JP2889126B2 - Method for setting gap between work and mask, and gap setting mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting a gap between a work and a mask in an exposure apparatus used in a semiconductor device manufacturing process, and a mechanism for setting the gap.

[0002]

2. Description of the Related Art Conventionally, so-called proximity exposure in which a work and a mask are arranged with a minute gap has been performed. A semiconductor wafer or a glass substrate for a liquid crystal display is used for the work at this time. (Hereinafter, a work is generally referred to as a wafer.) FIG. 12 is a schematic view of a proximity exposure apparatus. Light emitted from a light source 1 is incident on an integrator lens 3 by an elliptical reflecting mirror 2. The output light from the integrator lens 3 is output to the collimator lens 4
Then, the wafer W is irradiated through the mask M on which a circuit pattern and the like are drawn. The gap between the mask M and the wafer W is 2
The accuracy is required to be within about 2 μm.

Conventionally, using a spherical seat type stage,
By moving this stage up and down with respect to the mask, the above "micro gap" was created. FIG. 11 shows a mechanism using the spherical seat system. Stage 5 is a spherical seat 6
The wafer W is placed on the stage 5. The stage 5 has a vacuum line 8 for attracting the wafer W to the stage 5, and the spherical seat 6 has a vacuum line 9 for fixing the stage 5 to the spherical seat 6.
These vacuum lines 8 and 9 are connected to vacuum suction means (not shown). The spherical seat 6 can be moved up and down by the moving means 7. In such a mechanism, the following operation is performed. First, the stage 5 is sufficiently lowered by the moving means 7, and the wafer W is placed on the stage 5 in this state. Then, the vacuum suction means and the vacuum pipe 8 are operated to suck the wafer W onto the stage 5, and in this state, the moving means 7 is driven to raise the stage 5 toward the mask M. At this time, the vacuum pipe 9 has not yet been operated, and the positional relationship between the spherical seat 6 and the stage 5 is free.

When the wafer W rises until it comes into contact with the mask M, the moving means 7 is stopped to stop the elevation of the wafer W. At this time, the stage 5 is tilted by the spherical seat 6 so as to be parallel to the mask M, and a parallel positional relationship between the wafer W and the mask M is realized. Next, the vacuum line 9 is activated,
The stage 5 is fixed to the spherical seat 6 by suction. Thereafter, the stage 5 is lowered by a desired distance. This desired distance is a so-called “micro gap”. The gap between the wafer W and the mask M is set each time one wafer is exposed.
You have to do it each time. This is because when the wafer W is attracted to the stage 5, the wafer W
This is because the wafer W and the mask M are displaced because the wafers W have uneven thicknesses individually.

[0005]

In such a method for setting a gap between a mask and a wafer by the spherical seat method and a gap setting mechanism, fine surface accuracy is required for the spherical surface of the stage. In addition, the production cost is high, and considerable production time is required.

[0006]

Therefore, a method of setting a gap between a work and a mask according to the present invention is characterized in that it is performed as follows. First, the work is held on the work stage in a state where the work does not contact the mask. Next, the work stage and / or the mask stage holding the mask are moved by the moving means in the direction in which the work and the mask come into contact. Then, even if the work and the mask come into contact, the movement continues. At least three of the work stages or the mask stages are provided, and when the work and the mask come into contact with each other and the relative movement cannot be performed any more, the driving force from the moving means is absorbed and the displacement starts. Each of the adjustment mechanisms sends a signal to the system controller when the adjustment mechanism makes a predetermined amount of displacement. Next, the system controller stops the movement of the work stage and / or the mask stage by setting the time when the system controller receives the signal from all the adjustment mechanisms as a parallel state of the work and the mask, and in each adjustment mechanism , The displacement state at that time is held. Thereafter, the work stage and / or the mask stage are moved by a predetermined distance in the direction opposite to the moving direction to form a desired gap. The mechanism for setting the gap between the work and the mask according to the present invention holds the work. A work stage, a mask stage for holding a mask, moving means for moving the work stage and / or the mask stage in a direction of relatively approaching or separating the work and the mask, and a work stage or a mask stage And at least three adjusting mechanisms provided so as to connect the moving means and the moving means. When the moving mechanism is driven in a direction in which the work and the mask come into contact with each other, the moving mechanism is continuously driven even after the work and the mask come in contact with each other. From the point in time when the mask makes contact and the relative movement becomes substantially no longer possible, the mask absorbs the driving force from the moving means and starts to be displaced, and the adjustment mechanism is displaced by a desired amount. And a holding means for holding the displacement state at that time. Further preferably, the adjusting mechanism includes a casing, a shaft disposed in the casing, a guide member for restricting the movement of the shaft only in the vertical direction, and a first member located in the casing and acting on the shaft. An elastic member, a plate-like elastic body connected to the shaft, holding means for holding the position of the shaft at a fixed position via the elastic body, and detecting means for detecting an amount of displacement of the first elastic member When,
It is characterized by comprising a sphere located between the tip of the shaft and the work stage or the mask stage, and a second elastic member for attracting the shaft and the mask stage with a constant force.

[0007]

[Effects] Due to such a method of setting the gap between the work and the mask and the gap setting mechanism, a spherical structure requiring fine surface accuracy is not adopted unlike the spherical seat method, so that the manufacturing cost of the spherical seat method is provided. It is inexpensive and easy to create.

[0008]

FIG. 1 is a schematic view for explaining a method for setting a gap between a work and a mask and a gap setting mechanism according to the present invention. Work stage 10 on which wafer W is placed
(Hereinafter referred to as “stage”), base 20 and support 3
0, the adjustment mechanism 40 is connected. The stage 10 is made of, for example, aluminum, and is connected to the adjustment mechanism 40 by contact of a V-groove receiver described later with a hard sphere. Therefore, the stage 10 can be easily replaced according to the size of the wafer W. The column 30 is connected to a moving means (not shown). The moving means only needs to be able to move the column 30 up and down, and for example, an air cylinder or a rotating cam is used. Since the moving means is known, the description is omitted. Further, the moving means is connected to a system controller to be described later, and information on movement control is sent. A base 20 having substantially the same shape as the stage 10 is provided at the tip of the support 30. Base 2
At 0, a rod-shaped adjustment mechanism 40 is erected perpendicularly to the base 20. At the tip of the adjusting mechanism 40, as described above,
Since the stage 10 is mounted, at least three of them need to be erected in order to determine the position of the stage 10. The mask M is held on a mask stage M10. This structure is not shown, but is held from the lower surface (the side facing the wafer W) of the mask stage M10 by, for example, a vacuum suction method. Therefore, by releasing the suction, the mask can be easily replaced with another mask.

Next, a method for setting the gap between the wafer and the mask will be described. First, in order to expose a circuit pattern drawn on a mask, a wafer W is placed on the stage 10 by a transfer arm or the like. Then, the wafer W is held on the stage 10 by a vacuum suction function or the like. At this time, the distance between the mask M and the wafer W is about 3 to 4 mm. When the wafer W is placed on the stage 10, the column 30 moves upward (toward the mask M) in response to a signal from the system controller. Therefore, the base 20 and the stage 10 connected to the support 30 and the wafer W also move in the direction of the mask M. This movement proceeds, and the wafer W
Even if contacts the mask M, the movement is continued without stopping the driving of the moving means. Adjustment mechanism 40
Has a built-in compression coil as a first elastic member, which will be described later, and when the wafer W comes into contact with the mask M and cannot substantially move any more, the driving force from the moving means is It has a function to absorb and start displacing. When the compression coil is displaced by a predetermined amount, the detection means notifies the system controller of the displacement. As described above, at least three adjustment mechanisms 40 are provided, and a signal is transmitted from each adjustment mechanism to the system controller. When the system controller receives the signal from all the adjusting mechanisms 40, the system controller stops the movement of raising the support column 30. Then, as described later, a holding mechanism such as a vacuum suction function is operated for each adjusting mechanism 40 to hold the displacement state at that time. And
The support 30 is moved so as to descend. Stage 10
When the wafer W is placed on the wafer W, the exposure surface of the wafer W and the mask M are not necessarily parallel to each other. However, by performing such a gap setting method, the mask and the work are parallel and a certain gap is formed. Can be set.

In this embodiment, the method and mechanism for moving the wafer W up and down with respect to the mask M by providing the moving means for the wafer W have been described. However, the moving means is provided for the mask stage M10. Thus, the mask M can be moved up and down with respect to the wafer W. In this case, the adjustment mechanism 40 can also be provided on the mask M side. That is, it is sufficient that the mask M and the wafer W can be relatively moved so as to be in contact with each other.

FIG. 2 shows the structure of the adjusting mechanism 40 in an exploded manner. The structure and operation of the adjusting mechanism 40 will be described in detail with reference to FIG. The V-shaped receiver 11 is embedded in the lower surface of the stage 10 and is connected to the ball receiver 41 via the hard sphere 12. At the center of the ball receiver 41, a conical concave portion 14 corresponding to the hard sphere 12 is provided. The hard sphere 12 corresponds to a sphere located between the tip of the shaft 43 and the mask stage M10. The feature of this structure is that when the stage 10 moves up and down, the stage 10
The ability to move freely only in the groove direction. The stage 10 and the ball receiver 41 are attracted to each other by a tension spring 13 which is a second elastic member. The reason for providing the extension spring 13 is as follows.

The wafer W is coated with a material such as a resist used for exposure processing. This resist generates a small adhesive force on the mask M when the wafer W comes into contact with the mask M or when the mask W separates. Therefore,
Even if the support 30 or the base 20 starts moving by the moving means, the stage 10 does not interlock instantaneously due to its adhesive strength. Then, due to the gravity, the stage 10 cannot be moved downward until the bonding state between the wafer W and the mask M is broken, and the position is held. Then, when the bonding state is broken, the stage 10 falls on the hard sphere 12 and the ball receiver 41, and the impact causes a displacement of the position of the wafer W. In this sense, if the tension spring 13 is provided, the “fall phenomenon” of the stage 10
Can be prevented, and the positional deviation of the wafer W can be prevented.

A shaft 43 is connected below the ball receiver 41, and the shaft 43 reaches a casing 46 via a spline 42 as a guide member. The spline 42 restricts the movement of the shaft 43 only in the vertical direction. After penetrating the casing 46, the shaft 43 is connected to a leaf spring 45 which is a plate-like elastic body. A compression coil 44, which is a first elastic member and acts on the shaft 43, is provided inside the casing 46 and is in contact with the periphery of the shaft 43. Leaf spring 4
5 is sandwiched between a suction block 47 as a holding means, and has a convex part 49 in a part thereof. A sensor 48 as a detecting means is provided to detect the position of the convex part 49. The suction block 47 serving as a holding unit has a vacuum suction mechanism (not shown). This vacuum suction mechanism is, for example, a rotary vacuum pump. With such a structure, the wafer W comes into contact with the mask M,
Practically, when it becomes impossible to move relatively further, the compression coil 44 as the second elastic member starts to compress so as to absorb the driving force. Due to this compression, the relative position of the leaf spring 45 with respect to the suction block 47 is displaced, so that the protrusion 49 provided on the leaf spring 45 also moves, and the sensor 48 detects this movement. Therefore, a predetermined amount of displacement can be set based on the positional relationship between the projection 49 and the sensor 48. In this way, each adjusting mechanism 40
Informs the system controller when a predetermined amount of displacement has occurred. When all the adjustment mechanisms have made the desired displacement, the moving means is stopped as described above. Then, in each adjustment mechanism, the suction block 47 as the holding means operates the vacuum suction mechanism to maintain the compressed state of the compression coil 44 at that time. In this way,
By moving the wafer W away from the mask M, a constant gap can be created while maintaining the parallel positional relationship between the wafer W and the mask M.

Next, a method of setting a gap between the mask M and the wafer W by the adjusting mechanism 40 will be described in detail with reference to FIGS. FIGS. 3, 5, 7, and 9 are explanatory cross-sectional views of the adjustment mechanism 40 shown in FIG. 2 as viewed in the X direction. 4, FIG. 6, FIG. 8, and FIG. 10 are explanatory sectional views of the adjusting mechanism 40 shown in FIG. 3 and 4, 5
6, FIGS. 7, 8 and 9 and 10 show the same state, respectively, and the state changes in this order.

FIGS. 3 and 4 show that the wafer W
2 shows an initial state after being placed. Therefore, the wafer W and the mask M are not yet set in a parallel relationship. When the base 20 moves in the direction of the arrow Z from this state, the adjustment mechanism 40 also moves. Then, the distance between the mask M and the wafer W becomes shorter. In this state, the compression coil 44 in the casing 46 does not function at all.

FIGS. 5 and 6 show a state where the mask M and the wafer W are in contact with each other. That is, the movement of the wafer W in the direction of the arrow Z proceeds, and the wafer W abuts on the mask M. Since the wafer W rises while being not parallel to the mask M, a part of the wafer W comes into contact with the mask M, but the other parts are not yet in contact. The base 2 is provided with at least three adjustment mechanisms 40. From this state, compression of the compression coil 44 inside the adjustment mechanism 40 near the contact point starts. Eventually, the entire surface of the wafer W comes into complete contact with the mask M. Therefore, the compression amount of the compression coil 44 in each adjustment mechanism 40 is not always the same.

FIGS. 7 and 8 show a state in which the mask M and the wafer W come into contact with each other and cannot be moved further, and the base 20 continues to move in the Z direction. This shows a state where the coil spring 44 is compressed. In this state, the stage 10 has the shaft 43,
The compression force of the compression coil 44 is received in the direction of arrow Z via the ball receiver 41, the hard ball 12, and the V-shaped receiver 11.

FIGS. 9 and 10 show a state in which the movement in the direction of the arrow Z is further advanced, the compression coil 44 is compressed, and the projection 49 of the leaf spring 45 is detected by the sensor 48. FIG. The sensor 48 is an optical sensor including a light emitting unit and a light receiving unit, and detects interruption of light by the projection 49. Upon detection of the sensor 48, the signal is sent to the system controller. The above-mentioned predetermined amount of compression can be produced by the positional relationship between the sensor 48 and the projection 49.

The signals from the sensors 48 in at least three or more adjusting mechanisms 40 installed on the base 20 are sent to the system controller. Then, in the system controller, all the sensors 4
When the reception is completed from step 8, the moving means is stopped. In addition, with the processing of this signal, the suction function of the suction block 43 is activated, and all the leaf springs 45 are vacuum-sucked to the suction block 47.

In this state, the moving means is driven to move the wafer W downward and gradually move away from the mask M. Then, when the mask M and the wafer W are at a desired distance, the moving unit is stopped. The method by which the adjustment mechanism 40 detects the predetermined amount of displacement is not limited to the method based on the amount of compression by the compression coil. In addition, as long as the stage 10 can hold the wafer W, an opening can be provided at the center thereof. In that case, exposure from both sides of the wafer W can be performed. This is not possible with the conventional gap setting method using the spherical seat method.

[0021]

The mechanism for setting the gap between the mask and the work according to the present invention does not employ a spherical structure which requires a fine surface accuracy in its configuration, and therefore is inexpensive as compared with the manufacturing cost of the spherical seat method.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a main part of a gap setting mechanism according to the present invention.

FIG. 2 is a perspective view showing the structure of an adjustment mechanism 40 shown in FIG. 1 separately.

FIG. 3 is an explanatory view of FIG. 2 viewed from the X direction for specifically explaining a gap setting mechanism between the mask M and the wafer W by an operation of an adjusting mechanism 40 in the embodiment of FIGS. 1 and 2;

FIG. 4 is an explanatory view of FIG. 2 viewed from the Y direction for specifically explaining a gap setting mechanism between the mask M and the wafer W by the operation of the adjusting mechanism 40 in the embodiment of FIGS. 1 and 2;

FIG. 5 is an explanatory view of FIG. 2 viewed from the X direction for specifically explaining a gap setting mechanism between the mask M and the wafer W by the operation of the adjusting mechanism 40 in the embodiment of FIGS. 1 and 2;

FIG. 6 is an explanatory view of FIG. 2 viewed from the Y direction to specifically explain a gap setting mechanism between the mask M and the wafer W by the operation of the adjusting mechanism 40 in the embodiment of FIGS. 1 and 2;

FIG. 7 is an explanatory diagram of FIG. 2 viewed from the X direction to specifically explain a gap setting mechanism between the mask M and the wafer W by the operation of the adjusting mechanism 40 in the embodiment of FIGS. 1 and 2;

FIG. 8 is an explanatory diagram of FIG. 2 viewed from the Y direction for specifically explaining a gap setting mechanism between the mask M and the wafer W by the operation of the adjustment mechanism 40 in the embodiment of FIGS. 1 and 2;

FIG. 9 is an explanatory view of FIG. 2 viewed from the X direction for specifically explaining a gap setting mechanism between the mask M and the wafer W by the operation of the adjusting mechanism 40 in the embodiment of FIGS. 1 and 2;

FIG. 10 is an explanatory diagram of FIG. 2 viewed from the Y direction for specifically explaining a gap setting mechanism between the mask M and the wafer W by the operation of the adjusting mechanism 40 in the embodiment of FIGS. 1 and 2;

FIG. 11 is a diagram showing a conventional alignment method.

FIG. 12 is a diagram for explaining proximity exposure.

[Brief description of reference numerals]

 M Mask W Wafer 1 Light source 2 Elliptical reflecting mirror 3 Integrator lens 4 Collimator lens 5 Stage 6 Spherical seat 7 Moving means 8, 9 Vacuum conduit 10 Stage 11 V-shaped receiver 12 Rigid sphere 13 Tension spring 14 Depression 20 Base plate 30 Column 40 Adjusting mechanism 41 Ball receiver 42 Spline 43 Shaft 44 Compression coil 45 Leaf spring 46 Casing 47 Suction block 48 Sensor 49 Leaf spring convex

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-289553 (JP, A) JP-A-58-75833 (JP, A) JP-A-55-121638 (JP, A) JP-A 57-758 84306 (JP, A) JP 51-23310 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/027

Claims (3)

(57) [Claims] In a gap setting method for positioning a work and a mask in parallel and with a certain gap, first, a work is placed in a state where the work and the mask are not in contact with each other.
Then, the work stage and / or the mask stage holding the mask is moved by a moving means in a direction in which the work and the mask come into contact with each other. Subsequently, at least three work stages or mask stages are provided on the work stage or the mask stage, and when the work and the mask come into contact with each other and the relative movement cannot be performed any more, the driving force from the moving means is absorbed. When the adjusting mechanisms that start to displace make a predetermined amount of displacement, each adjusting mechanism sends a signal to the system controller, and when the system controller receives the signal from all the adjusting mechanisms, the parallelism between the workpiece and the mask is determined. As a state, the movement of the work stage and / or the mask stage is stopped, and each adjustment mechanism is stopped. And moving the work stage and / or the mask stage by a predetermined distance in a direction opposite to the moving direction to form a desired gap. Gap setting method. 2. A work stage for holding a work, a mask stage for holding a mask, and moving the work stage and / or the mask stage in a direction to relatively approach or separate the work and the mask. Moving means, and at least three adjusting mechanisms provided so as to connect the work means or the mask stage to the moving means, wherein the adjusting mechanism drives the moving means in a direction in which the work and the mask come into contact with each other. In the case, when the moving means is continuously driven in the direction even after the work and the mask come into contact with each other, from the time when the work and the mask come into contact and the relative movement cannot be performed any more, That the adjusting mechanism is displaced by a desired amount by absorbing the driving force from the moving means and starting to be displaced. A gap setting mechanism between a work and a mask, comprising: a detecting unit for detecting the displacement; and a holding unit for holding a displacement state at that time. 3. An adjusting mechanism comprising: a casing; a shaft disposed in the casing; a guide member for restricting the movement of the shaft only in a vertical direction; and a first member located in the casing and acting on the shaft. An elastic member, a plate-like elastic member connected to the shaft, holding means for holding the position of the shaft at a fixed position via the elastic member, and detecting means for detecting a displacement amount of the first elastic member And a second elastic member that attracts the shaft and the mask stage with a constant force, and a sphere located between the tip of the shaft and the work stage or the mask stage. Mask gap setting mechanism.