JPS60136314A - Treating equipment in low pressure atmosphere - Google Patents

Abstract

PURPOSE:To enable controlling the temperature of a substrate effectively by making the thickness of a gas layer smaller than the mean free pass of the gas even if the substrate is transformed to a projected shape by the gas pressure due to the projected surface of a plate supporting the substrate. CONSTITUTION:A vacuum chamber 24 is exhausted to a low pressure by an exhausting system 41, controlled by a vacuum gauge 39 and a control system 40 at a constant pressure and a treating gas is introduced from the inlet 25 of the treating gas. Within a lower electrode 37, a duct 32 is provided and a fluid maintained at a set temperature is supplied from a fluid supplying source 43. A substrate 34 is pressed by a substrate supporter 35 driven by a driving system 29 provided with a spring 36. Further, heat-conducting gas is sent into the gap between the substrate 34 and the lower electrode 37. The lower electrode 37 is also made a projected shape and the surface is polished to an extent of 3.2S. On this occasion, the projected shape is prevented to be transformed by a load on the back of the substrate due to the introduction of gas and the substrate 34 adheres closely to the lower electrode 37 whereby the substrate is prevented to be transformed unnecessarily.

Description

[Detailed description of the invention] [Field of invention] In the present invention, the film was etched at 1M on a substrate at 9°C.

The present invention relates to processing equipment in a low-pressure atmosphere that performs geological processes such as baking.

Rating L is for dry etching equipment.

A device for cooling the substrate so that the photoresist on the substrate is heated by the heat received from the plasma and the quality of the photoresist on the substrate is changed.Also, a device for effectively heating the substrate in a baking process for degassing the substrate. As necessary, a device for heating this substrate, a steam tank, and a sputtering evaporation device f
etc., relates to a temperature control device for the substrate necessary for controlling the grain size of the generated particles, optical reflectance, etc.

[@Ming background]

In a processing apparatus operating in a low-pressure atmosphere, it is likely that heat exchange between the substrate and the substrate support is not as sufficient as heat exchange under sound pressure. This is because intervening gas molecules play a major role in transferring heat between the two surfaces.

Therefore, simply controlling the temperature of the substrate support cannot effectively control the temperature of the substrate.

Therefore, several methods are known to effectively increase the exchange of heat between two surfaces.

This conventional substrate temperature control device is disclosed in Japanese Patent Application Laid-open No. 1158-324.
As shown in No. 10, the 5iC is constructed as shown in FIG.

That is, processing equipment for sputtering, dry etching, etc. is mainly equipped with a vacuum chamber 10. Spatter 19. Anode 2O
1 and a substrate support stand 12.

The vacuum chamber 10 is then evacuated to a low pressure by an exhaust device 18. The discharge is stopped between the sputtering plate 19, which is a cathode, and the anode 20, and the generated ions Z+a are blown out by the sputtering 19, and the molecules are ejected, and the substrate support 12
This is similar to the board 15 held by the board.

A thin film of the same material as the sputter W is formed on the substrate 15.

Here, a conduit 11 is provided in the substrate support stand 12, and a conduit 11 is provided from the water supply device 2.

By flowing temperature-controlled water, the substrate support stand 12 is maintained at an appropriate temperature.

The substrate 15 is pressed down with a uniform load i over the entire circumference by the substrate support 13 provided with the spring 14. Also, at this time, O
A ring 17 is provided to create a waste chamber 16, which is sealed from the vacuum chamber 10 by an O-ring 17.

Here, the waste reservoir 4 is the waste pressure gauge 8. The control thread 9 and the valve 3 control the amount of waste inflow from the jj supply pipe 1 . The waste chamber 16 formed in the gap between the substrate 15 and the substrate support stand 12 is connected to the waste storage 4 through the valve 6 and the waste v7.
The pressure is always controlled to one foot.

In the conventional processing apparatus described above, heat is transferred between the substrate 15 and the temperature-controlled substrate support by gas molecules in the waste chamber provided between the substrate 15 and the substrate support 12. 71, which is more effective than when the substrate is simply placed on the substrate support stand 12.

However, in this conventional processing device.

I solved the problem like K　o).

For example, the thickness of the substrate 15 is t = [J, 5
rum and a silicon substrate with radius α = 50 mm, the pressure p in the gas chamber 16 is 1000 pa, and the pressure in the vacuum chamber 1o is sufficiently small (p J: '),
The substrate deforms due to the pressure of the gas in the gas chamber 16.
The deformation mar at the position r in the radial direction from the center follows the following equation (11).

Here, E and V are the longitudinal elastic modulus of silicon and the Oyohi-Boisson ratio, respectively, and E = 13.1 x 10" (N
/-], Vyu is 0.3.

At this time, the position of the lid δ at the center of the board 7z, that is, r = 00 position. is approximately 270 μmK.

This value greatly exceeds the brutal thickness of the waste chamber 16 of 134 μm when cBe is used as the gas.

In other words, the designed effect cannot be obtained.

Furthermore, even though lig has high thermal conductivity, the gas in the waste chamber 16 cannot provide a sufficient heat transfer effect. It is clear that when using helium, the heat transfer effect seen with helium cannot be obtained.

As described above, in the conventional substrate temperature control device, sufficient heat transfer characteristics cannot be obtained even if helium, which is a highly conductive scum, is used, and the scum in the gas chamber 16 cannot be replaced with scum of the same type as the scum in the vacuum chamber 10. When using.

There was a problem in that it was difficult to obtain effective heat transfer characteristics by the machining chamber 16 in bulk.Furthermore, until the sealing effect of the O-ring was generated, the substrate 15 is impossible from the viewpoint of mechanical strength of the substrate.

Therefore, a gas leak inevitably occurred in the house.1. X
If a gas different from the processing gas introduced into the nitrogen chamber 10 is used as a heat transfer gas, the leaked heat transfer gas may have an adverse effect on the processing inside the vacuum chamber 10. there was.

[Purpose of the invention]

The purpose of the present invention is to make it possible to effectively control the temperature of the substrate in an apparatus that performs processes such as etching and xMj 4% baking in a low-pressure atmosphere in view of the problems of the rice promotion technique described above. An object of the present invention is to provide a processing device in a low pressure atmosphere.

[Summary of the invention]

In order to couple the above objects, the present invention provides that, in a range where the gap distance between the substrate and the substrate support is smaller than the mean free path of the gas existing within one gap, the heat exchange between the two surfaces can be Considering that the pressure does not depend on the type of gas, the substrate support is made convex so that even when the L°C substrate is deformed into a convex shape due to gas pressure, the thickness of the gas layer is smaller than the mean free path of the gas. In particular, the effective heat transfer characteristics between the two surfaces can be improved even in gases other than highly conductive gases.

[Embodiments of the invention]

The present invention will be specifically described below based on embodiments shown in the drawings.

That is, ii, the disadvantages of the present invention will be specifically explained using FIG.

Assuming that the thickness of the gas layer between the substrate and the substrate support is d, the time between the two surfaces per unit temperature difference when considering the pressure of the gas layer is:
Figure 2 shows the changes in the amount of heat (heat transfer rate) per unit area measured for helium, nitrogen, and carbon tetrachloride by a °C experiment.

Furthermore, one embodiment of the present invention will be specifically explained based on FIGS. 3, 4, and 5.

In this embodiment, A is the chamber 24. Hiroshi Kamibe & 30. Lower part'-pole 3
7. This is a parallel plate type dry etching device that is constructed directly from a high frequency tIL source 42.

The vacuum chamber 24 is evacuated to a low pressure by an exhaust system 41, brought to a foot pressure by a vacuum gauge 69 and a control system 40, and a processing gas, such as carbon tetrachloride, is introduced from the processing gas inlet 25. Further, a frequency wave is applied from a single frequency microwave rM42 between the upper electrode 50 and the lower electrode 37 via the insulator 38, and the processing gas becomes a glazma state, and the surface of the substrate 340 on the lower electrode 67 is exposed. The butter is etched into seven patterns formed by the surrounding resist.

As is clear from this figure, the same heat transfer rate as in the case of using a gas layer having a thickness of dlium can be obtained.

That is, if the thickness of the gas layer is always set to less than toIun; [, the heat transfer effect will be large.

In addition, the pressure of the scum depends on the type of gas, but the thickness of the gas layer is about 10 μm (at the limit of mechanical contact, it is about 16 μm).
Even if the value is higher than 00 Pα, the heat transfer rate does not increase, and the meaning is 7.
good.

Furthermore, for example, the load that a substrate with a radius of 50 nm receives from a gas of 1500 pα is 1 kg, and applying a load greater than this increases the possibility of destruction of the substrate. Therefore, summer is thought to be the limit for 1soopa.

In this figure, the direct source part 21 is a case where the mean free path of gas molecules is sufficiently larger than the thickness of the gas layer, and the heat transfer rate increases in an arm shape with the gas pressure, and the gas layer thickness and gas Regardless of type.

In the case of the straight section 22, the mean free path of the gas molecules is sufficiently smaller than the thickness of the gas layer, and as the thickness of the gas layer increases, the heat transfer rate decreases.

At this time, the heat transfer rate does not change even if the pressure increases if the gases are of the same polarity.

Further, the bending section 26 is in a transitional state between these two cases.

Here, the lower electrode 57 is provided with a dedicated tube 32 inside, and is supplied with fluid maintained at a set temperature from a fluid supply @ 43, and a lower electrode 67 is installed to maintain the set temperature. Methods for keeping feet warm include not only flowing fluid, but also heat pipes and heating sources. A method using w or the like is also acceptable.

The substrate &34 is pressed down with a total load of 3 to 4 kg by a substrate support 35 which is formed of an annular or 6 to 4 fish claw provided with a spring 36 and is driven by a drive system 29.

Further, heat transfer gas is supplied to a conduit 47 from a gas reservoir 44 whose pressure is controlled by a flow rate controller 46 and a vacuum gauge 45.
is introduced into the lower electrode 57 through.

1 mm diameter provided on circle 48 as shown in Figure 4
The gas is sent to the gap formed between the substrate 34 and the lower electrode 37 through a large number of gas introduction holes 31 .

Further, the gas introduced into the vacuum chamber 24 through the gas inlet 25 and the gas introduced into the vacuum chamber 24 through the lower electrode 37 are both supplied from one conduit 28 and controlled by the flow rate control device 27. Controls the amount of gas supplied from the gas supply port 26 to the vacuum chamber.

The lower electrode 37 is processed into a convex shape.

The surface is polished to a surface roughness of approximately 3.2S.

At this time, the shape of the convex surface is processed according to equation 1 (1) or slightly larger than equation (υ).This is so that even if gas is introduced and the substrate receives a load from the back side, it will further deform. As a result, the substrate 34 is closely cleaned to the lower electrode 37,
Moreover, it is possible to avoid making the board unnecessarily deformed.

In the above device 11 configuration, the process of controlling the temperature of the substrate will be explained.

The gas introduced from the gas introduction hole 31 to the & surface of the substrate 34 traces the gap between the two surfaces and is exhausted into the viewing chamber 24 while
The gas pressure inside the circle 48 is also introduced into the circle 48 and has the same pressure as the gas pressure in the gas introduction hole 31.

Experiments have shown that it takes only a few seconds for the foot to become unsteady if the gap between the surface and the silicon substrate is approximately 5.25 mm.

= Again. At the stage of exhaustion to the vacuum chamber 24 side, a pressure gradient exists outside the circle 48. This is due to the contactance of this part, which is the rMJ original distance of 10 μm.

At this time, the pressure in the radial direction I9 of the gas layer 33 is shown in FIG.

At this time, if the pressure of the gas layer 33 on the back side is set at a set pressure of 700 pa at many points on the substrate 64, as is clear from the graph shown in FIG. In a gas layer such as carbon (the same is thought to be true for other gases as well), it exhibits a large heat transfer coefficient of 500 W/m''·day.

Here, the pressure on the back surface of the substrate is low in the outer part of 1 yen 48, but the thermal conductivity of the substrate itself is sufficiently large compared to the heat transmission rate of the gas layer, so the difference in temperature from the center of the substrate is not a problem. No.

Here, the temperature of the substrate when the aluminum film on the silicon substrate was dry etched using a power of about 200 W from the high frequency m source 42 was about 30° C. when the lower electrode was set at 20° C. . This is a much better value than the value of 250° C. when the substrate is simply placed.

Furthermore, when measuring the amount of gas introduced into the vacuum chamber 24 through the lower electrode 37, it was found that a silicon substrate with a diameter of iQQmm was placed on the lower electrode polished to a 3.2S surface, and the pressure of the gas layer was 1 ooo pα and the amount of leakage is approximately 0 when introduced from a gas introduction hole provided on the circumference with a radius of 45 mm.
．． It is about 02~0.05pa*rn'/sec, which is 1 compared to the normal reaction gas flow rate of 0.5~2Pα・m'7''I a C' when performing dry etching.
The value is ~2 orders of magnitude smaller, and even more.

Reaction gas flow rate 0.04 to 0.06Pα in a microwave plasma processing apparatus using electron magnetic resonance that performs processing in a low pressure atmosphere of 10Pα to 10−'Pα/Z g
It has one shift, fewer than C. Therefore, it can also be used as a substrate temperature control device in a plasma processing apparatus using Mike Q discharge.

In addition, when the substrate support table is heated to 400 to 500°C and used for baking the substrate, the substrate temperature T is calculated by the following formula (
2 (rises due to

λ T =To + (Tg-To) arp (--1
) -... (21 Here, To and 1''- are the temperatures of the initial temperature electrodes of the substrate, respectively, and λ is the amount of heat passing over the entire surface of the substrate.

C is the heat capacity of the substrate. Here, λ= 5.4 F/
dg, c = 5.8 J/dg, To = 20
℃, Tg = 400℃, 360℃ in about 4 seconds
Experiments have shown that this value is almost similar to that of °C.

Furthermore, it will be apparent to those skilled in the art that the present invention is applicable to other processes not described in this embodiment where substrate temperature control in vacuum is essential.

0#, effect of brightness] As explained above, according to Honkotomei, by interposing a gas of around 700Pα in the gap between the substrate and the substrate support, it is possible to reduce the distance between each gap to about 10PL or less. Therefore, even if a processing gas with a large molecular weight is used, other than helium, which is a highly conductive gas, it is possible to increase the heat transfer rate between the substrate and the substrate support, thereby achieving good temperature characteristics. Moreover, since the same type of gas as the processing gas can be used as the heat transfer gas, the problem of leakage of the heat transfer gas can also be solved.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a conventional processing device, and FIG. 2 is a diagram showing the relationship between heat transfer rate and gas pressure. Fig. 6 is a vertical cross-sectional view showing an embodiment of the present invention, Fig. 4 is a transparent view of the lower electrode and the substrate, and Fig. 5 is a diagram showing the pressure distribution of the gas layer. 24. - Vacuum chamber 31... Gas introduction hole 36... Gas layer 34... Substrate 35... Substrate support 37... Lower electrode 44...
Because of the lack of gas, there are 4 scoldings and 34 lice! Figure 5 Cow strength l01 (sparrow msu)

Claims (1)

[Claims] t. In a processing apparatus in a low-pressure atmosphere, a heating source or a heat sink is connected to or supported in order to heat or cool the substrate, and a support is provided to support the substrate, and the support is provided with a support for supporting the substrate. 1. A processing apparatus in a low-pressure atmosphere, characterized in that a pressure gas is introduced between a support surface that supports a substrate and the lateral surface of the substrate to form the support surface in a convex shape. 2. The processing apparatus in a low-pressure atmosphere as set forth in claim 1, characterized in that a hole for introducing pressurized gas is provided on the support surface of the support base at a position close to the outer periphery of the substrate. 6. The second item of the claim, characterized in that the gas introduced between the support surface of the support stand and the reverse side of the substrate is the same type of gas as the gas introduced into the low-pressure atmosphere. Processing equipment in a low-pressure atmosphere.