JPH0851082A - Suscepter of semiconductor manufacturing device - Google Patents

Abstract

PURPOSE:To enable a CVD device to be enhanced in stability of plasma discharge and uniformity of electrical field distribution at the time when a film is formed or gas cleaning is carried out and to be improved in film quality and gas cleaning uniformity. CONSTITUTION:In a CVD device of double-bath structure, an exhaust groove 18 which enables an inner tank to communicate with an outer tank is cut in a suscepter where a substrate is placed, and an exhaust vent 17 communicating with the exhaust groove 18 is provided to the corners of the substrate respectively to make reactive gas that flows over the substrate uniform in flow when the substrate is rectangular in shape, and thus plasma is stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma CVD apparatus, and more particularly to a susceptor for mounting a substrate in a plasma CVD apparatus having a double tank structure.

[0002]

2. Description of the Related Art Plasma CVD (Chemical Vap) for forming a predetermined film on a substrate in one of semiconductor manufacturing processes.
or Deposition) film forming step. In this step, a substrate is loaded in an airtight processing chamber provided with a pair of electrodes facing each other, high frequency power is applied to the electrodes while supplying a reaction gas into the processing chamber to generate plasma, and gas in a gas phase is generated. The molecules are separated by plasma to form a thin film on the substrate surface.

Further, in recent years, a gas cleaning method for cleaning the inside of a processing chamber by plasma has attracted attention as well as film formation by plasma. Similar to the film formation, while supplying a cleaning gas such as NF ₃ into the processing chamber, high-frequency power is applied to the electrodes to generate plasma, gas phase cleaning gas molecules are separated by the plasma, and the electrodes are separated. The film adhered / deposited on the surface or the inner wall of the processing chamber is removed by etching.

The above gas cleaning method lowers the temperature of the processing chamber, releases it to the atmosphere, or vacuums it, as compared with the conventional cleaning work in which the temperature of the processing chamber is lowered, the atmosphere is opened to the atmosphere for decomposition, and physical cleaning is performed. Since it is possible to omit ancillary steps such as exhaust and temperature rise, it is very effective in improving the operating rate.

In the plasma CVD apparatus, a two-chamber structure that divides the processing chamber into an inner tank and an outer tank is mentioned as a processing chamber structure for efficiently performing the film formation and the gas cleaning. That is, by performing the film formation in the inner tank, the deposition of reaction by-products in the processing chamber due to the film formation can be stopped in the inner tank while increasing the plasma density to improve the efficiency of the film formation. Further, in the gas cleaning, not only the efficiency of cleaning can be improved similarly to the film formation, but also the cleaning residue that affects the film formation can be eliminated at an early stage.

Next, referring to FIG. 5, an outline of a plasma CVD apparatus having a double tank structure will be described.

An inner tank chamber wall 2 is provided on the ceiling surface of the processing chamber 1, and an upper electrode cathode 4 is provided inside the inner tank chamber wall 2 via an insulator 3. The inside of the cathode 4 is hollow, and the gas introducing pipe 5 communicates with the hollow portion 7. Further, a large number of pores 6 for showering the reaction gas introduced into the hollow portion 7 from the gas introduction pipe 5 are formed on the lower surface of the cathode 4 in a shower shape. A high frequency power source 8 is connected to the gas introduction pipe 5.

A lower electrode anode 9 is provided below the inner tank chamber wall 2 so as to face the cathode 4 and is movable up and down, and a susceptor 10 is provided on the anode 9 and the susceptor 1 is provided.
The substrate 11 to be processed is placed on the substrate 0. The susceptor 10
Closes the lower end opening of the inner tank chamber wall 2 to define an inner tank chamber 12 and an outer tank chamber 15 in the processing chamber 1. The susceptor 10
A required number of exhaust holes 13 that communicate the inner tank chamber 12 and the outer tank chamber 15 are formed around the periphery of the. In the figure, the processing chamber 1
The substrate loading and unloading port provided at the
4 is an outlet.

The substrate 11 to be processed with the anode 9 lowered.
Is installed in the susceptor 10, the anode 9 is raised to define the inner tank chamber 12, the reaction gas is introduced from the gas introduction pipe 5 into the hollow portion 7, and is dispersed and supplied from the pores 6 while High frequency power is applied to the cathode 4 to generate plasma in the inner tank chamber 12. The generated plasma has a high density because it is limited to a narrow space such as the inner tank chamber 12. High-density plasma enables highly efficient film formation. The gas after the reaction flows into the outer tank chamber 15 through the exhaust hole 13 and is further discharged through the exhaust port 14.

[0010]

By the way, in the above-mentioned double tank structure CVD apparatus, stability of plasma during film formation,
The uniformity of the gas cleaning is greatly affected by the uniformity of the flow rate distribution of the reaction gas flowing in the inner tank chamber 12, the exhaust structure between the inner and outer tanks, and the like.

In particular, when the substrate to be processed has a rectangular shape such as a display plate of a liquid crystal display, the plasma density becomes nonuniform in the peripheral portion, particularly at the four corners, and it is difficult to obtain a uniform gas flow. ,
The development of an exhaust structure that achieves plasma stability and gas flow rate uniformity over the entire substrate has been an important issue.

In view of the above situation, the present invention improves plasma deposition stability and electric field distribution uniformity both during film formation and during gas cleaning to improve film formation quality and gas cleaning uniformity. It is the one to try.

[0013]

According to the present invention, in a plasma CVD apparatus having a double tank structure, an exhaust groove for communicating between an inner tank chamber and an outer tank chamber is formed in a susceptor on which a substrate is placed, and When the substrate has a rectangular shape, an exhaust port communicating with the exhaust groove is provided in the vicinity of the ridge of the substrate, and the exhaust groove has a length longer than that of neutralizing charged particles in plasma. The present invention relates to a susceptor of a semiconductor manufacturing apparatus existing within a width of 30 mm with respect to a diagonal line of a substrate.

[0014]

The gas can be exhausted evenly from the ridges, the flow of the reaction gas flowing on the substrate is made uniform, the plasma is stable, and the film formation is uniform without film thickness distribution. Can perform gas cleaning.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Exhaust between the inner and outer tanks is performed through the susceptor 10. The present invention aims to improve the stability of plasma discharge and the uniformity of electric field distribution by improving the susceptor for the susceptor 10, particularly the rectangular substrate 11 to be processed.

A first embodiment will be described with reference to FIGS.

The structure of the CVD apparatus itself having a double tank structure, which is the object of the present embodiment, is the same as that described with reference to FIG.

The rectangular upper surface of the flat plate 20 is formed low,
A pedestal 16 for mounting a substrate to be processed is formed in the center, and the pedestal 1
An exhaust passage is formed in the peripheral portion of the lower surface of 6. The central portion of the pedestal 16 excluding the exhaust passage serves as a mounting space for the substrate 11 to be processed.

The exhaust ports 17 are provided at the four corners of the pedestal 16, on the diagonal line, or within a width of ± 30 mm with respect to the diagonal line.
An exhaust groove 18 corresponding to the periphery of the pedestal 16 is formed on the back surface of the flat plate 20, one end of which communicates with the exhaust port 17 and the other end of which is a dead end for each exhaust port 17. Set up. Further, the other end of each exhaust groove 18 communicates with an exhaust guide hole formed in a susceptor pedestal (not shown) on which the flat plate 20 is placed, and is connected to the outside of the inner tank chamber 12 through the exhaust guide hole. It is in communication.

The lengths of the exhaust grooves 18 are all the same for equalizing the conductance, and further, the lengths of the exhaust grooves 18 are the same as the charges in the plasma when the plasma in the inner chamber 12 flows into the exhaust grooves 18. The length is set to a sufficient length for neutralizing the particles, preferably 10 mm or more, to prevent plasma from leaking into the outer tank chamber 15.

A reaction gas is introduced through the gas introduction pipe 5, and high-frequency power is supplied between the cathode 4 and the anode 9 to generate plasma in the inner tank chamber 12. The reaction gas introduced into the inner tank chamber 12 flows into the exhaust groove 18 through the exhaust port 17, flows through the exhaust groove 18 and is exhausted into the outer tank chamber 15.

As described above, since the exhaust port 17 is located on the diagonal line of the substrate 11 to be processed, the reaction gas is the substrate 1 to be processed.
1 toward the four ridges, and the exhaust groove 1
Since all 8 have the same conductance, the flow of the reaction gas becomes uniform over the entire surface of the substrate 11 to be processed,
The film forming speed at the ridge portion where the film forming speed is conventionally decreased is similar to that at the central part of the substrate 11 to be processed.

Thus, the uniformity of film thickness and film quality on the rectangular substrate is greatly improved.

Depending on the process conditions, film formation and gas cleaning may be performed at a large gas flow rate. In this case, the number and arrangement of exhaust ports are changed so that the exhaust conductance increases. 3 and 4 show another embodiment of the present invention.

A total of eight exhaust ports 17 are provided at two corners of the pedestal 16 with two diagonal lines in between, and exhaust grooves 19 communicating with each exhaust port 17 are formed. Each of the exhaust grooves 19 communicates with an exhaust guide hole (not shown) and communicates with the outside of the inner tank chamber 12 through the exhaust guide hole.

The lengths of the exhaust grooves 19 are all the same for equalizing the conductance, and further, the length of the exhaust grooves 18 is the same as the charge in the plasma when the plasma in the inner tank chamber 12 flows into the exhaust grooves 18. Long enough to neutralize the particles,
It goes without saying that the thickness is preferably 10 mm or more.

The number and size of the exhaust ports 17, the length of the exhaust groove, etc. are determined by the flow rate of the reaction gas introduced into the inner tank chamber 12 and the high frequency power supplied to the cathode 4.
Set so that plasma is not concentrated and abnormal discharge does not occur.

[0029]

As described above, according to the present invention, the exhaust gas is exhausted from the four ridges of the rectangular substrate to be processed.
The flow of the reaction gas becomes uniform over the entire surface of the substrate to be processed, stability of plasma discharge during film formation, uniformity of electric field distribution and film thickness,
The uniformity of the film quality can be significantly improved, and the uniformity of gas cleaning can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3 is a plan view showing another embodiment of the present invention.

FIG. 4 is a view taken along the line BB of FIG.

FIG. 5 is a vertical cross-sectional view of a CVD apparatus having a double tank structure.

[Explanation of symbols]

 4 Cathode 9 Anode 10 Susceptor 11 Substrate 12 Inner Tank Chamber 15 Outer Tank Chamber 17 Exhaust Port 18 Exhaust Groove 19 Exhaust Groove

Claims (4)

[Claims] 1. A susceptor for a semiconductor manufacturing apparatus, characterized in that in a plasma CVD apparatus having a double tank structure, an exhaust groove is formed in a susceptor on which a substrate is placed and which communicates between an inner tank chamber and an outer tank chamber. . 2. The susceptor for a semiconductor manufacturing apparatus according to claim 1, wherein when the substrate has a rectangular shape, an exhaust port communicating with the exhaust groove is provided near a ridge of the substrate. 3. The susceptor for a semiconductor manufacturing apparatus according to claim 1, wherein the exhaust groove is an exhaust groove having a length that is equal to or longer than the neutralization of charged particles in plasma. 4. The exhaust port has a width of 30 mm with respect to the diagonal line of the substrate.
A susceptor for a semiconductor manufacturing apparatus characterized by being present within.