JPH0744168B2 - Substrate rotation type surface treatment equipment - Google Patents

Description

The present invention relates to a substrate such as a gas for surface treatment such as etching and cleaning of a substrate while rotating a substrate such as a semiconductor wafer, and a gas for film formation. The present invention relates to a substrate rotation type surface treatment apparatus that supplies a processing gas to a substrate surface, and more particularly to a technique for improving the uniformity of substrate surface treatment.

<Prior Art> As a nozzle for substrate surface treatment, a flow guide is arranged so as to face a horizontally rotating substrate, and a processing fluid is supplied from the center of the flow guide (rotation center of the substrate) to flow with the substrate. It is known that contaminants are prevented from adhering to the substrate by filling a narrow space between the guide and the fluid (for example, see Japanese Patent Laid-Open No. 61-40032).

FIG. 11 (a) shows a state in which the state of the etching process of the silicon thermal oxide film on the substrate surface is investigated using such a nozzle. The nozzle 51 is configured with a disc-shaped flow guide 53 having a gas ejection port 52 in the center.
The nozzle 51 is opposed to the vicinity of the upper side of the substrate W held by the mechanical chuck 54 which is horizontally rotated by a motor (not shown). Gas outlet in flow guide 53
Reference numeral 52 coincides with the rotation center O of the substrate W.

A mixed vapor for etching, which is composed of water vapor of hydrogen fluoride gas HF and pure H ₂ O, is jetted from the gas jet port 52 toward the surface of the substrate W, and is supplied to a narrow space between the flow guide 53 and the substrate W. A silicon vapor oxide film (SiO ₂ ) on the surface of the rotating substrate W was etched by flowing a mixed vapor, and the etching condition was examined.

Further, a nozzle 61 as shown in FIG. 12 (a) has been conventionally known (see, for example, JP-A-63-266825). This is for removing organic substances on the surface of the substrate. A gas ejection port 63 is provided at a location eccentric with respect to the center of the flow guide 62, and the substrate W is held from above the substrate W held by the mechanical chuck 54. It is configured to supply the mixed vapor to the surface of.

<Problems to be Solved by the Invention> FIG. 11B shows the result of etching using the nozzle 51 of FIG. 11A. Here, O indicates the rotation center of the substrate W, and A indicates the position of the gas ejection port 52.

As is clear from the figure, in the state of etching the silicon thermal oxide film 55, in the case of the nozzle 51 of FIG. 11 (a), the central portion of the substrate W located immediately below the gas ejection port 52 is deep and It became shallower as it approached, and it was found that uniform processing could not be performed over the entire surface of the substrate.

In the nozzle 61 of FIG. 12 (a), if the gas ejection port 63 is located exactly in the middle between the deepest position and the shallowest position of the etching shown in FIG. 11 (b), the etching depth can be made uniform. I expected it to be used. However, as shown in FIG. 12 (b), the etching state of the obtained silicon oxide film 64 is deep at the position directly below the gas ejection port 63, and gradually gets closer to the central portion and the outer peripheral portion from there. It became shallow, and it was found that uniform processing over the entire surface of the substrate was difficult.

Instead of the nozzle as described above, a chamber having a perforated plate facing the substrate is used, and the structure of the chamber and the perforated plate is designed so that the mixed vapor flowing into the chamber flows out uniformly (when the mechanical chuck is stopped). It was also found that the etching process becomes non-uniform even when devised. The cause seems to be that the uniform outflow is hindered by the air flow generated by the rotation of the substrate W.

The non-uniformity of processing is a problem not only in etching but also in cleaning or film formation.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a substrate rotary surface treatment apparatus capable of uniformly treating the entire surface of a substrate.

<Means for Solving the Problems> The present invention has the following configuration in order to achieve such an object.

That is, the substrate rotation type surface treatment apparatus of the present invention is a substrate rotation type surface treatment apparatus which supplies a substrate processing gas to the substrate surface while rotating the substrate so as to face the entire surface of the substrate near the rotating substrate. As well as arranging the rectifying plate, a large number of gas outlets are dispersedly formed on the rectifying plate,
It is characterized in that the outflow pressure of the substrate processing gas from the gas outlet is set to be higher as it goes away from the rotation center of the substrate.

<Operation> According to the structure of the substrate rotary surface processing apparatus of the present invention, the substrate processing gas is supplied from the gas outlets dispersedly formed on the current plate arranged near the substrate so as to face the entire surface of the substrate. Therefore, the space between the substrate and the current plate is filled with the substrate processing gas.

When the substrate is rotated, the substrate processing gas on the surface of the substrate rotates due to contact with the substrate, and the atmospheric pressure increases toward the outer side away from the center of rotation of the substrate due to centrifugal force.

However, the outflow pressure of the substrate processing gas from the gas outlet formed in the straightening plate was set higher than that on the outer side away from the center of rotation of the substrate. The substrate processing gas is supplied at a high outflow pressure so as to oppose it. Therefore, regardless of the position in the radial direction from the center of rotation, the outflow pressure of the substrate processing gas has a uniform pressure difference with respect to the atmospheric pressure on the substrate surface.
The supply amount of the substrate processing gas per unit area to the substrate surface is uniform, and the processing is also uniform in the radial direction.

Thus, even though the substrate is rotated, the supply amount of the substrate processing gas per unit area to the substrate surface is made uniform, so that the processing in the circumferential direction achieved by rotating the substrate is performed. By the synergistic effect of improving the uniformity of the substrate and improving the uniformity of the treatment in the radial direction, the surface of the substrate can be uniformly treated.

<Example> Hereinafter, an example of the present invention is described in detail based on a drawing.

First Embodiment FIG. 1 is a sectional view of a substrate rotary surface treatment apparatus of the first embodiment.

A mechanical chuck 2 for holding a substrate W such as a semiconductor wafer is provided inside a bottomed cylindrical substrate processing chamber 1. The rotary shaft 3 of the mechanical chuck 2 is connected to the substrate processing chamber 1
Is rotatably supported on the bottom plate of the bearing through a bearing 4 having a sealing function,
The end of the rotary shaft 3 is coupled to the motor 5 so that the substrate W held on the mechanical chuck 2 is horizontally rotated around the vertical axis.

The cup-shaped lid 6 covering the upper opening of the substrate processing chamber 1 includes a tapered peripheral wall portion 7, a chamber 8 integrated in a watertight state at a bottom portion thereof, and a ceiling plate integrally formed in a watertight state at an upper portion. It is composed of 9 and 9. The inside of the lid 6 is a constant temperature water bath
10, a hot water supply tube 11 and a hot water discharge tube 12 for keeping hot water of a constant temperature in the constant temperature hot water tank 10 at all times are attached to the tapered peripheral wall portion 7.

Inside the constant temperature water bath 10, a mixed vapor supply tube 13 for supplying a mixed vapor (substrate processing gas) of hydrogen fluoride gas HF and pure water H ₂ O for etching the surface of the substrate W, and a carrier gas. a carrier gas supply tube 14 for supplying nitrogen gas N ₂ as a aspirator 15 which the mixed vapor was sucked by the negative pressure caused by the flow of the carrier gas N _2, diluted vapor mixture with a carrier gas N _2, the aspirator A processing gas supply tube 16 for supplying the substrate processing gas diluted with 15 into the chamber 8 is provided.

Mixed vapor supply tube 13, Carrier gas supply tube 14
Respectively pass through the Taber-shaped peripheral wall portion 7 and are connected to a mixed vapor supply source and a nitrogen gas supply source (not shown). The mixed vapor supply tube 13, the aspirator 15, and the processing gas supply tube 16 are inserted into the constant temperature hot water tank 10 in order to prevent liquefaction of the mixed vapor. In this sense, the temperature of the mixed vapor supply tube 13 is controlled even outside the constant temperature hot water tank 10 over the entire length up to the supply source.

The mixed vapor supply tube 13 and the carrier gas supply tube 14 are bent inside the constant temperature hot water tank 10 because
This is to lengthen the internal flow path to maximize the contact area for heat exchange with the hot water and to stabilize the temperatures of the mixed vapor and the carrier gas N ₂ .

FIG. 2 is a perspective view of a half cross section showing a specific structure of the chamber 8, and the right end portion is cut off obliquely with respect to the radial direction. FIG. 3 is a partially cutaway bottom view of the chamber 8 from below with the perforated plate 23 removed.

The chamber 8 is formed by integrating the top plate portion 17 and the peripheral wall portion 18, and the aspirator 15 described above is mounted and fixed on the top plate portion 17. A connector 19 of the processing gas supply tube 16 is confidentially screwed into a connection port formed from the top plate portion 17 to the peripheral wall portion 18 in the peripheral portion of the top plate portion 17. A gas inlet 20 is formed on the peripheral wall 18 in a state of communicating with the connector 19 and is inclined at an appropriate angle (eg, 30 °) with respect to the radial direction of the chamber 8 so as to communicate with the inside of the chamber 8. There is. Reference numeral 21 is a plug that shuts off the outer portion of the gas inlet 20 from the outside.

The perforated plate 23 is fitted to the step portion formed inside the lower surface of the peripheral wall portion 18, and the perforated plate is formed by the ring-shaped contact plate 24 and the bolt 25.
23 is connected to the chamber 8. A large number of small holes 22 having a diameter of about 1 to 2 mm are formed in the porous plate 23 at a small pitch in a grid pattern. The perforated plate 23 corresponds to the straightening plate in the configuration of the invention, and the small hole 22 corresponds to the gas outlet in the configuration of the invention.

A pair of support plates 26 are attached to the chamber 8 at positions 90 ° apart from the connector 19 and 180 ° apart from each other. The peripheral wall portion 7 of the lid 6 having a tapered shape is watertightly joined to the outer peripheral surface of the peripheral wall portion 18 of the chamber 8, and the support plate 26 penetrates the tapered peripheral wall portion 7 in a watertight manner and projects outward.

In addition, in Fig. 1, gas inlets separated by 90 °
20 and the support plate 26 are shown in the same plane for convenience.

Since the gas inlet 20 to the chamber 8 is formed to be inclined with respect to the radial direction, the substrate processing gas rotates in a swirl manner in the chamber 8 as shown in FIG. About the side of the peripheral wall 18 than the center of the inside,
The atmospheric pressure of the substrate processing gas increases. Therefore, perforated plate
The outflow pressure of the substrate processing gas flowing out from the small holes 22 of 23 becomes higher than the rotation center of the substrate W on the outer side away from it. Therefore, when the rotation of the substrate W is stopped,
The outflow rate of the substrate processing gas per unit opening area in the small holes 22 of the porous plate 23 is larger in the peripheral small holes 22 and smaller in the central small holes 22. However, when the substrate W is rotated, the outflow pressure of the substrate processing gas is increased toward the outer side away from the rotation center of the substrate W, so that the substrate processing gas per unit area of the substrate W is supplied, as described later. The quantity becomes uniform.

The cup-shaped lid 6 is configured to be vertically movable, and comes into contact with the packing 27 at the upper edge of the substrate processing chamber 1 by descending to hermetically seal the inside of the substrate processing chamber 1. As a mechanism for moving the lid 6 up and down, a piston rod of an elevating air cylinder 28 is connected to the pair of support plates 26.

The main processing section 29 including the substrate processing chamber 1 and the cup-shaped lid 6 described above is covered with the housing 30 to form a double chamber structure. A substrate loading port 31a and a substrate loading port 31b are formed in the housing 30 at a position corresponding to the height position of the mechanical chuck 2, and a shutter 32 with a rack that opens and closes the loading port 31a and the loading port 31b by vertical sliding.
There are provided a and 32b, pinion gears 33a and 33b that mesh with the racks of the shutters 32a and 32b, and motors (not shown) that drive the pinion gears 33a and 33b. Note that the shutter
Neither racks 32a, 32b nor tooth portions of pinion gears 33a, 33b are shown.

Outside the housing 30, the substrate W is loaded into the housing 30 through the carry-in port 31a in a state where the substrate W is adsorbed and held, and the substrate W is loaded in a state where the lid 6 is lifted and the substrate processing chamber 1 is opened. A bending / extending arm type substrate loading mechanism 34a that is transferred to the mechanical chuck 2 and an unloading port 31b.
A substrate unloading mechanism 34b having a similar structure for unloading the substrate W from the housing 30 to the outside is provided. The structures of the substrate loading mechanism 34a and the substrate unloading mechanism 34b are disclosed in, for example, Japanese Utility Model Laid-Open No. 60-176548.

Reference numeral 35 is an exhaust tube of the substrate processing chamber 1, and 36 is an exhaust tube of the housing 30.

Next, the operation of the substrate rotary surface processing apparatus configured as described above will be described.

By supplying hot water having a constant temperature from the hot water supply tube 11 and discharging hot water cooled by heat exchange from the hot water discharge tube 12, the temperature in the constant temperature hot water tank 10 is kept constant.

The pinion gear 33a is driven to lower the shutter 32a and open the substrate carry-in port 31a. The other substrate unloading port 31b is a shutter 32b.
Is blocked by. Next, the elevating air cylinder 28 is extended to raise the lid body 6, and a space into which the substrate loading mechanism 34a can enter is secured between the lid body 6 and the mechanical chuck 2. Then, the substrate W is placed on the substrate loading mechanism 34a, the substrate W is held by vacuum suction, and the substrate W is loaded into the housing 30 through the loading port 31a by driving the substrate loading mechanism 34a to extend. Then, the substrate loading mechanism 34a is bent to move the loading port 31a.
The shutter 32a is lifted to close the carry-in port 31a.

By contracting the lifting air cylinder 28 and lowering the lid body 6,
The inside of the substrate processing chamber 1 is hermetically sealed by being pressed against the packing 27 of the substrate processing chamber 1. Then, by driving the motor 5,
The substrate W is rotated together with the mechanical chuck 2. Then, by feeding the carrier gas N ₂ into the aspirator 15 via the carrier gas supply tube 14, a negative pressure is generated, and the hydrogen fluoride gas HF and pure water H ₂ O are supplied via the mixed vapor supply tube 13. The mixed vapor of and is sucked into the aspirator 15 and mixed with the carrier gas N ₂ to dilute. The diluted substrate processing gas is supplied into the chamber 8 through the processing gas supply tube 16 from the inclined gas inlet 20.

The substrate processing gas becomes a vortex in the chamber 8, and the outflow pressure of the substrate processing gas increases as it goes away from the center of rotation of the substrate W. However, when the substrate W is rotated, as will be described later, the supply amount of the substrate processing gas per unit area of the substrate W becomes uniform, the substrate processing gas is uniformly supplied to the substrate W, and the silicon heat of the substrate W is reduced. Etch the oxide film. The detailed operation of this etching will be described later.

When the required etching is completed, the supply of the carrier gas N ₂ and the mixed vapor is stopped and the motor 5 is stopped,
Extend the lifting air cylinder 28 to raise the lid body 6,
The substrate processing chamber 1 is opened. The shutter 32b is opened by driving the pinion gear 33b, the substrate unloading mechanism 34b is extended to receive the substrate W, and the substrate W is unloaded to the outside through the unloading port 31b by the bending operation. Then, the shutter 32b is raised to close the carry-out port 31b.

Next, the flow rate of the substrate processing gas supplied to the substrate W during etching will be described.

Since the gas inflow port 20 is inclined with respect to the radial direction, the substrate processing gas rotates in a swirling manner in the chamber 8, and the substrate processing gas is closer to the peripheral wall 18 side than the center of the chamber 8. The gas pressure becomes high. Therefore, the outflow pressure of the substrate processing gas flowing out from the small holes 22 of the perforated plate 23 is
The smaller the small hole 22 on the outer side away from the center of rotation, the higher.

However, when the substrate W is rotating, the substrate processing gas on the substrate surface rotates along with the substrate W due to contact with the substrate W, and the outer side away from the center of rotation of the substrate W due to centrifugal force. The higher the atmospheric pressure is.

Therefore, the outer side away from the rotation center of the substrate W,
That is, since the substrate processing gas is supplied at a higher outflow pressure as the atmospheric pressure is higher, the outflow pressure of the substrate processing gas is different from the atmospheric pressure on the substrate surface at any position in the radial direction from the rotation center. As a result, the supply amount of the substrate processing gas per unit area on the surface of the substrate W is uniform, and the processing is also uniform in the radial direction.

Incidentally, it is desirable that the atmospheric pressure distribution of the substrate processing gas on the substrate surface in the radial direction of rotation and the outflow pressure distribution of the substrate processing gas flowing out from the small holes 22 of the perforated plate 23 match as much as possible. Can be done as follows:

First, the inner wall surface of the substrate processing chamber 1 and the mechanical chuck 2
A case will be described in which the points of and are close to each other and the horizontal airflow F generated with the rotation of the substrate W bounces on the inner peripheral wall surface of the substrate processing chamber 1 to generate an ascending airflow FU.

For example, in the case of controlling by the rotation speed, when the rotation speed is a low speed V _L , as shown in FIG. 4 (a), it becomes higher toward the outer side away from the rotation center of the substrate W, which is caused by the rotation. The pressure difference of the outflow pressure of the substrate processing gas flowing out from the small holes 22 group with respect to the total pressure obtained by adding the pressure added by the rebound on the inner peripheral wall surface of the substrate processing chamber 1 to the outer periphery is The flow rate of the substrate processing gas supplied from the chamber 8 per unit area is largely Q ₁ , the flow rate at the outermost circumference is Q ₁ , Q ₂ and Q ₃ toward the inner side, and Q _{4 at the} center.
_{When, Q 1> Q 2> Q} 3> Q 4 , and the distribution of the outflow rate from the small hole 22 group periphery central portion becomes small at large. As a result, the etching profile of the silicon thermal oxide film becomes mountainous. Since the horizontal airflow F generated by the rotation of the substrate W is not strong at the low speed V _L , it is strongly affected by the flow of the substrate processing gas and after bouncing on the inner wall surface of the substrate processing chamber 1. As it flows downward, no updraft FU occurs.

When the rotation speed is high V _H , the centrifugal force acting on the substrate processing gas on the substrate surface is strong as shown in FIG. In addition to the high pressure, the ascending air current FU is also strong. Therefore, the pressure difference between the outflow pressure of the substrate processing gas flowing out from the small holes 22 is small toward the outer circumference, and the chamber 8 has a small pressure difference. The flow rate of the substrate processing gas supplied from the unit area per unit area is Q ₁ <Q ₂ <Q ₃ <Q ₄ , and the distribution of the outflow rate from the small hole group 22 is small in the peripheral area and large in the central area. Becomes As a result, the etching profile becomes valley-shaped.

Then, when the rotation speed reaches the optimum speed V _M , as shown in FIG. 4B, the outflow pressure of the substrate processing gas flowing out from the group of small holes 22 and the above-mentioned total on the substrate W side. The pressure difference from the pressure becomes uniform everywhere in the radial direction, and the flow rate of the substrate processing gas supplied from the chamber 8 per unit area is Q ₁ = Q ₂ = Q ₃ = Q ₄ and all small holes Outflow rate of 22 becomes equal. As a result, the surface of the substrate W can be uniformly etched over the silicon thermal oxide film, and its profile becomes flat.

Moreover, the substrate processing gas flowing out from the group of small holes 22 is confined in the air curtain formed by the ascending air current FU ', and the contact amount of the substrate W with respect to the silicon thermal oxide film per unit time increases. Therefore, the etching process is sped up.

Next, the inner peripheral wall surface of the substrate processing chamber 1 and the mechanical chuck 2
When the horizontal airflow F generated along with the rotation of the substrate W bounces off the inner peripheral wall surface of the substrate processing chamber 1 due to the separation of, for example, the pressure change is substantially negligible. Will be described.

For example, in the case of controlling by the rotation speed, when the rotation speed is a low speed V _L , the centrifugal force acting on the substrate processing gas on the substrate surface is weak as shown in FIG. As shown by, the atmospheric pressure of the substrate processing gas is not so high even in the peripheral portion. Therefore, the pressure difference that the outflow pressure (indicated by the broken line L2) of the substrate processing gas supplied from the small holes 22 has with respect to the atmospheric pressure on the surface side of the substrate W is as indicated by the alternate long and two short dashes line L3. The amount of the supplied substrate processing gas per unit area is larger at the peripheral portion side, and the amount of the substrate processing gas per unit area is Q ₁ , the innermost amount is Q ₂ and Q ₃ , and the central portion is Q ₄ Then, Q ₁ > Q ₂ > Q ₃ > Q ₄ , and as a result, the etching profile of the silicon thermal oxide film has a mountain shape.

Further, when the rotation speed is high V _H , the centrifugal force acting on the substrate processing gas on the substrate surface is strong as shown in FIG. Then, the atmospheric pressure of the substrate processing gas becomes high. Therefore, the pressure difference that the outflow pressure (indicated by a broken line L2) of the substrate processing gas supplied from the small holes 22 has with respect to the atmospheric pressure on the front surface side of the substrate W is, as indicated by a two-dot chain line L3, The amount of the supplied substrate processing gas per unit area becomes smaller as the peripheral side becomes smaller than Q ₁ <Q ₂
<Q ₃ <Q ₄ , and as a result, the etching profile becomes valley-shaped.

Then, when the rotation speed reaches the optimum speed V _M , as shown in FIG. 5B, the centrifugal force acting on the substrate processing gas on the substrate surface has an appropriate strength, and the chain line L1 As shown in, the pressure difference of the outflow pressure (indicated by a broken line L2) of the substrate processing gas supplied from the small holes 22 with respect to the atmospheric pressure of the substrate processing gas is uniform everywhere in the radial direction. ,
As indicated by the chain double-dashed line L3, the amount of the substrate processing gas supplied to the surface of the substrate per unit area is Q ₁ = Q ₂ = Q ₃ = Q ₄ , which results in silicon thermal oxidation on the substrate W. The etching process on the film can be performed uniformly over the entire surface, and the profile becomes flat.

Next, an experiment was conducted to find out how the rotation speed V _M and the optimum conditions for uniformizing the gas flow rate are determined. The results are reported below.

A mixed vapor generated by evaporation of a mixed liquid of hydrofluoric acid HF and pure water H ₂ O diluted with nitrogen gas N ₂ is used as a supply source, and the temperature of the supply source is 25 ° C, 30 ° C, 40 ° C. , 50 ° C, and the supply flow rate (5 / min, 10 / min, 15 / min, 20 / min) of the mixed vapor 18 at each temperature to the chamber 8, the rotation speed (10 rpm to 1,000 rpm), and the silicon The relationship with the etching rate (Å / min) of the thermal oxide film was obtained. The concentration ratio of hydrogen fluoride gas, water vapor and nitrogen gas at each temperature is as follows at an atmospheric pressure of 760 mmHg.

As the sample substrate W, a 6-inch P-type (100) silicon wafer having a silicon thermal oxide film with a thickness of about 10,000 Å was used.

The results of the etching treatment at each temperature are summarized in Tables 2 to 5. In these tables, the first step is the etching rate, the second step is the range (maximum etching depth-minimum value; unit Å), the third step is the standard deviation σ (maximum value-minimum value), the fourth step. Is the in-plane uniformity (%; average value at 27 equidistant positions in the diameter direction), and the in-plane uniformity is the most important index. The in-plane uniformity is defined as (maximum value-minimum value) / 2 x absolute value of average value.

As is clear from Tables 2 to 5, it is understood that the in-plane uniformity becomes minimum at a certain rotation speed for each supply flow rate to the chamber 8. That is, supply flow rate 5 / m
100 rpm for in, 200-300 for 10 / min
When the rpm is 15 / min, the minimum is 250 to 350 rpm, and when the rpm is 20 / min, the minimum is 300 to 400 rpm.

FIG. 6 shows the relationship between the rotation speed (rpm) and the in-plane uniformity (%) when the temperature is 30 ° C. When the supply flow rate is determined, the flow velocity of the vortex flow in the chamber 8 is determined, and the extent to which the outflow pressure increases toward the outer side away from the rotation center is determined. It can be seen that the uniformity becomes minimal.

Next, when the cross-sectional profile of the silicon thermal oxide film after the etching treatment performed at 40 ° C. was examined for each rotation speed, the results shown in FIG. 7 were obtained. This profile shows that the supply flow rate is 5 / min, 10 / min, 15 / min, 20 / min.
It is for min.

The peripheral portion is strongly etched when the rotation speed is relatively low, but the in-plane uniformity is best at a certain rotation speed, and the center portion is strongly etched when the rotation speed is higher. I understand. That is, in the curve of FIG. 6, the profile on the left side of the minimum value is a mountain-shaped profile, and the profile on the right side is a valley-shaped profile.

Furthermore, the relationship between the distance from the rotation center O (mm) and the etching depth (Å) when the etching treatment was performed for 1 minute under the conditions of 40 ° C and 10 / min, and the results are shown in Fig. 8. Indicated. In this case, it can be seen that the best profile is obtained when the rotation speed is 250 rpm.

Further, FIG. 9 shows the relationship between the minimum value of the in-plane uniformity in Table 2 and the rotation speed. In order to obtain in-plane uniformity by changing the temperature at the same flow rate in FIG. 9,
The rotation speed increases with temperature. This is the first
As shown in the table, it is considered that this is due to the change in H concentration with temperature.

Comprehensively judging the above experimental results, it can be concluded that the in-plane uniformity of etching for the silicon thermal oxide film depends only on the supply flow rate of the mixed vapor to the chamber 8 and the rotation speed of the substrate W.

The relationship between the direction of the vortex flow of the mixed vapor in the chamber 8 and the rotation direction of the substrate W can be the same in the same direction or in the opposite direction.

By the way, it should be noted that even the worst of these profiles has a sufficiently good profile as compared with the conventional examples shown in FIG. 11 and FIG. That is, the proper setting of the rotation speed is necessary to maximize the in-plane uniformity, but in the sense that the in-plane uniformity is improved as compared with the conventional example, the substrate processing gas on the surface of the substrate W is While the atmospheric pressure of the substrate processing gas in the peripheral portion of the substrate W increases due to the centrifugal force used, the outflow pressure is adjusted so that the outflow pressure distribution of the substrate processing gas supplied from the small holes 22 is balanced. That is, it is only necessary to make the distribution of P.sub.2 higher toward the periphery of the rotating substrate W.

Second Embodiment FIG. 10 is a cross-sectional view of the main part of the second embodiment, in which a mixed vapor inlet 41 is provided in the center of the chamber 8 and the lower surface of the chamber 8 and the perforated plate 23. A baffle plate 42 is provided in the formed space S.

A ventilation hole 43 is provided on the peripheral end side of the baffle plate 42.

With this configuration, the mixed steam flowing into the space S flows to the outer peripheral side by the baffle plate 42, and a part of the mixed steam is vented.
Because the flow resistance of the porous plate 23 flowing through the perforated plate 23 toward the position toward the center of the perforated plate 23 is stronger, the small holes 22 on the side farther from the center of rotation of the substrate W can flow the mixed vapor with a larger outflow pressure. It has become.

As the mixed vapor in the above-mentioned embodiment, hydrogen fluoride gas is used.
In addition to mixed vapor of HF and water H ₂ O, mixed vapor of hydrochloric acid HCl and water H ₂ O, hydrogen fluoride gas HF, water H ₂ O and ethanol C ₂ H ₅ OH
Mixed vapor with, HF + HNO ₃ + H ₂ O, HCl + HNO ₃ + H ₂ O, NH ₄ OH
A mixed vapor such as + H ₂ O may be used. The substrate processing gas may be a gas other than mixed vapor, such as ozone gas. The type of gas is not limited.

In the above-mentioned embodiment, the etching for the substrate is mainly described, but the present invention can be applied to the surface cleaning of the substrate and the film forming process for the substrate.

<Effect of the Invention> According to the substrate rotary surface treatment apparatus of the present invention, the rectifying plate is arranged near the substrate so as to face the entire surface of the substrate,
Since the substrate surface treatment gas is supplied from the gas outlets dispersedly formed on the straightening vane, the space between the substrate and the straightening vane is filled with the substrate surface treating gas, and moreover, from the gas outlets dispersedly formed on the straightening vane. Since the outflow pressure of the substrate surface treatment gas is increased toward the outer side away from the center of rotation of the substrate, that is, near the periphery of the substrate, the substrate surface treatment of the substrate surface that rotates as the substrate rotates is performed. This balances the fact that the gas receives centrifugal force and the atmospheric pressure of the substrate surface treatment gas increases as it moves away from the center of rotation, and the supply amount of the substrate surface treatment gas per unit area to the substrate surface is It becomes uniform, and uniform processing can be performed even in the direction far from the rotation center of the substrate.

Therefore, despite the rotation of the substrate, the supply amount of the substrate surface processing gas per unit area to the substrate surface becomes uniform, and the uniformity of the processing in the circumferential direction of the substrate achieved by the rotation is improved. The surface treatment can be performed uniformly on the substrate surface by the synergistic effect of improving the treatment uniformity in the direction approaching the rotation center.

[Brief description of drawings]

1 to 10 relate to an embodiment of the present invention, FIG. 1 is a sectional view of a substrate rotary surface processing apparatus of the first embodiment, and FIG. 2 is a perspective view of a half section of a chamber. Fig. 3 is a bottom view of the chamber with the perforated plate removed, with a part of the chamber broken away;
FIG. 4 is an operation explanatory view showing the relationship between the rotational speed and the outflow flow rate when it is affected by the rebound from the inner peripheral surface wall surface of the substrate processing chamber, and FIG. 5 is from the inner peripheral surface wall surface of the substrate processing chamber. Of operation showing the relationship between the rotational speed and the outflow rate when not affected by the bounce of the water, FIG. 6 is a graph showing the relationship between the rotational speed and the in-plane uniformity, and FIG. 7 is each rotational speed. FIG. 8 is a graph showing a cross-sectional profile of the silicon thermal oxide film in FIG. 8, FIG. 8 is a graph showing the relationship between the distance from the rotation center and the etching depth, and FIG. FIG. 10 is a sectional view of the essential parts of the second embodiment. FIG. 11 is a diagram showing the structure and cross-sectional profile of a conventional device, and FIG. 12 is a diagram showing the structure and cross-sectional profile of another conventional device. W ... Substrate 1 ... Substrate processing chamber 2 ... Mechanical chuck 22 ... Small hole as gas outlet 23 ... Perforated plate as current plate

Claims (1)

[Claims] 1. A substrate rotating type surface processing apparatus for supplying a substrate processing gas to a substrate surface while rotating the substrate, wherein a rectifying plate is arranged so as to face the entire surface of the substrate near the rotating substrate. A plurality of gas outlets are dispersedly formed on the straightening plate, and the outflow pressure of the substrate processing gas from the gas outlets is set to be higher as the distance from the rotation center of the substrate increases. Substrate rotation type surface treatment equipment.