KR930010055B1 - Surface treating apparatus for semicondcutor manufacturing process - Google Patents

Abstract

No content.

Description

Substrate rotating surface treatment device

1 to 10 are related to the embodiment of the present invention, Figure 1 is a cross-sectional view of the substrate rotating surface treatment apparatus of the first embodiment.

2 is a perspective view of the chamber half section.

3 is a bottom partially broken view of the chamber with the rectifier plate removed.

4 is an operation explanatory diagram showing the relationship between the rotational speed and the outflow flow rate when it is effected to pop out from the wall surface of the inner peripheral surface of the substrate processing chamber.

5 is an operation explanatory diagram showing the relationship between the rotational speed and the outflow flow rate when not affected by the splashing from the wall of the inner peripheral surface of the substrate processing chamber.

6 is a graph showing the relationship between the rotational speed and in-plane uniformity.

7 is a cross-sectional profile view of a silicon thermal oxide film at each rotational speed.

8 is a graph showing the relationship between the distance from the center of rotation and the depth of etching.

9 is a graph showing the relationship between the rotational speed, flow rate and temperature.

10 is a sectional view of a main portion of the second embodiment.

11 is a view showing the structure and cross-sectional profile of a conventional apparatus.

12 is a diagram showing the structure and cross-sectional profile of another conventional apparatus.

* Explanation of symbols for main parts of the drawings

1 substrate processing chamber 2 mechanical chuck

3: axis of rotation 4: number of axes

5: motor 6: cover

7: main wall portion 8: chamber

10: constant temperature bath 11: hot water supply tube

12: hot water discharge tube 13: mixed steam supply tube

14 carrier gas supply tube 15 aspirator

16: process gas supply tube 17: ceiling plate part

18: main wall 19: connector

20 gas inlet 21 switch

22: small hole 23: perforated plate

24: plate 25: bolt

26: support plate 27: packing

28: cylinder 29: main processing unit

30 housing 31a substrate inlet

31b: substrate discharge port 32a, 32b: shoter

33a, 32b: Pinion gear 34a: Substrate loading mechanism

42: shield plate 43: ventilator

The present invention, while rotating a substrate such as a semiconductor wafer, in order to supply the gas for surface treatment such as etching, cleaning of the substrate, or gas for substrate treatment such as film forming gas to the surface of the substrate, the substrate is held in a horizontal position and vertically A substrate rotating surface treatment apparatus having a substrate holding means that rotates horizontally around an axis in a direction, and a substrate processing gas supply means for supplying a substrate processing gas to a surface of a substrate held by the substrate holding means.

As a nozzle for processing substrate surface, the flow guide is disposed to face the horizontally rotating substrate, the processing fluid is supplied from the center of the flow guide (the rotation center of the substrate), and the narrow space between the substrate and the flow guide is used as a fluid. It is known to fill the substrate to prevent contamination of the substrate (see, for example, Japanese Patent Application Laid-Open No. 61-40032).

Fig. 11A shows a state when the etching treatment status of the silicon thermal oxide film on the substrate surface is investigated using such a nozzle. The nozzle 51 is comprised as the disk shaped flow guide 53 which has the gas outlet 52 in the center. This nozzle 51 is opposed to the upper vicinity of the board | substrate W hold | maintained by the mechanical chuck 54 which rotates horizontally by the motor which is not shown in figure. The gas ejection opening 52 in the flow guide 53 coincides with the rotation center O of the substrate W. As shown in FIG.

From the gas ejection port 52, the mixed steam for etching, which consists of water vapor of hydrogenated hydrogen gas (HF) and pure water (H ₂ O), is ejected and supplied toward the surface of the substrate W, and the flow guide 53 and the substrate are supplied. Mixed steam was flowed into the narrow space between (W), the silicon thermal oxide film (SiO ₂ ) on the surface of the rotating substrate (W) was etched, and the etching condition was investigated.

Moreover, the nozzle 61 as shown in FIG. 12A is also known conventionally (for example, refer Unexamined-Japanese-Patent No. 63-266825). This is for removing organic substances on the surface of the substrate. The gas outlet 63 is provided at a position eccentric with respect to the center of the flow guide 62, and is located above the substrate W held by the mechanical chuck 54. Is configured to supply the mixed vapor to the surface of the substrate W.

The result of etching using the nozzle 51 of FIG. 11A is shown in FIG. 11B. Here, O denotes the center of rotation of the substrate W, and A denotes the position of the gas ejection port 52.

As is apparent from the figure, in the etching state of the silicon thermal oxide film 55, in the case of the nozzle 51 of FIG. 11A, the central portion of the substrate W located immediately below the gas ejection opening 52 is deep and close to the periphery. As it turned out, it became shallower gradually, and it turned out that the uniform process over the whole board | substrate cannot be performed.

The nozzle 61 of FIG. 12A was used in anticipation that the etching depth would be uniform if the gas ejection opening 63 was placed right in the middle of the deepest and shallowest positions of the etching of FIG. 11B. However, the etching state of the obtained silicon oxide film 64, as shown in FIG. 12B, is deeply etched at the position just below the gas ejection opening 63, and gradually becomes shallower as it approaches the central portion and the outer peripheral portion therefrom. It has been found that uniform processing over the entire substrate surface is difficult.

Instead of the nozzle as described above, a chamber having a rectifying plate made of a porous plate facing the substrate is used, and the mixed vapor introduced into the chamber is discharged evenly (at a stationary state of the mechanical chuck) of the chamber and the rectifying plate. Even when a structure was provided, it turned out that the etching process is not uniform. It is thought that the cause is that an equal outflow is inhibited due to the airflow generated by the rotation of the substrate W. FIG. In addition, the nonuniformity of a process is not only a etching but a problem which arises also in washing | cleaning or film-forming.

An object of the present invention is to provide a substrate rotating surface treatment apparatus capable of uniformly treating a substrate surface over its entire surface.

In order to achieve this object, the present invention provides a substrate holding means for holding the substrate in a horizontal position and rotating horizontally around the axis of the vertical direction, and supplying the dies for processing the substrate to the surface of the substrate held by the substrate holding means. A substrate rotating surface treatment apparatus having a substrate processing gas supply means, wherein the substrate processing gas supply means includes a rectifying plate disposed to cover the substrate in proximity to the substrate above the horizontally rotating substrate, and the rectifying plate. And outflow pressure adjusting means for increasing the outflow pressure of the gas outlet port formed in the gas outlet and the substrate processing gas from the gas outlet port toward the side away from the center of rotation of the substrate.

According to the substrate rotating surface treatment apparatus of the present invention, the rectifying plate is disposed above the substrate, and the substrate processing gas is supplied from the gas outlet formed in the rectifying plate. The space between the substrate and the rectifying plate is a substrate processing gas. Is filled.

When the substrate is rotated horizontally, the substrate processing gas on the surface of the substrate rotates by contact with the substrate, and the air pressure increases as the outer side moves away from the center of rotation of the substrate under centrifugal force.

However, since the outflow pressure of the substrate processing gas from the gas outlet formed in the rectifying plate was higher on the outer side away from the center of rotation of the substrate, the substrate surface gas was supplied at a high outflow pressure to counter the substrate surface. do.

Therefore, the supply amount of the substrate processing gas per unit area to the substrate surface becomes uniform at any position in the radial direction from the rotational center of the substrate, and the processing is uniform in the radial direction.

In this way, even though the substrate is rotated, the supply amount of the substrate processing gas per unit area to the substrate surface is made uniform, thereby improving the uniformity of the treatment in the circumferential direction achieved by the rotation and in the radial direction. Due to the synergistic effect of the uniformity of the treatment, the surface of the substrate can be uniformly treated.

In this way, the rectifying plate is disposed above the substrate, and the gas for processing the substrate surface is supplied from the gas outlet formed in the rectifying plate, so that the space between the substrate and the rectifying plate is filled with the gas for treating the substrate surface. Since the outflow pressure of the gas for surface treatment of the substrate from the formed gas outlet is higher on the outer side away from the center of rotation of the substrate, that is, on the periphery of the substrate, the gas for surface treatment of the substrate on the surface of the substrate that rotates with the rotation of the substrate Balanced with increasing centrifugal force and the air pressure of the substrate surface treatment gas away from the rotational center, the supply amount of the substrate surface treatment gas per unit area to the substrate surface becomes uniform on the entire surface of the substrate and the rotational center of the substrate. Uniform processing can be performed also in the direction away from or near.

Therefore, even though the substrate is rotated, the supply amount of the gas for processing the substrate surface per unit area to the substrate surface becomes uniform, thereby improving the uniformity of the treatment in the direction of the substrate circumference achieved by rotating, and falling or near the center of rotation. The synergistic effect with the improvement of the uniformity of the processing in the direction to be made can be uniformly surface treated to the substrate surface.

EMBODIMENT OF THE INVENTION Below, the Example of this invention is described in detail based on drawing.

[First Embodiment]

1 is a cross-sectional view of the substrate rotating surface treatment apparatus of the first embodiment.

The mechanical chuck 2 as a substrate holding means for holding a substrate W such as a semiconductor wafer in a horizontal posture is provided inside the bottomed cylindrical substrate processing chamber 1. The rotary shaft 3 of the mechanical chuck 2 is supported by the bearing 4 having a seal function on the bottom plate of the substrate processing chamber 1, and the end of the rotary shaft 3 is coupled to the motor 5, The board | substrate W hold | maintained by the mechanical chuck 2 is comprised so that horizontal rotation may be carried out around the vertical axis center.

The cup-shaped lid 6 covering the upper opening of the substrate processing chamber 1 includes a tapered main wall portion 7, a chamber 8 integrated at the bottom thereof with a watertight state, and a watertight state at the top thereof. It is comprised as the ceiling plate part 9 integrated. The inside of the cover (6) is a constant temperature bath (10), the hot water supply tube (11) and hot water discharge tube (12) for keeping the hot water at a constant temperature in the constant temperature bath (10) at all times ) Is attached to the tapered circumferential wall 7.

Inside the constant temperature bath 10, a mixed vapor (substrate processing gas) of hydrogen fluoride gas (HF) and pure water (hereinafter referred to as pure water (H ₂ O)) for etching the surface of the substrate W is and supplying mixed vapor supply tube probe (13), mixed by the generated negative pressure to accompany the flow of the carrier gas supply tube probe (14) and a carrier gas (N ₂₎ for supplying the nitrogen gas (N ₂₎ as the carrier gas An aspirator 15 for sucking vapor and diluting the mixed vapor with a carrier gas N ₂ , and a process gas supply tube 16 for supplying the substrate processing gas diluted with the aspirator 15 into the chamber 8; Is installed.

The mixed vapor supply tub 13 and the carrier gas supply tub 14 penetrate through the tapered main wall portion 7, respectively, and are connected to an unshown omitted mixed vapor supply source and a nitrogen gas supply source. The mixed steam supply tube 13, the suction unit 15, and the process gas supply tube 16 are inserted in the constant temperature bath 10 in order to prevent liquefaction of the mixed steam. In this sense, the temperature control of the mixed steam supply tube 1 is carried out over the entire length of the mixed steam supply tub 1 even from the outside of the constant temperature bath 10.

The mixed steam supply tub 13 and the carrier gas supply tub 14 are bent in the constant temperature bath 10 to lengthen the flow path in the constant temperature bath 10 so as to contact heat exchange with hot water. This is to make the area as large as possible and to stabilize the temperature of the mixed vapor and the carrier gas (N ₂ ).

2 is a perspective view of a half section showing the specific structure of the chamber 8, the right end being obliquely cut off with respect to the radial direction. 3 is a bottom view of a partial incision from which the rectifying plate 23 made of the perforated plate is removed and the chamber 8 is viewed from below.

The chamber 8 integrates the ceiling plate part 17 and the circumferential wall part 18, and the aspirator 15 mentioned above is re-fixed and fixed to the ceiling plate part 17. As shown in FIG. In the periphery of the ceiling plate part 17, the connector 19 of the process gas supply tub 16 is hermetically screwed to the connection port formed from the ceiling plate part 17 to the circumferential wall part 18. As shown in FIG. The gas inlet 20 inclined to the circumferential wall 18 at a suitable angle θ (for example, 30 °) in the horizontal direction with respect to the radial direction of the chamber 8 in a state of communicating with the connector 19. Is formed in communication with the interior of the chamber (8). 21 is a stopper for blocking the outer portion of the gas inlet 20 to the outside.

A rectifying plate 23 formed of a porous plate is fitted to an end formed inside the lower surface of the main wall portion 18, and the rectifying plate 23 is formed by the ring-shaped butting plate 24 and the bolt 25. ), The gas supply chamber S for substrate processing, which is provided in succession, and is surrounded by the ceiling plate portion 17, the circumferential wall portion 18, and the rectifying plate 23. In the rectifying plate 23, a plurality of small gas outlets 22 having a diameter of about 1-2 mm are formed in a checkerboard scale with a small pitch.

A pair of support plates 26 are attached to the chamber 8 at positions 90 degrees apart from the connector 19 and spaced 180 degrees apart from each other. The tapered circumferential wall portion 7 in the lid 6 is watertightly joined to the outer circumferential surface of the circumferential wall portion 18 of the chamber 8, and the support plate 26 connects the tapered circumferential wall portion 7. It penetrates watertightly and protrudes to the outside.

In FIG. 1, the gas inlet 20 and the support plate 26 at intervals of 90 degrees are shown in the same plane for convenience.

Since the gas inlet 20 with respect to the gas supply chamber S for substrate processing is formed in the state inclined horizontally with respect to the radial direction of the chamber 8, it is shown in FIG. 3 in the gas supply chamber S for substrate processing. As described above, the substrate processing gas rotates in a swirling manner, and the air pressure of the substrate processing gas increases as the main wall portion 18 side is larger than the center in the substrate processing gas supply chamber S. Therefore, the outflow pressure of the substrate processing gas which flows out from the gas outlet port 22 which became the small hole of the rectifying plate 23 becomes higher than the rotation center of the board | substrate W on the outward side falling from there. Therefore, in the rotation stop state of the board | substrate W, the flow volume of the substrate processing gas per unit opening area in the gas outlet 22 which became the small hole of the rectifying plate 23 is so that the gas outlet 22 of the periphery part is as much as possible. The more, the smaller the number of gas outlets 22 in the center portion. However, at the time of rotation of the substrate W, the outflow side of the substrate processing gas is increased as the outer side away from the rotation center of the substrate W increases, so as to be described later, per unit area in the substrate W. The gas supply amount for substrate processing becomes uniform.

In this way, the gas inlet 20 is inclined in the horizontal direction with respect to the radial direction of the chamber 8 so that the outflow pressure of the substrate processing gas from the gas outlet 22 increases as the side away from the center of rotation of the substrate W increases. A configuration formed in one state (an inclination angle, FIG. 3), that is, a configuration in which the configuration is inclined at a predetermined angle θ in the radial direction and is formed in a horizontal direction in the vertical direction is called outflow pressure adjusting means.

The structure which consists of the chamber 8, the substrate processing gas supply chamber S, and the said outflow pressure adjusting means is called a substrate processing gas supply means.

The cup-shaped lid 6 is configured to freely move up and down, and abuts against the packing 27 on the upper edge of the substrate processing chamber 1 by lowering, thereby making the inside of the substrate processing chamber 1 airtight. As a mechanism for moving the lid 6 up and down, the piston rod of the lifting and lowering air cylinder 28 is connected to the pair of support plates 26 described above.

The main processing part 29 which consists of the board | substrate processing chamber 1 mentioned above, the cup-shaped cover 6, etc. is covered by the housing 30, and has a double-room structure. In the position corresponding to the position of the height of the mechanical chuck 2, the substrate inlet 31a and the substrate outlet 31b are formed in the housing 30, and the inlet 31a and the outlet 31b are formed by the upper and lower slides. ) Racks with opening and closing rack gears 32a, 32b, and pinion gears 33a, 33b and respective pinion gears 33a, ((b) which engage the rack of each shoter 32a, 32b. A motor (not shown) for driving 33b) is provided. Further, the rack gears of the shoters 32a and 32b and the screw engagement portions of the pinion gears 33a and 33b are not shown.

Outside the housing 30, the substrate W is brought into the housing 30 through the inlet 31a while the substrate W is adsorbed and held, and the lid 6 is raised to raise the substrate processing chamber. The board | substrate W is moved from the housing 30 to the exterior via the board | substrate loading mechanism 34a of the inflexible arm type which carries the board | substrate W to the mechanical chuck 2 in the state (1) opened, and the outlet port 31b. The board | substrate carrying out mechanism 34b of the same structure which carries out W) is provided. The structures of these board | substrate carrying-in mechanism 34a and the board | substrate carrying-out mechanism 34b are disclosed by Unexamined-Japanese-Patent No. 60-176548, for example.

35 denotes an exhaust tube of the substrate processing chamber 1 and 36 denotes an exhaust tube of the housing 30.

Next, the operation of the substrate rotating surface treatment apparatus constructed as described above will be described. The hot water of a constant temperature is supplied from the hot water supply tub 11 and the hot water cooled by the heat exchange is discharged from the hot water discharge tub 12 to keep the temperature in the constant temperature bath 10 constant.

The pinion gear 33a is driven to lower the shoter 32a, and the substrate inlet 31a is opened. The other board | substrate carrying out opening 31b is closed by the shoter 23b. Next, the lifting air cylinder 28 is extended to raise the lid 6, and a space for allowing the substrate loading mechanism 34a to enter between the lid 6 and the mechanical chuck 2 is secured. do.

Subsequently, the substrate W is placed on the substrate loading mechanism 34a, the substrate W is held by vacuum suction, and the substrate loading mechanism 34a is extended and driven to carry the substrate W into the loading opening 31a. Is carried into the housing 30, loaded into the mechanical chuck 2, and then the substrate loading mechanism 34a is deflected to retreat from the loading opening 31a, and the shoter 32a is raised to lift the loading opening ( Close 31a).

The lid 6 is lowered by deflating the lifting air cylinder 28, and pressed into the packing 27 of the substrate processing chamber 1 to seal the inside of the substrate processing chamber 1. Next, by driving the motor 5, the substrate W is rotated together with the mechanical chuck 2. The negative pressure is generated by transferring the carrier gas N ₂ to the aspirator 15 through the carrier gas supply tube 14, and the hydrogen fluoride gas HF and the mixed vapor supply tube 13 are generated. The mixed vapor with pure water (H ₂ O) is sucked into the aspirator 15, mixed with the carrier gas (N ₂ ), and diluted. The diluted substrate processing gas is supplied into the substrate processing gas supply chamber S from the inclined gas inlet 20 through the processing gas supply tube 16.

The substrate processing gas becomes a vortex in the substrate supply gas supply chamber S, and the outflow pressure of the substrate processing gas increases as the outer side moves away from the rotation center of the substrate W. As shown in FIG. However, at the time of rotation of the substrate W, as described later, the supply amount of the substrate processing gas per unit area in the substrate W becomes uniform, the substrate processing gas is uniformly supplied to the substrate W, and the substrate The silicon thermal oxide film of (W) is etched. The detailed operation of this etching will be described later.

When the necessary etching is completed, the supply of the carrier gas (N ₂ ) and the mixed vapor is stopped, the motor 5 is raised, the lifting air cylinder 28 is extended to raise the lid 6, and the substrate processing chamber 1 Open). The pinion gear 33b is opened to open the shoter 32b, the substrate discharging mechanism 34b is extended to receive the substrate W, and the substrate W is externally opened through the discharging opening 31b by the refraction operation. Export to Then, the shoter 32b is raised to close the discharge port 31b.

Next, how much outflow amount of the substrate processing gas is supplied to the substrate W at the time of etching will be described.

Since the gas inlet 20 is inclined in the horizontal direction with respect to the radial direction, the substrate processing gas is rotated while swirling in the substrate processing gas supply chamber S, and the main wall portion ( 18), the atmospheric pressure of the substrate processing gas becomes higher. Therefore, the outflow pressure of the substrate processing gas flowing out from the gas outlet port 22 formed by the small holes of the rectifying plate 23 increases as the gas outlet port 22 formed by the small pores on the outer side away from the center of rotation of the substrate W. As shown in FIG.

However, if the substrate W is rotating, the substrate processing gas on the substrate surface rotates along the substrate W by contact with the substrate W, receives centrifugal force, and the center of rotation of the substrate W. The farther outward side is, the higher the pressure.

Therefore, the substrate processing gas is supplied at a higher outflow pressure as the outer side away from the rotational center of the substrate W, i.e., the side where the air pressure is higher, so that the substrate processing gas per unit area on the surface of the substrate W is supplied. Since the supply amount becomes uniform, the treatment becomes uniform also in the radial direction.

Further, the air pressure distribution of the substrate processing gas on the substrate surface in the radial direction of the rotation and distribution of the outflow pressure of the substrate processing gas flowing out from the gas outlet 22 formed by the small holes of the rectifying plate 23 will be obtained. It is desirable to match as much as possible, to do this:

First, the inner circumferential wall surface of the substrate processing chamber 1 and the mechanical chuck 2 are close to each other, so that the horizontal air flow F generated along the rotation of the substrate W is bounced off the inner circumferential wall surface of the substrate processing chamber 1. In the following description, a case in which rising air flow (FU) is generated is described.

For example, in the case of controlling by the rotational speed, when the rotational speed is a low speed (V _L ), as shown in FIG. 4A, the pressure increases as the outer side moves away from the center of rotation of the substrate W generated by the rotation. The pressure difference of the outflow pressure of the substrate processing gas which flows out from the small hole group which forms the gas outlet port 22 with respect to the total pressure which added the pressure added when it bounces off the inner peripheral wall surface of the process chamber 1 becomes larger as the outer periphery becomes larger. The flow rate per unit area of the substrate processing gas in the substrate processing gas supply chamber S in the substrate surface is Q ₁ , the flow rate at the center of Q ₂ , Q ₃ , or the central portion is Q ₄ , the innermost flow rate is less than or equal to the inner side. In this case, Q ₁ > Q ₂ > Q ₃ > Q ₄ , and the distribution of the outflow flow rate from the small pore group forming the gas outlet 22 is large in the periphery and small in the center. As a result, the etching profile of the silicon thermal oxide film is in the form of an acid.

And since the horizontal airflow F generated with the rotation of the substrate W does not become strong at a low speed V _L , the inner wall surface of the substrate processing chamber 1 is strongly affected by the flow of the gas for processing the substrate. The air flow Fu does not occur because it bounces off and flows downward.

Further, the outflow pressure of the substrate processing gas when supplied from the small pore group is the same as in the case of FIG. 4A, and when the rotational speed is the high speed (V _H ), as shown in FIG. 4C, the substrate surface. Because the centrifugal force acting on the gas for processing the substrate is strong, the atmospheric pressure of the gas for processing the substrate increases at the periphery, and furthermore, the rising air flow (FU) is also strong, so that the pressure is applied to the gas for both of these pressures. The pressure difference of the outflow pressure of the substrate processing gas flowing out from the small hole group forming the outlet 22 is smaller on the outer circumferential side than in the case of FIG. 4C, and becomes weaker than the total pressure on the substrate W side described above. The flow rate per unit area on the substrate surface of the substrate processing gas in the gas supply chamber S is Q ₁ <Q ₂ <Q ₃ <Q ₄ , from the small hole group forming the outlet 22. The distribution of outflow is small at the periphery and large at the center. As a result, the profile of the etching becomes a valley shape.

When the rotational speed has reached the optimum speed Vm, as shown in FIG. 4B, the outflow pressure of the substrate processing gas flowing out of the small hole group forming the gas outlet 22 and the substrate W described above. The differential pressure with the total pressure on the) side becomes uniform anywhere in the radial direction, and the flow rate per unit area on the substrate surface of the substrate processing gas in the substrate processing gas supply chamber S is Q ₁ = Q ₂ = is a Q ₃ = Q _4, becomes equal to the outlet flow rate of all of the pores forming the gas outlet (22). Thereby, the etching process with respect to the silicon thermal oxide film can be uniformly performed over the whole surface of the board | substrate W, and the profile becomes flat.

Furthermore, the substrate processing gas flowing out from the small pore group is confined in the air curtain formed by the upward air flow FU 'facing upward, and the amount of contact per unit time to the silicon thermal oxide film of the substrate W increases. This speeds up the etching process.

Next, because of the separation of the inner circumferential wall surface of the substrate processing chamber 1 and the mechanical chuck 2, etc., the horizontal air flow F generated by the rotation of the substrate W bounces off the inner circumferential wall surface of the substrate processing chamber 1. The following describes a case where the pressure change caused by the pressure change is practically negligible.

For example, when controlling at the rotational speed, when the rotational speed is low (V _L ), as shown in FIG. 5A, the centrifugal force acting on the substrate processing gas on the substrate surface is weak, so as indicated by the dashed-dotted line L1. Even at the periphery, the atmospheric pressure of the gas for substrate processing is not so high. For this reason, the outflow pressure (indicated by the broken line L2) of the substrate processing gas supplied from the gas outlet 22 formed as the small hole is represented by the dashed-dotted line L3 when the pressure difference with respect to the surface-side air pressure of the substrate W is indicated. Thus, the peripheral side the more the amount per unit area of the board that comes is large and the supply process gas, Q ₂ over a maximum amount of Q _1, following the inside of the outer periphery of the substrate (W), Q _3, to the amount of center la Q ₄ Q ₁ &gt; Q ₂ &gt; Q ₃ &gt; Q ₄ , and as a result, the etching profile of the silicon thermal oxide film becomes acid.

In addition, the outflow pressure of the substrate processing gas at the time of supply from the gas outlet port 22 formed as small pores is the same as in FIG. 5A, and as shown in FIG. 5C when the rotational speed is high speed (V _H ). Since the centrifugal force worn on the substrate processing gas on the substrate surface is strong, as indicated by the dashed-dotted line L1, the atmospheric pressure of the substrate processing gas becomes high at the periphery. For this reason, as the outflow pressure (indicated by the broken line L2) of the substrate processing gas supplied from the outlet port 22 formed as small pores with respect to the air pressure on the surface side of the substrate W, the pressure difference is indicated by the dashed-dotted line L3. As compared with the case of FIG. 5A, the periphery side becomes smaller and the quantity per unit area of the substrate processing gas supplied is Q ₁ &lt; Q ₂ &lt; Q ₃ &lt; Q ₄ , and as a result, the profile of the etch becomes a valley shape.

When the rotational speed becomes the optimum speed (V _M ), as shown in FIG. 5B, the centrifugal force acting on the substrate processing gas on the surface of the substrate is of moderate intensity, as indicated by the dashed-dotted line L1. The pressure difference of the outflow pressure (indicated by the broken line L2) of the substrate processing gas supplied in the small hole at the surface side of (W) is uniform anywhere in the radial direction, as a result, to the dashed-dotted line L3. As indicated, the amount per unit area of the substrate processing gas supplied to the substrate surface is Q ₁ = Q ₂ = Q ₃ = Q ₄ , thereby etching the silicon thermal oxide film on the substrate W. Can be carried out uniformly over the entire surface so that its profile becomes flat.

Next, experiments were conducted to determine how the optimum conditions for homogenizing the rotational speed V _M and the gas flow rate were determined. The result is demonstrated below.

min)와의 관계를 구하였다. 그리고, 각 온도의 불화수소가스, 수증기 및 질소가스의 농도비는, 대기압 760mmHg에 있어서 다음의 표-1에 나타낸 바와 같이 된다.Hydrofluoric acid (HF), and purified water mixed vapor generated by evaporation of the mixed solution of the hydrofluoric acid (HF) and pure water (H ₂ O) generated by the evaporation of the liquid mixture of the (H ₂ O), nitrogen gas (N ₂ The dilution with the above) is used as the source, and the temperature of the source is changed to 25 ° C, 30 ° C, 40 ° C and 50 ° C, and the supply flow rate to the chamber 8 of the mixed vapor 18 at each temperature (5 l / min , 10ℓ / min, 15ℓ / min, 20ℓ / min), rotation speed (10rpm to 1,000rpm), and etching speed of silicon thermal oxide film (

min). The concentration ratios of hydrogen fluoride gas, water vapor and nitrogen gas at each temperature are as shown in the following Table-1 at atmospheric pressure of 760 mmHg.

TABLE 1

의 두께의 실리콘 열산화막이 형성되어 있는 6인치의 P형(100)실리콘 웨이퍼를 사용하였다.Sample board (W), about 10,000

A 6-inch P-type (100) silicon wafer on which a silicon thermal oxide film was formed was used.

), 세 번째는 표준편차(최대치-최소치), 네번째가 면내균일성(Uniformity ; % ; 직경방향에 있어서의 등간격 27점의 위치에서의 평균치)이며, 이중 면내균일성이 가장 중요한 지표로 된다. 면내균일성은, (최대치-최소치)/2×평균치의 절대값으로 정의된다.The results of etching at each temperature are summarized in Tables 2 to 5 below. In these tables, the first is the etch rate, the second is the etch range (maximum-minimum value of etching depth: unit

), The third is the standard deviation (maximum value-the minimum value), the fourth is the uniformity (%; average value at the position of 27 equal intervals in the radial direction), and the double in-plane uniformity is the most important index. . In-plane uniformity is defined as the absolute value of (maximum value-minimum value) / 2 * average value.

[Table-2] Temperature of Source 25 ℃

[Table-3] In case of supply temperature 30 ℃

[Table-4] Temperature of Source 40 ℃

Table 5-Source Temperature 50 ℃

As is apparent from Tables 2 to 5, it is found that for each supply flow rate to the chamber 8, in-plane uniformity is minimized at any rotational speed. In other words, the supply flow rate is 5 L / min at 100 rpm, 10 L / min at 200 to 300 rpm, 15 L / min at 250 to 350 rpm, 20 L / min at 300 to 400 rpm, respectively.

6 shows the relationship between the rotational 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 in the gas supply chamber s for the substrate processing is determined, and the degree of how high the outflow pressure is in the outer side falling from the rotation center is determined, so that a specific rotation suitable for the degree It turns out that in-plane uniformity in speed is minimized.

Next, the cross-sectional profile of the silicon thermal oxide film after etching at 40 ° C. was examined for each rotational speed. As a result, the result as shown in FIG. 7 was obtained. This profile has a supply flow rate of 5 l / min [Fig. 7a], 10 l / min [Fig. 7b], 15 l / min [Fig. 7c], and 20 l / min [Fig. 7d].

When the rotational speed is relatively low, the periphery is strongly etched, but at any particular rotational speed, the in-plane uniformity is best, and when the rotational speed is higher, the central portion is strongly etched. In other words, in the curve of Fig. 6, the left side of the curve is a profile of the mountain shape on the left side, and the valley profile of the valley side on the right side.

)와의 관계를 조사하여, 그 결과를 제 8 도에 나타내었다. 이 경우, 회전속도가 250rpm 때에 최량의 프로필이 얻어지는 것이 판명된다.Then, the distance (mm) and the etching depth from the rotation center (0) in the case of performing the etching treatment for 1 minute under the condition of 40 ° C and 10 l / min (

) And the results are shown in FIG. In this case, it is found that the best profile is obtained when the rotational speed is 250 rpm.

Moreover, the relationship between the minimum value of in-plane uniformity of Table-2, and a rotational speed is shown in FIG. In FIG. 9, in order to obtain in-plane uniformity by changing the temperature at the same flow rate, the rotational speed is increased corresponding to the temperature. It is thought that this is due to the change of the (HF) concentration due to temperature as shown in Table-1.

Judging from the above experimental results, it is concluded that the in-plane uniformity of etching with respect to the silicon thermal oxide film depends only on the supply flow rate of the mixed vapor to the chamber 8 and the rotational speed of the substrate W.

In the gas supply chamber S for processing, the same result can be obtained even if the relationship between the direction of the vortex of the mixed steam and the rotational direction of the substrate W is the same or in the reverse direction.

However, it should be noted that even in the case of the worst profile among these, in the sense of improving the in-plane uniformity that the profile is sufficiently good as compared with the conventional example shown in FIGS. 11 and 12, Substrate force applied to the substrate processing gas on the surface of the substrate W increases the atmospheric pressure of the substrate processing gas at the periphery of the substrate W. The distribution of the outflow pressure may be made higher as the peripheral portion side of the substrate W rotates so that the distribution of the outflow pressure of the gas is balanced.

Second Embodiment

FIG. 10 is a cross-sectional view of the main portion of the second embodiment in which the outflow pressure adjusting means in the first embodiment is modified, and at the same time a gas inlet 41 for introducing mixed steam is provided in the central portion of the chamber 8; The shielding plate 42 is provided in the gas supply chamber S1 for substrate processing in which the ceiling plate part 17 and the circumferential wall part 18 of 8) are surrounded by the rectifying plate 23.

The ventilation hole 43 is provided in the peripheral part side of this shielding plate 42.

With such a configuration, the mixed vapor introduced into the gas supply chamber S1 for substrate processing flows to the outer circumferential side by the shielding plate 42, and a part of the mixed vapor flows through the vent hole 43, thereby processing the substrate processing gas. Is supplied to the gas outlet 22 which is bypassed toward the circumferential wall 18 side and becomes small pores, so that the flow resistance when flowing up to the position is strongly received at the center side of the rectifying plate 23, so that the rotation of the substrate W The gas outlet 22 formed by the pores on the side away from the center is configured to allow the mixed steam to flow out at a larger outlet pressure.

As the above-described mixed steam, in addition to the mixed vapor of hydrogen fluoride gas (HF) and water (H ₂ O), the mixed vapor of hydrochloric acid (HCℓ) and water (H ₂ O), hydrogen fluoride gas (HF) and water (H the ₂ O) may be a mixed vapor, such as ethanol (C ₂ H ₅ OH) with the mixed _{vapor, HF + HNO 3 + H 2} O, HCℓ + HNO 3 + H 2 O, NH 4 OH + H 2 O.

The substrate processing gas may be a gas other than a mixed vapor such as, for example, ozone gas. The kind of gas is not limited.

In the above embodiment, etching has been mainly performed on the substrate, but the present invention is also applicable to surface cleaning for the substrate and film formation processing for the substrate.

Claims (4)

Substrate holding means (2) for holding the substrate in a horizontal position and horizontally rotating around an axis in the vertical direction; and gas supply means for substrate processing for supplying substrate processing gas to the surface of the substrate held by the substrate holding means In the substrate rotating surface treatment apparatus provided with, The substrate processing gas supply means is disposed so as to cover the substrate (W) near the substrate (W) above the substrate (W) to rotate horizontally. The outflow pressure of the rectified plate 23, the gas outlet 22 formed in the rectifier plate 23, and the gas for processing the substrate from the gas outlet 22 is higher on the side away from the center of rotation of the substrate. Substrate rotary surface treatment apparatus comprising an outlet pressure adjusting means to be made. The method of claim 1, wherein the outflow pressure adjusting means comprises a chamber (8) consisting of a ceiling plate portion (17) and a circumferential wall portion (18) protruding downwardly thereof, and a rectifying plate on the circumferential wall portion (18). (23) is provided, the gas supply chamber (S) for substrate processing surrounded by the ceiling plate section (17), the main wall section (18), and the rectifying plate (23), and the horizontal direction with respect to the radial direction of the chamber (8). And a gas inlet (20) provided in the main wall portion (18) to supply the substrate processing gas to the substrate processing gas supply chamber (S) in an inclined direction. The substrate rotating surface treatment apparatus according to claim 2, wherein the substrate holding means (2) is configured to hold the substrate (W) horizontally. The method of claim 1, wherein the outflow pressure adjusting means comprises a chamber (8) consisting of a ceiling plate portion (17) and a circumferential wall portion (18) protruding downwardly thereof, and a rectifying plate on the circumferential wall portion (18). (23) is provided, the substrate processing gas supply chamber (S1) surrounded by the ceiling plate 17, the circumferential wall portion 18 and the rectifying plate (23), and the substrate at the center of the ceiling plate portion 17 The gas inlet 41 for supplying the substrate processing gas to the processing gas supply chamber and the substrate processing gas provided in the substrate processing gas supply chamber S1 and supplied from the gas inlet 41 are bypassed to the circumferential wall side. Substrate rotary surface treatment apparatus, characterized in that consisting of a shield plate 42 for supplying to the gas outlet (22).

Images