JPH054466U - Wafer processor - Google Patents

Abstract

(57) [Summary] [Purpose] Make the flow of the reaction gas near the wafer uniform,
Improves wafer processing uniformity. In a wafer processing apparatus, a wafer 6 is loaded on a sample table provided in a processing chamber 1, and gas molecules excited by thermal energy and plasma discharge in a reaction gas atmosphere are used to process the wafer. The processing chamber is partitioned by baffle plates 15, 17 and 18 into a reaction gas introduction side and a reaction gas discharge side, and exhaust conductance adjusting holes 16 and 20 are provided in the baffle plate. By changing the cross-sectional area depending on the position, the reaction gas flowing along the wafer is rectified by the baffle plate even if the reaction gas introduction position or the discharge position is unevenly distributed in the center of the processing chamber, and the entire surface of the wafer is rectified. Homogenize.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a wafer processing apparatus that is one of semiconductor processing apparatuses, and more particularly to a single wafer processing apparatus that processes one wafer at a time.

[0002]

[Prior Art]

 In the process of manufacturing a semiconductor device, there is a process of etching a silicon wafer on a sample table by using gas molecules excited by thermal energy or plasma discharge, or performing a process such as chemical vapor deposition (CVD). ..

This is to load a wafer into an airtight processing chamber, evacuate it to a vacuum, introduce a reactive gas, and use plasma ions or radicals (neutral active species) generated by high-frequency power. Alternatively, the heat of a heater or the like is used to perform etching or chemical vapor deposition (CVD).

Among conventional wafer processing apparatuses, a cathode-coupled parallel plate type plasma etching apparatus, in particular, will be outlined 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 other anode electrode 3 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 of the wafer 6 is generally performed as follows. A reactive gas is introduced from the lower surface of the anode electrode 3 or the outer periphery of the anode electrode 3 from the gas introduction system 7 into the processing chamber 1 in which the wafer 6 is loaded and evacuated. The inside of the processing chamber 1 is set to 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 etched by a synergistic effect of radicals in plasma and reactive gas ions accelerated by a cell bias voltage induced near the high frequency electrode.

[0009]

[Problems to be solved by the device]

 As for the connection position of the exhaust system 8 to the processing chamber 1, since the cooling system 5 and the like are provided at the center of the cathode electrode 2, it is difficult to provide the exhaust system 8 at a position concentric with the cathode electrode 2, and structurally. Since it becomes complicated, it is located off the center of the cathode electrode 2. Since the exhaust hole 11 through which the exhaust system 8 communicates with the processing chamber 1 is not concentric with the cathode electrode 2, the flow of the reaction gas near the wafer 6 concentrically loaded on the cathode electrode 2 is biased. Therefore, there arises a problem in uniformity of wafer processing such as etching processing of the wafer 6.

As shown in FIG. 8, assuming that the exhaust hole 11 is provided, if 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 situation, the present invention aims to make the flow of the reaction gas near the wafer uniform and improve the uniformity of the wafer processing.

[0012]

[Means for Solving the Problems]

 The present invention is a wafer processing apparatus for processing a wafer by loading a wafer on a sample table provided in a processing chamber and utilizing gas molecules excited by thermal energy and plasma discharge in a reaction gas atmosphere. The inside of the processing chamber is partitioned by a baffle plate into a reaction gas introduction side and a reaction gas discharge side, and an exhaust conductance adjusting hole is provided in the baffle plate to change the flow passage cross-sectional area of the exhaust conductance adjusting hole depending on the position. It is characterized by that.

[0013]

[Action]

 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]

【Example】

 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 baffle base 14 for partitioning the processing chamber 1 into upper and lower parts is provided around the cathode electrode 2, and the baffle base 14 is provided with a required number of dispersion holes 13 having the same diameter along a required pitch circle. Baffle plates 15a, 15b, 15c, ... Are attached to the respective dispersion holes 13. Exhaust conductance adjusting holes 16a, 16b, 16c, ... Are provided in the baffle plates 15a, 15b, 15c, ..., and the exhaust conductance adjusting holes 16a, 16b, 16c ,. 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 is increasing as the distance from the exhaust hole 11 increases.

Thus, the flow path resistance increases near the exhaust hole 11, and the flow path resistance decreases as the distance from the exhaust hole 11 increases. Therefore, the tendency that the reaction gas easily flows toward the exhaust hole 11 in the vicinity of the exhaust hole 11 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 influenced by the processing conditions such as the pressure in the processing chamber 1, the gas flow rate, the electrode spacing, the volume from the electrode outer circumference to the exhaust hole 11, and the like. Therefore, the attachment positions of the baffle plates 15a, 15b, 15c, ... Are not necessarily the baffle plate 15 of the exhaust conductance adjusting hole 16 having a small diameter located near the exhaust hole 11. The point is that the positions of the baffle plates 15a, 15b, 15c, ... May be appropriately selected so that the flow of the reaction gas becomes uniform.

FIG. 3 shows a second embodiment, in which the individual baffle plates 15a, 15b, 15c, ... Shown in the first embodiment 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 is provided with the exhaust conductance adjusting holes 16 at the same pitch as the dispersion holes 13 formed in the baffle base 14. It is provided.

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. By rotating 17 the opening ratio of the exhaust conductance adjusting hole 16 is changed.

In the first embodiment and the second embodiment, the dispersion hole and the exhaust conductance adjusting hole 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 ring-shaped exhaust conductance adjusting hole 20 formed by the exhaust hole 19 and the cathode electrode 2 is not symmetrical with respect to the electrode center, and as shown in FIG. It becomes narrow and widen on the side opposite to the exhaust hole 11, 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, so that 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 (anode electrode in this embodiment), but it is introduced from the lower electrode (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]

[Effect of the device]

 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, and uniform wafer processing can be performed. It is possible to contribute to the improvement of yield and 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 on arrow AA of FIG.

FIG. 3 is an explanatory view 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 14 Baffle Base 15 Baffle Plate 16 Exhaust Conductance Adjusting Hole 17 Baffle Plate 18 Baffle Plate 20 Exhaust Conductance Adjusting Hole

Claims (1)

[Claims for utility model registration] [Claim 1] A wafer is loaded on a sample stage provided in a processing chamber, and the gas molecules excited by thermal energy / plasma discharge in a reaction gas atmosphere are used to remove the wafer. In a wafer processing apparatus for processing, the processing chamber is partitioned by a baffle plate into a reaction gas introduction side and a reaction gas discharge side, an exhaust conductance adjusting hole is provided in the baffle plate, and a flow passage cross-sectional area of the exhaust conductance adjusting hole is provided. A wafer processing apparatus characterized in that the position is changed depending on the position.