JP2798158B2 - Film exposure equipment - Google Patents

Description

The present invention relates to a film exposure apparatus most suitable for manufacturing a film circuit board used for mounting, for example, a TAB (Tape Automated Bond-ing) type electronic component. is there.

[Prior Art] In the production of a film circuit board used for mounting a semiconductor integrated circuit or a TAB type electronic component, a photolithography technique is generally used. This photolithography usually includes a photoresist coating process, a mask aligning exposure process for transferring a circuit pattern, a developing process,
This is performed through an etching step, a photoresist removing step, and the like.

In the exposure step of this step, an exposure apparatus for transferring a circuit pattern to a photoresist is required. As the exposure apparatus, there are a contact exposure method and a proximity exposure method for forming an equal-magnification image, and a projection exposure method for forming a reduced image or an enlarged image using an imaging lens is preferable.

In such an apparatus, the film before exposure is held on a film supply reel, and the film supplied from this reel is transported to an exposure position. Then, the exposed film is taken up by a film take-up reel.

However, in such an apparatus, it is difficult to accurately hold the film to be exposed at the exposure position (that is, to keep the distance between the reticle and the film at a predetermined interval), and the projection exposure is performed on the film. There is a problem that the size (magnification) of the image is out of order.

To solve this problem, for example, Japanese Patent Laid-Open No.
No. 293248 proposes a method in which a film is transported in a vertical direction, and a reticle on which a wiring pattern is formed is projected and exposed from a projection optical system whose image plane side is telecentric from a direction perpendicular to the horizontal direction (horizontal direction).

In the case of this device, since a telecentric projection optical system is used, exposure can always be performed at a predetermined position and size even if the film is slightly shifted.

[Problems to be Solved by the Invention] However, in the above-described conventional technology, since a telecentric projection optical system is used, the apparatus becomes expensive.

Also, a large number of rollers and a reel for holding the film are required to transport the film, and the positional relationship of the projection optical system deviates from the set value due to the vibration, the precision during the production of the original image (reticle), and the expansion and contraction of the work. This can cause defects. This phenomenon can occur not only due to the vibration of the device but also due to an increase in the outside air temperature.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances of the related art, and has as its object to provide a film exposure apparatus capable of correcting a positional deviation of a projection optical system.

[Means for Solving the Problems] To achieve the above object, the present invention provides a reticle,
A non-telecentric projection lens for projecting the image of the reticle onto a vertical projection surface, a transport mechanism for feeding the belt-like film one frame at a time in the vertical direction, and positioning one frame of the film on the vertical projection surface; Detecting means for detecting a displacement from a horizontal projection surface of one frame of the film, and controlling means for displacing a reticle and / or a projection lens in an optical axis direction so as to correct a change in a projection magnification due to the detected displacement. Is provided.

[Operation] According to the above-described means, even when the projection optical system is misaligned due to the processing accuracy or the influence of the outside air, the projection lens and the reticle of the projection optical system are adjusted so that the displacement is corrected. Displace in the direction. Therefore, it is possible to eliminate the exposure failure due to the displacement of the projection optical system, and to improve the product yield.

Example An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing one embodiment of a film exposure apparatus according to the present invention.

The optical mechanism includes an irradiation unit 1 that generates light, and a projection optical system 2 that uses the light from the irradiation unit 1 to project a reticle set in an optical path onto a film F of an exposure unit. An exposure unit 3 that guides and positions the film F inserted therein is provided so as to face the projection optical system 2. Further, an auxiliary roller 4 for supplying the film F smoothly is disposed above the exposure unit 3.

A film supply reel 5 for supplying the film F is provided adjacent to the auxiliary roller 4, and a film take-up reel 6 for winding the exposed film F is provided below the film supply reel 5. I have. The film F used here has a width of, for example, 35 mm and a thickness of 110 μm.

The irradiation unit 1 includes a discharge lamp 11 (a lamp that efficiently radiates a photosensitive wavelength of a resist, for example, an ultra-high-voltage discharge lamp of 500 W) serving as a light source, and an elliptical condensing mirror 12 that guides light emitted from the discharge lamp 11 in one direction. An integrator lens 13 for condensing the light from the elliptical condensing mirror 12, a reflecting mirror 14 for reflecting the light from the lens 13 in a horizontal direction, and a condenser lens disposed on an output optical path of the reflecting mirror 14. Consisting of each of the 15

Further, the projection optical system 2 is configured such that a reticle 20 can be disposed on the exit optical path of the condenser lens 15 and includes a non-telecentric projection lens 21 disposed behind the reticle 20. The circuit pattern for the frame is projected on the exposure position 31 of the film F in the exposure unit 3.

Further, in the exposure section 3, a pair of step feed rollers 32 and 33 are provided on the upper side of the film F in pressure contact with both surfaces thereof, and a sprocket roller 34 is disposed on a lower part of the step feed roller 33 on the lower side. A pressing roller 35 is in pressure contact with the sprocket roller 34 with the pressure roller 35 interposed therebetween. The sprocket roller 34 has projections provided at regular intervals in the circumferential direction of the peripheral surface, and the projections are fitted into the perforations opened at regular intervals on the side ends of the film F, and are rotated. The transport of F is performed. The step feed rollers 32 and 33, the sprocket roller 34, the pressing roller
35 constitutes a transport mechanism.

Further, a detection unit 36 (detection means) for detecting the displacement of the projection optical system 2 is provided on the back side of the film F so as to face the exposure position 31.

The detection unit 36 is connected to a system controller 7 as control means. The system controller 7 includes a reticle movement adjustment mechanism 8 for moving the position of the reticle 20 and a projection lens movement mechanism 9 for moving the projection lens 21. Is connected.

As shown in FIG. 3, the film F is provided with an F10 to which a circuit pattern is transferred, a film-side mark F11 described later, and a performance to be fitted into the sprocket roller 34.

FIG. 3 is a view of the film F viewed from the projection lens 21 side.

In the above configuration, the unexposed film F is wound around the film supply reel 5. When performing exposure, the film F is pulled out from the film supply reel 5, and is wound on the film take-up reel 6 via the auxiliary roller 4 and the exposure unit 3. In the exposure section 3, the film F is sequentially inserted between the step feed roller 32 and the step feed roller 33 and between the sprocket roller 34 and the pressing roller 35, and the projection optical system 2 performs exposure at this portion.

In the exposure, the discharge lamp 11 is turned on, and this light reaches the exposure position 11 through the path of the integrator lens 13 → the reflecting mirror 14 → the condenser lens 15 → the reticle 20 → the projection lens 21, and the circuit pattern formed on the reticle 20 Is projected onto the surface of the film F on the exposure position 31. After projecting for a certain period of time, the discharge lamp 11 is turned off (or light is blocked using a shutter), and the step feed rollers 32, 33,
The sprocket roller 34 and the film take-up reel 6 are rotationally driven to convey the film F by a predetermined length. At this time, since the sprocket roller 34 rotates while fitting into the performance of the film F, the film F can be transported with high accuracy. By performing the above operations one by one, exposure over the entire length of the film F is performed.

In this way, the film F fed step by step for each frame
, A projected image is detected to confirm whether or not there is displacement between the projection optical system 2 and the projection surface. This operation will be described below.

The reticle 20 is provided with two reticle-side marks in addition to the circuit pattern to be projected. This mark indicates a portion that transmits light in a cross shape. In film F,
Film side mark F11 corresponding to this reticle side mark
(For example, holes) are formed. The detector 36 is provided with a photodetector made of a photodiode,
The light that has passed through the reticle mark is the film mark F11.
Is received via the FIG. 3 shows a state in which the cross of the reticle side mark matches the hole of the film side mark F11.

 Next, this control will be described.

When one frame of the film F is conveyed to the exposure position, the light is transmitted through the reticle-side mark from the irradiation unit 1 and is projected onto the film F by a wavelength that does not expose the film F. At this time, although not shown, a filter that transmits a wavelength that does not expose the film can be interposed in the optical system to irradiate the reticle-side mark.

From this state, the reticle 20 is scanned (moved) in the feed direction (vertical direction) of the film F. As a result, as shown in FIG. 3, the cross of the reticle side mark is scanned in the X direction, and the detector
Received by 6. At this time, the electric signal obtained by the detection unit 36 becomes as shown in FIG. 2 with the scanning.

As shown in FIG. 2, a rising portion T1 at which the projected image begins to overlap the reticle-side mark on the film-side mark, a flat portion T2 at which the overlapping area of both is substantially constant, and a projection position of the reticle-side mark at the film-side mark A trapezoidal waveform consisting of a falling portion T3 that begins to deviate from

Therefore, while moving the reticle 20 in the X direction (vertical direction), the flat portion T2 overlapping area of the mark is at a maximum, for example, by detecting the position at time t ₃ of the center position, which the system controller 7 Stored as position information. Further, the reticle 20 is moved in the X direction, and another film-side mark is similarly detected.

When the detection of the positions of the two film side marks in the X direction is completed in this way, the reticle 20 is similarly moved in the Y direction (horizontal direction) to detect the positions of the two film side marks. When the positions of the reticle 20 and the projection lens 21 are as set, the positional relationship between the reticle-side mark and the film-side mark F11 is as shown in FIG. However, if this relationship deviates, the X of the two marks
The distance between the direction and the Y direction is displaced, which causes the projection magnification to deteriorate. This displacement can be known from the above-described position detection information. When these detection signals are input, the system controller 7 sends signals to the reticle movement adjusting mechanism 8 and the projection lens moving mechanism 9 to move the projection lens 21 and the reticle 20, and restore the positional relationship.

In this way, one of the films F fed stepwise
An inexpensive optical system and a control mechanism can be used to detect whether or not the projection magnification can be accurately set for each frame.

[Effects of the Invention] As is clear from the above, according to the present invention, a projection optical system for receiving light from a light source and projecting a reticle circuit pattern on a belt-like film disposed at an exposure position, and the film Transport means for transporting one frame at a time from the vertical direction to the exposure position, detection means for detecting a displacement from a horizontal projection plane of one frame of the film at the exposure position, and projection magnification of the detected displacement. Control means for displacing at least the reticle or the projection lens in the optical axis direction so as to correct the change is provided, so that exposure defects due to the displacement of the projection optical system are eliminated, and the product yield is improved. Can be.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a film exposure apparatus according to the present invention, FIG. 2 is a waveform chart showing a detection signal waveform by a detection unit, and FIG. 3 explains how the film side mark and the reticle mark overlap. FIG. In the figure. 1: Irradiation section, 2: Projection optical system 3: Exposure section, 4: Auxiliary roller 5: Film supply reel 6: Film take-up reel 7: System controller 8: Reticle movement adjustment mechanism 9: Projection lens movement mechanism 11: Discharge lamp 20: Reticle 21: Projection lens 31: Exposure position 35: Press roller 36: Detector, F: Film

Claims (1)

(57) [Claims] 1. A reticle, a non-telecentric projection lens for projecting an image of the reticle on a vertical projection surface, and a belt-like film are fed one frame at a time in the vertical direction, and one frame of the film is sent on the vertical projection surface. A transport mechanism for positioning, a detecting means for detecting a displacement from a horizontal projection plane of one frame of the fed film, and a reticle and / or a projection lens so as to correct a change in a projection magnification due to the detected displacement. And a control unit for displacing the light in the optical axis direction.