KR19990020391A - Plasma Etching Device and Oxide Etching Method Using the Same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma etching apparatus of an semiconductor device and an oxide layer etching method using the same, wherein a clamp and a pin post pin for fixing the clamp are removed, and the thickness of the base plate is increased. The oxide etching process is performed using a plasma etching apparatus having a reduced thickness of the Si-heat shield, but the temperature and power of the chamber are lowered during the oxide etching process, and C ₂ F ₆ , C ₃ F ₈ and Ar It is possible to extend the life of the etching apparatus by supplying a mixed gas of ethylene and improving the selectivity of the oxide film and the polysilicon film and improving the contact resistance.

Description

Plasma Etching Device and Oxide Etching Method Using the Same

The present invention relates to a plasma etching apparatus and an oxide layer etching method using the same, and in particular, to improve the internal structure of the plasma etching apparatus to extend the life of the etching apparatus, and to improve the process atmosphere during the oxide layer etching process using the particles. A plasma etching apparatus capable of suppressing generation and lowering contact resistance and an oxide layer etching method using the same.

In general, in the manufacture of semiconductor devices, oxide films are used for the purpose of device protection and electrical insulation. In a process such as a contact process of a semiconductor device, an oxide film is etched, and the oxide film etching process is performed in a plasma etching apparatus.

1 is a cross-sectional view schematically illustrating a chamber portion of a conventional plasma etching apparatus, and the oxide film etching method will be described with reference to the following.

In the conventional plasma etching apparatus, the chamber includes an ESC 7 on which the wafer 1 is placed; A collar 3 and a clamp 4 provided at the periphery of the ESC 7 to stably fix the wafer 1 in the correct position; A base plate 2 provided at the periphery of the collar 3 to maintain a constant temperature inside the chamber; And a chamber wall 8 and a roof 9.

The clamp 4 is actuated by a clamp post pin 6. In order to keep the temperature in the chamber constant and to not overwhelm the etching reaction, quartz is used for the base plate 2, the collar 3, and the clamp 4. One side of the base plate 2 is formed thin. In order to improve the etching selectivity with the underlying film containing the silicon component when etching the oxide film, a silicon top plate 10 is attached to the loop 9, and also thick on the clamp 4; Fit the Si-heat shield (5).

The oxide film formed on the wafer 1 is etched by using the plasma etching apparatus having the above-described configuration. An oxide film etching process will be described below.

In order to etch the selected portion of the oxide film, the wafer 1 having the photoresist pattern formed thereon is loaded in the chamber, and C ₂ F ₆ gas is introduced into the chamber. At this time, the loop 9 temperature is set to 260 to 275 ° C, and the chamber wall 8 temperature is set to 200 to 220 ° C so that the internal temperature of the chamber is maintained at about 230 to 245 ° C. Further, the source power is 2600 to 2800 W, the bias power is 1400 to 1600 W, and the pressure is 5 to 7 mTorr. Under these conditions, after removing the selected portion of the oxide film, the wafer 1 is unloaded, and then the photoresist pattern is removed. If the oxide film is BPSG (Boro Phospho Silicate Glass), the etching rate is about 9500 Å / min, the etching selectivity for the photoresist pattern is about 3 to 4: 1, and the etching selectivity for the polysilicon layer is 15 to 17. : 1 The overall uniformity of the wafer 1 is about 5%. The etch profile of the oxide film is vertical. In this case, when the temperature of the loop 9 is increased, the reaction of the silicon (Si) of the silicon top plate 10 and the fluorine (F) contained in the etching gas becomes active, so that the amount of carbon (C) is relatively increased, and thus high selection is made. You get rain. However, to achieve this high selectivity, the chamber temperature must be kept constant. In order to keep the temperature constant, quartz which has good heat transfer and does not impede the reaction, is used, which generates particles of silicon (Si) at high temperature and reduces the lifetime of the etching apparatus. Is generated.

The following problem occurs when etching the oxide film formed on the wafer 1 by using the plasma etching apparatus having the above configuration.

First, part life time shortening and silicon particles are generated due to deterioration of silicon material.

Second, the uniformity of the specific film etched by the shadow effect due to the clamp 4 covering the outer portion of the wafer 1 is lowered.

Third, particles of silicon and quartz are generated due to the use of the clamp 4.

Fourth, the quartz equipment is lost during the etching process, the durability of the equipment is reduced.

Fifth, contact resistance due to high etching selectivity is increased.

Finally, the thick formed silicon heat shield 5 results in a smaller margin when loading and unloading the wafer 1.

Accordingly, the present invention improves the internal structure of the plasma etching apparatus to extend the life of the etching apparatus, and improves the process atmosphere during the oxide etching process using the same, thereby reducing particle generation and lowering the contact resistance. And an oxide film etching method using the same.

Plasma etching apparatus of the present invention for achieving this object is a plasma etching apparatus, located in the lower portion of the chamber, the wafer is placed, the ESC, the collar provided along the ESC peripheral portion, the base provided along the collar peripheral portion And a plate, a chamber wall located at the side of the chamber, and a loop located at the top of the chamber, wherein the clamp is free.

In addition, in the oxide film etching method using the plasma etching apparatus, the loop temperature is 200 to 220 ° C. and the chamber wall temperature is 160 to 180 ° C. in a mixed gas atmosphere of C ₂ F ₆ , C ₃ F ₈ and Ar. The internal temperature is about 175 to 200 ° C., the source power is 1800 to 200 W, the bias power is 1200 to 1400 W, and the pressure is 5 to 7 mTorr.

1 is a cross-sectional view schematically showing a chamber portion of a conventional plasma etching apparatus.

2 is a cross-sectional view schematically showing the chamber portion of the plasma etching apparatus according to the present invention.

Explanation of symbols for main parts of the drawings

1 and 11: wafer 2 and 12: base plate

3 and 13: color 4: clamp

5 and 15: silicon heat shield 6: clamp post pin

7 and 17: ESC8 and 18: Chamber Wall

9 and 19: loop 10 and 20: silicon top plate

Hereinafter, with reference to the accompanying drawings of the present invention will be described in detail.

2 is a cross-sectional view schematically showing a chamber portion of the plasma etching apparatus according to the present invention, with reference to this description of the oxide film etching method as follows.

In the plasma etching apparatus of the present invention, the chamber includes an ESC 17 on which a wafer 11 is raised; A collar 13 provided at the periphery of the ESC 17, in order to stably fix the wafer 11 in the correct position; A base plate 12 provided at a periphery of the collar 13 to maintain a constant temperature inside the chamber; And a chamber wall 18 and a loop 19.

In order to keep the temperature in the chamber constant and to not overwhelm the etching reaction, quartz is used for the base plate 12 and the collar 13. In order to improve the etching selectivity with the underlying film containing the silicon component when etching the oxide film, the silicon top plate 20 is mounted on the loop 19, and also a thin thickness in a circular shape on the base plate 12. Fit the silicon heat shield (15).

In the above, the base plate 12 of the present invention as compared to the conventional base plate 2 is formed to be generally thick to extend the life. By reducing the thickness of the silicon heat shield 15, it is possible to secure a moving margin of the wafer 11 when loading and unloading the wafer 11. In addition, it is possible to reduce the cost of manufacturing the plasma etching apparatus by removing the conventional clamp (4) and clamp post pin (6).

The oxide film formed on the wafer 11 is etched by using the plasma etching apparatus having the above configuration. The oxide film etching process will be described below.

In order to etch the selected portion of the oxide film, the wafer 11 having the photoresist pattern formed thereon is loaded into the chamber, and a mixed gas gas of C ₂ F ₆ , C ₃ F ₈ and Ar is introduced into the chamber. Ar in the mixed gas acts as a diluent of fluorine, improves an etching profile, and increases physical sputtering, thereby cleaning the silicon surface after etching. C ₂ F ₆ is 5 to 10, C ₃ F ₈ is 15 to 20, and Ar is 50 to 100. At this time, the loop 19 temperature is set to 200 to 220 ° C, and the chamber wall 18 temperature is set to 160 to 180 ° C so that the internal temperature of the chamber is about 175 to 200 ° C. The source power is 1800 to 2000 W, the bias power is 1200 to 1400 W, and the pressure is 5 to 7 mTorr. Under these conditions, after removing the selected portion of the oxide film, the wafer 11 is unloaded, and then the photoresist pattern is removed. If the oxide film is BPSG (Boro Phospho Silicate Glass), the etching rate is about 12000 μs / min, the etching selectivity for the photoresist pattern is about 3 to 4: 1, and the etching selectivity for the polysilicon layer is about 10: 1 The overall uniformity of the wafer 11 is about 2%. The etch profile of the oxide film is vertical.

As described above, the etching effect of the oxide film formed on the wafer using the plasma etching apparatus of the present invention has the following effects.

First, by lowering the temperature and power of the chamber compared to the conventional, and by supplying the mixed gas of C ₂ F ₆ , C ₃ F ₈ and Ar, the etching selectivity to polysilicon while maintaining the etching selectivity for the photosensitive film pattern And the etching rate of the oxide film is increased, thereby reducing the etching loss of the underlying film forming the contact base to improve contact resistance, suppress the generation of polymer, silicon particles and quartz particles, and increase productivity. The durability of the equipment can be increased.

Second, by removing the clamps and clamp post pins provided in the conventional plasma etching apparatus, it is possible to obtain uniform etching characteristics on the entire wafer, to prevent the generation of particles due to the clamps and clamp post pins, and to manufacture the plasma apparatus. The cost can be reduced.

Finally, the thinly formed silicon heat shield 5 increases the margin upon loading and unloading the wafer 1.

Claims (7)

In the plasma etching apparatus, Located in the lower part of the chamber, the ESC on which the wafer is placed, A collar provided along the periphery of the ESC, A base plate provided along the collar periphery; A chamber wall located at the side of the chamber, Plasma etching apparatus, characterized in that consisting of a loop located above the chamber. The method of claim 1, And a silicon top plate is mounted on the loop, and a silicon heat shield having a thin thickness is mounted on the base plate in a circular shape. Loading the wafer on which the oxide film is formed into a chamber of the plasma etching apparatus; Etching the oxide film in a mixed gas atmosphere of C ₂ F ₆ , C ₃ F _8, and Ar, And unloading the wafer after etching the oxide film. The method of claim 3, The ratio of the mixed gas is C ₂ F _{6 It} is 5 to 10, C ₃ F _{8 It} is 15 to 20, and the oxide film etching method, characterized in that 50 to 100 Ar. The method of claim 3, The oxide film etching process may be performed by setting the loop temperature of the plasma etching apparatus to 200 to 220 ° C., the chamber wall temperature to 160 to 180 ° C., and the chamber internal temperature to about 175 to 200 ° C. The method of claim 3, The oxide film etching process is performed with a source power of 1800 to 200W and a bias power of 1200 to 1400W. The method of claim 3, The oxide film etching process is carried out with a pressure of 5 to 7mTorr.