JPS6329735Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention This invention relates to a plasma etching apparatus, and particularly to an improvement in the structure of the plasma etching apparatus to improve its etching characteristics.

Prior Art Figure 1 is a schematic cross-sectional view showing the configuration of a conventional plasma etching apparatus, where 1 is a reaction chamber, and 2 is a reaction chamber 1.
3 is a reactive gas inlet, 3 is a reactive gas outlet,
4 is an upper electrode provided in the reaction chamber 1; 5 is a lower electrode provided in the reaction chamber 1 facing the upper electrode 4; 6 is a cooling water inlet into the hollow lower electrode 5; 7 is a cooling water outlet from inside the lower electrode 5;
8 is a high frequency power source that supplies a high frequency voltage to the lower electrode 5; 9 is a member to be etched placed on the lower electrode 5; The lower electrode 4 is grounded and connected to a high frequency power source 8.
A high frequency voltage from is applied between the lower electrode 5 and the upper electrode 5.

Now, the operation of this conventional device will be explained.
A reactive gas is introduced into the reaction chamber 1 through the reactive gas inlet 2, and then high frequency power is applied to the reactive gas from the high frequency power source 8 via the lower electrode 5 and the upper electrode 4, causing plasma discharge. The active species and ions of the reactive gas atoms generated at this time chemically react with the member to be etched 9 to generate volatile substances, and the electric field generated near the lower electrode 5 for applying high frequency power. The member 9 to be etched is etched by physically bombarding the member 9 with ions of the reactive gas. Here, in order to prevent the temperature of the member to be etched 9 from rising due to plasma discharge or to keep the temperature constant, the lower electrode 5 is usually water-cooled or kept constant with a liquid having an appropriate temperature. maintained at temperature.

However, in the conventional plasma etching apparatus described above, although the member to be etched 9 is cooled by cooling water or kept at a constant temperature by a liquid at a predetermined temperature, in reality, the adhesion between the member to be etched 9 and the lower electrode 5 is poor. Therefore, the heat transfer efficiency is poor, and it is impossible to prevent the temperature of the member 9 to be etched from rising during etching or to maintain the temperature constant. The inability to keep the temperature of the member 9 to be etched constant is a major cause of changes in the etching rate during etching or as the number of etching operations increases, and is a serious problem.

Summary of the invention This invention was made in view of the above points. A reactive gas heating mechanism is provided at the reactive gas inlet, and the surface temperature of the lower electrode is detected, thereby controlling the reaction described above. The object of the present invention is to provide a plasma etching apparatus that can keep the temperature of the lower electrode and the member to be etched constant and keep the etching rate constant by controlling the hot gas heating mechanism.

Embodiment of the Invention FIG. 2 is a schematic sectional view showing the configuration of an embodiment of the invention. The same reference numerals as in the conventional example of FIG. The lower electrode 5a in this embodiment does not have a structure through which cooling water passes. 10 is a heating mechanism including a coiled heater wound around a part of the reactive gas inlet 2;
Reference numeral 1 denotes a temperature detection mechanism provided on the lower electrode 5a, and 12 supplies driving power to the heating mechanism 10 according to the output of the temperature detection mechanism 11 to control the temperature of the reactive gas supplied to the reaction chamber 1. temperature control mechanism.

The etching operation itself of the apparatus of this embodiment is exactly the same as that of the conventional example. However, in this embodiment, the surface temperature of the lower electrode 5a is detected by the temperature detection mechanism 11, and the temperature control mechanism 1
2 controls the driving power to the heating mechanism 10, adjusts the temperature of the reactive gas supplied into the reaction chamber 1, and maintains the lower electrode 5a and the member to be etched 9 thereon at a predetermined temperature. I'm starting to be able to do it. Therefore, by setting the circuit constants of this control loop, the member 9 to be etched can be maintained at a constant desired temperature.

The above embodiments have been explained using a reactive ion etching apparatus as an example, but this method of isothermalization at a temperature higher than room temperature can be applied to other types of etching apparatus,
It can be applied to general plasma etching equipment including sputter etching equipment, etc., and it is possible to make the etching characteristics uniform. In addition, the proposed method can be applied to all dry process-related equipment that uses gas, such as thin film production equipment such as sputtering equipment and plasma chemical vapor deposition equipment, and has the same effect on uniforming film formation characteristics. be.

Effects of the invention As explained above, the plasma etching apparatus according to this invention detects the temperature of the lower electrode, and controls the temperature of the reactive gas supplied into the reaction chamber according to this detection output, thereby controlling the temperature of the lower electrode. By providing a closed control loop for determining the temperature of the electrode, the temperature of the lower electrode and therefore the member to be etched can be maintained constant, and the etching rate can be maintained constant.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing the structure of an example of a conventional plasma etching apparatus, and FIG. 2 is a schematic sectional view showing the structure of an embodiment of this invention. In the figure, 1 is a reaction chamber, 2 is a reactive gas inlet, 5a is a lower electrode, 9 is a member to be etched, 1
0 is a heating mechanism, 11 is a temperature detection mechanism, and 12 is a temperature detection mechanism. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A reactive gas is introduced into a reaction chamber from a reactive gas inlet to generate plasma, and a member to be etched placed on a lower electrode disposed in the reaction chamber is subjected to plasma etching,
A temperature detection mechanism that detects the temperature of the surface of the lower electrode, a heating mechanism that is provided at the reactive gas inlet and that raises the temperature of the reactive gas introduced through it, and a temperature detection output from the temperature detection mechanism. and a temperature control mechanism that controls the power supplied to the heating mechanism to maintain the temperature of the introduced reactive gas at a desired value, and maintains the lower electrode and the member to be etched at a desired constant temperature. A plasma etching device characterized by: