JPH0499281A - Device for forming film by cvd and cleaning method - Google Patents

Abstract

PURPOSE:To prolong the service life of electrodes for forming a film by CVD by setting an electrode for cleaning. CONSTITUTION:Discoid upper and lower electrodes 12, 13 are arranged in a single wafer processing CVD device for forming a film for a semiconductor process and a larger ringlike electrode 19 for cleaning than the discoid electrodes 12, 13 is further set in the device. Though a movable electrode for cleaning enables cleaning under optimum conditions, a fixed electrode may be used. Damage to the electrodes 12, 13 for forming a film by CVD is reduced, the service life is prolonged and films can stably by formed over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a CVD film forming apparatus and its plasma cleaning method.

[Conventional technology]

The conventional cleaning method for CVD equipment is plasma CV
Taking the method of manufacturing a silicon oxide film by method D as an example, as shown in FIG.
After transporting the substrate 37 on which the VD film is to be deposited, and evacuating the inside of the container, monosilane and nitrous oxide are poured into the container. After the gas flow rate and pressure reach predetermined values, radio frequency (RF) is applied to the electrodes.
is applied and maintained for a certain period of time to grow a silicon oxide film in a vapor phase, and then the radio frequency (RF) is stopped. After the gas in the container is evacuated and discharged, the vacuum container is returned to atmospheric pressure and the substrate 37 is carried out.

After transporting the substrate, so-called plasma cleaning is performed to remove the metallic silicon oxide film formed inside the vacuum chamber by flowing a mixed gas of fluorocarbon gas such as CFa and Oe and applying RF. Ta.

[Problem to be solved by the invention]

However, in the conventional technology, in order to clean the inside of the vacuum container in a short time, the RF output and the flow rate of the cleaning gas must be increased, which can cause significant damage to the electrodes and cause the surface insulation layer to break down. The lifespan was extremely reduced, and as a result, abnormal discharge during formation of the CVD film, film thickness uniformity, and growth rate were adversely affected. Further, since the optimum position of the electrode for cleaning is different from that when forming the CVD film, a sufficient cleaning effect has not been obtained.

However, the present invention solves these problems,
The purpose is to provide a CVD film forming apparatus and a cleaning method that have a long electrode life and can form stable CVD F4.

[Means to solve the problem]

The CVD film forming apparatus according to the present invention has the following features: 1) It has a third electrode for plasma cleaning in addition to the two parallel plate type electrodes facing each other. 2) The third electrode is closer to the first or second electrode. 3) The third electrode is movable.

Further, the method for cleaning a C V D Il'A forming apparatus according to the present invention is characterized in that: 4) a third electrode is used.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to FIG. Here, since a single-wafer type CVD film forming apparatus is taken as an example, a movable ring-shaped cleaning electrode is provided in addition to two disc-shaped electrodes.

First, a semiconductor substrate 17 on which semiconductor elements such as transistors and resistors and aluminum wiring are formed is kept at about 400° C. and transported into a vacuum container 14 in which an insulated upper electrode 12 and lower electrode 13 are arranged in parallel. After the inside of this container was evacuated, a frequency of 1.3.56 MHz was applied to the electrode 12.13 under conditions of approximately 11,003 CC of monosilane gas, approximately 15,003 CC of nitrogen oxide gas, and a pressure of approximately 5 Torr.
Apply 500 W of radio frequency (RF) to form a silicon oxide film. After taking out the substrate, move the cleaning [M19] to a predetermined position and use the CFalooSCCM.
, Ot200SCCM, pressure 2T.

Under the conditions of rr, the cleaning electrode 19 and the top! lol
IJil 2ffi'H: JitlJ wave number 13. 56
Radio frequency (RF) of 700 W (MHz) is applied to remove the excess silicon oxide film formed inside the vacuum container.

By providing cleaning flI4?19, C
Damage caused by RF application to ff:M13 for VDM formation has been drastically reduced, and the electrode, which conventionally required replacement after 3000 film formations, can now be used continuously for about 10000 times. Furthermore, the growth rate and in-plane uniformity during CV D M formation were stabilized.

Here, we will introduce single-wafer CVD film formation &
! tWi, in addition to the two disk-type electrodes, a ring-shaped cleaning electrode 1iE larger than the disk is provided. A movable cleaning electrode is suitable for M and can be cleaned under leaning conditions, but even if it is not movable it will require 7 tons.
The damage dealt to [can be reduced.

Furthermore, although we have explained here a monosilane-nitrous oxide-based silicon oxide film, similar results can be obtained for cleaning CVD films such as TE01-oxygen-based silicon oxide films and monosilane-ammonia-based silicon nitride films. Obtained. CFs regarding cleaning gas
/ 02 and other C2Fg102. NF嘗/02+N
Gases such as F 2 / N to can be similarly applied.6 [Effects of the Invention] As described above, according to the present invention, by providing a cleaning electrode separately from an electrode for CVD film formation, CVD
Damage to the electrode for film formation can be reduced, and it becomes possible to supply a stable CVD film for a long period of time.

[Brief explanation of drawings]

FIGS. 1 and 2 are a schematic cross-sectional view and a projected view of a CVD film forming apparatus according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a conventional CV D N@ forming apparatus. 11.31...RF oscillator 12.32...-[4 part electrode 13.23 33...Lower electrode 14.24.34...Vacuum container 15.35...Gas inlet 16.36... ...Gas outlet 17...Substrate 18...Insulator 19.29...Cleaning electrode or higher

Claims (1)

[Claims] 1) A CV characterized by having a third plasma cleaning electrode in addition to two parallel plate type electrodes facing each other.
D film forming device. 2) The third electrode according to claim 1 is the first or second electrode.
A CVD film forming apparatus characterized in that it is larger than the electrode. 3) A CVD film forming apparatus characterized in that the third electrode according to claim 1 or 2 is movable. 4) A cleaning method using the third electrode according to claim 1, claim 2, or claim 3.