TW405181B - Dry etching method of the silicon dioxide - Google Patents

Abstract

A kind of dry etching method of the silicon dioxide that uses a recipe of C2F6/Ar/O2 as the etch gas to prevent the etching ceased and ensures a fine electric connectivity of the subsequent process is introduced. It uses a high-density plasma etcher in which a silicon is settled in the reactive chamber as the dry etcher and uses the composite gas with the flow rate of C2F6/Ar/O2 is 30-60 sccm/40-200sccm/3-10 sccm respectively to dry etching the silicon dioxide.

Description

Printed by the Shellfish Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs j) e I 5 7 61 w 1 'd ο c / Λ rdc η ne / 0 0 5 ___40518t_ V. Description of the invention (/) ~~ The present invention has A dry etching (and etch) method of silicon dioxide (OXIDE), and in particular, a dry etching method of silicon dioxide formed by nitrogen (No treatment). (Sub-quarter micron) sand dioxide etching technology, usually using carbon fluoride (CxFy) as a gas, in the reaction chamber (chamber) combined with silicon blocks (sUiC0n r〇〇f) §11 Density Plasma »HDP) dry worm. For example, the HDP 5300 etching machine produced by AppHe (j Material) puts a silicon block on the upper end of the reaction chamber. The purpose is to absorb the gas atoms (fluorine) in the reaction chamber. ), So that the silicon oxide's etching selectivity of the underlayer (etching selectivity) can be improved. Conventional silicon dioxide etching method, the gas used is a single carbon hexafluoride (C2F6) gas; the other A gas composed of C2F6 / C4F8 / Ar formula proposed by AMAT 'or He / C2F6 / CHF3 formula An experimental combination of the formed gas and the like. For example, the flow rate of the latter formula is about 7 & 400sccm, 30-50sccm, and CHF3 about 5-15sccm. Please refer to Fig. 1 and Fig. 2, which are drawn separately Scanning electron microscope (Scanning Elect—etching silicon dioxide using three He or C2F6 / CHF3 and C2F6 / C4F8 / Ar formulas)

Microscope; SEM). C2F6 or He / C2F6 / CHF3 etching will have a double iLIfKetch stop) phenomenon, which will cause problems in subsequent electrical connections. For example, Figure 1 shows the typical results of its etching. C2F6 / C4F "Ai · Etching can be used to stop etching, but the effect is not good, as shown in Figure 2. nnn ^^ 1 i ^ l i > 1 ^ 1 In ^ n · an--( Please read the notes on the back and fill in this first.) This paper size applies Chinese National Standard (.CNS) A4 specification (21.0 > < 297 mm) f; H c I 5 7 61 w Γ. D 〇c / A rde η nc / 0 0 5 ___ i〇5l8lj [V. Description of the invention (>) " Therefore, 'the main purpose of the present invention is to provide an etching method of sand dioxide' with a new formula as an etching gas to prevent The termination of etching occurs to ensure good electrical connection in subsequent processes. According to the main purpose of the present invention, a dry-axis engraving method of sand dioxide is proposed, which uses a high-concentration plasma etching machine in which a silicon block is placed in the reaction chamber. The dry etching machine performs the silicon dioxide dry etching at a flow rate of about 30-60 sccm of dicarbon hexafluoride, about 40-200 sccm of argon, and about 3-10 sccm of oxygen, respectively. To make the silicon dioxide dry etching. And other purposes, features, and advantages can be more clearly understood, a preferred embodiment is given below. In conjunction with the attached drawings, the detailed description is as follows: Brief description of the drawings: Figure 1 is a scanning electron microscope image of the conventional etching of silicon dioxide with Cj6 or He / C2F6 / CHF3 as the etching gas formula; The figure is a scanning electron microscope image of conventionally etched silicon dioxide using C2F6 / C4F8 / Ar as the etching gas formula; Figure 3A is an optical emission spectrum of a thin film without N2 treatment; and the sheller of the Central Standards Bureau of the Ministry of Economy Consumption Cooperatives India Fan 1-.-Ϋ 1 I--n I--. 1--i-I-Ding, i-9 f {谙 Please read the precautions on the back before filling out this page} Figure 3B is Optical emission spectrum of N2 treated thin film during etching. Best Practice Imitation 1 Please refer to Figures 3A and 3B. Figure 3A shows the optical emission spectrum (Optical Emission 4) of the film without N2 treatment when touched. This paper size applies to Chinese National Standard (CNS) A4 (210X 297 mm) Printed by the Consumer Cooperatives of the Central Standardization Bureau of the Ministry of Economic Affairs T05181 I7 V. Description of the invention (;)

Spectroscopy; OES) diagrams, such as axon-etched plasma-enhanced tetraethyl oxalate (? 1 & 51113 £ 11! 1 & 115 € (1-but £ 08;? £ -but £ 08) film. Figure 38 The optical emission spectrum of the N2 treated thin film is etched, for example, a self-aligned chemical vapor deposition (SA-CVD) silicon dioxide thin film treated with 1 ^ 2 is etched. According to the experimental findings of the present invention, Figure 3A has no carbon nitride (CN) peak and no etch termination; Figure 3B has CN peak and etch termination. Therefore, it is judged that the formation of CN and the etch termination are very large. The high-concentration plasma system is very sensitive to the environment of the reaction chamber, and the carbon (Carbon; C) content in the reaction chamber has a great impact on the etching ability. Maintaining a high carbon content in the system can obtain a high "dioxide Silicon / photoresist (oxide / PR) etch selectivity. However, when the system carbon content is high and etched to N2-treated films (eg, BP-TEOS, PE Oxide / SA-CVD), it usually occurs Etching is terminated. Therefore, the present invention considers that the etching is terminated because C and > 12 caused by the additional reaction of CN. When CN is formed during etching, it will be deposited on the bottom of the hole to form a CN film, which prevents the etching from continuing and causes the etching to stop. The etching reaction model is as follows:

Cx--Fy + Si02— ^ s_ ^ SiF4 + CO + COF2 Cx--Fy + N-sp ,, eous) CN + NF3 Therefore, the present invention assumes that the termination of silicon dioxide etching is caused by CN formation. Taking this hypothetical theory as a starting point, the present invention performs etching experiments with three formulations, such as C2F6 + Ar, CA + Hei CHf3, and C2F6 + 02. H HI ^^ 1 n —-I In ^^ 1 In αψan (Please read the notes on the back before filling this page) This paper size is applicable to China ^ $ (CNS) A4 size (210X 297 mm) ~ Printed by Shellfish Consumer Cooperative, Central Bureau of the Ministry of Economic Affairs

Filcl576twfdoc / Ardennc / 005 ____405181 B7___ 5. Description of the Invention (Order) It was found that: (1) C2F6 + 〇2: It can effectively prevent the termination of etching, but the photoresistance loss increases: (2) C2F6 + He + CHF3: It cannot effectively prevent etching Termination; (3) C2F6 + Ar: It can prevent the termination of etching, but the effect is not as good as c2F6 + 〇2, which has the advantage of less photoresistance loss. The preferred embodiment of the present invention selects the best formula as CJJAr / O2 based on the results of the above-mentioned dummy load test, which not only avoids the termination of etching, but also maintains a higher "silicon dioxide / photoresist" etching selectivity. For example, using a high-concentration plasma touch engraving machine as a dry etcher, and placing a sand block in the reaction chamber, and using C ^ FJAr / O2 as a gas, dry contact etch for oxidizing xi. Among them, the C2F6 / Ar / 02 gas flow rate is (: about 30-60 sccm, Ar about 40-200 sccm, 〇2 about 3-10 sccm.) From the above-mentioned preferred embodiment of the present invention, it can be known that 'the application of the preferred embodiment of the present invention The proposed dry shaft engraving method of sand dioxide can not only solve the problem of contact termination, but also has the advantages of high "silicon dioxide / photoresist" touch selectivity and high "silicon dioxide / underlayer" etching selectivity. The invention has been disclosed in the preferred embodiment as above, but it is not intended to limit the invention. Anyone skilled in the art can make various modifications and retouches without departing from the spirit and scope of the invention. The scope of protection shall be defined as the scope of the patent application attached as follows: & 6 scales are applicable to China National Stone Cricket (CNS) A4 specification (210X297 mm) n ^ i ^ nf It l ^ 11 ^ 1 n ^ — (Please read the notes on the back before filling in this page)

Claims (1)

[; ile 1 5 7 6 1 w Γ d ο c / A rdc ίΐ η c Ό Ο 5 405181 A8 B8 C8 D8 Application scope of patent 1. A dry etching method of silicon dioxide, which uses silicon in a reaction chamber One of the high-concentration plasma etching machines is a dry etching machine, and a composition gas of about 30-60 sccm of hexafluoride, 40-200 sccm of argon, and about 3-lOsccm of oxygen is used as the reaction gas. The silicon dioxide is dry etched. 2. A dry etching method of silicon dioxide, which uses a carbon monoxide / argon / oxygen composition gas as the reaction gas for the dry etching method. 3. The dry etching method as described in item 2 of the patent application scope, wherein The dry etching method further includes a high-concentration plasma etching machine in which a silicon block is placed in the reaction chamber as a dry etching machine. 4. The dry etching method according to item 2 or 3 of the scope of patent application, wherein the carbon fluoride is dicarbon hexafluoride. 5. The dry etching method according to item 2 of the scope of the patent application, wherein the flow rates of the dicarbon hexafluoride / argon / oxygen composition gas are about 30-60 sccm of the dicarbon hexafluoride, and about 40-200 sccm of argon. , Oxygen is about 3-10sccm. (Please read the precautions on the back before filling this page) i. Order. Printed by the Central Consumers Bureau of the Ministry of Economic Affairs, printed by the Employees' Cooperatives. The paper size applies to the Chinese National Standard (CNS) A4 (210X2S · 7mm)