JP3590712B2 - Resist developing apparatus and resist developing method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a resist developing apparatus and a resist developing method suitable for manufacturing an VLSI using a wafer having a large diameter.
[0002]
[Prior art]
2. Description of the Related Art In recent years, in the manufacture of VLSI, the progress of miniaturization of elements such as transistors and the increase in the diameter of wafers for increasing the number of wafers per wafer has been remarkable. For example, with an exposure apparatus using an excimer laser as a light source, a resist pattern having a minimum element size of 0.25 μm to 0.2 μm is formed, or a super LSI is manufactured using an 8-inch diameter Si wafer. To form this resist pattern, the following resist coating apparatus and resist developing apparatus are used.
[0003]
In the method disclosed in JP-A-56-104440, first, in a step of applying a resist solution, a wafer is held on a wafer holding table having a rotating mechanism by using an apparatus called a rotary resist coating apparatus. After the resist solution is dropped on the wafer, the wafer is rotated to apply the resist solution over the entire surface of the wafer so as to have a thickness as uniform as possible.
[0004]
Further, in the method disclosed in Japanese Patent Application Laid-Open No. 57-133641, an apparatus for applying a resist by dropping a resist on a roller and rotating the roller on the wafer surface has been proposed as an apparatus for applying to a large-diameter wafer. I have.
[0005]
On the other hand, as an apparatus for developing a resist solution, as disclosed in Japanese Patent Application Laid-Open No. Hei 7-326559, a resist solution which sprays a developing solution onto a resist after exposure while rotating a wafer or sprays a developing solution onto a resist after exposure is used. There is a developing device. In addition, there is a rotary resist developing apparatus in which a developer is dropped on a resist surface, and the wafer is rotated to dry the resist.
[0006]
[Problems to be solved by the invention]
However, the above-described conventional resist coating apparatus and resist developing apparatus have the following problems, respectively.
First, in a rotary resist coating apparatus as disclosed in JP-A-56-104440, as the wafer size increases, for example, as the wafer diameter increases from 6 inches, 8 inches to 12 inches, Because the centrifugal force at the center of rotation of the wafer and the peripheral part of the wafer are largely different, the resist spread around the wafer is easily blown off. That is, there is a disadvantage that the uniformity of the resist film thickness within the wafer surface is significantly reduced. An analysis result performed by the inventor on this point will be described.
[0007]
When the resist is dropped on the wafer and rotated, F = m × r × ω ²
Centrifugal force F is applied. here,
m: weight of the resist at a certain point r: distance from the center of rotation ω: angular velocity of rotation
[0008]
Therefore, at present, when the wafer diameter is changed from 6 inches or 8 inches to 12 inches, the centrifugal force of the resist around the 12-inch wafer is twice as large as that of the 6-inch wafer and 1.5 times that of the 8-inch wafer. Then, as a result of examining the uniformity of the rotation speed, the resist film thickness, and the resist thickness in the wafer surface, the present inventors obtained the results shown in FIG. In the figure, lines L6, L8, and L12 show the relationship between the thickness of the resist film and the number of rotations on a 6-inch wafer, an 8-inch wafer, and a 12-inch wafer, respectively. Lines R6, R8, and R12 indicate variations in the uniformity of the thickness of the resist film on the 6-inch wafer, the 8-inch wafer, and the 12-inch wafer, respectively.
[0009]
As shown in the figure, the resist film thickness monotonously decreases with an increase in the rotation speed, so that the desired film thickness can be controlled by the rotation speed. On the other hand, the uniformity variation of the resist film thickness in the wafer surface increases when the rotation speed is extremely low because the resist solution hardly flows in the wafer surface due to the influence of the viscosity of the resist solution. When the rotation speed of the wafer is increased to a certain degree or more, the uniformity of the resist film thickness in the wafer surface increases due to the influence of the centrifugal force described above. When the wafer diameter increases, the uniformity variation of the resist film thickness due to the centrifugal force occurs from a low wafer rotation speed. In particular, in the case of a 12-inch wafer (line R12), since the uniformity of the resist film thickness in the wafer surface varies greatly, it is difficult to form a fine resist pattern uniformly in the wafer.
[0010]
The roller type resist coating apparatus disclosed in Japanese Patent Application Laid-Open No. 57-133641 is different from the above-mentioned rotary type resist coating apparatus in that the resist is once dropped on a roller and then applied to a wafer. This is not suitable for forming a fine resist pattern due to the deterioration of the particles and adhesion of particles.
[0011]
On the other hand, in the spray type resist developing apparatus disclosed in Japanese Patent Application Laid-Open No. 7-326559, since the consumption of the developing solution is large, and it is difficult to control the contact between the resist film to be developed and the developing solution due to spraying, the fine patterning is difficult. It is not suitable for developing a resist pattern.
[0012]
Further, in the case of a conventional rotary resist developing apparatus, due to the miniaturization of the resist pattern and the increase in the wafer size, for example, a 6-inch wafer is 0.1 μm wide (a resist thickness is about 0.1 μm) by an SOR (synchrotron orbital resonance) exposure apparatus. When a 2 μm) pattern is exposed and developed, there is a disadvantage that the fine resist pattern collapses and cannot be used for manufacturing an LSI. This is because the rotation speed at the peripheral portion of the wafer is higher than that at the central portion of the wafer, so that the developing solution scattered from the wafer receives the liquid pressure at the time of scattering and the wind pressure due to the rotation of the wafer.
[0013]
The present invention has been made in view of the above problems, its object, upon coating or resist developing, to form a fine resist pattern even when the wafer diameter is increased cormorants Relais resist developing apparatus Or a method thereof.
[0014]
[Means for Solving the Problems]
The resist developing apparatus of the present invention includes a developing solution supply mechanism for supplying a resist developing solution onto a wafer, and a rotating mechanism for rotating the wafer and spreading the resist developing solution supplied on the wafer over the wafer. When, and a to order decompressor a space where the wafer is placed in a reduced pressure state.
[0015]
Thereby, in the process of applying the resist developer, the wind pressure generated by the rotation of the wafer suppresses the force applied to the side surface of the fine resist pattern, so that the fine pattern does not fall over even for a large-diameter wafer. A resist developing device capable of developing a resist is obtained.
[0016]
Resist development process of the present invention, in the resist developing method of forming a resist pattern on the wafer, a resist developing solution supplied onto the wafer, the resist developer and rotated supplied onto the wafer to the wafer above a step of spreading on a wafer, the method comprising the steps of: in a reduced pressure state space in which the wafer is placed.
[0017]
According to this method, in the process of applying the resist developing solution, the wind pressure generated by the rotation of the wafer suppresses the force applied to the side surface of the fine resist pattern, so that the fine pattern can be overturned even for a large-diameter wafer. And the development of the resist is performed.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of a resist coating device and a resist developing device of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is a perspective structural view of a resist coating apparatus according to the present embodiment.
[0020]
1 (a) and 1 (b), 11 is a semiconductor wafer, 12 is a wafer holder, 13 is a wafer moving mechanism, 14 is a resist coating container, 15 is a resist, 15a is a resist film applied to a semiconductor wafer, Reference numeral 16 denotes a resist supply container, and 17 denotes a resist supply pipe.
[0021]
Next, the procedure of applying a resist by the method of the present embodiment will be described with reference to FIGS.
[0022]
As shown in FIG. 1A, a semiconductor wafer 11 is held by a wafer holding table 12, and is moved by a wafer moving mechanism 13 from a resist coating container 14 toward a resist 15 which is pushed up in a convex shape. The resist 15 is supplied from the resist supply container 16 to the resist coating container 14 via the resist supply pipe 17. At this time, as shown in FIG. 1B, the semiconductor wafer 11 moves while being in contact with the resist 15 which is pushed upward from the tip of the resist coating container 14. As a result, the resist film 15a is applied to a region of the surface of the semiconductor wafer 11 that has passed the tip of the resist coating container 14.
[0023]
Here, the thickness of the resist film 15a to be applied depends on factors such as the specific gravity and viscosity of the resist material, the applied surface tension, the wettability of the resist on the semiconductor wafer 11, and the like. And the contact pressure of the resist 15 and the contact time between the two (controlled by the speed at which the semiconductor wafer passes over the resist). Therefore, since the semiconductor wafer 11 does not rotate after the resist 15 is applied, there is no non-uniformity of the centrifugal force acting on the resist in the wafer surface, so that a resist film 15a having excellent film thickness uniformity can be formed. Become. Further, when the resist 15 flows from the resist supply container 16 to the resist coating container 14 through the resist supply pipe 17, the resist 15 does not come into contact with a mechanism other than the passage route or air, so that the deterioration of the resist and generation of particles are extremely large. Since the resist pattern can be kept low, a resist pattern finer than 0.25 μm can be uniformly applied to a large-diameter wafer.
[0024]
In the present embodiment, the semiconductor wafer 11 is moved, but the resist coating container 14 may move, or each may move, or a slow rotational movement may occur. Furthermore, even if both move in the same direction, both may move relatively due to different moving speeds. In short, it is sufficient that the semiconductor wafer 11 and the resist coating container 14 move relatively.
[0025]
In addition, when the resist 15 is pushed up in a convex shape, the resist 15 may overflow from the tip of the resist coating container 14.
[0026]
(Second embodiment)
Next, a second embodiment of the present invention will be described.
[0027]
FIG. 2 is a perspective view partially showing the structure of the resist coating apparatus according to the second embodiment in a sectional view.
[0028]
In FIG. 2, 20 is a sealed container, 21 is a semiconductor wafer, 22 is a wafer holder, 23 is a wafer rotating mechanism, 24 is a resist dropping nozzle, 25 is an exhaust port, 26 is a valve, and 27 is a pressurized gas inlet. Show.
[0029]
As shown in the figure, a semiconductor wafer 21 is held on a wafer holding table 22, a resist is dropped on the semiconductor wafer 21 from a resist drop nozzle 24, and the semiconductor wafer 21 is rotated by a wafer rotating mechanism 23. The resist is applied in a film form by centrifugal force. At this time, since the diameter of the semiconductor wafer 21 is large, the uniformity of the resist film thickness in the plane of the semiconductor wafer 21 is poor. Thereafter, before the resist liquid dries, the valve 26 of the exhaust port 25 is closed, and an inert gas is introduced from the pressurized gas inlet 27 to pressurize the inside of the sealed container 20. By this pressing, the applied resist receives a uniform pressing in the wafer surface, so that the uniformity of the resist film thickness in the wafer surface is improved.
[0030]
In this embodiment, the pressure treatment is performed after the spin coating of the resist, but the pressure treatment may be performed during the spin coating.
[0031]
(Third embodiment)
Next, a third embodiment relating to the resist developing apparatus will be described.
[0032]
However, the third to fifth embodiments described below are based on the following findings. That is, in the development of a fine resist pattern under normal pressure, various observations of the overturning of the resist pattern show that, when the resist film thickness is constant, the overturning occurs when the width of the resist pattern becomes minute. Therefore, when this phenomenon is carefully examined, for example, in a conventional resist developing apparatus, a resist film having a thickness of about 2 μm and a width of 0.2 μm is not so likely to fall, The resist film was found to be easily overturned. This indicates that the smaller the area that is in close contact with the base, the easier it is to fall. In other words, if the vertical dimension in the cross-sectional shape becomes larger than the horizontal dimension, the balance between the rotational moment acting around one of the corners at the lower end of the resist film and the drag force against it will be lost, and the resist film Is likely to fall down. Here, the force acting as a rotational moment for overturning the resist film includes a centrifugal force acting on the resist film as the wafer rotates at a high speed, a wind pressure applied to the resist film from a lateral direction, an inertial force of the resist film itself, and the like.
[0033]
First, the centrifugal force applied to the resist pattern due to the rotation of the semiconductor wafer decreases in proportion to the decrease in the width of the resist pattern. On the other hand, since the wind pressure applied from the lateral direction of the semiconductor wafer acts on the side surface of the resist pattern and is defined by the resist film thickness, it is substantially constant even if the width of the resist pattern becomes small. For this reason, it was found that the smaller the area of contact with the base, the smaller the adhesive force of the resist pattern to the wafer, and the larger the wind pressure, which contributed to overturn. When the number of rotations of the wafer changes, an inertial force proportional to the change in the rotation speed, that is, the acceleration acts on the resist film. Therefore, in the following embodiments, a means for preventing the resist pattern from overturning is taken in consideration of the centrifugal force, wind pressure, and inertia force due to the rotation of the semiconductor wafer.
[0034]
FIG. 3 is a perspective view showing the structure of the resist developing device according to the third embodiment.
[0035]
3, reference numeral 30 denotes a resist film, 31 denotes a semiconductor wafer, 32 denotes a wafer holder, 33 denotes a wafer moving mechanism, 34 denotes a resist developing container, 35 denotes a resist developing solution, 36 denotes a resist developing solution supply container, and 37 denotes a resist. Each shows a developer supply pipe.
[0036]
Here, a method for developing a resist will be described with reference to FIGS.
[0037]
As shown in FIG. 3A, the semiconductor wafer 31 is held on a wafer holding table 32, and is moved toward a resist developing solution 35 which is pushed upward from a tip of a resist developing container 34 by a wafer moving mechanism 33. To be moved. A resist developing solution 35 is supplied to the resist developing container 34 from a resist developing solution supply container 36 via a resist developing solution supply pipe 37. Then, as shown in FIG. 3B, the semiconductor wafer 31 moves while making the resist film 30 formed on the surface come into contact with the resist developing solution 35 which is pushed upward from the resist developing container 34 in a convex shape. I do. By this processing, the exposed region of the resist film 30 is developed, and a resist pattern 30a is formed. At this time, the developer used for the development overflows from the resist developing container 34 and is discharged, so that the developer 35 used for the development is constantly supplied in a fresh state.
[0038]
As described above, according to the present embodiment, the semiconductor wafer 31 is not rotated when the resist film 30 on the semiconductor wafer 31 is developed, so that the centrifugal force applied to the resist pattern due to the rotation of the semiconductor wafer 31 becomes uneven in the wafer surface. Since there is no wind pressure on the resist pattern due to the rotation of the semiconductor wafer 31 or the semiconductor wafer 31, it is possible to prevent the fine resist pattern from overturning during development.
[0039]
In the present embodiment, the semiconductor wafer 31 is moved. However, the resist developing container 34 may be moved, or both may move, or there may be a slow rotational movement. Further, both may move in the same direction, or may move relatively due to different moving speeds. In short, it is sufficient that the semiconductor wafer 31 and the resist developing container 34 move relatively.
[0040]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
[0041]
FIG. 4 is a perspective view partially showing the structure of the resist developing apparatus according to the present embodiment in a sectional view.
[0042]
4, reference numeral 40 denotes a sealed container, 41 denotes a semiconductor wafer, 42 denotes a wafer holding table, 43 denotes a wafer rotating mechanism, 44 denotes a resist developing liquid drop nozzle, 45 denotes an exhaust port, 46 denotes a valve, and 47 denotes a pressure reducing mechanism such as a pump. Are respectively shown.
[0043]
Here, at the time of developing the fine resist pattern, the semiconductor wafer 41 is held on the wafer holding table 42 by using the resist developing device shown in FIG. The resist developer is removed from the surface of the semiconductor wafer 41 by rotating the semiconductor wafer 41 on the wafer holding table 42 by the wafer rotating mechanism 43.
[0044]
At this time, it was found that when the resist developing container 40 was developed at various rotation speeds under normal pressure without operating the pressure reducing mechanism 47 from the exhaust port 45, the fine resist pattern did not fall at a low rotation speed.
[0045]
Examining the above phenomena in detail, it has been found that in the case of a resist pattern having good adhesion to the base, it is effective to perform the rotation start operation and the rotation stop operation of the semiconductor wafer 41 slowly. When the resist pattern fell, the rotation speed was increased at a speed of 5000 rpm / sec, and the rotation speed was decreased at a speed of 5000 rpm / sec. When this speed was halved to 2500 rpm / sec, the resist pattern did not fall over when the number of revolutions during development was in the range of 2,000 rpm to 5,000 rpm.
[0046]
This is because, under general acceleration and deceleration conditions, for example, a part of the bottom of the resist pattern is centered by inertial force m · α (m is mass, α is acceleration) acting on the center of gravity of one resist pattern. It is considered that since a rotating moment occurs, the resist pattern whose lateral dimension is miniaturized is likely to fall over. In particular, in the case of a large-diameter wafer, a large rotational moment acts on the outer peripheral portion. Therefore, by gradually performing acceleration and deceleration, the rotational moment acting on the resist pattern can be reduced, and even a fine resist pattern can be prevented from overturning.
[0047]
In the present embodiment, the resist pattern is prevented from falling down by reducing the rotation speed increasing speed and the rotation speed falling speed of the semiconductor wafer 41. However, even if the rotation speed increasing speed and the rotation speed falling speed are large, the semiconductor The same effect can be obtained even if the rotation speed is increased from the maximum rotation speed to the maximum rotation speed and the rotation speed is reduced from the maximum rotation speed to the stop in multiple stages.
[0048]
In this embodiment, the pressure in the sealed container may be reduced during the application of the resist development.
[0049]
(Fifth embodiment)
Next, a fifth embodiment will be described.
[0050]
In the present embodiment, the same device as that of the fourth embodiment shown in FIG. 4 is used, and therefore, the description of the device will be omitted.
[0051]
In this embodiment, similarly to the above-described fourth embodiment, the semiconductor wafer 41 is held on the wafer holding table 42 by using the apparatus shown in FIG. The resist developing solution is applied to the wafer 41 and removed from the surface of the semiconductor wafer 41 by the wafer rotating mechanism 43.
[0052]
Here, in the present embodiment, the valve 46 of the exhaust port 45 is opened at the same time as the rotation of the semiconductor wafer 41, and the pressure inside the sealed container 40 is reduced by the pressure reducing mechanism 47.
[0053]
According to the present embodiment, since the rotation of the semiconductor wafer 41 after applying the resist developing solution is performed under reduced pressure, the wind pressure acting on the side surface of the resist pattern can be greatly reduced, and the fine resist pattern Can be prevented from falling during development.
[0054]
In this embodiment, the rotation of the semiconductor wafer and the depressurization of the resist developing container are performed at the same time, but there is no problem even if the time is different.
[0055]
【The invention's effect】
According to the resist developing device of the present invention, as the resist developing device , a mechanism for supplying the resist developing solution onto the wafer, a rotating mechanism for rotating the wafer and spreading the resist developing solution on the wafer, since the space which is installed to a structure in which the to order decompressor in a reduced pressure state, to provide a resist developing apparatus capable of forming a fine resist pattern without causing a fall of the resist pattern due to the action of wind pressure Can be planned.
[0056]
According to the resist developing method of the present invention, in the resist developing method of forming a resist pattern on a wafer, a resist developing solution is supplied on the wafer , and the resist developing solution supplied on the wafer is rotated by rotating the wafer. a step of spreading a. Thus a step of a reduced pressure state space in which the wafer is placed, can wind pressure to suppress force applied to the side surface of the fine resist pattern, thus a large-diameter wafer The fine resist pattern can be developed without causing the resist pattern to fall.
[Brief description of the drawings]
FIG. 1 is a perspective view and a sectional view showing the structure of a resist coating apparatus according to a first embodiment of the present invention.
FIG. 2 is a perspective view partially showing a structure of a resist coating apparatus according to a second embodiment of the present invention in a cross-sectional view.
FIG. 3 is a perspective view and a sectional view showing a structure of a resist developing apparatus according to a third embodiment of the present invention.
FIG. 4 is a perspective view partially showing the structure of a resist coating apparatus according to fourth and fifth embodiments of the present invention in a sectional view.
FIG. 5 is a diagram showing the relationship between the wafer rotation speed, the resist film thickness, and the uniformity of the resist thickness in the wafer surface with respect to the wafer size in the conventional example.
[Explanation of symbols]
Reference Signs List 11 semiconductor wafer 12 wafer holder 13 wafer moving mechanism 14 container for resist coating 15 resist 15a resist film 16 resist supply container 17 resist supply pipe 20 sealed container 21 semiconductor wafer 22 wafer holder 23 wafer rotating mechanism 24 resist dropping nozzle 25 exhaust port 26 valve 27 pressurized gas inlet 30 resist film 30a resist pattern 31 semiconductor wafer 32 wafer holding table 33 wafer moving mechanism 34 resist developing container 35 resist developing solution 36 resist developing solution supply container 37 resist developing solution supply pipe 40 sealed container 41 Semiconductor wafer 42 Wafer holding table 43 Wafer rotating mechanism 44 Resist developing liquid drop down nozzle 45 Exhaust port 46 Valve 47 Pressure reducing mechanism

Claims (2)

A developer supply mechanism for supplying a resist developer onto the wafer;
The resist developing solution supplied onto the wafer by rotating the wafer and rotating mechanism for spreading on said wafer,
Resist developing apparatus is characterized in that it comprises a to order decompressor a space where the wafer is placed in a reduced pressure state. In a resist developing method for forming a resist pattern on a wafer,
The resist developer is supplied onto the wafer, the resist developer and rotated supplied onto the wafer to the wafer and a step of spreading on said wafer,
Depressurizing the space in which the wafer is installed, and
Resist development method, which comprises a.

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