory components. . In order to obtain high-performance integrated circuits and increase the mounting density of wafers, the size of semiconductor components has been continuously reduced in the ultra-large integrated circuit (ULSI) technology. The self-aligning contact-window process is an important part of the semiconductor process, and mainly provides a channel for the electrical connection between the conductor structure and the active area of the substrate. The conventional method mainly includes forming a field oxide region (not shown) on the semiconductor substrate 2 to define an active region, and then depositing a gate oxide layer 6 and a polycrystalline silicon layer 8 on the field oxide region and the substrate 2 to compound the crystal. A silicon dioxide layer or a gasified stone layer 10 is then deposited over the silicon layer, as shown in the first figure. Define the mask last name with the gate oxide layer 6, complex crystal fragment layer 8 and the oxidized layer 10. Covered < Please read the precautions on the back before filling this page) * c Order- ------- Line private air scales. 卞. Qin single mortise rate. ((^ Fen 合 4: .. 楼 明 7 ... 分 箄 辕)

A7 B7 V. Description of the invention The gate structure of the () layer (c a p 1 a y e r) 1 0 is shown in the second figure. The cap layer 10 described above is to prevent the subsequent deposition of the samarium layer from making electrical contact with the samarium electrode and causing a short circuit. The next step 1 is to deposit a dielectric layer, and then etch the dielectric layer to form a sidewall gap I 2 on the sidewall of the gate structure. After the fabrication of the sidewall gap is completed, the source and drain electrodes 14 are doped, and the structure of the LDD 16 can be fabricated before the sidewall gap is fabricated. A dielectric layer 18 is deposited on the surface of the above structure. Generally, silicon oxide is used, and a photoresist pattern 20 is defined on the dielectric layer 18, as shown in the third figure. With the photoresist pattern 20 as a mask, the above-mentioned dielectric layer 18 is etched by an etching technique to make a contact window, and finally the photoresist is removed to complete the fabrication of the contact window. Generally, the sidewall gap 12 uses silicon nitride as a material, and the sidewall gap is easily lost during the SAC etching process. In order to prevent the above phenomenon, it is necessary to increase the etching selectivity between silicon nitride and silicon oxide to avoid chemical conversion. . The silicon is etched. Generally, C4F3 / CO-based etching gas can be used for SAC etching. However, with the above-mentioned etchant, the reactive gas will react with the C = C bond in the photoresist, causing the polymer 22 on the surface of the SAC to remain. The above polymer 22 will cause an increase in the SAC resistance value. Furthermore, it will cause an open state of the SAC. Moreover, during the above SAC process, the substrate will also be etched during the etching process. Therefore, it is urgently needed What is a SAC process can overcome the above-mentioned shortcomings (please read the precautions on the back before filling this page) „---- Order * -------- Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 439208 Α7 ----------- Β7 V. Description of the invention () Loss of β Purpose and summary of the invention: The main purpose of the present invention is a self-aligning contact window that prevents the polymer from being damaged and the substrate being damaged. (Self aiigrl contact) process. Another purpose of the present invention is to use SA post-processing procedures to prevent the polymer from self-aligning contact with the substrate being destroyed. The window (se If align contact) process. The gate structure is made by technology. The structure of the gate includes a silicon nitride masking layer and a silicon argon sidewall gap. Next, a dielectric layer composed of silicon nitride or a similar material is deposited for the purpose of electrical insulation. Next One step for definition The resist pattern is on the silicon oxide layer to define the area of the contact window. Behind the table, high-selectivity is used; PjEdreactiveionetchingJIi is used to make contact window SAC. This etch uses argon as the ion source, and the reaction gas is composed of CO, C4F8 or CO , C4F8, and CF4 »This highly selective dry etching can etch the silicon oxide layer. The contact window will expose the drain or source. The polymer and C-containing residue will remain on the sac structure, and the substrate Caused 'a certain degree of damage β —I --------— 0 installed, please read the precautions on the back before filling out this page) l · 丨! Order --------- line: Printed by the Consumer Cooperatives of the Ministry of Intellectual Property Bureau w 豸 ·;.; ..-.- ^ .- 'A.:· ... Xianhai:

Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs i43 9 2 〇 8 Α7 __Β7_ V. Description of Invention () In terms of (), cf4, c2f6, or c4fs can be used. Alternatively, chf3, CH2F2, or CH3F can also be used. The above-mentioned damage caused by RIE etching, and high molecular and hindered residues can be repaired or eliminated by using down s t r e a m plasma containing II. Also. After that, the photoresist can be removed together. Therefore, the post-processing procedure of the present invention can integrate a photoresist removal step (PR ashing). In a preferred embodiment, the pressure of the post-treatment reaction chamber is about 500 to 3000 mT, the power of the plasma is about 300 to 1000 W, the flow rate of the oxygen gas is about 1000 to 2000 sccm, and the flow rate of the fluorine-containing gas is about 25 to 400sccm, the processing temperature is about 50 to 120 t. Brief description of the figure: The first figure is a cross-sectional view of forming a field oxide layer and completing the deposition of a polycrystalline silicon layer and a cover layer in a conventional self-aligned contact window process. The second figure is a cross-sectional view of the gate structure completed in the traditional self-aligning contact window process. The third figure is a cross-sectional view of SAC etching performed in a conventional self-aligned contact window process. The fourth aspect is a cross-sectional view of a gate structure formed in the self-aligning contact window manufacturing process of the present invention. The fifth figure is a cross-sectional view of the self-aligned contact window manufacturing process of the present invention. The sixth figure is a cross-sectional view of a post-processing program executed by the present invention. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)--f! I ----------- r--J Order --------- p (Please read the notes on the back before filling in this page) V. Description of the invention () A7 B7

Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs, as shown in the fourth figure, 'Single crystal semiconductor with one crystal plane < Voo > as the substrate, such as a p-type single crystal silicon substrate 40. Next, as the isolation area for the isolation between components, field oxidation fabrication technology or trench isolation technology can usually be used. According to an embodiment, 'the traditional L 0 C 0 S process is used to produce a thick field oxidation region (not shown) as an insulator of the active region. The formation of this field oxidation region is heated in an aerobic vapor environment. Oxidation * temperature produces silicon dioxide between 8 50-1 0 50 ° C, with a thickness of 4000-6000 Angstroms. Next, a gate oxide layer 42 is formed on the substrate, and then a polycrystalline silicon layer 44 is deposited by a chemical vapor deposition method to cover the gate oxide layer 42 and the field oxide layer, and the thickness is I 0 0 0 to 2 0 0 0 Egypt. A first silicon argon layer 46 is deposited on the surface of the above-mentioned polycrystalline silicon layer 44 by chemical vapor deposition to cover the polycrystalline silicon layer 44 with a thickness ranging between 300 and 2000 angstroms. Next, a first photoresist layer is defined on the first silicon nitride layer 46, and the above-mentioned silicon nitride layer 46, the polycrystalline silicon layer 44 and the gate oxide layer 42 are etched by an etching technique. This etching can use dry etching to remove the area not covered by the first photoresist to form a gate structure as shown in the fourth figure. The silicon nitride layer 46 is used as a cover layer for the gate structure 44. Its main function is ( (阅读 Read the notes on the back before filling out this page)

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Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 ___B7_ V. Description of the invention () Prevent short circuit between the polycrystalline silicon layer 44 and the subsequent conductive plutonium layer. Materials with similar functions can also replace gasification. Referring to the fifth figure, a dielectric layer such as a silicon oxide layer or a silicon nitride layer 48 is formed on the surface of the gate structure and the cover layer, and silicon nitride is used as the silicon argon layer 4 in the first embodiment. Chemical vapor deposition, such as low-pressure chemical vapor deposition, generally forms a nitride SiH4 'NH3' N2 'N2〇 or other suitable reactants in the reaction chamber at a temperature of 300 to S00 degrees Celsius 5th floor. The next step is the production of a side wall gap (sidewa U spacer :). This step uses an anisotropic etching technique to etch the silicon argon layer 48 to form a side wall space (side wall space 04S) on the side wall of the gate structure. The hand-carved reaction gas is CHF3, CF4 / H2 or CHF3CHF2. The function of the side wall gap 4 S is the same as that of the covering layer 4 6. The barrier carved by the last name is to prevent the polycrystalline dream layer 4 4 A short-circuit phenomenon with the subsequent conductive layer is difficult. A dielectric layer 50 composed of silicon oxide or a similar material with a thickness of about 150 to 300 angstroms is deposited, and the silicon oxide dielectric layer 50 is used as electrical The purpose of the insulating insulation. The next step is to define the photoresist pattern 52 on the silicon oxide layer 50 to define the area of the contact window. Finally, the contact window SAC is fabricated using highly selective RiE (reactive ion etching) etching. Etching uses argon as an ion source, and the reaction gas includes C0, C4F8 or C0, C4F8 and CF4. This high ----------------------------- -Order ---- ^ ---- (Please read the notes on back lying before filling this page) Nickel

Printed by a member of the Intellectual Property Bureau of the Ministry of Economic Affairs and a consumer cooperative. A7 ____B7 V. Description of the invention () As is known in the art, polymers and C-containing residues 5 4 will remain on the S A C structure and cause some damage to the substrate. One of the important points of the present invention is to eliminate the damage of the polymer and the C-containing residue 5 4 and the recovery substrate caused as described above. Referring to the sixth figure, after the self-aligning contact window SAC is completed, a post-treatment process is performed, and the post-processing procedure provided by the present invention can eliminate the above-mentioned defects. The etching machine generally has a RIE mode and a downstream mode. The RIE mode generally generates charged ions, and the downward stream mode generates high-energy uncharged particles. 3 The subsequent processing procedure is to use a money engraving machine. Downstream m mode generates plasma to execute SAC post-processing program. The reaction gas used to generate the plasma is a gas containing 02 and fluorine, such as CxFy. For example, cf4, c2fs, or C4F8 can be used. In addition, CHF3, CH2F2, or CH3F »oxygen gas can also be used in the plasma to increase the dissociation of oxygen molecules to free radicals;; .. Ability 1 oxygen radicals are the main reactants for the removal of anything and photoresist. The damage caused by the RIE etching as well as the polymer and carbon-containing residues mentioned above can be repaired or eliminated by using a fluorine-containing downward flow radiocommunication. The mechanism used in this step is mainly the reaction of fluorine radicals with the damaged silicon substrate. Also. After that, the photoresist 50 can be removed together. Therefore, the post-processing procedure of the present invention can integrate a photoresist removal step (PR ashing). Applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) on this paper scale ------------- Ί Γ -L --- 1 l · --- ^ --- -I--I (Please read the precautions on the back before filling this page) 439 2 0 8 A7 B7 V. Description of the invention () In a preferred embodiment, the pressure of the post-processing reaction chamber is about 5 0 0 to 3000 mT, the power of the plasma is about 300 to 1000 W, the flow of oxygen gas is about 1000 to 2000 seem, the flow of fluorine-containing gas is about 25 to 400 s'c cm, and the processing temperature is about 50 to 120 ° C. One of the advantages of the present invention is that after the etching of the contact window is completed, 1 the post-processing procedure provided by the present invention can be used to remove the polymer and carbon-containing residues, so the contact resistance of the contact window can be reduced and the open circuit can be prevented. In addition, the substrate damage caused by RIE during SAC can be repaired. Furthermore, the post-processing procedure of the present invention can simultaneously remove photoresist and integrate process steps. The present invention is described above with a preferred embodiment, and if you are familiar with the skill in this field, you can make some modifications to it without departing from the spirit of the present invention. The equivalent field depends on 11-II. Lit .--- I I --------- 1 l · 1 11 -------- line (please read the precautions on the back before filling in this Page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs This paper is sized for the Chinese National Standard (CNS) A4 (210 X 297 mm)

Claims (1)

ABCD 1 A process for aligning contact windows in i rows. The process includes at least: forming a semiconductor element on a semiconductor substrate, the semiconductor element including a sidewall gap formed on a sidewall of the semiconductor element: forming a dielectric layer to cover the semiconductor The substrate and the semiconductor element are used as an insulating layer, and the dielectric layer 俾 is etched with a engraved mask to form the self-aligning contact window. The self-aligning window has a polymer remaining thereon; and A self-aligning contact window post-processing program. The self-aligning contact window post-processing program includes using a down stream electro-polymerization, and using oxygen and fluorine-containing gas as a reaction gas to remove the above-mentioned polymers and repair them. Damage to the substrate caused by cooking. 2 If f, please apply the self-aligning contact window process in item 1 of the patent scope, wherein the above-mentioned self-aligning contact window post-processing procedure includes removing the etching mask 3 3 If the self-aligning contact window process in the scope of patent application, The above-mentioned fluorine-containing gas includes CXFY. 4. The self-aligning contact window process according to item 3 of the patent application scope, wherein the above-mentioned fluorine-containing gas is selected from one of the clusters consisting of CF ,, C2Fs, C ^ FS, CHF3, CH2F2, and CH3F or any combination thereof. j ------—— (Please read the notes on the back before filling in this page) Order 10 copies of paper printed by the Employees' Cooperatives of the Ministry of Economic Affairs and the Ministry of Economic Affairs. (彳 / 彳 ^ mm) .. 6. Scope of patent application 5 The self-aligning contact window manufacturing process as described in item 1 of the patent application scope, wherein the above-mentioned self-aligning contact window post-processing procedure includes an oxygen gas flow of about 1,000 to (Please read the note on the back first Please fill in this page again for details) 2 0 0 0 seem ° 6 If the self-aligning contact window system of item 1 of the scope of patent application is used, the above-mentioned self-aligning contact window post-processing procedure includes a fluorine-containing gas flow of about 2 5 To 40 seem ° 7 As in the self-aligning contact window process of the first patent application, the above-mentioned self-aligning contact window post-processing procedure includes a plasma power of about 300 to 1,000 W. 8 If the self-aligning contact window manufacturing process of item 1 of the patent application scope, wherein the above-mentioned self-aligning contact window post-processing procedure includes the reaction chamber pressure of about 500 to 3 0 0 mT 9 The alignment window process, wherein the above-mentioned self-aligning contact window post-processing procedure includes a reaction chamber temperature of about 50 to 120 ° C. The Ministry of Economic Affairs ’Smart Money is a self-aligning contact window process printed by the Bureau of Industrial and Commercial Cooperatives, such as item 1 of the scope of patent application, in which the reaction gas forming the above-mentioned self-aligning contact window includes CO, C4F8, or 8 〇 2 9 3 4 ABC0 ττ, scope of patent application (please read the precautions on the back before filling out this page) CO 'C4F8 and CF4. 11 A method for removing polymer, the method includes at least: using a down stream plasma, using oxygen and a fluorine-containing gas as a reaction gas to remove the above polymer, wherein the above-mentioned fluorine-containing gas contains CxFγ ° 12 The method according to item 11 of the scope of patent application, wherein the above-mentioned fluorine-containing gas is selected from one of the clusters consisting of cf4, C2F6, C4Fs, chf3, ch2f2 & ch3f, or any combination thereof. 13 The method according to item 11 of the patent application, wherein the above-mentioned oxygen gas flow rate is about 1000 to 2000 sccm ° 14 The method according to item 11 of the patent application, wherein the above-mentioned fluorine-containing gas flow is approximately 25 to 40 seem. Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 15 If the method of item 11 of the patent application is applied, the power of the above plasma is about 300 to 1000W. 16 The method according to item 11 of the patent application range, wherein the pressure of the reaction is about 500 to 3000 mT. This paper size is applicable to National Standards (CNS) A4 Regulation K 210X297 mm 2 A8 B8 C8 D8 VI. Application for patent scope 1 7 The method of item 11 in the scope of patent application 'where the temperature of the reaction chamber is about 50 to UOt: a For printing by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs ..... i Suitable for 1 ^ .. · Ruler ... I Sheet-Paper ...: 本 .-'... c ::;.橾: ... country V country ... I country 'A4 ·.' ..: 3%. One 7 .-2 'X. Ο ··