JPH03291389A - Plasma treating device - Google Patents

Abstract

PURPOSE:To improve the reliability of wafer attraction and subject the wafer to a stable plasma treatment by pressing an elastic member of a ground potential to the rear of the wafer at the time of subjecting the wafer held on a susceptor to the plasma treatment by an electrostatic attraction force. CONSTITUTION:The wafer 18 is imposed on the susceptor 11 in a vacuum treating chamber 1 and a gas for an etching treatment is introduced from a gas supplying pipe 6 into the chamber and is converted to plasma by the interaction of the microwave electric field generated by a magnetron 4 and the magnetic field generated by a solenoid coil 5. A high-frequency power is simultaneously impressed by a high-frequency power source 16 to the susceptor 11 to etch the wafer 18. The wafer 18 is imposed on the susceptor 11 by lowering an ejecting pin 14 and a conductive leaf spring 25 having elasticity is pressed to the rear of the wafer. The spring 25 is deformed to the same level as the surface level of the susceptor 11 by the weight of the wafer 18 and the electrostatic attraction force so that the wafer 18 is brought into sure contact with the conductive leaf spring 25 even if the wafer is warped. The attraction reliability of the wafer is thus improved and the wafer is subjected to the stable plasma treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to plasma processing l1NIi using electrostatic adsorption.

[Conventional technology]

As a conventional device, for example,
As described in the publication, there is no need for the inside of the insulation layer, M
A first electrode is provided at the boundary between the first and second materials, and a second electrode that penetrates the insulating layer is made to come out on the surface of the insulating layer or to the east from the surface, and a voltage is applied between these two electrodes to separate the wafer. There are things that absorb.

[The problem that JR Akira is trying to solve]

The above conventional technology uses wafer adsorption CL! About i-sense'TT
If the wafer is not placed and a ta of 1g2 is exposed, it is good for picking up warped wafers, but if you want to pick up warped wafers, !f12 t of
There is a possibility that the pole may not come into contact with the wafer and the suction may fail.

On the other hand, if you are arrogant in protruding the second electrode, it is good for picking up warped wafers, but if you are using a wafer without warping, the second body is There is a possibility that the wafer and the insulator y may not be completely attached to each other and cannot be sucked.

Furthermore, since the wafer and the second IL pole, which is at ground potential, are in contact with each other for the etching process, ions incident on the wafer are unevenly distributed, resulting in an uneven distribution of the etching characteristics, especially the etching characteristics. There is no fear that it will have a negative effect on sexual groups.

An object of the present invention is to provide a plasma processing apparatus that can improve the reliability of wafer suction and that does not cause the plasma processing characteristics to fall short of the negative IF'.6. −ゐz)0〔Means for solving the problem〕: To achieve the stated purpose with a duck, directly onto the sample stage, ? 9
The elastic part that contacts the back side of the wafer can be connected to the ground potential by connecting the wafer and placing the wire on the sample.
X'- is provided.

[For production]

Since an elastic member that can be connected to the ground potential is installed on the back of the wafer, the elastic member deforms to the same level as the surface of the sample stage due to its own weight, pressure, and adsorption force.
. Thereby, the elastic member can be brought into contact with the wafer regardless of whether or not the wafer is warped, and the reliability of sucking the wafer can be improved.

Furthermore, the elastic member 5' can be kept in a floating state during plasma processing, thereby preventing adverse effects on plasma processing characteristics.

[Example of sacrifice]

Hereinafter, an example of the present invention will be described in FIGS. 1 to 4.

In the second case, the plasma processing apparatus is one in which, for example, Masako Yukifune's zero wave device is applied. A discharge tube 2 made of, for example, quartz ν is provided in the upper part of the vacuum chamber 1 to form a vacuum processing chamber. The vacuum plug 1 is provided with a gas supply hole 6 connected to a gas supply source (not shown) that provides a processing gas for plasma processing, for example, etching processing, in the vacuum processing chamber. A vacuum pump 9 that reduces and exhausts the inside of the processing chamber to a predetermined pressure and a pressure adjustment valve 8
There is an exhaust lower that connects through.

A waveguide 3 is installed surrounding the discharge tube 2, and a solenoid coil 5 is installed outside the discharge tube 2 to generate a magnetic field inside the discharge tube 2. is the provision. At the end of the waveguide 3 is a magnetron 4 that emits microwave fj5.
is the provision.

A sample stage 11 is provided at the bottom of the vacuum chamber 1 on which a wafer 18 as an object to be processed can be placed with an insulating material 10 interposed therebetween.

On the top surface of the sample stage 11, #! The green membrane 17 is, for example,
The wafer layer is provided on the insulating film 17. A self-current % source η is connected to the sample stage 11 via a high @ wave power source and a row of low-pass filters, so that a high frequency t and a DC voltage can be applied to the sample stage 11. The direct voltage source 22 can be switched between positive and negative voltages by a switching switch.

Inside the sample stand 1.2, there is a cold tofu Wj1 path υ, and a refrigerant supply system ffi tin for circulating a refrigerant S capable of cooling the sample stand 11 is connected. In the center of the sample stage 11,
A push-up bin 14 is provided for use when transporting wafers.
The push-up bin 14 is connected to a push-up device if L'). Gap in the space where the push-up bottle 14 of the sample stand 11 is installed 1. - can be supplied with a heat transfer gas, for example, He gas, through valve 4 and mass 70 - controller m, and can be supplied to the back side of the wafer. Also, the gap 1 is connected to the vacuum pump 9 via the valve.
An exhaust path for He gas is provided.

Furthermore, as described in detail in FIGS. 2 and 3, an elastic member 4 is provided on the upper part of the sample stage 11 at a position corresponding to the back surface of the wafer 18 outside the convex portion on the upper surface of the sample stage 11. A plate spring δ is provided at #, and the conductive plate spring b is supported by the susceptor 241 and fixed with a screw y.

A lead wire η is connected to the conductor [, board b, b, and the other end is grounded to the earth via the low-pass filter array and the sweep 1l'f' silver. Lead wires n are drawn out through feedthroughs 31 and 32 in one row of vacuum plugs I.

DC electrolyte device lively
The eyebrows are connected to the control unit 2I7, which is activated by the control compensation from the haze.When the control unit 8 is electrostatically attracted to the control unit 8, the switching switch p3 is connected to the contact a. In
- connect, apply a negative voltage to the sample stage IX, and switch 21
Connect 11 to ground. During the plasma processing of X Hanu B, the control device P31) turns off the switch η and puts it in an electrically and electrically floating state. In addition, depending on the case, the earth U-connection may be made even during processing. When removing the control device [1, 2, and 18 from the sample stage 11, connect the switching switch/chi switch to contact bc-connection 1. ).

A positive voltage is applied to the sample stage, and at this time the switch is connected to ground.

From the apparatus 11 constructed in this way, the t-processing gas is introduced into the empty processing chamber through the gas supply hole 6, and is generated by the magnetron 4, the microphone 0, and the solenoid coil 5. The interaction with the generated magnetic field is used to turn it into plasma, and the high-frequency power source 16 generates a high-frequency power source 111. Without controlling the energy of the ions, 7. X-p-chip 18.

Second outside, sample stand refrigerant supply -3T cold #!
Technical cooling can be achieved by the refrigerant Ir- supplied to the flow path 12.

When the wafer 18 is subjected to a cooling force using the He gas supplied to the 3 sides of the wafer IB as a heat transfer body, the valve 18 is opened ``C'', and the valve 21 is open ``C''. Closed.

Here, the wafer fat is placed on the sample stage 11 LT and held, and processing is performed.
The steps up to removing the sample from the sample stage 11 will be explained with reference to FIG.

First, switch 8! ! 1 to the conductive plate spring 21''] to the 21st position h=1./ (This is done in step 311.-
show. ), the wafer] J3 is not placed on the sample stage 11 by the transport device r in a double position;! h(:″, Step 32
Note that the wafer 1B is carried into the vacuum processing chamber by a progressive means (not shown) for details of the arrangement of the wafer 1B.
8, push up the bin 14, take the receiving number i,
After the conveyance means escapes, the push-up pin 14 descends and the wafer lB
is placed on the sample stage 11. As a result, when the wafer 1B is placed on the sample stage Il, the conductive plate springs 5 come into contact with each other.

Next, the changeover switch is operated by the control unit 1 [30], a negative voltage is applied to the sample stage j1 by the DC source device 1iz2, and the wafer 1B is placed on the sample stage 11. (This is shown in step 331).

In this state, the valve 19 is opened to introduce IIe gas to the back surface of the wafer (this is shown in step A).

As a result, the temperature of the wafer 18 rapidly decreases to approximately the same temperature as m degrees of the sample stage 11.

Then, when the wafer 18 is cooled to the target temperature (
This is shown in Step 5. ), turn off the keyaki l, leaf spring b, and show this to stepfather in an electrically deafening manner. ), plasma is generated to start the etching process (this is not shown in step 3).

Thereafter, when the etching process is completed, the plug 1 is extinguished (this is shown on the stem blade) 11: At the same time, the valve 19 is closed and the gas 14e is stopped (Xli-
This is shown in step (5) 6), and the conductive plate spring stone is set to the ground τ again by switch y (this is shown in step 5).

Then, in this state, the changeover switch η is operated by the control device '73111, and the direct 1M power supply YFZ2 is connected to the sample stage 11. , pressure is applied for a certain period of time (this is shown in step 41). As a result, approximately R membrane 8 is coated with cloth,
The wafer 7 can be easily removed by erasing the remaining charges.

Well, after a certain amount of illumination, change the selector switch 7:3 to 7.
The output from the DC iI source 1ai22 is set to 0.-TINO (this is shown in step 421).
- Open the valve to evacuate the flow path for supplying heat transfer gas (this is shown in step 43).

With the above operations, one etching process is completed, and the wafer 7 is transferred from the transfer device port to another stage (this is shown in the stepper material).

As described above, by placing the wafer 1B on the sample stage U, the conductive plate spring 2 is attached to the back surface of the wafer 18.
is in contact with the wafer plate, and the conductive plate 5 is pushed against the wafer by its own weight or electrostatic adhesion force and is bent, so that the wafer 18 is reliably adsorbed and held on the sample stage H. This improves the reliability of wafer suction.

Further, during plasma processing, the wafer is processed in a switched electrical floating state, so ions in the plasma do not locally flow through the wafer chamber and do not adversely affect plasma processing characteristics.

Further, when removing the wafer, since a positive voltage can be applied to the sample stage H, the wafer can be easily removed.

In addition, the conductive plate spring b is covered by the susceptor and the wafer 18, and is protected by the He gas leaking from the back surface of the wafer, preventing plasma from entering the conductive plate spring 5, thereby preventing damage to the conductive plate spring. I won't give anything.

Next, other embodiments of the present invention are shown in part 45 and 4! [6
This will be explained using figures.

Above in this figure! ! The same reference numerals as in FIGS. 1 to 3 indicate the same members, and their explanations will be omitted. This figure is 1 [Figure 1 and lB
The difference from FIG. 2 is that the conductive plate spring 5 is provided at the upper end of the push-up bottle 14. In this case, the lead wire 4 passes through the inside of the push-up pin 14 and exits to the outside of the vacuum Nl.

In the apparatus configured as described above, processing is performed using the same step as in the embodiment described above. This makes it possible to obtain the same effects as in the previous embodiment.

Furthermore, in this embodiment, since the conductive plate spring 2 is provided on the push-up bottle 14, the structure of the sample stage is simplified.

In this embodiment, the elastic member is a conductive plate spring, but a conductive material may be provided at the tip of the elastic member such as a plate spring or a coil spring.

〔Effect of the invention〕

According to the present invention, it is possible to improve the reliability of wafer suction, and furthermore, it is possible to prevent an adverse effect on plasma processing characteristics.

[Brief explanation of the drawing]

@ Figure 1 is a configuration diagram showing a plasma processing apparatus that is the first embodiment of the present invention, Figure 2 is a detailed cross-sectional view of the conductive plate spring part of Figure 1, and Figure 1/3 is a human view of Figure 2. The plan view shown in Figure 4 is I.
Step diagram for carrying out the present invention using the apparatus shown in JI diagram, 1
Fig. jI5 is a configuration diagram showing a plasma processing apparatus according to a second embodiment of the present invention, and Fig. i@6 is a detailed sectional view of the thick plate spring portion of Fig. 5. 2...Discharge tube, 4...Magnetron,
5... Curved solenoid coil, ■... Sample stand, 1
4... Push-up pin, 17... Insulating layer, 1
8...Wafer, n...DC power supply device,
23... Changeover switch, 2... Conductive plate spring, 9 Fig. 4 Fig.

Claims (6)

[Claims] 1. In an apparatus that performs plasma processing while holding a wafer on a sample stage by electrostatic adsorption force, a DC power source is connected to the sample stage, and the elastic member that comes into contact with the back surface of the wafer is moved by connecting the DC power source to the sample stage and placing the wafer on the sample stage. A plasma processing device characterized by being connectable to earth potential. 2. The plasma treatment is performed by applying a high frequency bias to the sample stage, the DC power source is connected to the sample stage through a low-pass filter, and the elastic member is connectable to a ground potential through the low-pass filter. 2. The plasma processing apparatus according to claim 1. 3. 2. The plasma processing apparatus according to claim 1, wherein the elastic member is connected to a ground potential during adsorption and removal of the wafer, and the elastic member is placed in a floating state during plasma processing. 4. When the wafer is attracted, the DC power source is set to a negative voltage;
2. The plasma processing apparatus according to claim 1, wherein the DC power source is set to a positive voltage when the wafer is removed. 5. 2. The plasma processing apparatus according to claim 1, wherein the elastic member contacts an outer back surface of the wafer. 6. 2. The plasma processing apparatus according to claim 1, wherein the elastic member is provided on a member for pushing up the wafer.