JPH10149990A - Gas cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the throughput of a gas cleaning method by shortening the preparation time for the method by performing gas cleaning which has been performed for every lot in the conventional example for every plural lots. SOLUTION: The number of lots which becomes the gas cleaning interval is set in advance. After the gas cleaning interval is set (step 101), it is confirmed that a cassette is a newly fed cassette (step 102) and a gas cleaning integral counter is increased by '1' (step 103). One substrate is extracted from the cassette and carried to a film forming chamber (step 104) and a film is formed on the substrate (step 105). When the film formation is completed on all substrates contained in the cassette (step 106), the starting condition of the gas cleaning treatment is discriminated (step 107). When the acquired gas cleaning interval is equal to the count value of the gas cleaning interval counter, the gas cleaning treatment is performed (step 108). After treatment, the gas cleaning interval counter is cleared to the original state (step 109).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas cleaning method for a semiconductor manufacturing apparatus such as an LCD, and more particularly to a method for improving the cleaning efficiency.

[0002]

2. Description of the Related Art In an LCD semiconductor manufacturing apparatus, as shown in FIG. 3, an LCD substrate 2 is sequentially taken out of a cassette 1 and transferred to a film forming chamber 4 via a preheating chamber 3 to form a film one by one. , Taken out of the cooling chamber 5. This LC
When the D-semiconductor manufacturing apparatus is operated continuously, a film causing particles or the like adheres to the inside of the film forming chamber 4 during the film formation. Therefore, it is necessary to periodically clean the film. Generally, as this cleaning method, a dry gas cleaning method using NF ₃ gas or the like is adopted for the purpose of improving the cleaning performance.

Conventionally, when the last substrate of each cassette has passed by the data of each substrate called the sub-management information data, the process has always been shifted to the gas cleaning process irrespective of the number of film-formed substrates.

FIG. 2 shows the flow of the conventional gas cleaning process. A new cassette is loaded (Step 201), one substrate is transported from the cassette to the film formation chamber (Step 202), and a film is formed (Step 20).
3). The processes of steps 202 and 203 are repeated until the transfer of one cassette is completed (step 204), and when completed, a gas cleaning process is performed (step 205). After the processing, steps 201 to 205 are repeated for each cassette. As described above, the conventional gas cleaning is performed for each cassette. Note that one cassette is synonymous with one lot, and the number of substrates in the cassette does not matter.

[0005]

However, in the above-described conventional gas cleaning method, gas cleaning is performed for each lot, so that the etching preparation time, the residue processing time, and the residue processing preparation time are collected for each lot. Gas cleaning preparation time). For this reason, the gas cleaning time occupied in the operation time of the apparatus was long, and the throughput did not increase.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems of the prior art by performing gas cleaning for each of a plurality of lots, to shorten the time required for gas cleaning,
The purpose is to improve the throughput.

[0007]

According to the present invention, there is provided a gas cleaning method for a semiconductor manufacturing apparatus in which substrates are transferred one by one from a loading lot to a film forming chamber to perform a film forming process. The process is set to be performed each time a plurality of lots is completed, the number of input lots is counted, and when the set plurality of lots are processed, gas cleaning of the film forming chamber is performed.

Since the number of input lots is counted and the film forming chamber is cleaned when a plurality of set lots are processed, the gas cleaning preparation time is shortened compared with the conventional example in which each lot is processed, and the throughput is reduced. Is improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The LCD semiconductor manufacturing apparatus is the same as the conventional example shown in FIG.

Referring to FIG. 3, a gas supply line 6 for forming a thin film, a gas supply line 9 for cleaning, and a gas discharge line 13 are connected to the film forming chamber 4. The gas supply line 6 for forming a thin film is connected to a SiH ₄ through a gas valve 7.
The gas cylinder 8 is connected. An NF ₃ gas cylinder 1 is connected to a cleaning gas supply line 9 through a gas valve 10.
One is connected. A pump 14 is connected to the gas discharge line 13. Then, the gas valves 7, 10 and the pump 1
4 is totally controlled by the controller 12. The controller 12 also controls a heater, a gas flow sensor, and the like (not shown).

In the present embodiment, by controlling the LCD semiconductor manufacturing apparatus by the controller 12, the film cleaning chamber 4 is subjected to the gas cleaning process not for every lot but for every plural lots as shown in FIG. Do.

In FIG. 1, first, a gas cleaning interval is obtained (step 101). The system parameters are set in advance so that the gas cleaning of the film forming chamber 4 is performed every time a plurality of lots (gas cleaning intervals) of the film forming process are completed. The gas cleaning interval is obtained from the system parameter for which the gas cleaning interval is set.

After the acquisition, it is determined whether the loaded cassette 1 is a newly loaded cassette (step 102). In order to confirm the gas cleaning interval, that is, the number of lots, it is determined whether or not the cassette is a newly loaded cassette. If the number of substrates initially contained in the cassette matches the current number of remaining sheets, it is determined that the cassette is a newly inserted cassette.

In the case of a newly loaded cassette, 1 is added to the gas cleaning interval counter 15 (step 103).
If it is not a new cassette, the process jumps to step 104.

Next, only one substrate 2 is taken out of the cassette 1 and transferred to the film forming chamber 4 (step 104).

After the transfer, the gas valve 7 is opened and the pump 14
Is operated to send a SiH ₄ gas to the film forming chamber 4 to perform a film forming process for laminating a single-layer film on the substrate 2 (Step 105).

After the film forming process, it is determined whether or not all the substrates 2 for one cassette have been transported (step 106). Whether it is the last substrate of one cassette is determined based on the sub management information. When all the film forming processes are completed, one cassette has been transported. If not completed, steps 104 and 105 are repeated until completed.

After one cassette has been conveyed, it is determined whether the gas cleaning start condition is satisfied (step 107). If the acquired gas cleaning interval = gas cleaning interval count value, the gas cleaning start condition is satisfied. If not, steps 102 to 106 are repeated until the case is satisfied.

When the gas cleaning start condition is satisfied,
A gas cleaning process is performed (Step 108). The gas valve 10 of the cleaning gas supply line 9 is opened to supply NF ₃ gas to the film forming chamber 4 to perform a gas cleaning process. Here, the general conditions of gas cleaning are as follows.

Temperature 200-350 ° C. Pressure 0.3-0.6 Torr Gas Type NF ₃ and Diluent Gas Gas Flow Rate NF ₃ 300-500 ccm When the gas cleaning process is completed, the gas cleaning interval counter 15 is cleared, and step 101 is performed. Return to (Step 109).

As described above, in the present embodiment, a process for counting the number of newly inserted cassettes and a process for determining whether the gas cleaning start condition is satisfied after one cassette has been conveyed are added to the conventional gas cleaning process flow. The gas cleaning process is performed for each set plurality of lots.

As a result, the cleaning time is shortened as compared with the conventional cleaning performed for each lot as follows.

Cleaning shortening time = (E ₀ + ES + P) × N− (E _n + ES + P) (1) N (N ≧ 2): Number of lots to be gas-cleaned P: Residual processing time + Preparatory time before and after total residual processing E ₀ : conventional etching time E _n: plural lots each of the etching time ES: cleaning time first term of the right side of a conventional total before and after etching preparation time equation (1), second
Is the cleaning time according to the present embodiment. formula
By rearranging (1), the following can be obtained: cleaning shortening time = (P + ES) × (N−1) + E ₀ × N−E _n (2)

When the effect of performing the gas cleaning process for every two lots is calculated using the equation (2), the residual processing time = 141 sec. The conventional etching time = 540 sec. Time = 1
080 sec (540 × 2) Accordingly, from equation (2), the cleaning shortening time = {(141 + 25) +90} × (2-1) + 540 × 2-1080 = 256 sec. This shows that the gas cleaning time per two lots is reduced by 256 seconds.

Further, assuming that the operation time of the apparatus is 96 sec / substrate, the conventional processing time of 40 substrates is 42.6 substrates (22.6 substrates).
(56 sec / (96 sec / sheet) = about 2.6 sheets) can be processed, which leads to an improvement in throughput.

In the above embodiment, a semiconductor manufacturing apparatus for manufacturing an LCD substrate has been described. However, the present invention can be applied to a CVD apparatus for manufacturing a semiconductor wafer. The cleaning gas is C Other NF ₃
It may be used lF _3.

[0027]

According to the present invention, since the gas cleaning is performed for each of a plurality of lots, the gas cleaning time per lot can be reduced. In addition, since the film formation processing of the substrate can be additionally performed for the shortened time, the throughput is improved.

[Brief description of the drawings]

FIG. 1 is a process flowchart of a gas cleaning method according to an embodiment of the present invention.

FIG. 2 is a processing flowchart of a conventional gas cleaning method.

FIG. 3 is a schematic view of an LCD semiconductor manufacturing apparatus common to the conventional example and the present embodiment.

[Explanation of symbols]

 1 cassette, 2 substrates, 4 deposition chamber

Claims (1)

[Claims] In a gas cleaning method for a semiconductor manufacturing apparatus in which a substrate is transferred one by one from a charging lot to a film forming chamber and a film forming process is performed, the gas cleaning of the film forming chamber is completed in a plurality of lots in advance. A gas cleaning method wherein the number of input lots is counted, and when the set plural lots are processed, gas cleaning of the film forming chamber is performed.