JPS621873A - Washing method for deposit film-forming device - Google Patents

Abstract

PURPOSE:To wash the inside of a reaction cell in high efficiency and to maintain at a high level the quality of deposit films to be formed, by washing the inside of a reaction cell for use in formation, by a vapor-phase process, of deposit films by using plural gases having different reactivities to allow them to react plural times. CONSTITUTION:In the process for washing by gas-phase reactions the inside of the reaction cell used for forming deposit films by the vapor-phase process such as plasma CVD method, glow-discharge method, arc-discharge method, etc., plural reactions are operated by the use of the plural gases having different reactivities. The gases used in the above method are properly combined by considering reactivities with the substance to be the object of the removal by washing, interactivities among the washing gases, or the like and are further selected by synthetically judging their residual properties to the inside of the reaction cell after the gas-phase reactions, the influences upon deposit films when they remain, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a deposited film forming apparatus, a plasma CVD method,
[Conventional technology] Forming a functional deposited film on a substrate by a vapor phase method, regarding a cleaning method for an apparatus that forms a deposited film by a glow discharge method, an arc discharge method, etc. (hereinafter collectively referred to as a vapor phase method) This technique has already been widely used in electrophotography to uniformly form a photoconductive member on a drum. When forming a deposited film by such a vapor phase method, it is unavoidable that a part of the reaction product adheres as a film or powder to a portion other than the intended substrate, that is, to the inner wall of a reaction tank or the like. These adhered coatings or powders are easily peeled off, and the peeled off pieces and powder fly inside the reaction tank and adhere to the substrate on which the functional deposited film is to be formed, causing film defects such as pinholes in the deposited film. This is one of the causes of this.

Conventionally, as an example of a deposited film formed by a vapor phase method, there is a deposited film for a photoconductive member whose main component is silicon atoms, which is formed by a plasma reaction using a silane compound. . In the reaction tank in which this deposited film was formed, a heavy composite of silane (called /resilane) was generated as a by-product in parts other than the substrate, and conventional methods for cleaning and removing this were, for example, a mixture of CF4 and 02. A method of cleaning by plasma reaction using gas is used. With this method, production efficiency can be increased by alternately performing deposited film formation and cleaning.

However, the method described above removes the polysilane, which results in 9810. remains as a residue, and 0
2.1 molecules, etc. remain as adsorbents and are injected into the deposited film during the next deposited film formation, resulting in, for example, deterioration of the characteristics of use as a photobackable member (decrease in charging ability, image blurring, etc.), or Deterioration of photoconductive properties [photoconductivity (σph)/dark conductivity (σ,
) and mobility.

Therefore, if the above-mentioned deposited film formation and cleaning are repeated in cycles, the characteristics gradually deteriorate, and the product quality exceeds the allowable limit in a relatively short period of time. Therefore, until now, in addition to the above-mentioned cleaning, it has been necessary to disassemble and clean the reaction tank every few cycles, resulting in a decrease in productivity.

[Problems to be solved by the invention]

The present invention solves the conventional problems, makes it possible to efficiently clean the inside of a reaction tank in which a deposited film is formed by a vapor phase method, and maintains the quality of the deposited film formed at a high level. This invention was made to provide a method for cleaning a deposited film forming apparatus.

[Means for solving problems]

The method for cleaning a deposited film forming apparatus of the present invention, which was discovered as a means to solve the above problems, is a method for cleaning the inside of a reaction tank by a reaction including a gas phase for forming a deposited film by a gas phase method. This method is characterized by performing multiple reaction operations using multiple gases each having a different reactivity.

[Detailed description and examples of the invention]

The gases used in the cleaning method of the present invention can be appropriately combined in consideration of the reactivity with the substance to be cleaned and the reactivity of the cleaning gases, etc. It is necessary to comprehensively judge whether the substance remains in the reaction tank or, if it remains, the influence on the deposited film.

Specifically, for example, when cleaning and removing a heavy composite of silane that is produced as a by-product when forming a deposited film for a photoconductive member mainly composed of silicon atoms formed by the above-mentioned plasma reaction, For the first reaction operation using plasma reaction, it is preferable to select the above-mentioned mixed gas of CF4 and 02. Although it is known to use ammonium fluoride or the like, 5INx is generated and adheres to the inner wall surface of the reaction tank during the progress of the reaction, covers the surface to be cleaned, and reduces the cleaning efficiency.

If such a selection is made, in the second and subsequent reaction operations, it is necessary to prevent gas phase reactions from occurring with solid residues such as 8102 and adsorbates such as 0□, 1 molecule, etc., and remaining in the reaction tank. Of course, it is necessary to select a gas that can generate a compound that is not present, but it is also necessary to select a gas that takes into account the effect on the next deposited film formation if the cleaning gas itself remains. Therefore, as the gas used for the second and subsequent cleaning operations, it is preferable to select, for example, a mixed gas of CF4 and H2, a mixed gas of Ar and H2, or the like. In some cases, multiple reaction operations can be performed using these gases, e.g.
A cleaning operation using a mixed gas of Ar and H2 and a cleaning operation using a mixed gas of Ar and H2 can be performed one after the other. Of these, it is particularly desirable to use a mixed gas of CF4 and H2 for the second cleaning, and to use a mixed gas of Ar and H2 for the third cleaning.

Hereinafter, specific examples for demonstrating the effects of the present invention will be described.

Example 1, Comparative Example 1 Using the apparatus shown in FIG. 1, by plasma CVD method,
A deposited film for a photoconductive member is formed under the following production conditions, and in conjunction with this, the method of the present invention is carried out under the following cleaning conditions, the inside of the reaction tank is cleaned by plasma reaction, and deposited film formation and cleaning are performed continuously. [Explosion conditions] Lamination order of deposited film Raw material gas used Film thickness (μm) Charge injection blocking layer SiH4, B2H60,6 photoconductive layer S lH420 Surface protective layer SiH4, C2H40,1 substrate (aluminum cylinder) Temperature of 5: Control at 250M5℃ Internal pressure in deposition chamber during deposited film formation: 0.3 Torr Discharge frequency: 13.56 MH deposited film formation rate: 20 i/sec Discharge electric crab 0.18 W/crtt" Flow rate: 2
00 m/Hata Gas flow rate: Charge injection blocking layer 5iH4200SCCMB
200ppm for 2H65IH4 Photoconductive layer 5iH4200SCCM surface protective layer
5iH410SCCMCH4200SCCM [Cleaning conditions] Example 1: First CF4 (flow rate 1000 SCCM
) and 02 (flow rate 200SCCM), 2nd time CF4 (flow rate 500SCCM) and H2 (flow rate 101005CC gas mixture).

Comparative Example 1: Only the first run of the example process.

In this way, the charging ability of the photoconductive member after repeating 20 cycles of deposited film formation and cleaning (initial charging ability of 1.0
Ratio), and evaluation of image sharpness (A indicates excellent image condition; A, B).

Evaluation was made on a 5-grade scale of C, D, and E. The results are shown in Table 1.

Table 1 From Table 1, it can be seen that by cleaning according to the method of the present invention, there is no change in the characteristics of the deposited film and the reproducibility of quality is maintained.

Examples 2 to 5, Comparative Example 2 Under the cleaning conditions shown in Table 2, deposited film formation and cleaning were repeated 20 times in a row in the same manner as in Example 1. After 20 cycles, the resulting photoconductive member Characteristics were evaluated. The results are shown in Table 2.

As can be seen from Table 2, the method of the present invention stabilizes the characteristics of the deposited film, prevents contamination into the film, and allows uniform film formation, making it possible to maintain a high level of quality. Moreover, it does not require decomposition and cleaning of the reaction tank.

〔Effect of the invention〕

According to the present invention, the interior of a reaction tank in which a deposited film is formed by a vapor phase method can be efficiently cleaned, and the quality of the deposited film formed can be maintained at a high level.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a deposited film forming apparatus that can be used in the present invention. DESCRIPTION OF SYMBOLS 1... Ashstone tank container, 3... Container bottom plate, 4... Base support is a stand, 5... Cylindrical conductive base, 6... Top lid or goo), 8.8... Gas introduction pipe, 9, 9.9...Gas introduction hole, 12...High frequency matching index, 13
...Gas exhaust pipe...14...Resistance heating element. Agent Patent Attorney Sekihei Yamashita Figure 1

Claims (1)

[Claims] In a method of cleaning the inside of a reaction tank by a reaction involving a gas phase for forming a deposited film by a gas phase method, a deposition method is characterized in that reaction operations are performed multiple times using multiple gases each having a different reactivity. Method for cleaning film forming equipment.