JPH088239A - Wafer treatment device - Google Patents

Abstract

PURPOSE:To improve uniformity in wafer treatment by making uniform the flow of a reaction gas near a wafer. CONSTITUTION:In a wafer treatment device for treating a wafer 6 by filling the wafer 6 onto a sample stand provided in a treatment chamber and utilizing a gas molecule excited by thermal energy/plasma discharge under a reaction gas atmosphere, the inside of a treatment chamber is screened into a reaction gas introduction side and a reaction gas exhaust side by flow-rate distribution adjusting means 15 and 16 and an exhaust conductance adjustment hole 16 is provided at the flow-rate distribution adjusting means. Then, the channel area of an exhaust conductance adjustment hole is changed depending on the position along the peripheral direction and the flow of a reaction gas flowing along the wafer is controlled even if the introduction position of the reaction gas or an exhaust position is maldistributed without being located at the center of the treatment chamber by a baffle plate, thus making uniform the reaction gas over the entire surface of the wafer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer processing apparatus which is one of semiconductor processing apparatuses, and more particularly to a single wafer processing apparatus for processing one wafer at a time.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, gas molecules excited by thermal energy, plasma discharge, etc. are used to etch a silicon wafer on a sample table or a process such as chemical vapor deposition (CVD). There is a step of performing.

This is because a wafer is loaded into an airtight processing chamber, the inside of the processing chamber is evacuated to a vacuum, a reactive gas is further introduced, and ions of plasma generated by high frequency power,
Alternatively, a radical (neutral active species) is used, or the heat of a heater or the like is used to perform etching or a process such as chemical vapor deposition (CVD).

Among the conventional wafer processing apparatuses, an outline of a cathode coupling type parallel plate type plasma etching apparatus will be described with reference to FIG.

Electrodes 2 and 3 are provided inside the processing chamber 1 so as to face each other, and a high frequency power source 4 is connected to the electrodes 2.
A wafer 6 is loaded on one of the electrodes and on the cathode electrode 2 side. The electrodes 2 and 3 are cooled by a cooling system 5, and a reaction gas is introduced from a gas introduction system 7 from the anode electrode 3 on the other side of the electrodes.

Further, an exhaust system 8 is connected to the processing chamber 1 so as to exhaust the reaction gas. In FIG. 7, 9 is a flow rate adjusting valve, and 10 is an exhaust pump.

The plasma etching process for the wafer 6 is
Generally, it is performed as follows. A reactive gas is introduced from the gas introduction system 7 into the processing chamber 1 into which the wafer 6 is loaded and evacuated, or the lower surface of the anode electrode 3 or the anode electrode 3.
It is introduced from the outer periphery of. The inside of the processing chamber 1 is made to have a required pressure by the exhaust system, and high frequency power is applied to the cathode electrode 2 to generate plasma.

The wafer 6 is a radical in the plasma,
Etching is performed by the synergistic effect with the reactive gas ions accelerated by the self-bias voltage induced near the high frequency electrode.

[0009]

The exhaust system 8 is connected to the processing chamber 1 at a concentric position with the cathode electrode 2 because the cooling system 5 and the like are provided at the center of the cathode electrode 2. Since it is difficult to provide and the structure is complicated, it is located off the center of the cathode electrode 2. Exhaust hole 1 through which the exhaust system 8 communicates with the processing chamber 1
Since 1 is not concentric with the cathode electrode 2, a bias occurs in the flow of the reaction gas in the vicinity of the wafer 6 concentrically loaded on the cathode electrode 2. Therefore, there is a problem in uniformity of wafer processing such as etching processing of the wafer 6.

Assuming that the exhaust hole 11 is provided as shown in FIG. 8, assuming that the center of the wafer 6 is 0, the exhaust hole 11 side is −, and the opposite exhaust hole 11 side is +, the etching rate of the same wafer is seen. As shown in FIG. 9, the non-uniformity that the speed becomes faster on the exhaust hole 11 side is shown.

In view of the above circumstances, the present invention aims to improve the uniformity of wafer processing by making the flow of the reaction gas near the wafer uniform.

[0012]

According to the present invention, a wafer is loaded on a sample table provided in a processing chamber, and the wafer is processed by utilizing gas molecules excited by thermal energy plasma discharge or the like in a reaction gas atmosphere. In the wafer processing apparatus described above, the processing chamber is partitioned into a reaction gas introduction side and a reaction gas discharge side by a flow rate distribution adjusting means, an exhaust conductance adjusting hole is provided in the flow rate distribution adjusting means, and a flow of the exhaust conductance adjusting hole is provided. It is characterized in that the road cross-sectional area is changed depending on the position along the circumferential direction.

[0013]

The reaction gas flowing along the wafer is rectified by the baffle plate and uniformized over the entire surface of the wafer even if the introduction position or the discharge position of the reaction gas is unevenly distributed in the center of the processing chamber.

[0014]

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

In FIG. 1, the same parts as those shown in FIG. 7 are designated by the same reference numerals.

A flow rate distribution adjusting means 21 for partitioning the processing chamber 1 into upper and lower parts around the cathode electrode 2 is provided. The flow rate distribution adjusting means 21 includes a baffle base 14 and a baffle plate 15.
a, 15b, 15c, ... A baffle base 14 is provided at a boundary position between the periphery of the cathode electrode 2 and the processing chamber 1, and a required number of dispersion holes 13 having the same diameter are formed in the baffle base 14 along a required pitch circle. For each dispersion hole 13, baffle plates 15a, 15b,
15c, ... Are superposed on the baffle base 14 and attached. The baffle plates 15a, 15b, 15c, ... Have exhaust conductance adjusting holes 16a, 16b, respectively.
16c, ... Are provided, and the exhaust conductance adjusting holes 16a, 16b, 16c ,.
Pore size is different. That is, in the baffle plate 15 close to the exhaust hole 11, the diameter of the exhaust conductance adjusting hole 16 is small, and the diameter of the exhaust conductance adjusting hole 16 increases as the distance to the exhaust hole 11 increases.

Thus, the flow path resistance increases near the exhaust hole 11, and the flow path resistance decreases with increasing distance from the exhaust hole 11. Therefore, in the vicinity of the exhaust hole 11, the exhaust hole 1
The tendency that the reaction gas easily flows with respect to No. 1 is improved, and the flow of the reaction gas becomes uniform over the entire surface of the wafer 6.

Here, the deviation of the flow of the reaction gas is affected by the processing conditions such as the pressure in the processing chamber 1, the gas flow rate, the electrode interval, the volume from the electrode outer circumference to the exhaust hole 11 and the like. Therefore, the baffle plates 15a, 15b, 15c, ...
The baffle plate 15 of the small-diameter exhaust conductance adjusting hole 16 is not necessarily located near the exhaust hole 11. In short, the baffle plates 15a, 15b, 15 should be arranged so that the flow of the reaction gas becomes uniform.
The positions of c, ... May be appropriately selected.

FIG. 3 shows the second embodiment, and the individual baffle plates 15a, 1 shown in the first embodiment are shown.
5b, 15c, ... Are integrated. That is, a donut-shaped baffle plate 17 is provided by being superposed on the baffle base 14, and the baffle plate 17 has a dispersion hole 1 formed in the baffle base 14.
Exhaust conductance adjusting holes 16 are provided at the same pitch as in No. 3.

In this case, both the dispersion hole 13 and the exhaust conductance adjusting hole 16 have a smaller hole diameter as they get closer to the exhaust hole 11, and have a larger hole diameter as they get farther from the exhaust hole 11, and the donut-shaped baffle plate 17 is provided. By rotating the exhaust conductance adjusting hole 16
The aperture ratio of is changed.

In the above-mentioned first and second embodiments, the dispersion holes and the exhaust conductance adjusting holes do not necessarily have to be circular, and may be elliptical or rectangular.

Further, FIGS. 4 to 6 show a third embodiment in which a baffle plate 18 in which the baffle plate and the baffle base are integrated is provided. An exhaust hole 19 which is sufficiently larger than the cathode electrode 2 is eccentrically formed in the baffle plate 18. Due to the eccentricity of the exhaust hole 19, the exhaust hole 19 and the cathode electrode 2
Ring-shaped exhaust conductance adjusting hole 2 formed by
0 becomes not symmetrical with respect to the electrode center, becomes narrower on the exhaust hole 11 side and widen on the side opposite to the exhaust hole 11 as shown in FIG. 5, and the flow rate of the reaction gas is adjusted.

Further, by rotating the baffle plate 18, the positions of the narrow width portion and the wide width portion of the exhaust conductance adjusting hole 20 are moved, and the flow rate adjusting state of the reaction gas can be changed.

In the above embodiment, it is assumed that the reaction gas is introduced from the upper electrode (the anode electrode in this embodiment), but it is introduced from the lower electrode (the cathode electrode in this embodiment). In this case, the exhaust hole is provided on the upper electrode side, and the exhaust system is also connected to the upper electrode side.

[0025]

As described above, according to the present invention, even if the exhaust holes are provided at a deviated position other than the center, the flow of the reaction gas can be made uniform over the entire surface of the wafer, It enables uniform processing and improves yield,
It can help improve product quality.

[Brief description of drawings]

FIG. 1 is a schematic sectional 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 an explanatory diagram showing another embodiment, which is AA of FIG.
FIG.

FIG. 4 is a schematic sectional view showing still another embodiment.

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

6 is a BB arrow view of FIG. 4 in which the rectification state is changed.

FIG. 7 is a schematic cross-sectional view of a conventional example.

FIG. 8 is a view on arrow CC of FIG.

FIG. 9 is a diagram showing an etching rate at each position of a wafer in a conventional example.

[Explanation of symbols]

 1 Processing Chamber 2 Cathode Electrode 3 Anode Electrode 4 High Frequency Power Supply 6 Wafer 11 Exhaust Hole 14 Baffle Base 15 Baffle Plate 16 Exhaust Conductance Adjusting Hole 17 Baffle Plate 18 Baffle Plate 20 Exhaust Conductance Adjusting Hole 21 Flow Rate Distribution Means

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Claims (4)

[Claims] 1. A wafer processing apparatus in which a wafer is loaded on a sample table provided in a processing chamber and a wafer is processed by utilizing gas molecules excited by thermal energy, plasma discharge, etc. in a reaction gas atmosphere, The processing chamber is partitioned into a reaction gas introduction side and a reaction gas discharge side by a flow rate distribution adjusting means, an exhaust conductance adjusting hole is provided in the flow rate adjusting means, and a flow passage cross-sectional area of the exhaust conductance adjusting hole is circumferentially arranged. The wafer processing equipment is characterized in that it is changed depending on the position. 2. The wafer processing apparatus according to claim 1, wherein the flow rate distribution adjusting means has a plurality of exhaust conductance adjusting holes. 3. A baffle base having flow rate distribution adjusting means provided at a boundary between a reaction gas introducing side and a reaction gas discharging side and having a plurality of dispersion holes, and a baffle plate having an exhaust conductance adjusting hole which is superposed on the dispersion holes. The wafer processing apparatus of claim 1, wherein the wafer processing apparatus comprises: 4. The wafer processing apparatus according to claim 1, wherein the flow passage cross-sectional area of the exhaust conductance adjusting hole is small at a position close to the exhaust hole communicating with the reaction gas discharge side and increases as the distance increases.