JPH0380537A - Substrate rotation type surface treating equipment - Google Patents

Abstract

PURPOSE:To enable uniform treatment of a substrate surface and the whole part thereof, by arranging a straightening plates in the vicinity of a rotating substrate so as to cover the substrate, and making the flowing-out pressure of substrate treating gas from a gas flowing outlets formed on the straightening plate higher in accordance with the distance further from rotation center of the substrate. CONSTITUTION:A wafer W is carried into a housing 30 from a carrying inlet 31a, and transferred on a mechanical chuck 2. A lid body 6 is made to descend, and the substrate is brought into contact with a packing of a substrate treating chamber with pressure, thereby tightly closing the inside of the substrate treating chamber 1. The substrate W is rotated together with the mechanical chuck 2. Diluted gas for treating a substrate is supplied into a chamber 8 from a inclined gas flowing inlet 20, via a treating gas supplying tube 16. Since the gas flowing inlet 20 is inclined with respect to the radial direction, the gas for treating a substrate in the chamber 8 rotates so as to swirl. The flowing-out pressure of the gas, for treating a substrate, which flows out from small holes 22 of a multi-hole plate 23 becomes high in accordance with the distance further from the rotation center of the substrate W. As the result, the supply amount of the gas for treating a substrate per unit area on the substrate W surface becomes uniform, and the treatment becomes uniform also in the radial direction.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention applies a gas for surface treatment such as etching and cleaning of the substrate, a gas for film formation, etc. to the substrate while rotating the substrate such as a semiconductor wafer. The present invention relates to a substrate rotation type surface processing apparatus that supplies a processing gas to a substrate surface, and particularly relates to a technique for increasing the uniformity of substrate surface processing.

<Prior art> As a nozzle for substrate surface treatment, a flow guide is placed facing a horizontally rotating substrate, and a processing fluid is supplied from the center of the flow guide (rotation center of the substrate), and the flow is connected to the substrate. A device is known that prevents contaminants from adhering to the substrate by filling a narrow space between the guide and the guide (for example, see Japanese Patent Laid-Open No. 61-40032).

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

Hydrogen fluoride gas f (F and pure water H80
A mixed vapor for etching consisting of water vapor and water vapor is jetted and supplied toward the surface of the substrate W, and the mixed vapor is caused to flow into a narrow space between the flow guide 53 and the substrate W to remove silicon on the surface of the rotating substrate W. A thermal oxide film (SIOt) was etched and the etching situation was investigated.

Furthermore, a nozzle 61 as shown in FIG.
This is for removing organic substances on the surface of the substrate, and a gas jet port 63 is provided at a location eccentric to the center of the flow guide 62, above the substrate W held by the mechanical chuck 54. The configuration is such that mixed vapor is supplied from the substrate W to the surface of the substrate W.

<Problems to be Solved by the Invention> The results of etching using the nozzle 51 of FIG. 11(a) are shown in FIG. 11(b), where 0 is the rotation center of the substrate W, and A is the gas The position of the spout 52 is shown.

As is clear from the figure, in the case of the nozzle 51 of FIG. 11(a), the etching state of the silicon thermal oxide film 55 is deep in the center of the substrate W located directly below the gas ejection port 52;
It was found that the depth gradually became shallower as it approached the periphery, making it impossible to perform uniform processing over the entire surface of the substrate.

The etching depth of the nozzle 61 in FIG. 12(a) can be evened out by positioning the gas outlet 63 exactly midway between the deepest and shallowest etching positions in FIG. 11(b). I used it as I expected.

However, as shown in FIG. 12(b), the etched state of the obtained silicon oxide film 64 is such that the etching is deep at a position directly below the gas jet port 63, and gradually increases from there as it approaches the center and outer periphery. As a result, it was found that uniform processing over the entire surface of the substrate was difficult.

Instead of the above nozzle, a chamber with a perforated plate facing the substrate is used, and the structure of the chamber and perforated plate is designed so that the mixed vapor that has entered the chamber flows out evenly (when the mechanical chuck is stopped). It has also been found that even when devised, the etching process becomes non-uniform. The reason seems to be that the airflow generated by the rotation of the substrate W prevents uniform outflow.

Incidentally, the non-uniformity of processing is a problem that occurs not only in etching but also in cleaning or bottom film.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a substrate rotation type surface processing apparatus that can uniformly process the entire surface of a substrate.

Means for Solving the Problems> In order to achieve the above objects, the present invention has the following configuration.

That is, the substrate rotation type surface treatment apparatus of the present invention is a substrate rotation type surface treatment apparatus that supplies a substrate processing gas to the substrate surface while rotating the substrate, in which a rectifying plate is provided near the rotating substrate so as to cover the substrate. The present invention is characterized in that the outflow pressure of the substrate processing gas from the gas outlet formed in the rectifier plate is configured to be higher as the distance from the center of rotation of the substrate increases.

<Function> According to the structure of the substrate rotation type surface processing apparatus of the present invention, the substrate processing gas is supplied from the gas outlet formed in the rectifier plate arranged near the substrate so as to cover the substrate, so that the substrate processing gas is The space between the current plate and the current plate is filled with 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 due to centrifugal force, the air pressure becomes higher on the outer side away from the center of rotation of the substrate.

However, since the outflow pressure of the substrate processing gas from the gas outlet formed in the rectifying plate was made higher toward the outer side away from the center of rotation of the substrate, the pressure at the outer side of the rotation where the pressure is higher on the substrate surface is higher. To counter this, a substrate processing gas is supplied at a high outflow pressure. Therefore, no matter where you are in the radial direction from the center of rotation, the pressure difference between the outflow pressure of the substrate processing gas and the atmospheric pressure on the substrate surface is uniform.
The amount of substrate processing gas supplied per unit area to the substrate surface is uniform, and the processing is uniform in the radial direction as well.

In this way, even though the substrate is rotated, the amount of substrate processing gas supplied per unit area to the substrate surface is made uniform, so that processing in the circumferential direction achieved by rotating the substrate The synergistic effect of improving the uniformity of the process and improving the uniformity of the process in the radial direction makes it possible to uniformly process the surface of the substrate.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

Figure 1 is a cross-sectional view of the substrate rotation type 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 substrate processing chamber 1 having a cylindrical shape with a bottom. A rotating shaft 3 of the mechanical chuck 2 is supported on the bottom plate of the substrate processing chamber 1 via a bearing 4 having a sealing function. W is configured to horizontally rotate around a vertical axis.

A cup-shaped lid 6 that covers the upper opening of the substrate processing chamber l has a tapered peripheral wall 7, a chamber 8 that is integrated in a watertight manner at the bottom, and a top plate that is integrated in a watertight manner at the top. The inside of the 0M body 6 composed of 9 and 9 is constant temperature hot water [
10, and a hot water supply tube 11 and a hot water discharge tube 12 for constantly retaining hot water at a constant temperature in the constant temperature bath 10 are attached to the tapered peripheral wall portion 7.

Inside the constant temperature hot water tank IO, there is a mixed steam supply tube 1 for supplying a mixed steam of hydrogen fluoride gas HF and pure water H,0 (substrate processing gas) for etching the surface of the substrate W.
3, a carrier gas supply tube 14 that supplies nitrogen gas N8 as a carrier gas, and an aspirator 15 that sucks the mixed vapor by the negative pressure generated with the flow of the carrier gas N and dilutes the mixed vapor with the carrier gas N8. and a processing gas supply tube 16 for supplying the substrate processing gas diluted by the aspirator 15 into the chamber 8.

Mixed steam supply tube 13. The carrier gas supply tubes 14 each penetrate the tapered peripheral wall portion 7,
It is connected to a mixed vapor supply source and a nitrogen gas supply source (not shown). Mixed steam supply tube 13, aspirator 15
The reason why the processing gas supply tube 16 is inserted into the constant temperature hot water bath 10 is to prevent the mixed vapor from liquefying. In this sense, the temperature of the mixed steam supply tube 13 is controlled over its entire length up to its supply source even outside the constant temperature hot water tank 10.

The reason why the mixed steam supply tube 13 and the carrier gas supply tube 14 are bent in the constant temperature hot water bath 10 is to lengthen the flow path in the constant temperature hot water bath 10 to increase the contact area for heat exchange with hot water as much as possible. This is to stabilize the temperature of the steam and carrier gas N.

FIG. 2 is a perspective view of a half section showing the specific structure of the chamber 8, with the right end section cut away obliquely with respect to the radial direction. FIG. 3 shows the chamber 8 with the perforated plate 23 removed.
FIG.

The chamber 8 is formed by integrating a top plate portion 17 and a peripheral wall portion 18, and the top plate portion 17 is provided with the above-mentioned aspirator 15.
is fixed in place. In the peripheral part of the top plate part 17,
A connector 19 of the processing gas supply tube 16 is hermetically screwed into a connection port formed from the top plate part 17 to the peripheral wall part 18. A gas inlet 20 is formed in the peripheral wall 18 in communication with the connector 19 and is inclined at an appropriate angle (for example, 30°) with respect to the radial direction of the chamber 8 . There is. Reference numeral 21 denotes a plug that blocks the outer part of the gas inlet 20 from the outside.

A perforated plate 23 is fitted into a stepped portion formed inside the lower surface of the peripheral wall portion 18, and is connected to the chamber 8 by a ring-shaped backing plate 24 and bolts 25. A large number of small holes 22 each having a diameter of about 1 to 2 ms+ are formed in the perforated plate 23 at small pitches in the shape of a grid pattern.

Note that the perforated plate 23 corresponds to the rectifying plate in the configuration of the invention,
Moreover, the small hole 22 corresponds to the gas outlet in the configuration of the invention.

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

In FIG. 1, the gas inlet 20 and the support plate 26, which are separated by 90@, 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 swirling manner within the chamber 8 as shown in FIG. The pressure of the substrate processing gas increases closer to the peripheral wall 18 than the center. Therefore, the outflow pressure of the substrate processing gas flowing out from the small holes 22 of the porous plate 23 becomes higher toward the outside of the rotation center of the substrate W. Therefore, when the rotation of the substrate W is stopped, the flow rate of the substrate processing gas per unit opening area in the small holes 22 of the porous plate 23 is large in the small holes 22 in the peripheral area, and large in the small holes 22 in the center. becomes less. However, when the substrate W is rotated, by increasing the outflow pressure of the substrate processing gas toward the outer side away from the rotation center of the substrate W,
As will be described later, the amount of substrate processing gas supplied per unit area of the substrate W becomes uniform.

The cup-shaped lid 6 is configured to be vertically movable, and when lowered, it comes into contact with the backing 27 at the upper edge of the substrate processing chamber l, thereby making the inside of the substrate processing chamber l airtight. As a mechanism for moving the lid body 6 up and down, an air cylinder 2 for raising and lowering is attached to the pair of support plates 26.
Eight piston ronds are installed in series.

Substrate processing chamber 1 explained above. The main processing section 29 consisting of a cup-shaped lid 6 and the like is covered by a housing 30 and has a double chamber structure. A substrate loading port 31a and a substrate loading port 31b are formed in the housing 30 at a location corresponding to the height position of the mechanical chuck 2, and the loading port 31a is opened by vertically sliding.

A shutter 32a with a rack that opens and closes the export port 31b.

32b, pinion gears 33a and 33b that mesh with the racks of each shutter 32a and 32b, and each pinion gear 33
A motor (not shown) is provided to drive the motors a and 33b. Note that the racks of the shutters 32a, 32b and the teeth of the pinion gears 33a, 33b are not shown.

On the outside of the housing 30, the substrate W is held at the housing 30 through the loading port 31a.
At the same time, the lid 6 rises to open the substrate processing chamber 1.
a bending-arm-type substrate loading mechanism 34a that transfers the substrate W onto the mechanical chuck 2 in an open state, and a substrate loading mechanism 34b having a similar structure that carries the substrate W out of the housing 30 through the loading port 31b. is provided. These board loading mechanisms 348. Regarding the structure of the substrate unloading mechanism 34b, for example,
It is disclosed in Japanese Patent No. 548.

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 rotation type surface treatment apparatus configured as described above will be explained.

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

The pinion gear 33a is driven to lower the shutter 32a to open the substrate loading port 31a, and the other substrate loading port 31b is closed by the shutter 32b. Next, the lifting air cylinder 28 is extended to raise the lid 6, and the lid 6 is raised.
A substrate loading mechanism 34a is installed between the mechanical chuck 2 and the mechanical chuck 2.
Secure a space that allows the person to enter. Then, the board loading mechanism 3
Place the board W on 4a! 3! At the same time, the substrate W is held by vacuum suction, and the substrate carry-in mechanism 34a is driven to extend to carry the substrate W into the housing 30 from the carry-in port 31a, and after being transferred to the mechanical chuck 2, the substrate carry-in mechanism 34a is moved. It is refracted and retreated from the entrance 31a, and the shutter 32a is raised to close the entrance 31a.

The lifting air cylinder 28 is contracted to lower the lid 6, and the lid body 6 is pressed against the backing 27 of the substrate processing chamber 1 to seal the inside of the substrate processing chamber 1.Next, by driving the motor 5, the lid body 6 is moved together with the mechanical chuck 2 by driving the motor 5. Rotate the substrate W. Then, negative pressure is generated by supplying carrier gas N to the aspirator 15 via the carrier gas supply tube 14, and hydrogen fluoride gas HF and pure water H, O are supplied via the mixed steam supply tube 13. The mixed vapor is drawn into the aspirator 15 and mixed with carrier gas N to dilute it. The diluted substrate processing gas is supplied into the chamber 8 from the inclined gas inlet 20 via the processing gas supply tube 16 .

The substrate processing gas forms a vortex flow within the chamber 8, and the outflow pressure of the substrate processing gas increases as it moves outward from the rotation center of the substrate W. However, when the substrate W is rotated,
As will be described later, the amount of substrate processing gas supplied per unit area of the substrate W becomes uniform, the substrate processing gas is uniformly supplied to the substrate W, and the silicon thermal oxide film on the substrate W is etched. The detailed operation of this etching will be described later.

When the required etching is completed, the carrier gas N! Then, the supply of the mixed steam is stopped, the motor 5 is stopped, the lifting air cylinder 28 is extended, the lid 6 is raised, and the substrate processing chamber 1 is opened.

Drive the binion gear 33b to open the shack 32b,
The substrate unloading mechanism 34b is extended to receive and receive the substrate W, and the bending operation is performed to unload the substrate W to the outside through the unloading port 31b. Then, the shutter 32b is raised to
1b is occluded.

Next, the flow rate at which the substrate processing gas is supplied to the substrate W during etching will be explained.

Since the gas inlet 20 is inclined with respect to the radial direction, the substrate processing gas rotates in a swirling manner within the chamber 8, and the closer to the peripheral wall 18 than the center of the chamber 8,
The pressure of the substrate processing gas increases. Therefore, the outflow pressure of the substrate processing gas flowing out from the small holes 22 of the porous plate 23 is as follows:
It gets expensive.

However, when the substrate Fiw is rotating, the substrate processing gas on the substrate surface comes into contact with the substrate W and rotates with the substrate W, and due to the centrifugal force, the substrate processing gas moves outward away from the center of rotation of the substrate W. The higher the pressure is, the higher the pressure is.

Therefore, the further away from the rotation center of the substrate W, the more
In other words, the higher the atmospheric pressure, the higher the outflow pressure of the substrate processing gas is supplied, so no matter where you are in the radial direction from the center of rotation, the difference between the outflow pressure of the substrate processing gas and the atmospheric pressure on the substrate surface is As a result, the amount of substrate processing gas supplied per unit area on the surface of the substrate W becomes uniform, and the processing becomes uniform in the radial direction as well.

Note that it is desirable that the 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 peripheral wall surface of the substrate processing chamber l and the mechanical chuck 2
The following describes a case in which the horizontal airflow F generated as the substrate W rotates bounces off the inner circumferential wall surface of the substrate processing chamber 1 and generates an upward airflow FU.

For example, when controlling by rotational speed, when the rotational speed is low speed vL, as shown in FIG. The pressure difference between the outflow pressure of the substrate processing gas flowing out from the group of small holes 22 with respect to the total pressure including the pressure added by the rebound on the inner peripheral wall surface of the substrate processing chamber 1 is as follows: However, the flow rate per unit area of the substrate processing gas supplied from the chamber 8 is calculated by multiplying the flow rate at the outermost periphery by Q1, and multiplying the flow rate at the innermost periphery by Q2. Q5, if the flow rate at the center is Q4, then Q+ >Qt >Qs>Qn
Therefore, the distribution of the flow rate outflow from the group of small holes 22 is large at the periphery and small at the center. As a result, silicon thermal oxidation 11
The etching profile of No. 9 is mountain-like. Note that the horizontal airflow F generated with the rotation of the substrate W is not strong at low speed V, so it is strongly influenced by the flow of the substrate processing gas, and after bouncing off the inner wall surface of the substrate processing chamber 1. Since the air flows downward, no updraft FU occurs.

In addition, when the rotation speed is high speed V, as shown in Figure 4(c), the centrifugal force acting on the substrate processing gas on the substrate surface is strong, so the pressure of the substrate processing gas in the periphery is In addition to being high, the upward airflow FU is also strong, so the pressure difference between the outflow pressure of the substrate processing gas flowing out from the small holes 22 group is small at the outer periphery and The flow rate per unit area of the substrate processing gas supplied from 8 is Ql < Qt < Qs < Ql, and the distribution of the flow rate outflow from the small holes 22 group is small at the periphery and large at the center. As a result, the etching profile becomes valley-like.

Then, when the rotational speed reaches the optimum speed V, the fourth
As shown in (b) of the figure, the pressure difference between the outflow pressure of the substrate processing gas flowing out from the group of small holes 22 and the above-mentioned total pressure on the substrate W side is uniform everywhere in the radial direction, and from the chamber 8 The flow rate per unit area of the supplied substrate processing gas is Ql =Qm -Q--94, and the outflow flow rates of all the small holes 22 are equal. As a result, the substrate W
The silicon thermal oxide film can be etched uniformly over the entire surface, resulting in a flat profile.

Moreover, the substrate processing gas flowing out from the group of small holes 22 is confined within the air curtain formed by the upward airflow FU', increasing the amount of contact with the silicon thermal oxide film of the substrate W per unit time. 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 pressure change caused by the horizontal airflow F generated due to the rotation of the substrate W bouncing off the inner circumferential wall of the substrate processing chamber 1 is only negligible because the substrates are separated from each other. I will explain about it.

For example, when controlling by rotational speed, when the rotational speed is low vL, as shown in FIG. 5(a), the centrifugal force acting on the substrate processing gas on the substrate surface is weak, so -
As shown by the dotted line L1, the pressure of the substrate processing gas is not very high even in the peripheral area, so the outflow pressure (indicated by the broken line L2) of the substrate processing gas supplied from the small hole 22 is lower than the surface of the base FiW. As shown by the two-dot chain line L3, the pressure difference with respect to the atmospheric pressure on the side is larger toward the periphery, and the amount of supplied substrate processing gas per unit area is smaller than the substrate W.
The amount of the outermost circumference is Ql, and the amount of the innermost circumference is Ql.

Qs, and the amount at the center is Q, then Ql > Ql > Q
'3>Ql, and as a result, the etching profile of the silicon thermal oxide film becomes mountain-like.

Furthermore, when the rotational speed is high vH, as shown in FIG. 5C, the centrifugal force acting on the substrate processing gas on the substrate surface is strong, so that the peripheral part In this case, the pressure of the substrate processing gas increases. Therefore, the small hole 22
The pressure difference between the outflow pressure (indicated by the broken line L2) of the substrate processing gas supplied from the substrate W and the atmospheric pressure on the surface side of the substrate W is smaller toward the periphery, as shown by the two-dot chain line L3. Therefore, the amount of supplied substrate processing gas per unit area is Ql < Ql < Ql < Ql, and as a result,
The etching profile has a valley shape.

Then, when the rotational speed reaches the optimum speed vH, the fifth
As shown in (b) of the figure, the centrifugal force acting on the substrate processing gas on the substrate surface has an appropriate strength, and as shown by the - dotted chain line Ll, it is small relative to the atmospheric pressure of the substrate processing gas. The pressure difference in the outflow pressure (indicated by the broken line L2) of the substrate processing gas supplied from the hole 22 is uniform both in the radial direction and in the radial direction. The amount of substrate processing gas per unit area is Q.

"Q--Qs = Q4, and by this, the basic anti-W
In this process, the silicon thermal oxide film can be etched uniformly over the entire surface, resulting in a flat profile.

Next, the rotation speed ■. We investigated through experiments how the optimal conditions for equalizing the gas flow rate are determined. The results are reported below.

The mixed vapor generated by the evaporation of a mixture of hydrofluoric acid HF and pure water H and O is converted into nitrogen gas N! The temperature of the source is 25℃.

The supply flow rate of the mixed vapor 18 to the chamber 8 at each temperature (51/m+n
10j2/min, 15I! ,/min, 2
0e/min) and rotational speed (10ytm ~ 1.0
The relationship between etching rate (in/rnin) of the silicon thermal oxide film was determined. In addition, the concentration ratio of hydrogen fluoride gas, water vapor, and nitrogen gas at each temperature is
At atmospheric pressure of 760 MHg, it is as follows.

Table 1 As the sample substrate W, a 6-inch P-type (100) silicon wafer on which a silicon thermal oxide film with a thickness of about 10,000 Å was formed was used.

The results of the etching treatment at each temperature are summarized in Tables 2 to 5. In these tables, the first row is the etching rate, the second row is the range (maximum value - minimum value of etching depth; unit: person), the third row is the standard deviation σ (maximum value - minimum value), and the fourth row is the etching rate. is the in-plane uniformity (Uniformfty; %;
The average (i
), and among these, in-plane uniformity is the most important index. In-plane uniformity is defined as the absolute value of (maximum value - minimum value)/2 x average value.

(The following is a margin) As is clear from Tables 2 to 5, it can be seen that for each flow rate supplied to the chamber 8, the in-plane uniformity becomes minimum at a certain rotation speed. That is, the supply flow rate 517
In case of sin, it is 1100yp, 10I2.7sin
In the case of 200-300 rpm, 15I! In case of min, 250-350rpI11, 20f/s+t
In the case of n, each becomes minimum at 300 to 400 ypm.

Figure 6 shows the rotation speed (rpm) when the temperature is 30°C.
) and in-plane uniformity (%).

Determining the supply flow rate determines the flow velocity of the vortex flow within the chamber 8, and also determines how high the outflow pressure increases toward the outside away from the center of rotation. It can be seen that the uniformity is minimal.

Next, the cross-sectional profile of the silicon thermal oxide film after the etching process performed at 40°C was examined at various rotational speeds, and the results shown in FIG. 7 were obtained. This profile has a supply flow rate of 517IIIin, ion
/l1in, 15I! , /ain , 201/
This is from the time of sin.

When the rotation speed is relatively low, the periphery is strongly etched, but at a certain rotation speed, the in-plane uniformity is the best, and when the rotation speed is higher than that, the center may be strongly etched. I understand. In other words, the curve in FIG. 6 has a mountain-like profile on the left side of the minimum value, and a valley-like profile on the right side.

Furthermore, 40°C, 10j! Distance from the center of rotation O when etching is performed for 1 minute under the condition of /mfn (
Investigate the relationship between etching depth (person) and
The results are shown in FIG. In this case, the rotation speed is 25
It can be seen that the best profile is obtained at 0 ypm.

Further, FIG. 9 shows the relationship between the minimum value of the in-plane uniformity in Table 2 and the rotation speed. In addition, in this Figure 9, in order to obtain in-plane uniformity by changing the temperature at the same flow rate,
The rotation speed increases depending on the temperature. This is the first
As shown in the table, this is thought to be due to changes in HF concentration due to temperature.

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

Note that even if the direction of the vortex flow of the mixed vapor in the chamber 8 and the rotation direction of the groups Fi and W are the same,
The same result can be obtained even in the opposite direction.

By the way, it should be noted that even the worst profile among these is a sufficiently good profile compared to the conventional examples shown in FIGS. 11 and 12. In other words, appropriate setting of the rotational speed is necessary to achieve the best in-plane uniformity, but in the sense of improving in-plane uniformity compared to conventional examples, it is necessary to set the rotation speed appropriately in the substrate processing gas on the surface of the substrate W. While the pressure of the substrate processing gas at the periphery of the substrate W increases due to the centrifugal force that acts, the outflow pressure is adjusted so that the distribution of the outflow pressure of the substrate processing gas supplied from the small holes 22 is balanced. This means that it is only necessary to make the distribution higher toward the periphery of the rotating substrate W.

JLII Abukuni Figure 10 is a cross-sectional view of the main part of the second embodiment, in which an inlet 41 for mixed vapor is provided in the center of the chamber 8, and it is formed by the lower surface of the chamber 8 and the perforated plate 23. A baffle plate 42 is provided in the 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 toward the outer circumference by the baffle plate 42, and some of the mixed steam flows through the ventilation hole 43, and flows toward the center of the perforated plate 23 to that position. The small holes 22 on the side away from the center of rotation of the substrate W are designed so that the mixed vapor can flow out with a very high outflow pressure, since the small holes 22 are exposed to strong flow resistance.

The mixed vapor in the above embodiments includes a mixed vapor of hydrogen fluoride gas HF and water H30, a mixed vapor of hydrochloric acid HCl1 and water HtO, and a mixed vapor of hydrogen fluoride gas HF and water H8O.
and ethanol C! Mixed steam with HsOH, HF+)IN
Os +HtO1H (1+HNo, +H!O.

A mixed vapor of NH, OH and 10HzO may also be used.

Further, the substrate processing gas may be a gas other than mixed vapor, such as ozone gas, and the type of gas is not limited.

In the above embodiments, the etching of the substrate was mainly explained, but the present invention is also applicable to surface cleaning of the substrate and film forming treatment to the substrate.

<Effects of the Invention> According to the substrate rotation type surface treatment apparatus of the present invention, the rectifier plate is arranged near the substrate so as to cover the substrate, and the substrate surface treatment gas is supplied from the gas outlet formed in the rectifier plate. So,
The space between the substrate and the rectifier plate is filled with a substrate surface treatment gas, and the outflow pressure of the substrate surface treatment gas from the gas outlet formed in the rectifier plate is increased as the distance from the center of rotation of the substrate increases. In other words, since the pressure is increased toward the periphery of the substrate, as the substrate rotates, the substrate surface treatment gas on the rotating substrate surface is subjected to centrifugal force, and the pressure of the substrate surface treatment gas increases as it moves away from the center of rotation. Balanced with the increase in
The amount of substrate surface treatment gas supplied per unit area to the substrate surface is uniform over the entire surface of the substrate, and uniform treatment can be performed even in directions near and far from the center of rotation of the substrate.

Therefore, even though the substrate is rotated, the amount of substrate surface treatment gas supplied per unit area to the substrate surface is uniform, and the uniformity of processing in the circumferential direction of the substrate is improved by rotation. Due to the synergistic effect of this and the improvement in the uniformity of processing in the direction away from the center of rotation, the surface of the substrate can be uniformly processed.

[Brief explanation of drawings]

1 to 10 relate to embodiments of the present invention, in which FIG. 1 is a sectional view of the substrate rotary surface treatment apparatus of the first embodiment, FIG. 2 is a perspective view of a half cross section of the chamber, and FIG. Figure 3 is a partially broken bottom view of the chamber with the perforated plate removed;
Fig. 4 is an explanatory diagram of the operation showing the relationship between the rotational speed and the outflow flow rate when it is affected by rebound from the inner circumferential wall of the substrate processing chamber, and Fig. 5 is an operation explanatory diagram showing the relationship between the rotational speed and the outflow flow rate when it is affected by rebound from the inner circumferential wall of the substrate processing chamber. Figure 6 is a graph showing the relationship between rotational speed and in-plane uniformity, and Figure 7 is a graph showing the relationship between rotational speed and in-plane uniformity when not affected by rebound. 8 is a graph showing the relationship between the distance from the rotation center and the etching depth, and FIG. 9 is a graph showing the relationship between the rotation speed, flow rate, and temperature. FIG. 1O is a sectional view of the main part 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 l...Substrate processing chamber 2...Mechanical chuck 22...Small hole 23 as a gas outlet...Porous plate as a rectifying plate

Claims (1)

[Claims] (1) In a substrate rotation type surface treatment device that supplies substrate processing gas to the substrate surface while rotating the substrate, a rectifying plate is placed near the rotating substrate to cover the substrate, and the gas formed on the rectifying plate is A substrate rotating type surface processing apparatus characterized in that the outflow pressure of a substrate processing gas from an outflow port is configured such that it increases as the distance from the center of rotation of the substrate increases.