JP2000243679A - Resist applicator, and baking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a resist applicator and a baking device that the degree of freedom in adjustment of the equality of the resist film applied on a wafer is large and the further improvement of the equality of film thickness is possible. SOLUTION: This is a resist applicator which forms a resist film on a wafer W by dropping resist R onto a wafer W retained horizontally and rotating the wafer W, and this has a heater 40 and temperature adjustment part 11 as temperature adjusting means which adjust the temperature of the resist R applied on the wafer W from the rear side of the resist application face of the wafer. This enables the degree of freedom in adjustment of the equality of the film thickness of the resist film applied on the wafer, and the rise of the film thickness becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist coating apparatus for applying a resist on a wafer and a baking apparatus for heating the resist applied to the wafer, for example.

[0002]

2. Description of the Related Art In a resist coating apparatus called a spin coater, in which a resist is dropped on a horizontal wafer and the wafer is rotated to form a resist film on the wafer, a uniform thickness of the resist film is obtained. Influence factors include, in addition to the resist material, for example, the temperature of the resist dropped on the wafer, the temperature and humidity in the spin cup of the spin coater, the displacement of the spin cup, the process sequence when applying the resist, and the like. is there. By adjusting these elements, the uniformity of the resist film on the wafer can be improved.

[0003]

However, depending on the device, there are cases where it is not possible to adjust each of the above-mentioned adjusting elements due to problems in the device specifications and configuration. For example, under the condition that a plurality of types of resists are used, there may be only one temperature controller for controlling the resist temperature for all the resists. In such a case, the set temperature of each nozzle system for supplying each resist is the same, and the set resist temperature is an intermediate value between the maximum value and the minimum value of the film thickness uniformity of each resist film. . For this reason, the film thickness uniformity deteriorates as a whole, and it is necessary to improve the film thickness uniformity by other adjustment factors. Also, for example, in the case of the displacement of the spin cup, there is no problem if the spin coater is provided with an exhaust system in which the displacement is automatically adjusted for each type of resist, but otherwise, the same as above. To
It is necessary to set an intermediate value between the exhaust amount at the maximum value and the minimum value of the film thickness uniformity of each resist film. As described above, even if there are a plurality of adjustment elements for improving the thickness uniformity of the resist film,
If there is an adjustment element that cannot be adjusted due to a problem in the specifications of the apparatus, it is necessary to compensate for the adjustment element with another adjustment element. Further, in some cases, the above-described adjustment elements alone may not sufficiently improve the film thickness uniformity.

The present invention has been made in view of the above-mentioned problems, and has a great degree of freedom in adjusting the film thickness uniformity of a resist film applied on a wafer, and can further improve the film thickness uniformity. It is an object of the present invention to provide a resist coating apparatus and a baking apparatus.

[0005]

According to the present invention, there is provided a resist coating apparatus for dropping a resist on a horizontally held wafer and rotating the wafer to form a resist film on the wafer. And a temperature adjusting means for adjusting the temperature of the resist applied to the wafer from the back side of the resist applied surface of the wafer.

In the resist coating apparatus of the present invention, the temperature of the resist applied to the wafer through the wafer is adjusted by the temperature adjusting means, and the uniformity of the thickness of the resist film applied to the wafer can be controlled.

The temperature adjusting means is an electric heater provided on the back side of the wafer.

[0008] The electric heater comprises a plurality of electric heaters, each of which is independently adjusted in temperature. By providing a plurality of electric heaters and adjusting the temperature independently, the temperature distribution of the resist applied on the wafer surface can be set to an arbitrary temperature distribution, and the film thickness uniformity of the resist film can be controlled more accurately. It becomes possible.

There is a spin chuck for sucking and holding a central portion on the back side of the wafer and rotating the wafer, and the plurality of electric heaters are arranged concentrically around the spin chuck.

[0010] The electric heater is surrounded by a protective cover.

The temperature control means comprises a temperature control container provided on the back side of the wafer, for supplying and circulating a temperature-controlled liquid.

A spin chuck for sucking and holding a central portion on the back surface side of the wafer and rotating the wafer; the plurality of electric heaters are arranged concentrically around the spin chuck; The heater is divided in the circumferential direction, and the temperature is adjusted independently of each other.

A temperature / humidity adjusting means for supplying an atmosphere in which the temperature and humidity in the spin cup are adjusted, and a temperature of a resist dropped on the wafer; The apparatus further includes a resist temperature adjusting means for adjusting, and a cup exhaust amount adjusting means for adjusting an exhaust amount in the spin cup.

The baking apparatus of the present invention is a baking apparatus for heating the wafer from the back side of the resist-coated surface of the resist-coated wafer, and is capable of forming an arbitrary temperature distribution within the back side of the wafer. It has a heating means.

The heating means comprises a plurality of electric heaters, and each electric heater is independently adjusted in temperature.

In the baking apparatus of the present invention, the temperature distribution of the resist film in the wafer surface can be arbitrarily formed when the resist-coated wafer is subjected to dehydration baking, pre-development baking, pre-baking or post-baking, The thickness uniformity can be controlled.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a configuration diagram of a resist coating unit according to an embodiment of the present invention. In FIG. 1, a resist coating unit 1 includes a spin cup 3 provided on a base 2, a resist coating mechanism 4, a temperature control unit 11, a temperature / humidity control unit 12 in a cup, a cup displacement control unit 13, a resist And a temperature control unit 14.

In the spin cup 3, a spin chuck 31 for sucking and holding the wafer W and rotating the wafer W, and a heater unit 40 for adjusting the temperature of a resist applied on the wafer W from the lower surface side of the wafer W are provided. Is provided. The spin chuck 31 has a rotating shaft 31a and a suction unit 31b. The suction unit 31b vacuum-suctions the wafer W through a pipe formed in the rotating shaft 31a, and the rotating shaft 31a is driven in this state. . Thus, the wafer W held by suction rotates.

FIG. 2 is a sectional view showing the structure around the heater section 40, and FIG. 3 is a top view of FIG. As shown in FIGS. 2 and 3, the heater section 40 has a plurality of electric heaters 41 a to 41 c, and the electric heaters 41 a to 41 c are arranged concentrically around the spin chuck 31. The electric heaters 41a to 41c are housed in a protective heater box 52 in order to avoid the influence of a solvent or the like used when applying the resist. Also,
Each of the electric heaters 41a to 41c is provided with a temperature controller 1
1 electrically. The temperature controller 11 controls the heating temperature of each of the electric heaters 41a to 41c independently. In addition, the nozzle 51 disposed on the outer periphery on the lower surface side of the wafer W may generate dust due to chipping of the resist when the end of the wafer W comes into contact with the positioning portion in each step. This is a solvent supply nozzle for so-called edge rinsing, in which the resist at the peripheral portion of the wafer is removed with a solvent in order to prevent the problem.

The resist coating mechanism 4 includes a resist supply pipe 5 provided with a resist supply nozzle 5a for supplying a resist onto the wafer W at the tip, an arm 6 for holding the resist supply pipe 5, an x-axis of the arm 6, an xy table 7 for moving in the y-axis direction, a rotary lift 9 for moving the cylinder shaft 8 holding the xy table 7 in the z-axis direction and rotating in the θ direction, and a resist supply device (not shown) for supplying a resist R The temperature of the resist R supplied from the resist supply device is adjusted, and the resist R is supplied to the resist supply pipe 5.
And a resist temperature control unit 14 for supplying the resist.

The resist supply nozzle 5a is made of, for example, a material such as stainless steel or Teflon resin. From the viewpoint of preventing the resist from dropping and improving the suck-back characteristic, various measures are taken for the shape, inner diameter, outer diameter and the like. It has been subjected.
As a resist supply device (not shown) for supplying the resist R to the resist temperature control unit 14, for example, a device having an air pressure control pump called a diaphragm pump can be used in order to drop the resist R precisely and with good reproducibility. .

The resist temperature controller 14 controls the resist R supplied from the resist supply device to a temperature specified by a sequence program, for example.
This is supplied to the resist supply pipe 5.

The arm 6 is formed in an L shape, supports the resist supply pipe 5 by a horizontal portion extending horizontally, and is fixed on an xy table 7. The xy table 7 is configured to rotate a feed screw shaft screwed in the x-axis and y-axis directions to a table held movably in the x-axis and y-axis directions by a drive motor, for example. It is positioned at any position in the axial direction. The rotary lift 9 is driven by, for example, high-pressure air or the like, and moves the cylinder shaft 8 in the z-axis direction and θ
Perform a rotation in the direction. xy table 7 and rotary lift 9
Is controlled by a control device (not shown), and the resist supply nozzle 5a is moved and positioned at an arbitrary position above the wafer W mounted on the spin chuck 31 in the spin cup 3.

The temperature / humidity adjusting section 12 in the cup includes, for example,
It is configured by a clean bench having a constant temperature function and a constant humidity function, and supplies the air G adjusted to a predetermined temperature and humidity into the spin cup 3 and also adjusts the supply amount. The temperature and the humidity are specified by a sequence program prepared in advance.

The cup displacement adjusting unit 13 controls the displacement of the air G in the spin cup 3. Specifically, for example, the opening and closing amount of an exhaust port formed in the spin cup 3 is controlled to adjust the exhaust amount of the air G. The displacement of the air G is defined by a sequence program prepared in advance.

Next, the resist coating unit 1 having the above structure
Will be described. First, air G having a temperature and a humidity set according to the type of the resist R to be applied from now on is supplied into the spin cup 3 from the cup internal temperature / humidity adjusting unit 12. In addition to this, the exhaust amount of the air G from the spin cup 3 is adjusted by the cup exhaust amount adjusting unit 13 to the exhaust amount set according to the type of the resist R to be applied.

Next, the wafer W chucked on the spin chuck 31 is rotated at a set number of rotations, and the arm 6 holding the resist supply pipe 5 is driven to move the resist supply nozzle 5a above the rotation center of the wafer W. Go to

On the other hand, a predetermined temperature distribution is formed in the plane of the wafer W by a heater section 40 provided below the wafer W according to a sequence program prepared in advance. For example, the resist R whose temperature is adjusted by the resist temperature controller 14 supplied on the wafer W
It is assumed that the higher the temperature, the thicker the resist film at the center of the wafer W. In such a case,
For example, instead of the temperature adjustment by the resist temperature adjustment unit 14, the temperature distribution in the surface of the wafer W is adjusted by the temperature adjustment unit 11 to a temperature distribution in which the temperature decreases from the center toward the periphery. Specifically, the temperature is adjusted by the temperature adjustment unit 11 so that the heating temperature increases from the electric heater 41a located on the center side of the wafer W to the electric heater 41c located on the outer periphery. That is, from the electric heater 41a located on the center side of the wafer W to the electric heater 41 located on the outer periphery.
Form a temperature gradient toward c.

In this state, the wafer W rotating at a predetermined speed
A predetermined amount of resist R is dropped from the resist supply nozzle 5a to the center of the substrate. Resist R dropped on wafer W
Is spread toward the outer periphery of the wafer W by centrifugal force due to the rotation of the wafer W, and a resist film is formed on the wafer W. At this time, the temperature of the central portion of the wafer W is lower than the outer peripheral side of the wafer W, and the resist R present on the central portion of the wafer W is harder to solidify than the outer peripheral side. Therefore, the resist R dropped on the central portion of the wafer W is hard to solidify before spreading toward the outer periphery of the wafer W, and it is possible to adjust the timing of solidification between the central portion and the outer peripheral portion of the wafer W. Become. As a result, the film thickness uniformity of the resist film formed on the wafer W can be controlled, and by adjusting the temperature distribution formed by the electric heaters 41a to 41c, the film thickness uniformity of the resist film can be improved. it can.

As described above, according to the present embodiment, since the heater section 40 capable of adjusting the temperature is provided on the lower surface side of the wafer W, for example, the adjustment temperature of the resist temperature adjustment section 14 is fixed. In the case where the temperature cannot be adjusted for each type of the resist R, the temperature of the resist R can be adjusted by the heater unit 40 and the temperature adjusting unit 11, and the film thickness uniformity can be controlled for each type of the resist R. Become. In the present embodiment, the heater section 40 includes a plurality of electric heaters 41a.
To 41c, and each of the electric heaters 41a to 41c can be independently controlled in temperature.
Temperature distribution can be arbitrarily formed in the surface of the wafer W on which the resist film is applied, and the uniformity of the film thickness of the resist film can be controlled more accurately. As a result, the uniformity of the film thickness of the resist film is improved. Can be done. Furthermore, according to the present embodiment, the cup temperature and humidity adjustment unit 12 that adjusts the resist temperature, the cup exhaust amount, and the cup temperature and humidity, which are factors that affect the uniformity of the resist film thickness, respectively, In addition to the amount adjustment unit 13 and the resist temperature control unit 14,
By providing the heater unit and the temperature control unit 11 that can directly control the temperature of the resist film applied on the wafer W, the parameter for adjusting the uniformity of the film thickness of the resist film increases, and various adjustment elements The degree of freedom of adjustment is increased by the combination, and the uniformity of the film thickness can be controlled.

Modification 1 FIG. 4 is a view showing a modification of the heater section 40 of the above-described embodiment. The heater unit shown in FIG.
A plurality of electric heaters 61a to 61c are arranged concentrically around one.
, And each of the electric heaters 61a to 61c is divided into four in the circumferential direction. Divided electric heaters 61a1-6
1a4, 61b1 to 61b4 and 61c1 to 61c4
Are temperature-controlled independently of each other. In the present embodiment, the electric heaters 61a1 to 61a4, 61b1
61b4 and 61c1 to 61c4 are arranged in the radial direction and the circumferential direction of the wafer W, so that the temperature distribution in the surface of the wafer W can be formed in a wider variety. In particular, when compared with the above-described embodiment, not only can a temperature gradient be formed from the center of the wafer W toward the outer periphery, but also a temperature gradient can be formed in the rotation direction of the wafer W, More precise control of the film thickness uniformity of the resist film becomes possible.

Second Embodiment FIG. 5 is a cross-sectional view showing the structure of a heater of a resist coating apparatus according to a second embodiment of the present invention. In FIG. 5, a spin cup (not shown) sucks and holds the wafer W and rotates the wafer W, and a heater unit for adjusting the temperature of the resist applied to the wafer W from the lower surface side of the wafer W. 52 are provided. The heater unit 52 includes a storage box 53 having a temperature-regulated medium L, for example, an inner cavity filled with hot water, and the temperature-controlled medium L is supplied from a supply unit 53 a of the storage box 53. The medium L supplied into the storage box 53 circulates through the storage box 53 and is discharged from the discharge unit 53.
b. With such a configuration,
The heater unit 52 can adjust the temperature of the wafer W from the back side corresponding to the temperature of the medium L. As a result, the wafer W
It is possible to control the thickness uniformity of the resist film applied thereon. In this embodiment, the heater 52
Has a uniform temperature in the plane of the wafer W. However, similarly to the above-described embodiment, the heater 52 is divided into a plurality of heaters on a concentric circle, for example, and the media L, each of which is independently temperature-adjusted, It is also possible to adopt a configuration in which the heater is supplied to the divided heater units.

Third Embodiment FIG. 6 is a block diagram showing an embodiment of a baking apparatus according to the present invention. The baking apparatus is an apparatus for heating a resist applied to a wafer before and after a resist coating step or a developing step. As the heat treatment step, specifically, for example, in order to reduce the deformation of the resist pattern due to the standing wave effect when exposed to light of a single wavelength, a pre-development bake performed before exposure and development or a resist treatment As a pretreatment, in order to strengthen the adhesion between the resist and the wafer, a dehydration bake to remove moisture and after applying the resist on the wafer, evaporation of the residual solvent in the resist film and the adhesion between the resist film and the wafer After the pre-baking and the development of the resist pattern, the developer and the rinsing liquid remaining in or on the resist film are removed by evaporation to harden the resist and strengthen the adhesion with the wafer. There is post bake. In each of these heat treatment steps, the film thickness uniformity of the resist film is controlled by optimizing the temperature distribution when heating the wafer in accordance with conditions such as the type of the resist film and the state of formation of the resist film, The uniformity of the film thickness can be improved.

In FIG. 6, a plurality of electric heaters 71a to 71f are built in a hot plate section 70. Each of the electric heaters 71a to 71f is electrically connected to a temperature adjusting unit 76. The temperature adjustment unit 76
The temperature of each of the electric heaters 71a to 71f can be independently adjusted. Upper surface 70a of hot plate 70
On the upper side, gap pins 73 for forming a predetermined amount of gap between the upper surface 70a and the back surface of the wafer W are provided, and the wafer W is mounted on the gap pins 73.

In the baking apparatus having the above-described structure, the temperature distribution within the wafer W is arbitrarily formed by the electric heaters 71a to 71f, and the wafer W coated with the resist is placed on the baking apparatus in this state. In a heating process such as baking, dehydration baking, pre-baking, or post-baking, it is possible to form an optimal temperature distribution in the wafer W surface, thereby improving the uniformity of the thickness of the resist film.

[0036]

According to the resist coating apparatus of the present invention, the degree of freedom in adjusting the film thickness uniformity of the resist film applied on the wafer can be increased, and the film thickness uniformity can be further improved. According to the baking apparatus of the present invention, in a heating process such as pre-development bake, dehydration bake, pre-bake, and post-bake, it is possible to form an optimal temperature distribution in the wafer surface coated with the resist, Thickness uniformity can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a resist coating unit according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure around a heater unit 40;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is an explanatory view showing a modification of the heater unit.

FIG. 5 is a cross-sectional view illustrating a configuration of resist coating according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a configuration of a hot plate according to still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Resist application unit, 11 ... Temperature control part, 40 ...
Heater section, W: wafer, R: resist.

Claims (10)

[Claims] 1. A resist coating apparatus for dropping a resist on a horizontally held wafer and rotating the wafer to form a resist film on the wafer, the resist coating apparatus comprising: A resist coating apparatus having a temperature adjusting means for adjusting the temperature of a resist applied to a wafer. 2. The resist coating apparatus according to claim 1, wherein said temperature adjusting means is an electric heater provided on the back side of said wafer. 3. The resist coating apparatus according to claim 2, wherein the electric heater comprises a plurality of electric heaters, and the temperature is independently adjusted. 4. A spin chuck for sucking and holding a central portion on the back side of the wafer and rotating the wafer, wherein the plurality of electric heaters are arranged concentrically around the spin chuck. Item 4. A resist coating apparatus according to Item 3. 5. The resist coating apparatus according to claim 2, wherein said electric heater is surrounded by a protective cover. 6. The resist coating apparatus according to claim 1, wherein said temperature adjusting means comprises a temperature adjusting container provided and circulated on a rear surface side of said wafer, for supplying and circulating a temperature-adjusted liquid. 7. A spin chuck for attracting and holding a central portion on the back side of the wafer and rotating the wafer, wherein the plurality of electric heaters are arranged concentrically around the spin chuck, and 4. The electric heater is divided in the circumferential direction, and the temperature of each electric heater is adjusted independently.
3. The resist coating apparatus according to 1. 8. A cup temperature / humidity adjusting means having a spin cup surrounding the periphery of the wafer, for supplying an atmosphere in which the temperature and humidity in the spin cup are adjusted, and a resist for dropping the resist dropped on the wafer. 2. The resist coating apparatus according to claim 1, further comprising: a resist temperature adjusting unit for adjusting a temperature; and a cup exhaust amount adjusting unit for adjusting an exhaust amount in the spin cup. 9. A baking apparatus for heat-treating the wafer from the back side of the resist-coated surface of the resist-coated wafer, the baking apparatus having heating means capable of forming an arbitrary temperature distribution in the back side of the wafer. apparatus. 10. The baking apparatus according to claim 9, wherein said heating means comprises a plurality of electric heaters, and each electric heater is independently adjusted in temperature.