JPH0799185A - End point detector and treatment apparatus - Google Patents

Abstract

PURPOSE:To prevent an influence on a plasma state and to enhance the degree of freedom of a designing operation even when a light-transmitting member is installed at a through opening part in the sidewall of a treatment chamber in order to monitor the plasma state inside the treatment chamber at the outside of the treatment chamber. CONSTITUTION:An edge 51a at a fitting part 51 into a through opening part in a light-transmitting member 50 is formed so as to be flush with the inner circumferential face 2b on the sidewall 2a of a treatment chamber. Thereby, a recessed part is not formed on the inner circumferential face of the sidewall of the treatment chamber, and a plasma state is not changed when the light- transmitting member is attached. The light-transmitting member can be attached in an arbitrary part on the sidewall.

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 and a processing device.

[0002]

2. Description of the Related Art For example, a semiconductor wafer (hereinafter, "wafer")
The plasma etching apparatus configured to perform the etching processing by plasma will be described as an example. In such a plasma etching apparatus, the plasma processing end point is detected and the plasma state during other processing is observed. For this reason, JP-A-2-2243
No. 30, JP-A-3-236483, JP-A-3
As disclosed in Japanese Patent Publication No. 75389, etc., a through opening is formed in a side wall of a hermetically sealed processing chamber, and a light transmitting member made of, for example, quartz glass is provided in the through opening. . Further, these light transmitting members may be provided with an appropriate heating device in order to suppress the adhesion of reaction products generated during etching.

Regarding the structure for fixing the light transmitting member to the side wall, a plate-like light transmitting member larger than the opening surface of the through opening is penetrated from the outside (atmosphere side) by an appropriate mounting member. It is configured to be pressed and fixed to the peripheral portion of the opening.

[0004]

However, since the inside of the processing chamber needs to be maintained at a high degree of vacuum of, for example, 10 ^-6 Torr, the processing chamber is robustly formed of, for example, alumite-processed aluminum. . Therefore, like the above-mentioned prior art, a flat light-transmitting member,
If it is simply fixed to the peripheral portion of the through-opening from the outside, the peripheral edge of the through-opening inside the processing chamber remains as it is with the corners formed. In other words, the recess is just formed on the peripheral wall of the processing chamber.

However, if the above-mentioned concave portion is formed on the peripheral wall of the processing chamber as described above, the plasma state generated inside the processing chamber is likely to be biased, and there is a possibility of abnormal discharge to the corners. However, there is a possibility that the predetermined etching process cannot be performed.

Further, in order to observe the plasma state and detect the plasma processing end point by plasma emission,
It is necessary to provide the light transmitting member at a position facing the wafer mounted on the mounting table in the processing chamber. Moreover, in order to improve the detection accuracy of the plasma processing end point, the light transmitting member is taken into consideration in consideration of refraction of the transmitted light. The member must be installed at a position that is perpendicular to the optical axis of the plasma emission to the outside,
As long as the above-mentioned plate-shaped light transmitting member is used, the positions of the through opening and the light transmitting member are necessarily limited to the substantially central portion of the side wall of the processing chamber. For this reason, for example, the layout of various devices and members such as the light receiving portion of the end point detector and other valves has been limited.

The present invention has been made in view of the above point, and even if the light transmitting member is provided in the through opening formed in the side wall of the processing chamber, it does not affect the plasma state in the processing chamber and is stable. It is an object of the present invention to solve the above-mentioned problems by providing an end point detection device and a processing device that can perform plasma processing and have a high degree of freedom in the mounting position of the light transmitting member.

[0008]

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 a processing chamber, comprising:
A light transmission member that is provided from outside the processing chamber in a through opening formed in the sidewall of the processing chamber and that transmits plasma emission generated in the processing chamber to the outside of the processing chamber, and plasma that has passed through the light transmission member portion. In the end point detection device including a device for receiving light emission, the light transmitting member has a form fitted into the through opening, and the end surface of the light transmitting member on the processing chamber inner side of the fitted portion. Is provided so as to be flush with the inner peripheral surface of the side wall.

According to a second aspect of the present invention, plasma is generated in the processing chamber, and the object to be processed on the mounting table provided in the processing chamber is plasma-processed, and the side wall of the processing chamber is provided. In the processing device in which a light transmitting member is provided from the outside of the processing chamber facing the upper space of the mounting table in the formed through opening, the light transmitting member has a form fitted in the through opening. Further, there is provided a processing apparatus, wherein an end surface of the light transmission member, which is fitted into the processing chamber, is formed to be flush with an inner peripheral surface of the side wall.

[0010]

According to the end point detection device of the first aspect, the end surface of the light transmitting member for transmitting the plasma emission inside the processing chamber to the outside is flush with the inner peripheral surface of the side wall of the processing chamber. Since it is molded as described above, no recess is formed on the peripheral wall of the processing chamber. Therefore, it is possible to detect the plasma processing end point without affecting the plasma state generated in the processing chamber.

Moreover, since the end surface of the light transmitting member on the inner side of the processing chamber is formed flush with the inner peripheral surface of the side wall of the processing chamber, even if the peripheral wall of the processing chamber is circular, for example,
It is possible to form the through opening in the radial direction at any position over the entire circumference thereof and to provide the light transmitting member at a position perpendicular to the optical axis of the plasma emission to the outside. Therefore, the mounting position of the light transmitting member can be set at any position around the side wall of the processing chamber, and accordingly, the degree of freedom of the arrangement position of the end point detector and the like installed facing the light transmitting member also increases.

According to the processing apparatus of the second aspect,
Similarly to the first aspect, since the end surface of the light transmitting member on the inner side of the processing chamber is formed to be flush with the inner peripheral surface of the side wall of the processing chamber, no recess is formed on the peripheral wall of the processing chamber. Therefore, the provision of the light transmitting member does not affect the plasma state in the processing chamber, and it is possible to perform the predetermined plasma processing on the object to be processed.

Further, since the light transmitting member can be provided at an arbitrary position on the side wall of the processing chamber, the degree of freedom in layout of the monitor for observing the plasma state and other various devices necessary for the processing apparatus is improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an etching processing apparatus will be described below with reference to the drawings. FIG. 1 schematically shows a side cross section of the etching processing apparatus 1. Is a so-called parallel plate type etching processing apparatus, and the processing chamber 2 configured to be airtightly occludable has a substantially square planar outer shape and a circular inner circumferential surface made of, for example, aluminum whose surface is anodized. It is configured to be eggplant.

An insulating member 3 made of ceramic or the like and having a substantially concave cross section is provided in the lower portion of the processing chamber 2, and a susceptor support base 4 is housed inside the insulating member 3. . A cooling chamber 5 such as a cooling jacket is formed inside the susceptor support 4, and the cooling chamber 5 is introduced into the cooling chamber 5 through a refrigerant introduction pipe 6 provided at the bottom of the processing chamber 2. Moreover, the cooling refrigerant discharged from the refrigerant discharge pipe 7 is configured to circulate.

On the upper surface of the susceptor support 4, there is provided a susceptor 8 which is made of a material such as aluminum whose surface is alumite treated and which constitutes a lower electrode.
Further, on the upper surface of the susceptor 8, there is provided an electrostatic chuck 9 on which a semiconductor wafer (hereinafter referred to as “wafer”) W which is an object to be processed is placed and held.

Inside the susceptor 8, a gas introducing pipe 1 is provided.
A gas flow path 11 communicating with 0 is formed, and when, for example, He gas is supplied to the gas introduction pipe 10 by a separately provided gas supply device (not shown), the He gas is cooled to a predetermined temperature by the preceding cooling refrigerant. The cold heat of the susceptor support base 4 that has been cooled down is conducted. The He gas cooled in this way is configured to maintain the semiconductor wafer W placed and held on the electrostatic chuck 9 at a predetermined temperature.

The susceptor 8 is connected to a high frequency power source 14 via a blocking capacitor 12 and a matching circuit 13 outside the processing chamber 2.
4, the susceptor 8 has a frequency of 1
The high frequency power of 3.56 MHz is applied.

The electrostatic chuck 9 has a construction in which a conductive layer 15 made of, for example, electric field foil copper is sandwiched between upper and lower sides by an insulator such as a polyimide film, and the conductive layer 15 is further provided with a supply lead wire 16. Is connected to a high-voltage DC power supply 17 outside the processing chamber 1 via. Then, with this high-voltage DC power supply 17, a DC voltage of, for example, 2 kv is applied to the conductive layer 1
5, the wafer W is attracted and held by the electrostatic chuck 9 by the Coulomb force generated at that time.

An exhaust pipe 21 is provided near the bottom of the processing chamber 2, and the exhaust pipe 21 is connected to an exhaust means 22 such as a vacuum pump.
Then, by operating the exhaust means 22, the processing chamber 2
The inside is evacuated to a predetermined reduced pressure atmosphere, for example 0.5
It is configured so that it can be maintained at Torr.

On the other hand, at the upper part of the processing chamber 2, a ground wire 3 is provided.
An upper electrode 32, which is grounded by 1, is provided.
The upper electrode 32 has a hollow portion 33, and a surface 34 facing the susceptor 8 is made of a material such as amorphous carbon. A large number of discharge ports 35 communicating with the hollow portion 33 are provided in the facing surface 34, and on the other hand, a gas introducing port 36 communicating with the hollow portion 33 is provided above the upper electrode 32. Therefore, when an etching reaction gas is supplied to the gas introduction port 36 from a separately provided processing gas supply device (not shown), the etching reaction gas is evenly distributed from the multiple ejection ports 35 toward the susceptor 8. It is configured to be discharged.

The side wall 2a on one side of the processing chamber 2 is provided with a window portion 41 as shown in FIG. 2. The structure will be described in detail. First, the side wall 2a penetrates the side wall 2a. Further, a through opening 42 having an approximately elliptical opening surface is formed, and a recess 43 larger than the through opening 42 is formed outside the through opening 42. Then, a fitting groove 44 is formed around the through opening 42 on the side wall surface of the processing chamber 2 in the recess 43, an O-ring 45 is fitted in the fitting groove 44, and further, an optical ring 45 is inserted into the through opening 42. The fitting portion 51 of the transparent member 50 is fitted, and the locking portion 52 is fitted into the recess 4
3 inside, and finally from the outside of this locking portion 52,
An appropriate mounting member 46 is attached to the side wall 2a by a bolt 47.
It is fixed by pressing.

The light transmitting member 50 is shown in FIG. 3, FIG. 4 and FIG.
As shown in these figures, the locking portion 52 and the fitting portion 51 projecting at a right angle from the locking portion 52 form the entire outer shape, and the material is , Quartz glass, for example.

The end surface 51a of the fitting portion 51 on the processing chamber 2 side is formed into a curved surface having the same curvature as the inner peripheral surface 2b of the side wall 2a of the processing chamber 2 as shown in FIG. When the fitting portion 51 is fitted into the through opening 42, the end surface 51a and the inner peripheral surface 2b of the side wall 2a are flush with each other.

On the inner surface of the fitting portion 51, an appropriate number of locking pins 53 and 54 are provided on the upper and lower sides, for example, four, respectively, and at predetermined intervals along the end wall 51b of the fitting portion 51. It is provided with. A tape-shaped heater 55 is provided between the end wall 51b and each of the locking pins 53 and 54 so as to be located between them.
b It is attached to the inner surface of b, and from there, a silicon rubber 56, for example, a holding plate 57 made of a thin plate of stainless steel.
Are provided so as to be press-fitted between the locking pins 53 and 54, respectively. Since the heaters 55 are provided on the light transmitting member 50 in this way, there is no positional deviation.

As shown in FIG. 4, a non-penetrating hole 58 is provided in the end wall 51b of the fitting portion 51, and a temperature sensor 59 is provided in the hole 58. The detection signal of the temperature sensor 59 is input to the temperature control device 60, and the temperature control device 60 controls the heater 55 on the basis of the detection signal to cause the fitting portion 5 in the light transmitting member 50.
The end wall 51b of No. 1 is, for example, + 100 ° C to + 300 ° C.
It is configured so that it can be set and maintained at any value up to.

The light transmitting member 5 having the above structure
As shown in FIGS. 1 and 6, outside the front exit window portion 41 having 0, through the end wall 51b of the fitting portion 51 of the light transmitting member 50, the processing space S in the processing chamber 2, That is, the light receiving unit 6 for facing the space between the susceptor 8 and the upper electrode 32 and receiving the plasma light emission generated in the processing space S.
The end point detector 62 including 1 is arranged. In the present embodiment, as shown in FIG. 6, the light receiving axis of the light receiving section 61 is located exactly in the center of the processing space S, that is, the light receiving section 61 is located on the extension line of the radius of the wafer W.
The end point detector 62 is arranged.

The etching processing apparatus according to this embodiment is configured as described above. Next, the operation thereof will be described. First, the gate valve (not shown) provided on the side surface of the processing chamber 2 is opened, The wafer W is carried into the processing chamber 2 by a transfer device (not shown) such as a transfer arm and placed at a predetermined position on the electrostatic chuck 9, and the transfer device is evacuated to the outside of the processing chamber 9. After that, by applying a DC voltage from the high voltage DC power supply 17, the wafer W is attracted and held on the electrostatic chuck 8.

Then, an etching reaction gas, for example, CF ₄ gas, which is supplied from a separate processing gas supply device, is discharged from the gas introduction port 36 toward the wafer W through the discharge port 35 of the upper electrode 32, and at the same time. Exhaust means 2
2 operates and the pressure in the processing chamber 2 is 0.5 To, for example.
maintained at rr. Next, when the high frequency power having the frequency of 13.56 MHz and the power set to 1 kw is applied to the susceptor 8 by the high frequency power supply 14,
Plasma is generated between the upper electrode 32 and the susceptor 8,
A predetermined etching process is performed on the wafer W.

At this time, the plasma light emission is received by the light receiving portion 61 of the end point detector 62 through the end wall 51b of the fitting portion 51 of the light transmitting member 50. For example, when the light emission intensity in the steady state of plasma is 100, The point of time when this drops to 60 is determined as the plasma processing end point.

Then, in order to detect the plasma processing end point by receiving the plasma emission as described above, the side wall 2 of the processing chamber 2 is
Since the end surface 51a of the fitting portion 51 of the light transmitting member 50 provided in a is formed so as to be flush with the inner peripheral surface 2b of the side wall 2a as described above, the end surface 51a is formed to perform the etching process. The desired etching process can be performed on the wafer W without affecting the plasma state.

Moreover, as shown in FIG. 6, even if the light transmitting member 50 is not provided in the central portion of the side wall 2a of the processing chamber 2, the optical axis of plasma emission is in the fitting portion 51 of the light transmitting member 50. Since the light passes through the end wall 51b at a right angle, refraction of light does not occur, and the detection accuracy of the plasma processing end point does not decrease. Therefore, the degree of freedom in the location of the light transmitting member 50 and the end point detector 62 is improved as compared with the conventional case, and the design of the etching processing apparatus 1 as a whole and the layout of various devices are facilitated accordingly.

On the other hand, during the above-mentioned etching process, the end wall 51b is heated to, for example, 200 ° C. by the heater 55 so that reaction products do not adhere to the end surface 51a of the fitting portion 51 of the light transmitting member 50. However, the heat at that time is generated by the locking portion 52 of the light transmitting member 50.
The heat is also conducted to the O-ring 45 provided between the processing chamber 2 and the side wall 2a of the processing chamber 2.

However, the heater 55 that heats the end wall 51b has the fitting portion 5 protruding from the locking portion 52.
As shown in FIG. 5, the distance to the engaging portion 52 in contact with the O-ring 45 is as shown in FIG.
Side walls 51c, 51 of the fitting portion 51 forming the protruding portion
It is largely separated by d. Since the quartz glass itself, which is the material of the light transmitting member 50, has a low thermal conductivity, if the side walls 51c and 51d are separated from each other, the side walls 51c and 51d are, so to speak, heat transfer isolation walls. As a result, heat conduction to the O-ring 45 is significantly suppressed.

For example, the temperature of the end wall 51b itself is 200
Even if the temperature is ° C, the temperature of the locking portion 52 can be suppressed to about 100 ° C. Therefore this O-ring 4
The temperature of 5 does not rise so much and thermal deformation does not occur. Also, the durability of the O-ring 45 is improved. Therefore, even if the light transmitting member 50 is heated by the heater 55, the airtightness of the side wall 1a of the processing chamber 2 is not impaired, the airtightness in the processing chamber 2 is maintained well, and a predetermined etching process can be performed. It is possible.

Although the fitting portion 51 of the light transmitting member 50 in the above-described embodiment has a form projecting at a right angle from the locking portion 52, instead of this, for example, as shown in FIG. It is also possible to use the light transmitting member 73 in which the fitting portion 72 is configured such that the end wall 72a of the fitting portion 72 is projected at a predetermined angle and faces the substantially central portion of the processing space S.
In such a case, the light transmitting member 73 can be mounted closer to the end of the side wall 2a, and the detection accuracy of the plasma processing end point is the same as that of the light transmitting member 50 used in the above embodiment. Further, if such a light transmitting member 73 is used, the design of the etching processing apparatus 1 as a whole and the layout of various devices can be made easier than in the above-described embodiment.

Although the above embodiment is an example applied to an etching processing apparatus, the present invention is not limited to this, and the present invention is applicable to other plasma processing apparatuses that generate plasma in the processing chamber, such as an ashing apparatus and a CVD apparatus. However, it can be applied.

[0038]

According to the end point detecting device of the first aspect, the plasma state generated in the processing chamber is not affected, and
It is possible to detect the end point of plasma processing, and the degree of freedom of the mounting position of the light transmitting member is large.

According to the processing apparatus of the second aspect, it is possible to monitor the plasma state during processing from the outside, and at the same time, since the recess is not formed in the peripheral wall of the processing chamber, the plasma state in the processing chamber has an influence. It is possible to perform a predetermined plasma treatment on the object to be processed without receiving the plasma, and the yield is improved. Moreover, the degree of freedom in designing the device is great.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing a cross section of an etching processing apparatus according to 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.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is an explanatory view showing a state of a plane cross section of the etching processing apparatus for showing the operation of the embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a state of a plane cross section of the etching processing apparatus for showing an operation when another example of the light transmitting member is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Etching processing apparatus 2 Processing chamber 2a Side wall 2c Inner peripheral surface 8 Susceptor 14 High frequency power source 32 Upper electrode 41 Window part 42 Through opening 50 Light transmitting member, 51 Fitting part 51a End face 61 Light receiving part 62 End point detector W Wafer

Claims (2)

[Claims] 1. A device for detecting a plasma processing end point of plasma processing performed in a processing chamber, the device being provided from the outside of the processing chamber at a through opening formed in a sidewall of the processing chamber. In an end point detection device comprising a light transmitting member for transmitting generated plasma light emission to the outside of the processing chamber, and a device for receiving plasma light emission transmitted through the light transmission member portion, wherein the light transmission member is the through opening. Characterized in that the end surface on the processing chamber side of the fitted portion of the light transmitting member is formed so as to be flush with the side wall inner peripheral surface. Endpoint detection device. 2. A plasma is generated in the processing chamber so that the object to be processed on a mounting table provided in the processing chamber is subjected to the plasma processing, and a through opening formed in a side wall of the processing chamber. In the processing apparatus in which a light transmitting member is provided from outside the processing chamber facing the upper space of the mounting table, the light transmitting member has a form fitted into the through opening, and the light transmitting member is provided. The processing apparatus is characterized in that an end surface on the processing chamber inner side of the fitted portion of the above is formed to be flush with the side wall inner peripheral surface.