JPH0799184A - End point detector - Google Patents

Abstract

PURPOSE:To prevent a state that the airtightness of a seal member such as an O-ring or the like installed around a window part in order to ensure the airtightness of a treatment chamber is obstructed when the seal member is thermally deformed and to enhance the heating efficiency of a heating device when the heating device which is used to prevent a reaction product from adhering is installed at the window part used to monitor plasma luminescence inside the treatment chamber. CONSTITUTION:A heat-conduction separating groove 59 is formed in a light- transmitting member 46 in such a way that it is situated between an O-ring 45 which is installed in the sidewall 1a of a treatment chamber and which is arranged and installed around an opening part 42 and a cartridge heater 53 which is installed in the light-transmitting member 46 in a window part 41. Thereby, since linear heat conduction from the cartridge heater 53 is cut off by the heat-conduction separating groove 59, the O-ring 45 is not deformed thermally, and the heating efficiency of the heater is enhanced by a portion which has been cut off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end point detecting device.

[0002]

2. Description of the Related Art For example, a semiconductor wafer (hereinafter, "wafer")
The plasma etching apparatus configured to perform etching processing by plasma will be described as an example. In such a plasma etching apparatus, an end point detection device for detecting the plasma processing end point is provided. A conventional end point detection device of this type is provided with a window for monitoring the inside of the processing chamber, which is generally formed in an airtight side wall of the processing chamber. It is configured to detect the plasma processing end point by measuring with a container or the like.

However, when the number of treatments is increased, a reaction product at the time of etching adheres to the window, the input light to the end point detector is attenuated, and as a result, the accuracy of the end point detection deteriorates. Therefore, it is complicated to properly clean the monitor window. In view of such a point, conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 3-75389, a means for heating the window for the monitor is provided in the window, and the window is heated by the means to react the reactive organisms. Adhesion is suppressed.

[0004]

By the way, in a plasma processing apparatus such as a plasma etching apparatus, it is necessary to perform processing under a predetermined reduced pressure atmosphere, and therefore the processing chamber thereof is required to have a high degree of airtightness. There is. Therefore, when the monitor window is provided on the side wall of the processing chamber, the monitor window is configured to be attached via a sealing material such as an O-ring.

However, according to the above-mentioned prior art, since the window for monitoring is simply provided with means for heating the window, the sealing material such as the O-ring may be thermally deformed due to heating. is there. When the sealing material undergoes thermal deformation in this way, the airtightness of the processing chamber is hindered, the predetermined plasma processing cannot be performed, and the yield is reduced. Further, the heating efficiency is not so good simply by providing a heating means such as a heater on the monitor window.

The present invention has been made in view of the above points, and even if a monitor window or the like provided for monitoring the above-mentioned plasma emission is directly heated, the sealing material such as the O-ring is heated. Providing a new end point detection device that does not cause deformation and has improved heating efficiency compared to the past,
The purpose is to solve the above problems.

[0007]

According to a first aspect of the present invention, there is provided an apparatus for detecting a plasma processing end point of plasma processing performed in an airtight processing chamber, the apparatus comprising: A light-transmitting member that is provided on the side wall of the processing chamber through a sealing material and that transmits plasma emission generated in the processing chamber to the outside of the processing chamber; and heating that is provided in the light-transmitting member and heats the light-transmitting member An end point detection device comprising an apparatus and a device for receiving plasma light emission transmitted through the light transmitting member portion, wherein the light transmitting member between the sealing material and the heating device is formed from the inside of the processing chamber. An end point detection device is provided, which is characterized in that a groove is provided.

According to a second aspect of the present invention, in the end point detecting device having such a configuration, a heating device is provided in a mounting groove formed from the outside of the light transmitting member, and the heating device and the mounting device are further provided. There is provided an end point detection device characterized in that a filler having good thermal conductivity is provided between the inner wall of the working groove and the inner wall.

[0009]

According to the end point detection device of claim 1, since the groove formed from the inside of the processing chamber is provided in the light transmitting member between the sealing material and the heating device,
The heat from the heating device, which tries to linearly conduct to the sealing material through the material forming the light transmitting member, for example, quartz glass, is blocked by the groove. Therefore, the conduction heat transmitted from the heating device to the sealing material is significantly reduced as compared with the conventional case. Further, since the conduction heat is blocked by the groove as described above, the amount of heat radiated to the surroundings is reduced accordingly, and the light transmitting member can be efficiently heated.

According to the end point detecting device of the second aspect, in the end point detecting device configured as described above, a heating device is further provided in the mounting groove formed from the outside of the light transmitting member, and the heating is performed. Since the filler having good thermal conductivity is provided between the device and the inner wall of the mounting groove, the light transmitting member is heated even more efficiently.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of an etching processing apparatus for a semiconductor wafer (hereinafter, referred to as "wafer") in which an end point detection apparatus according to the embodiment is used. The cross section is schematically shown, and the processing chamber 1 which is airtightly closed and closed is formed into a substantially cylindrical shape by, for example, aluminum whose surface is anodized.

A susceptor support 3 is provided in the lower part of the processing chamber 1 via an insulating member 2 such as ceramics. Inside the susceptor support 3, a cooling chamber such as a cooling jacket is provided. 4 is formed, and a cooling refrigerant introduced through a refrigerant introduction pipe 5 provided at the bottom of the processing chamber 1 and discharged through a refrigerant discharge pipe 6 is circulated in the cooling chamber 4. Has been done.

On the upper surface of the susceptor support base 3, there is provided a susceptor 7 which is made of a material such as aluminum whose surface is anodized and constitutes a lower electrode.
Further, on the upper surface of the susceptor 7, there is provided an electrostatic chuck 8 on which a wafer W which is an object to be processed is placed.

Inside the susceptor 7, a gas introducing pipe 9 is provided.
When a He gas is supplied to the gas introduction pipe 9 by a separately provided gas supply device (not shown), the He gas is brought to a predetermined temperature by the preceding cooling refrigerant. The cold heat of the susceptor support base 3 thus generated is conducted. And the He thus cooled
The semiconductor wafer W placed and held on the electrostatic chuck 8 is cooled to a predetermined temperature by the gas.

The susceptor 7 is connected to a high frequency power source 13 via a blocking capacitor 11 and a matching circuit 12 outside the processing chamber 1. The high frequency power source 1 is connected to the high frequency power source 1.
3, the susceptor has, for example, a frequency of 13.
The high frequency power of 56 MHz is applied.

The electrostatic chuck 8 has a structure in which a conductive layer 14 made of, for example, an electric field foil copper is sandwiched between upper and lower sides with an insulator such as a polyimide film and bonded, and the conductive layer 1 is formed.
4 is further connected to a high voltage DC power supply 17 outside the processing chamber 1 via a supply lead wire 16. Then, when a DC voltage is applied to the conductive layer 14 by the high-voltage DC power supply 17, the wafer W is attracted and held by the electrostatic chuck 8 by the Coulomb force generated at that time.

On the other hand, at the upper part of the processing chamber 1, a ground wire 2 is provided.
An upper electrode 22 grounded by 1 is provided.
The upper electrode 22 has a hollow portion 23, and a surface 24 facing the susceptor 7 is made of a material such as amorphous carbon. And the hollow portion 2
A large number of discharge ports 25 communicating with 3 are provided in this facing surface 24, while a gas introducing port 26 communicating with the hollow portion 23 is provided above the upper electrode 22. Therefore, when the etching reaction gas is supplied to the gas introduction port 26 from the processing gas supply device (not shown) provided separately, the etching reaction gas is uniformly distributed from the plurality of ejection ports 25 toward the susceptor 7. It is configured to be discharged.

As for the exhaust system of the processing chamber 1, an exhaust pipe 31 is provided in the vicinity of the bottom of the processing chamber 1, and the exhaust pipe 31 is exhaust means 32 such as a vacuum pump. It is connected to the. Then, the inside of the processing chamber 1 is evacuated by the operation of the exhaust means 32 so that a predetermined reduced pressure atmosphere, for example, 0.5 Torr can be maintained.

On the side wall 1a on one side of the processing chamber 1, there is provided a window portion 41 as shown in FIG. The structure of the window portion 41 is as follows. That is, the side wall 1a is provided with an opening 42 penetrating the side wall 1a, and a recess 43 larger than the opening 42 is provided outside the opening 42, and the side wall surface of the processing chamber 1 in the recess 43 is formed. A fitting groove 44 is provided around the opening 42. Then, an O-ring 45 is fitted into the fitting groove 44, a light transmitting member 46 is fitted into the recess 43 from the outside thereof, and finally an appropriate mounting member 47 is fitted from the outside of the light transmitting member 46. Is fixed to the side wall 1a by pressing the light transmission member 46.
Is fixed to the side wall 1a to form the window portion 41.

The light transmitting member 46 is made of a material such as quartz glass and has a rectangular parallelepiped shape as a whole, and has an outer shape slightly smaller than that of the recess 43, and expands when heated. However, the expansion is allowed to prevent the light transmitting member 46 from being damaged.

On the outer side of the light transmitting member 46,
Two mounting grooves 51 and 52 are provided in upper and lower two stages, and rod-shaped cartridge heaters 53 are respectively mounted as heating devices in the respective mounting grooves 51 and 52. In such mounting, as shown in FIG. 3, silicon rubbers 54 and 55 are applied to both ends of the cartridge heater 53, respectively, and delivered into the mounting grooves 51 and 52 as they are,
Further, as shown in FIG. 2, heat transfer cement 56 is filled and fixed so as to fill the gaps between the delivered cartridge heater 53 and the inner walls of the mounting grooves 51, 52. The heat transfer cement 56 has a heat resistance of about 400 ° C. and is made of a material having a very good heat conductivity.

The light transmitting member 46 is further provided with a temperature detecting device 57 composed of a thermocouple or the like, and the detected signal is the temperature controlling device 5 as shown in FIG.
8 and the temperature control device 58 controls the cartridge heater 53 based on the input data to the light transmission member 46 to set and maintain the light transmission member 46 at an arbitrary value between + 100 ° C. and + 300 ° C., for example. Is configured to be possible.

A heat transfer separation groove 59 is provided on the inner surface of the processing chamber 1 of the light transmitting member 46, as shown in FIGS. As shown in FIG. 5, the heat transfer separation groove 59 surrounds the two cartridge heaters 53 and is provided between the contact position A (the hatched portion in FIG. 5) of the O-ring 45 and the cartridge heaters 53. It is provided to be located in.

The front window portion 41 having the above-mentioned structure
As shown in FIG. 1, on the outside of the
An end point detector 61 having a light receiving unit 60 for receiving plasma emission generated between the susceptor 7 in the processing chamber 1 and the upper electrode 22 is disposed via the terminal 6.

The etching processing apparatus in which this embodiment is used is constructed as described above. Next, its operation will be described. First, a gate valve (not shown) provided on the side surface of the processing chamber 1 is opened. Then, the wafer W is loaded into the processing chamber 1 by a transfer device (not shown) such as a transfer arm and placed at a predetermined position on the electrostatic chuck 8, and the transfer device is moved outside the processing chamber 1. After evacuating, high voltage DC power supply 1
The wafer W is attracted and held on the electrostatic chuck 8 by the application of the DC voltage from 7.

Then, an etching reaction gas, for example, CF ₄ gas, which is supplied from a separately provided processing gas supply device, is discharged from the gas introduction port 26 to the wafer W through the discharge port 25 of the upper electrode 22. Exhaust means 32 at the same time
Is activated and the pressure in the processing chamber 1 is 0.5 Tor, for example.
maintained at r. Next, when high-frequency power whose frequency is set to 13.56 MHz and power is set to 1 kw is applied to the susceptor 7 by the high-frequency power source 13, plasma is generated between the upper electrode 22 and the susceptor 7, and the wafer is A predetermined etching process is performed on W.

The plasma emission at this time passes through the light transmitting member 46 of the window portion 41 and the light receiving portion 6 of the end point detector 61.
When the light is received at 0 and the light emission intensity in the steady state of plasma is set to 100, when it is reduced to 60, it is determined as the plasma processing end point. During that time, the light transmitting member 46 is heated to, for example, 200 ° C. by the cartridge heater 53 so that reaction products do not adhere to the side surface of the processing chamber 1 of the light transmitting member 46, and the heat at that time is conducted by conduction. An O-ring 4 that ensures airtightness between the light transmitting member 46 and the side wall 1a of the processing chamber 1.
I try to reach 5 straight.

However, since the heat transfer separation groove 59 is provided between the cartridge heater 53 and the O-ring 45, the heat transfer is interrupted at this heat transfer separation groove 59. Therefore, the amount of heat transferred to the O-ring 45 is significantly reduced, and as a result, the temperature of the O-ring 45 does not rise so much and thermal deformation does not occur. Therefore, the airtightness between the light transmitting member 46 and the side wall 1a of the processing chamber 1 is favorably maintained.

Further, since the heat conduction is largely blocked at the portion of the heat transfer separation groove 59 as described above, the heat dissipation due to the heat conduction is suppressed, and as a result, the inner area surrounded by the heat transfer separation groove 59 is heated. Efficiency is improving. In other words, the area surrounded by the heat transfer separation groove 59 is, so to speak, a heating area, and the cartridge heater 53 mainly heats only this heating area. Therefore, the heating efficiency is greatly improved as compared with the conventional one.

Further, between the cartridge heater 53 and the mounting grooves 51, 52 of the light transmitting member 46, a heat transfer cement 56 having a good thermal conductivity is filled.
The heat directly generated by the cartridge heater 53 is efficiently conducted to the light transmitting member 46, and the heating efficiency of the cartridge heater 53 with respect to the heating region is further improved.

Further, since silicone rubbers 54 and 55 are provided at both ends of the cartridge heater 53, each cartridge heater 53 has the mounting groove 51 in combination with the filling of the heat transfer cement 56. There is no wobbling in the 52, 52, and it is mounted stably.

Moreover, since the silicone rubbers 54 and 55 are provided at both ends of the cartridge heater 53, the expansion of the cartridge heater 53 itself during the heating operation is absorbed by the silicone rubbers 54 and 55. By the expansion of the cartridge heater 53,
The light transmitting member 46 is not damaged by the excessive pressure applied to the inner walls of the mounting grooves 51, 52.

As described above, according to the present embodiment, the light transmitting member 46 is provided with a simple structure, so that
O which secures the airtightness between the side wall 1a of the processing chamber 1 and
Thermal deformation of the ring 45 is prevented, and the heating efficiency of the cartridge heater 53 is greatly improved.

In the above embodiment, the etching processing apparatus is used, but the present invention is not limited to this, and for example, an ashing apparatus or C
The present invention can be used for other plasma processing apparatuses that generate plasma in the processing chamber, such as a VD apparatus.

[0035]

According to the end point detecting device of the first aspect, even if the light transmitting member for measuring plasma emission is heated by the heating device, it is interposed between the light transmitting member and the side wall of the processing chamber. The sealing material that secures the airtightness is not thermally deformed. Therefore, the airtightness of the processing chamber can be favorably maintained. Moreover, it is possible to heat the light transmitting member more efficiently than before.

According to the end point detecting device of the second aspect, thermal deformation of the sealing material is prevented, and the light transmitting member can be heated more efficiently than the first aspect.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing a cross section of an etching processing apparatus using an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of an essential part of the etching processing apparatus for showing the configuration of the embodiment of the present invention.

FIG. 3 is a perspective view of a light transmitting member according to an embodiment of the present invention.

FIG. 4 is a front view of a light transmitting member according to an embodiment of the present invention.

FIG. 5 is a rear view of the light transmitting member according to the embodiment of the present invention.

[Explanation of symbols]

 1 Processing Chamber 7 Susceptor 13 High Frequency Power Supply 22 Upper Electrode 41 Window 45 O-ring 46 Light Transmission Member 53 Cartridge Heater 56 Heat Transfer Cement 59 Heat Transfer Separation Groove 60 Photoreceptor 61 End Point Detector W Wafer

Claims (2)

[Claims] 1. A device for detecting a plasma processing end point of plasma processing performed in an airtight processing chamber, the device being provided on a side wall of the processing chamber via a sealing material, and being generated in the processing chamber. A light transmitting member for transmitting plasma emission to the outside of the processing chamber, a heating device provided on the light transmitting member for heating the light transmitting member, and a device for receiving the plasma emission transmitted through the light transmitting member portion. In the end point detection device including the end point detection device, a groove formed from the inside of the processing chamber is provided in the light transmitting member between the sealing material and the heating device. 2. A heating device is provided in a mounting groove formed from the outside of the light transmitting member, and a filler having good thermal conductivity is provided between the heating device and the mounting groove inner wall. The end point detection device according to claim 1, wherein the end point detection device is provided.