JPH04113615A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce dust particles which adhere to a semiconductor substrate and to restrain that the functional defect of a semiconductor device occurs frequently by providing the following: a process to deposit a first thin film on the inner wall surface of a reaction chamber in a manufacturing apparatus; and a process to insert the semiconductor substrate in the reaction chamber on which the first thin film has been deposited and to deposit a second thin film on the substrate. CONSTITUTION:A valve 4 is closed and valves 10, 11 are opened. In this state, the inside of a reaction chamber 1 is evacuated down to 5X10<-3>mbar by using a vacuum pump 5. Then, the number of dust particles immediately after this evacuation operation has been started is counted. When the number of dust particles is less than 100, it is not required to deposit a first thin film 7. When the number is more than 100 pieces, the first thin film 7 is deposited in a state that the valve 4 is opened and that the valves 10, 11 are closed, and the inside of the reaction chamber 1 is purged by using nitrogen gas and is returned to atmospheric pressure. When the number is less than 100 pieces, a semiconductor substrate 6 is inserted in the reaction chamber 1, a second thin film is deposited in the state that the valve 4 is opened and that the valves 10, 11 are closed, the inside of the reaction chamber 1 is purged by using nitorogen gas and is returned to atmospheric pressure. The inside of the reaction chamber 1 is evacuated by using the vacuum pump 5 in the state that the valve 4 is closed and that the valves 10, 11 are opened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a semiconductor device that reduces dust adhering to a substrate. The impact of dust on yields is being talked about more than ever.

In addition, although dust from semiconductor manufacturing equipment has become a problem due to unmanned clean rooms, conventional techniques for reducing dust from semiconductor manufacturing equipment include optimizing the semiconductor substrate transport system and improving the performance of material gas supply system components. Improvements have been made in mechanical factors such as improvements in maintenance technology and improvements in dust generation.
The method for manufacturing a semiconductor device will be explained with reference to the figures. FIG. The exhaust section 3 is composed of a valve 4 and a vacuum bomb 5. Further, a semiconductor substrate 6 is inserted into the reaction tube 1, and a thin film is deposited.

In the conventional deposition method, the reaction chamber 1 is connected to the valve 4 using a vacuum pump 5.
Next, the material gas 2 is introduced and the first thin film 7 is deposited on the inner wall of the reaction chamber 1 in several batches to a thickness that prevents dust from falling off. After that, the semiconductor substrate 6 is inserted into the reaction chamber 1 and the material gas 2 is introduced to deposit the second thin film 8.4 When the cumulative thickness of the second thin film 8 starts to peel off, the second thin film 8 Finishing the deposition of the first
There is also a method of depositing the second thin film 8 by inserting the semiconductor substrate 6 into the reaction chamber 1 and introducing the material gas 2 without depositing the second thin film 7.

Problems to be Solved by the Invention In the conventional thin film deposition method, the first thin film 7 is deposited on the inner wall of the reaction chamber 1 in several batches until no more dust falls off. Due to insufficient deposition, dust 9 adheres to the inner wall surface of the reaction chamber 1. Due to the introduction of the material gas, it peels off from the inner wall surface of the reaction chamber 1 and adheres to the semiconductor substrate 6, resulting in the formation of semiconductor devices. This may cause loss of functionality.Also, there is a method of depositing the second thin film 8 by inserting the semiconductor substrate 6 into the reaction chamber l and introducing the material gas 2 without depositing the first thin film 7. (The second thin film is applied to the semiconductor substrate 6 to increase the number of dust particles 9 attached to the inner wall surface of the reaction chamber 1 that peel off from the inner wall surface of the reaction chamber 1 and adhere to the semiconductor substrate 6 than in the above method.) 8 is deposited several times. When the film thickness increases, the second thin film s itself peels off, causing loss of functionality of the semiconductor device. 4 In this way, in the conventional method, the first thin film 7, the The cumulative thickness of the thin film 8 in 2 is a value determined based on experience, and depending on how it is taken, a large amount of dust 9 may adhere to it, resulting in frequent loss of functionality of the semiconductor device.The present invention solves the above problems. It is an object of the present invention to provide a method for manufacturing a semiconductor device that reduces dust adhering to a semiconductor substrate 6 and suppresses frequent occurrence of functional defects in the semiconductor device.

Means for Solving the Problems The present invention is directed to solving the above problems.The present invention includes a step of depositing a first thin film on a wall surface of a reaction chamber of a semiconductor device manufacturing apparatus, and a step of depositing the first thin film on a semiconductor substrate. The present invention also provides a method for manufacturing a semiconductor device, which comprises inserting the semiconductor device into a reaction chamber and depositing a second thin film on the semiconductor substrate. By covering with a film, it is possible to achieve a large dust trapping effect with the minimum necessary film, significantly reducing dust adhering to semiconductors, and preventing loss of functionality of semiconductor devices due to dust adhesion, making it possible to manufacture high-performance semiconductor devices. Examples in which the yield could be improved Below are examples in which the present invention was applied using a low-pressure CVD apparatus.
The first will be explained in detail with reference to Fig. 2 and Fig. 3. Fig. 1 is a reduced pressure CVD apparatus, which consists of a reaction chamber 1, a material gas 2 introduction part, and an exhaust part 3, and the exhaust part 3 is a valve. 4 or connected to the vacuum pump 5 via the valve 10, dust counter 12, and valve 11.L to the semiconductor substrate 6
Insert into reaction chamber 1. Hereinafter, the operation of the apparatus will be explained along the flow shown in Figure 2. Figure 2 (1)].

(2) Next, the number of dust immediately after the start of exhaust is counted with a dust counter [see Fig. 2 (2).

Here, the judgment value for the number of dust particles will be explained with reference to Fig. 3. Fig. 3 shows the relationship between the cumulative film thickness on the inner wall of the reaction chamber 1 and the number of dust particles counted by the dust counter 12. Thin film 7 and second thin film 8 are both 5i02 films and the temperature inside the reaction chamber is ↓ 812°C. If the cumulative film thickness is thin, there will be a large number of dust particles, and if it is too thick, the number of dust particles will be 1.% or less. Cumulative film thickness
(3) If the number of counted dust particles is less than 100 (less than the judgment value A), there is no need to deposit the first thin film 7, and go to (6). If there are many, proceed to step U(4) [Second
Figure (3)].

<If there are many cases> (4) Valve 4 closed The first thin film 7 is deposited with the valve lO111 closed [see FIG. 2 (4).

(5) Return to step 1) of purging the inside of the reaction chamber 1 with nitrogen gas and returning it to atmospheric pressure [Figure 2 (5)].

<If the quantity is small> (6) Insert the semiconductor substrate 6 into the reaction chamber 1 [see Fig. 2 (
6) Ko.

(7) 4 valves When valves 10 and 11 are closed, the second
A thin film 8 is deposited [FIG. 2 (7)].

(8) Purge the inside of reaction chamber 1 with nitrogen gas and return to atmospheric pressure [
Figure 2 (8)]. 1 (9) 4 valves With valves 10 and 11 open, the inside of the reaction chamber 1 is evacuated using the vacuum pump 5 [see Figure 2 (9).

(10) The number of dust immediately after exhaust is counted by the dust counter 12 [FIG. 2 (10)].

(11) If the counted number of dust particles is less than the judgment value B (6
) to many cases! Proceed to step 1 (12) [Figure 2 (1)
1)].

(12) Purge the inside of the reaction chamber 1 with nitrogen gas and return it to atmospheric pressure [Figure 2 (12)].

As described above, according to the manufacturing method of the embodiment of the present invention, as shown in FIG. 1, the first thin film completely covers the dust on the inner wall of the reaction chamber 1, and when the material gas is introduced, the dust can fly onto the semiconductor substrate 6. disappears. Also, peeling L of the second thin film 8 itself
This is known before depositing the second thin film 8 on the semiconductor substrate 6.

As a result, it is not possible to achieve an improvement in yield. As long as it is a deposition device (t or
The force between the first thin film 7 and the second thin film 8 (in this embodiment, the force was of the same type (although it may be different) By covering the walls of the reaction chamber with a film, it is possible to achieve a large dust trapping effect with the minimum necessary film, significantly reducing dust adhering to semiconductors, preventing functional loss of semiconductor devices due to dust adhesion, and achieving high performance. We were able to improve the manufacturing yield of semiconductor devices.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a semiconductor device manufacturing apparatus used in an embodiment of the present invention. FIG. 2 is a flowchart of a semiconductor device manufacturing method showing an embodiment of the present invention. FIG. Figure 4 is a graph showing the relationship between film thickness and the number of dust particles measured by a dust counter.・Exhaust hole 4
, 10, 11, ・Pulse 5・Vacuum pump,
6... Semiconductor substrate, 7... First thin WL 8...
・Second thin film 9...Dust 12...Dust counter agent's name Patent attorney Akira Okaji and two others Figure 1 Figure Figure 2

Claims (2)

[Claims] (1) A step of depositing a first thin film on the wall of a reaction chamber of a semiconductor device manufacturing apparatus, inserting a semiconductor substrate into the reaction chamber in which the first thin film has been deposited, and depositing a second thin film on the semiconductor substrate. Method for manufacturing a semiconductor device including a step of depositing (2) In the step of depositing the first thin film, the amount of dust present in the reaction chamber is counted, and when the amount of dust is less than a preset determination value, the deposition of the first thin film is terminated. A method for manufacturing a semiconductor device according to claim 1 (3) In the step of inserting a semiconductor device into a reaction tube in which a first thin film has been deposited and depositing a second thin film on the semiconductor device, in the reaction chamber. The semiconductor according to claim 1 or 2, characterized in that the step of counting the amount of dust present and repeatedly depositing the second thin film when the amount of dust is less than a preset determination value is performed. Method of manufacturing the device.