JPS60183788A - Developing unit for printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an apparatus for developing a photoresist formed on a printed circuit board, and in particular to an apparatus for developing a photoresist formed on a printed circuit board, and more particularly, to The present invention relates to a developing device as applied thereto.

[Background of the invention]

An example of a conventional developing apparatus for photoresist formed on a printed circuit board will now be described with reference to FIG. 1st
In the figure, a spray developer tank 1 is provided with a spray nozzle 6 for a printed circuit board conveyed by a horizontal conveyor 5.
This is a developing tank that sprays an organic solvent onto the wiring pattern to develop it. The spray rinse tank 6 is a cleaning tank equipped with a spray nozzle 6 for spraying an organic solvent, and used to wash away the organic solvent containing the photoresist on the printed circuit board with a new organic solvent. In addition, the washing spray tank 4 is
This cleaning tank is equipped with a spray nozzle 6 that sprays water and removes organic solvents from printed circuit boards.

In such a conventional developing device η, when the wiring pattern becomes denser and the interval between the wiring patterns becomes smaller, the following problems arise. That is, in areas where the wiring pattern spacing is small, as the development progresses, the sprayed organic solvent tends to accumulate between the wiring patterns, making it difficult to supply fresh solvent. On the other hand, in areas where the pattern spacing is relatively large, the liquid flows easily, so the sprayed organic solvent does not accumulate, and a sufficient amount of fresh organic solvent is supplied. This difference in the amount of organic solvent supplied results in a difference ζ in the development speed of the photoresist, and the development speed is slow in areas where the wiring pattern spacing is small, and the development speed is fast in areas where the wiring pattern spacing is relatively large. Therefore, if there are areas with different wiring pattern intervals on the same surface of a printed circuit board, the dimensions of the photoresist pattern after development will differ due to the difference in development speed. cannot be applied to

Furthermore, in the horizontal transport spray process, the flow of the sprayed organic solvent on the top and bottom surfaces of the printed circuit board is different, which also results in different photoresist development speeds. Furthermore, even on the top surface of a printed circuit board, the sprayed organic solvent tends to stay in the center, and the organic solvent tends to fall off at the edges, so the development speed varies depending on this, and the pattern size of the photoresist after development. will be different.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to address the above-mentioned problems and to provide a printed circuit board development apparatus that provides uniform wiring pattern dimensions.

[Summary of the invention]

Photoresist development involves dissolving and removing the unexposed photoresist with an organic solvent.In order to make the dissolution rate the same in wide and narrow areas regardless of the pattern spacing, it is necessary to apply an organic solvent to the area to be dissolved and removed. It is good if the supply of is the same. It is best to use immersion to uniformly supply new organic solvent and remove the organic solvent that has dissolved the photoresist, and by adding ultrasonic waves to it, the development speed can be increased.

That is, the present invention provides a developing device that includes an ultrasonic vibrator that emits ultrasonic waves toward the wiring pattern surface of the printed circuit board in a developing tank in which the printed circuit board to be developed is immersed in a developer (organic solvent). It is characterized by

Furthermore, as an example of the method of arranging ultrasonic transducers below, multiple ultrasonic transducers are installed along the route along which the printed circuit board is conveyed into the developer tank, and the wiring pattern surface is intermittently irradiated with ultrasonic waves. Examples are disclosed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. This developing device includes an immersion developing tank 7, a spray +3 ounce tank 6, a washing spray tank 4, a horizontal conveyor 5, and an ultrasonic vibrator 10. The immersion developer Ml 7 is provided with a circulation path through which an organic solvent is supplied from a storage tank 11 by a circulation pump 12 and the overflowing organic solvent returns to the storage tank 11 to keep the liquid level in the immersion development tank 7 constant. ing. In addition, the immersion developer tank 7 is located above and below the horizontal transport conveyor 5 (
A total of 4 ultrasonic transducers 10, 2 each
It is arranged individually. The liquid level height of the immersion developing tank 7 is set to such a level that these ultrasonic imagers 10 are immersed in the organic solvent. The printed circuit board is first transported to an immersion developer tank 7 by a horizontal transport conveyor 5 driven by a drive motor (not shown). As soon as it enters the immersion developing tank 7, it is immersed in an organic solvent, and the unexposed photoresist begins to dissolve. While the printed circuit board is being conveyed horizontally, the unexposed photoresist is gradually melted, and when the printed circuit board passes near the ultrasonic transducer 10, ultrasonic vibration is applied to the printed circuit board, and the unexposed photoresist is dissolved. Dissolution is promoted. Particularly in areas with small wiring pattern spacing on printed circuit boards, immersion alone does not allow sufficient diffusion of organic solvents, which slows down the development speed. Diffusion takes place, and the development speed can be increased.

However, if ultrasonic vibration is applied for a long period of time, the organic solvent will not diffuse sufficiently and the dissolution of unexposed photoresist will be promoted too much, resulting in damage such as a large difference in development speed due to the difference in wiring pattern spacing. It's coming. Therefore, by providing the ultrasonic vibrators 10 at appropriate intervals as in this embodiment, it is possible to solve the problem of frequent customers where the difference in development speed becomes large when ultrasonic vibration is applied intermittently to the printed circuit board.

In this way, the printed circuit board is transported and developed while alternating between simply immersing the board in an organic solvent and irradiating it with ultrasonic waves. Since development is performed by immersion in an organic solvent, there is no difference in development speed due to differences in wiring pattern spacing, which was a problem with conventional spray development. In addition, the difference in development speed between the upper and lower surfaces of the printed circuit board can be determined by installing ultrasonic vibrators 10 on the upper and lower sides of the horizontal transport conveyor 5, and adjusting the strength of the ultrasonic vibration.
In other words, the distance between the ultrasonic transducer 10 and the printed circuit board may be set so that the strength of cavitation is constant on the printed circuit board on the horizontal conveyor 5.

The printed circuit board emerging from the immersion developer tank 7 enters a spray rinse tank 5, where the organic solvent containing the photoresist adhering to the printed circuit board is washed away with fresh organic solvent. Since the dissolution of the unexposed photoresist on the printed circuit board is almost completed in the immersion developer bath 7, the dissolution of the unexposed photoresist in the spray rinse bath 3 is small, so that the patronage caused by spraying can be ignored.

According to this embodiment, development can be performed to obtain uniform photoresist pattern dimensions regardless of the difference in the wiring pattern spacing of the printed circuit board. Hereinafter, examples of the effects of the present invention will be specifically explained with reference to the drawings. FIG. 3 shows the mask pattern width and the amount of change in the photoresist pattern width from the mask pattern width when conventional spray processing is performed. In the figure, the horizontal axis is the mask pattern width, and the vertical axis is the amount of change in the photoresist pattern width. FIG. 4 is a diagram showing the same correlation as FIG. 5 when development is performed by irradiating ultrasonic waves while immersing according to the present invention. In conventional spray processing, when the mask pattern width changes from 70 μm to 300 μm, the amount of change in photoresist pattern width after development is +6
．． The difference in the amount of change is 5.0 μm. On the other hand, in the device of the present invention that irradiates ultrasonic waves while being immersed, the difference is from +2.4 μm to +0.4 μm, and the difference in the amount of change is 2.0 μm.

Therefore, the difference in the amount of change in the present invention is 40 inches compared to that in the case of spray processing, which has the effect of greatly improving the uniformity of photoresist pattern dimensions.

Note that when the printed circuit board has a wiring pattern on only one side, the ultrasonic transducer 10 may be provided only on the upper side or the lower side.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a developing device for a printed circuit board that provides uniform wiring pattern dimensions.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the configuration of a conventional developing device, and FIG. 2 is a side view showing the configuration of a developing device according to an embodiment of the present invention.
FIG. 5 is a diagram showing an example of the correlation between the mask pattern width and the amount of change in the photoresist pattern width from the mask pattern width when developed with a conventional developing device, and FIG. 4 is a diagram when developed with the developing device of the present invention. FIG. 3 is a diagram showing a correlation example similar to FIG. 3 of FIG. DESCRIPTION OF SYMBOLS 1... Spray developing tank, 3... Spray rinsing tank, 4... Washing spray tank, 5... Horizontal transport conveyor, 6... Spray nozzle, 7... Immersion developing tank, 10...・Ultrasonic vibrator. Representative Patent Attorney Akio Takahashi%i / Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a developing device for developing a photoresist formed on a printed circuit board, the wiring pattern of the printed circuit board is placed in a developing tank in which the printed circuit board to be developed is immersed in a developer solution. A developing device characterized by being provided with an ultrasonic vibrator that emits ultrasonic waves toward a surface. 2. A plurality of the ultrasonic transducers are provided along the route along which the printed circuit board is conveyed into the developer tank, and the wiring pattern surface is intermittently irradiated with ultrasonic waves. A developing device according to claim 1.