JPS63155615A - Photoresist wafer exposure system - Google Patents

Abstract

PURPOSE:To execute the highly accurate alighment by a method wherein the connection among a wafer, a gauge and a mask frame is detected by making use of the air pressure at a bearing part which is composed of a spherical material and a spherical support and can be inclined freely in the 360 deg. direction while the wafer is made to face a pattern mask. CONSTITUTION:A prealigned photoresist wafer W is mounted on a wafer stage 10. After a gauge arm 4 has been advanced, the wafer stage 10 is pushed up. The under surface of a hollow-cylindrical gauge 3 on the gauge arm 4 is pressed to the periphery of the wafer W while its top is pressed to a mask frame 2. The wafer stage 10 is supported on a spherical and sliding part which can be inclined horizontally in the 360 deg. direction, that is to say, on a spherical material 12 and a spherical support 14. The bottom face of the frame 2 and the face of the wafer W on the wafer stage 10 are made to face in parallel with each other. The gap between the material 12 and the support 14 is made to be smooth by compressed air. The contact at both edges of the gauge 3 is detected by the compressed air. By this method, the highly accurate alignment is executed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a photoresist wafer exposure apparatus used for printing integrated circuit patterns in the integrated circuit manufacturing process in the electronics industry, and particularly to a photoresist wafer exposure apparatus. The present invention relates to the structure of the holding portion and the positional and directional alignment with the pattern for printing, that is, the alignment means.

(Prior Art) In general, when handling an article whose surface is coated with a photoresist film, that is, a photoresist wafer, care must be taken not to rub the surface of the wafer in order to avoid staining or damage.

Furthermore, when manufacturing a semiconductor element having a three-dimensional structure, each photoresist wafer is divided into two sides, the front and the back, and patterns are printed on each side at predetermined positions. In this case, in order to know the position of the pattern baked on the photoresist wafer, an orientation flat of a straight notch is provided on the outer circumference of each photoresist wafer, and a rough orientation flat is provided during the second baking. So-called pre-alignment is performed to match the positions of the patterns.

Pre-aligned photoresist wafer
Patent 1ill dated March 6, 1996
4) Alignment of each pattern on the front and back sides Alignment with the patterns sequentially printed on both the front and back sides, as in the method described in claims 1 and 2 of the exposure apparatus
After performing (alignment), the photoresist wafer is brought close to or in close contact with the pattern mask and exposed.

(Problems to be Solved by the Invention) During the above alignment, the photoresist wafer is moved in the orthogonal direction X-Y and rotationally on a plane parallel to the pattern mask in a non-contact state. ,
In other words, it is desired that they face each other via an alignment gear.

However, in the case of a mechanism that changes the distance between two surfaces separated from each other, it is difficult to support these two surfaces in accurate parallelism, and furthermore, the photoresist wafer constituting one surface has thickness deviations and Since curvature was also expected, it was difficult to obtain highly accurate parallelism.

Further, during exposure after alignment, it is generally required that the pattern mask and the photoresist wafer be in perfect contact, although this varies depending on the type of light source used for exposure (baking). In this case, of course, care must be taken not to apply more force than necessary to the photoresist wafer or the glass pattern mask.

Furthermore, during alignment, since the alignment marks are observed through a microscope, the field of view of the optical system is limited, and there is a demand for an improvement in the drawback that it is difficult to capture the alignment marks.

(Means for Solving the Problems) In order to solve the above problems, we provide the following photoresist wafer exposure apparatus.

1. A hollow cylindrical gauge with a predetermined length that can move forward and backward between the mask frame that supports the pattern mask, the wafer stand that supports the photoresist wafer, and these image frames, and whose inner diameter is at least larger than the diameter of the effective range of the photoresist wafer. and a gauge arm to which a gauge arm is attached, and further includes a bowl-shaped spherical sliding support mechanism disposed on the support portion of the wafer table with the center facing upward, and supplying pressurized fluid to the gap between this one dynamic surface. means for detecting the internal pressure in the gap, and means for bringing the lower surface of the mask frame into pressure contact with the wafer stand via the gauge, and detecting the internal pressure in the gap by the detection signal of the internal pressure in the gap. Pressure welding of 11
4g1 photoresist web exposure system W.

2. In the photoresist wafer exposure apparatus described in the preceding section, respective means for rotating and moving the pre-aligned photoresist wafer in a plane parallel to the pattern mask and along X-Y axes orthogonal to each other; A means for detecting the position of the photoresist wafer corresponding to the pattern mask, a means for storing the rotation and movement amounts, and a work origin function electrical unit for roughly setting the direction and position of the photoresist wafer based on these stored values. A photoresist wafer exposure device equipped with a circuit.

(Function) In the method described in item 1 above, a pre-aligned photoresist wafer is placed on a wafer stand, a gauge arm is advanced, the wafer stand is pushed up, and the hollow cylinder on the gauge arm is pushed up. The lower surface of the gauge is pressed against the periphery of the photoresist wafer, and the upper surface is pressed against the mask frame.

On the other hand, since the wafer stand is supported on a spherical sliding part that can be tilted horizontally 360 degrees, the bottom surface of the mask frame and the surface of the photoresist wafer on the wafer stand are They are forced to face each other in a parallel state. Moreover, the sliding movement of the gap between the spherical sliding parts is made smooth by pressurized air, and the air pressure detects pressure contact between both ends of the gauge to prevent excessive pressurization.

That is, the wafer stand can be moved close to the mask frame by controlling the length of the gauge with precision corresponding to the thickness of the mask frame, and the photoresist can be applied to the mask pattern without contact, without the risk of damaging the pattern mask. It is possible to obtain an alignment gap for rotating and moving the wafer on parallel planes with highly accurate dimensional spacing.

Therefore, increasing the accuracy of microscopic alignment,
In addition, the reproducibility of the gap immediately before the alignment gap (alignment gap) during exposure is high, and the dimensional accuracy of the gap is also excellent. By lifting the photoresist wafer toward the pattern mask, sufficient adhesion can be achieved without fear of damaging the pattern mask.

The method described in item 2 of the above means rotates (θ angle) or moves (X-axis) the photoresist wafer to be printed when performing high-precision alignment of the pre-aligned photoresist wafer with an exposure device. , Y-axis) and locate the alignment mark on the photoresist wafer with a high magnification microscope.

However, since the optical field of view of the microscope is small, the device of the present invention stores and sets these values during operation, and prior to alignment work, the rotation and movement are performed in accordance with the stored values, and alignment is performed. Plan to speed up work.

(Embodiment) FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, and a portion thereof is shown broken away for explanation. , FIG. 2 is a block diagram of the electric circuit of the origin work function utilized in the present invention.

In Figure 11EI, (1) is a pattern mask, (2) l
;i A pattern mask (1) is suctioned to the lower surface of the window periphery by vacuum means (not shown) in a window frame-shaped mask frame.

The pattern mask (1) is a transparent glass plate with a
A pattern to be printed is formed on a photoresist wafer W (hereinafter referred to as wafer) that is exposed to light for printing.

Note that alignment marks are attached to this pattern. Furthermore, this bottom surface and pattern mask (
1) The thickness D between the bottom surface and the top surface that it contacts is machined with high precision.

(3) is a gauge cylinder (hereinafter referred to as cage) having a hollow cylinder length L, and the inner diameter of the gauge cylinder is at least larger than the diameter of the effective usable range of the wafer W and smaller than the diameter of the wafer W. (4) supports the gauge (3) and the mask frame (
2) and the wafer W. As shown in the figure, a flange-like protrusion is provided on the upper outer periphery of the gauge (3), and the gauge arm (4) is attached to the gauge arm (4) so as to be slidable up and down. This prevents the attached gauge from falling off. (5) is an adsorption plate made of a transparent glass material, and ventilation holes (6) are distributed in areas other than the portion through which light passes for alignment. (7) is an intermediate barrel into which the lens barrel of the microscope is inserted, and a negative pressure pipe (8) to the ventilation hole (6) passes through it vertically, and a microscope lens barrel insertion hole (9) is narrowed on the side. ing. (10) is the suction plate (
The wafer stand (11) that holds the wafer stand (5) is a flexible material seal that is airtightly attached to the wafer stand (10) surrounding the suction plate (5), and when the gauge (3) is removed, the wafer stand (11) 1
0) comes into contact with the lower surface of the mask frame (2) in a state close to the pattern mask (1), and exhausts air between the wafer W and the pattern mask (1) through the ventilation hole (6) to facilitate close contact. Make it.

(12. A spherical member of the spherical sliding bearing according to claim 1, whose central portion passes through a pipe (13) connected to the negative pressure pipe (8).

In (14), the spherical part is a member, and the central part is the pipe (13).
) is provided with a sliding surface seal (16) that largely surrounds the area.

-10~ On the other hand, a pressurized air inlet (15) is provided on the side surface, and the spherical receiver supplies pressurized air to the sliding surface between the member (14) and the spherical member (12), and provides fluid support for the spherical member (12). smooth 1
enable habits.

In (17), the spherical receiver is disposed below the member (14), and the intermediate cylinder (7), the wafer frame (10), and the suction plate (
5) etc. Orthogonal axis X in the direction of the surface of pattern mask (1)
-Y movement and rotation θ drive device (1st) is a device that moves the suction plate (5) and others in the vertical direction Z toward the pattern mask (1).

A pressure detector (not shown) is provided in the pressure air supply line to the pressure air inlet (15), and the Z-axis drive mechanism (18
), the mask frame (2), the gauge (3), and the wafer W are connected, and when the sliding surfaces of the spherical member (12) and the spherical receiver are brought into pressure contact with the member (14), this pressure detector It can be detected by

Pattern mask (1) and Z perpendicular to the surface of the wafer W
Stop pushing in the direction. In reality, if the pressing in the Z direction is stopped at the same time as the pressure is detected, the accuracy of the pressing may become unstable, so a slip mechanism is provided in the drive system in the Z direction to The timer device is started by the detection signal, and the parallelism between the pattern mask ( ) and the wafer W is achieved with high precision, which is necessary to stabilize the pressure contact and obtain the desired alignment gear.

Note that the same result can be obtained even if the pressure welding in the Z direction is feedback-controlled using the detection signal.Furthermore, the spherical member (12) and the spherical receiver are provided between the member (14). The same function as in the embodiment can be obtained even if a liquid is used in place of a gas such as air.Next, in order to obtain the desired alignment gap, the length L of the gauge and the thickness D of the mask frame must be adjusted. The pattern mask (
1) in the Z direction.

In this case, a pulse motor is used for driving in the Z direction by the Z-axis drive mechanism (18), and movement in the Z direction is performed at a pitch of 1 micrometer with one pulse applied to the pulse motor, and the desired movement distance is can be obtained with high precision.

When bringing the pattern mask (1) and wafer W into close contact for exposure, the wafer W is further pushed toward the pattern mask (1) in accordance with the thickness of the alignment gear. At this time, the flexible wafer seal (11) comes into contact with the back side of the mask frame (2), and the air is exhausted from the ventilation hole (6), maintaining negative pressure between the pattern mask (1) and the wafer W. The dimensions in the Z direction are also the same as the length of the gauge (3) and the mask frame (2).
) is used as a reference, there is no risk of excessively pressing the wafer W against the pattern mask (1).

In Figure 2, (17) is X as in Figure 1.

The Y and θ drive mechanisms (19) are pulse motors for driving X-axis, Y-axis, and θ-angle rotation, and are attached to the parts (22) via threaded rods (20) and feed nuts (21), respectively. The upper spherical member (12), suction plate (5), etc. are moved in x and Y directions and rotated θ to capture the alignment mark of the wafer W placed on the suction plate (5) in the field of view of the microscope. and perform alignment.

(23) are x, y, and θ sensors, and the rotation of each threaded rod (20) is detected as a pulse by the amount of X and Yθ movement of the suction plate (5), that is, the wafer W, using an optical sensor. It is sent to storage means (24).

Note that the amount of movement in the X and Y axes for one pulse is 1 micrometer similarly to the Z axis, and the θ angle is also set to be approximately the same length around the outer periphery of the wafer W.

(25) is the operation panel, (26) is the pulse generator and the operation panel (
25) sends each pulse to the pulse motor (19), and the x, y, θ drive mechanism (17)
to align the target wafer W in front of the pattern mask (1) across the alignment gap.
·I do.

(27) is an accumulation circuit that individually calculates the detection pulses of each sensor (23), and these integrated values correspond to the amounts of movement in X, Y, and θ at that time.

These accumulated values are stored in the storage means (24) according to commands from the operation panel (25), and read by the operation panel (25) as needed to send pulses equal to and opposite to the accumulated values to the pulse generator (26). to return the wafer frame (10) to the work origin.

The printing of a large number of pre-aligned wafers W is a work, and when the work starts, the first wafer W is returned to the work origin when the alignment of the first wafer W is completed, and the memorized values at that time are left behind, and the second wafer W is When aligning the wafer W thereafter, the stored value is repeatedly set on the operation panel (25). As a result, the alignment mark of the pre-aligned unprocessed wafer W is within or near the field of view of the microscope, and alignment work can be performed quickly.

The stored value is updated with data for each alignment, and the pre-alignment mechanism is feedback-controlled using the data, which can be expected to speed up the operation.

(Effects of the Invention) 1 According to the invention described in claim 1, the spherical member (12) and the spherical portion are supported by the member (14) so as to be tiltable in a 360 degree direction, and are supported accurately on both upper and lower surfaces. The parallelism is determined by using a gauge cylinder and by using the air pressure of the support section to detect the connection between the wafer W, the gauge, and the mask frame, so that the wafer W is correctly parallel to the pattern mask (1). Therefore, it is possible to provide a photoresist wafer exposure apparatus that enables highly accurate alignment without contact and is free from the risk of applying abnormal loads to various parts.

2 Special i! According to the invention set forth in claim 2, when using a high-magnification microscope to perform highly accurate alignment of the pre-aligned wafer W, the alignment mark on the wafer W is Although it is difficult to capture a photoresist wafer, the work is simplified by storing and utilizing the actual alignment data of the X, Y axes and rotation angle θ, and capturing the alignment mark of the wafer W within the field of view in advance. Exposure equipment can be provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view for explaining the structure of an embodiment of the present invention, with a portion broken away. FIG. 2 is a block diagram for explaining the operation of an embodiment of the present invention. Pattern mask (1) Mask frame (211 gauge (3) Gauge arm (4) Suction plate (5)
) Vent hole (6) Intermediate barrel (7) Negative pressure line (8) Lens barrel insertion hole (9
) Wafer frame (10) Wafer seal (11)
Spherical member (12) Pipe line (13) Spherical part is member (14) Pressure air inlet (15) iM moving surface seal (16)
) x, y, θ drive mechanism (17) Z-axis drive mechanism (18) Pulse motor (19) Threaded rod (
20) Feed Nand (21) Attach part (2)
2) Sensor (23) Storage means (24) Operation panel (25) Pulse generator (26) Integration circuit (27) Patent applicant Dinis Giken Co., Ltd. Engraving of drawings (no change in content) Material II ¥1 42 drawing procedure (Amendment form) % form % 1, Indication of case 1985 Patent application No. 302612
No. 2, Name of the invention Photoresist wafer exposure device 3 Relationship with the case of the person making the amendment Patent applicant address: 425-4 Kuze Oyabucho, Minami-ku, Kyoto City, No attorney 5, Date of amendment order: March 1988 31st (shipment date) 6. Subject of amendment 1, "Number of inventions stated in the scope of claims" section 2 of the application, Drawing 7, Contents of amendment 1, As per the attached application.

Claims (1)

[Claims] 1. A mask frame that supports a pattern mask, a wafer stand that supports a photoresist wafer, and a wafer stand that supports a photoresist wafer, which can be moved back and forth between these frames, and whose inner diameter is smaller than the diameter of the photoresist wafer, and which has an effective usage range. a gauge arm to which a gauge of a predetermined length of a hollow cylinder, which is at least larger than the diameter of the hollow cylinder, is attached; means for supplying pressure fluid to the gap between the sliding surfaces; means for detecting the internal pressure in the gap; and means for bringing the lower surface of the mask frame into pressure contact with the wafer stand via the gauge; A photoresist wafer exposure apparatus that controls pressure contact between the two frames based on a detection signal of the internal pressure of the frame. 2. In the photoresist wafer exposure apparatus according to claim 1, the pre-aligned photoresist wafer is rotated and moved along mutually orthogonal X and Y axes in a plane parallel to the pattern mask. a sensor for detecting the position of the photoresist wafer corresponding to the pattern mask; a storage means for storing the rotation and movement amounts; A photoresist wafer exposure apparatus equipped with a work origin function electrical circuit for roughly setting the direction and position.