JPS6244718A - Pattern exposing device - Google Patents

Abstract

PURPOSE:To obtain a device which eliminates the need to store a wiring pattern mask and suits to various kinds of small - medium quantity production without spoiling productivity by providing a computer which reads stored graphic data and controls the pattern of a variable pattern mask. CONSTITUTION:A light source 1 for exposure, the variable pattern mask 3 where numbers of liquid crystal picture elements are arrayed on a two-dimensional plane, and a body to be exposed are arranged on the same optical path, and this exposing device consists of a liquid crystal control circuit 11 which controls the liquid crystal of the pattern mask for each picture element, a storage device 14 which is stored with graphic data on a wiring pattern to which a printed board is exposed, and the computer 13 for control which reads graphic data out of the storage device 14 and sends wiring pattern information necessary for the 1st exposure to the liquid crystal control circuit 11. Consequently, various kinds of wiring pattern masks need not be formed and stored at an actual article, and stored in the form of the graphic data in the storage device 14 and read out selectively by the control computer 13 in a short time when necessary, thereby producing a small quantity of various kinds of printed boards efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a wiring pattern on a photoresist for chemically etching copper foil used in the manufacturing process of printed wiring boards (printed boards) for electronic circuits, etc. The present invention relates to a pattern exposure device that can be used for exposure, etc.

BACKGROUND OF THE INVENTION FIG. 2 shows a part of a typical printed board manufacturing process. FIG. 2A shows the exposed state, in which a copper foil 18a is pasted on the surface of the substrate 19, and a photoresist 17a is coated on the entire surface of the copper foil.

Light from a light source 15 (indicated by a dotted line) is irradiated onto this 7-photoresist through a wiring pattern mask 16.
i, B, I'm-27KJ""61""""The black colored parts block light, and the transparent parts allow light to pass through.

The part of the photoresist that is exposed to light reacts with light and hardens.
The parts that are not exposed to light do not change qualitatively.

Next, when this plate is placed in a solvent solution of 7 Otoresist, the second
As shown in Figure B, the hardened portion of the photoresist 17b remains and the rest is melted and removed. The copper foil surface is exposed in the removed portion.

The board is then placed in a copper solvent solution, which removes the exposed copper foil. Finally, when the photoresist (17b) remaining after hardening is removed with a solvent, as shown in Figure 2C,
The copper foil 18b according to the wiring pattern remains on the board.

The above printed board manufacturing method is suitable for mass producing printed boards with the same wiring pattern.The exposure process can be repeated many times using a single wiring pattern mask, and the solvent treatment process is Multiple sheets can be placed in a liquid tank at once.

Problems to be Solved by the Invention However, there are problems in producing small quantities of printed boards of various types with different wiring patterns.

In order to do this, it is necessary to prepare in advance ζ-turn masks for the various types of wiring that are required, and to selectively take them out in a short period of time and attach them for exposure many times. Mounting for this exposure requires highly accurate positioning, and in particular in multilayer laminated printed boards, pattern alignment of each layer is important, and the time required is long.

Another problem is how to store such a wide variety of wiring pattern masks in large quantities.

For this reason, there is an exposure method that does not use a wiring pattern in manufacturing printed boards for large computers.

This method uses a point light source such as a laser beam as a light source, stores the graphic information of the wiring pattern in a storage device, and uses a control computer to read out the graphic information while controlling the movement of the position where the light is applied to draw and expose the wiring pattern. This is the way to do it.

The problem with this method is that the area of light is a point, so it takes a long time to apply the light to the required area of the entire printed board, so direct exposure to the printed board is not practical, and it is not suitable for mask production. In addition, the price of the equipment has become expensive.

The present invention solves the above-mentioned conventional problems, and is suitable for small to medium volume production of printed circuit boards, etc., without compromising productivity even in multi-product production, and eliminating the need to store wiring pattern masks. A pattern exposure device is provided.

Means for Solving the Problems The present invention arranges a light source for exposure, a variable pattern mask in which a large number of liquid crystal pixels are arranged on a two-dimensional plane, and an object to be exposed on the same optical path. The variable pattern mask is composed of a control computer that stores graphic data of an exposure pattern to be exposed to light, reads out the graphic data, and controls the pattern of the variable pattern mask. Furthermore, it has a configuration including a tape knife that supports the object to be exposed and is movable in two orthogonal axes directions, and seven light beams.

Effect By using the above-mentioned means, for example, in the production of a wide variety of printed circuit boards in small quantities, it is not necessary to prepare and store various types of wiring pattern 7 masks in advance and to selectively input graphic data using a control computer. The variable pattern mask is read out from the storage device, and the necessary wiring pattern is configured in a short time. In addition, it is possible to easily deal with large-sized objects to be exposed by moving the table, and compared to point light sources such as laser beams as mentioned in the conventional example, the exposure area is wider and productivity is better.It has an excellent utility model effect. It is something.

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

Figure 1 shows the overall configuration. Light emitted from a light source 1 passes through a shutter 2 when it is open, passes through a variable pattern mask 3 shown enclosed by a dotted line, and is enlarged or reduced by a lens 4. The object to be exposed, in this case the surface of a printed board 6 coated with photoresist, is irradiated. This is the basic exposure optical path. The variable pattern mask 3 consists of a deflection plate 3a, a liquid crystal 3b, and the other deflection plate 3C. This configuration and operation will be explained in detail using FIG. 3.

Thin transparent electrodes M3b-2 and 3b-4 are formed on the inner surfaces of the two glass plates 3b-1 and 5b-s, respectively, and a liquid crystal 3b-3 is sandwiched between them. It is a typical LCD panel. There are different types of liquid crystals with different operating principles, but here we will use Twisted-Nemat (Twisted-Nemat), which is often used in light-transmissive liquid crystal TVs, as an example.
ic) method.

In FIG. 3A, switch 11-2 is connected to power supply 11-1.
Since the electrodes 3b-2 and 3b-4 of the liquid crystal are open, no voltage is applied to the liquid crystal electrodes 3b-2 and 3b-4, so there is no electric field in the liquid crystal 3b-3.

A TN liquid crystal is made so that its molecular orientation is twisted by 90 degrees when there is no electric field. Therefore, the incident light 2 to the liquid crystal
When θ passes through the liquid crystal, it becomes output light 21a with a deflection plane rotated by 90°.

A polarization filter 3a is provided on the incident light side, and only light with a certain polarization plane is incident on the liquid crystal.

On the other light exit side, a deflecting plate 3C is arranged on the deflecting plate 3a.
As a result, the light 21a of the deflection plane rotated by 90 degrees by passing through the liquid crystal is
It can pass through the deflection plate 3C.

In FIG. 3B, since the switch 11-2 is closed, the voltage of the power supply 11-1 is applied to the liquid crystal 3b-3. This electric field untwists the molecular orientation of the liquid crystal, and the incident light 20 passes through without rotating the deflection plane, becoming output light 21b. Since the polarization plane of this light is perpendicular to the polarization plane of the deflection plate 3C, it cannot pass through.

Using the above configuration, light can be transmitted and blocked by opening and closing the switch 11-2.

When a large number of light switches as shown in FIG. 3 are arranged as one unit in the form of a flat panel, a two-dimensional surface pattern like a TV screen can be formed. The constituent units of such a screen are called pixels or dots that make up the screen.

Next, using Figure 4, 2
Explain how to configure a dimensional screen.

A band-shaped transparent electrode as shown in FIG. 4 is provided on the inner surface of each of the two glass plates.

On the other hand, the 'glass plate' has xl, x2. A large number of X electrodes are provided in the horizontal direction like X3..., and Y, Y2... are provided on the other glass plate. A Y electrode is provided in the vertical direction as shown in Y3. In the figure, only the xl and Yl electrodes are shown with diagonal lines. When these two glass plates are stacked as shown in FIG. 5 and a liquid crystal is sandwiched between them, the intersection of the X electrode and the Y electrode becomes one pixel (dot) constituting the optical switch. In a liquid crystal TV, 240 X electrodes and 240 Y electrodes are arranged in a matrix, and the number of pixels is more than 40,000 dots.

An example of a method for selectively controlling the opening and closing of a large number of such optical switches individually according to the putter desired to be displayed on the screen will be described.

The liquid crystal used here is a general TN type as shown in Figure 7.
It has the operating characteristics of a liquid crystal type liquid crystal.

The horizontal axis is the voltage applied to both electrodes, and 2v means twice the voltage of V. The vertical axis is the transmittance of light including the polarizing plate due to the twisting of the liquid crystal.

When the applied voltage is low, from 0 to V''&, the twist of the liquid crystal does not change and light passes through (the same state as in Figure 3A).When the applied voltage is between V and 2V, the twist of the liquid crystal is untwisted and the liquid crystal becomes 2V. At such a high voltage, light is reliably blocked (same condition as in Figure 3B).A liquid crystal with such characteristics is used by sandwiching it between the electrodes as shown in Figure 5, and its xl and Yl A case will be described in which the light is blocked at three points: the intersection of , the intersection of X2 and T2, and the intersection of is applied to each electrode.

The X electrode is a scanning electrode for a certain period of time (X, T
+V voltage 22 is applied at 1 o'clock, and +V voltage is applied to the X2 electrode at 12 o'clock.
V voltage 23 is applied, and +V voltage 2 is applied to the X3 electrode at 73 o'clock.
Apply 4. Although the following description is omitted, +V lightning voltage is similarly applied to all the X electrodes sequentially for a fixed short period of time, and this is repeated continuously.

On the other hand, the Y electrode is an electrode that selectively controls the voltage as necessary, and at the time of T1, a voltage of 25 is applied to the Y electrode, and a +V voltage of 26.27 is applied to the T2 and Y3 electrodes. There is.

I As a result, +V at the intersection of Xl and Yl
A double voltage of 2V is applied by the voltage 22 and the -V voltage 26, and the liquid crystal is untwisted and light is blocked.

+V voltages 22 and 26 are applied to the intersection of X and T2, both of which have the same +V lightning voltage, and no electric field is applied to the liquid crystal. The same applies to the intersection of Xl and T3.

T1 with X2. Since all other X electrodes such as X3... are at 0 voltage, there is no intersection point where the voltage reaches 2V, regardless of whether the voltage applied to the Y electrode is +V or -V, and the light passes through.

Next, when looking at 12 o'clock, +V voltage 23 is added to X2, T
A -V voltage 28 is added to 2, and this intersection becomes a 2V voltage, and light is blocked. The other Y electrode (Y,.

T3...) are all +■ voltage, so no electric field is applied to their intersections. Furthermore, at 73, +■ voltage 2 to x3
4 is applied, a voltage of 29 is applied to T3, and only this intersection becomes a voltage of 2V, and light is blocked.

As mentioned above, among the dots on the X electrode being scanned, if you control the voltage so that the Y electrode where you want the light to pass through has +V voltage, and where you want to block the light, it has -V voltage. I know it's good.

Since the response time of an actual liquid crystal is slow, the liquid crystal does not fully operate at the moment the 2V voltage is applied, but by repeating the above voltage control without a break, the liquid crystal will be able to operate. . Such a delay operation has a slow recovery time and is convenient for intermittent driving as shown in FIG.

Due to this principle of operation, even multi-dot devices such as liquid crystal TVs have been put into practical use today.

In addition, in order to further improve the operational response speed and the contrast between light transmission and blocking, the X and Y electrodes mentioned above are made extremely narrow, and a small switching transistor is placed at the intersection of these. This transistor is controlled by the control voltage applied to the electrode, and the voltage applied to the transparent electrode for the pixel (for the optical switch) is controlled by the output of this transistor.

This method has come to be used when the number of pixels increases, such as in color TVs.

The variable pattern mask 3 in FIG. 1 is composed of the above-mentioned liquid crystal and a polarizing plate, and is a mask whose pattern through which light passes can be varied by electrical control.

Today, printed circuit board wiring patterns are created using CAD (Comp).
They are now often created using a computer-based graphic creation system called ``Utor Aided Des+ign''.

Graphic data created using this method is commonly called CAD data. The CAD data of such a wiring pattern is stored in the storage device shown in FIG. .

Based on this information, the liquid crystal control circuit controls the operation of each pixel of the liquid crystal to form one screen of wiring patterns. These techniques can be realized using a computer graphics configuration in which graphics are displayed on a TV screen by a computer.

The wiring pattern formed on the liquid crystal is optically enlarged or reduced by the lens 4, and the surface of the printed board 6 is exposed. As already mentioned, the dimensions of the liquid crystal screen are determined by the position of the transparent electrodes provided on the glass plate, and since glass does not expand or contract due to temperature changes, it can be manufactured and used with highly accurate dimensions.

However, the dimensions of the wiring pattern formed on the liquid crystal by the control computer 13 are always accurate, and the lens 4
If the optical magnification or reduction is performed at an accurate magnification, the dimensions of the pattern exposed on the surface of the printed board 5 will be accurate.

Utilizing this dimensional accuracy, it is possible to expose a printed board larger than the area of the variable pattern mask 3. This method will be explained using FIG. 8.

FIG. 8 shows one printed board, and the shaded area is the wiring pattern to be exposed. If the area that can be exposed at one time using the variable pattern mask 3 in FIG. 1 is the area of the part A in FIG. Display the wiring pattern in the area on the LCD and expose it to the upper left of the printed board. Next, the control computer 13 is moved in the horizontal direction by exactly the dimension P.
Under the control of , the wiring pattern of portion B is displayed on the liquid crystal and exposed. Next, the wiring pattern is moved further horizontally by a dimension P, and the wiring pattern shows part C on the liquid crystal. Above operation i.

2. By uniformly applying light to the entire vertical and horizontal surfaces of the printed board, even printed boards larger than the variable pattern mask can be exposed over the entire surface. At this time, the wiring pattern is A.

Since the patterns are connected like B, C, D, E, and F, a pattern with accurate positions and dimensions is required, and this configuration is suitable for this purpose.

In fact, in order to prevent disconnection from occurring at the connection portion of the wiring patterns, it is desirable to provide minute overlapping portions as shown in FIG. 9 and double expose the connection portions to ensure the connection of the wiring patterns.

As described above, the entire surface of the printed board is exposed to light by relative movement of the pattern mask and the printed board. The embodiment shown in FIG. 1 shows a configuration in which a printed board 6 is moved, and the printed board 6 is placed on a Y-table 6y, which is driven by a drive screw (not shown) by the rotation of a motor 7y. through the y-axis direction (depth direction in the figure)
Move to.

All of these y-axis moving mechanisms are placed on an X table 6x, which is driven by a drive screw 8x by the rotation of a motor 7x.
is rotating! The nut 9x fixed to the table is in the X-axis direction (
(horizontal direction in the figure). With the above configuration, the printed board 5 can be moved in both x-7 directions by the motor.

Rotation is controlled by the currents of the motors 7x and 7yid motor drive circuit 12, and control information for the currents is sent from the control computer 13. Note that another control computer may be used for the control information.

A shutter 2 is provided to block all light from the light source 1 during the period, and a signal from the control computer 13 is sent to the shutter drive circuit 1o to control appropriate opening and closing of the shutter. This shutter has a structure that mechanically blocks light like that used in cameras,
Alternatively, it may be of a type in which an optical mirror or prism is mechanically moved to switch the optical path.

Providing this shutter also aims at other effects. This is done when you want to shorten the time that light is shining on the liquid crystal as much as possible in order to extend the life of the liquid crystal, and by opening the shutter only for a short period of time necessary for exposure, and closing the shutter at all other times, the liquid crystal is exposed to light. By suppressing the light irradiation time, the number of times the liquid crystal can be used can be increased.

If there is no problem with such a lifespan and the purpose is simply to block light, the shutter 2 can be omitted and the liquid crystal 3b of the pattern mask 3 can also serve that role.

In the description of the above embodiments, the object to be exposed was a printed board, but when using other objects, exposure may be performed using a chemical reaction such as hardening or softening with light, or Needless to say, this method can also be applied to exposure for controlling electric charges and magnetization by light.

Furthermore, although the liquid crystal shown in the example was of the TN type, other types, such as DSM (Dynamic
- Scattering Mode = a method that utilizes changes in light transmittance due to scattering) can also be used.

Effects of the invention As described above, the present invention provides a light source for exposure, a variable pattern mask in which a large number of liquid crystal pixels are arranged on a two-dimensional plane, and an object to be exposed are placed on the same optical path, and the liquid crystal of the pattern mask is a liquid crystal control circuit that controls each pixel; a storage device that stores graphic data of the wiring pattern to be exposed on the printed board; and a storage device that reads the graphic data from this storage device and stores the wiring pattern information necessary for one exposure. With a configuration consisting of a control computer that sends data to the liquid crystal control circuit, a wide variety of wiring pattern masks can be prepared in advance, as in the past.
There is no need to store it in physical form; it can be stored in a storage device as graphic data and can be selectively read out by a control computer in a short time as needed. Since the readout pattern is formed by electrically controlling the liquid crystal, there is no need to replace the pattern mask, and the pattern mask can be attached very quickly and in a short time, i.e., variable pattern switching time/'i.

i This makes it possible to efficiently produce small quantities of various kinds of pre-printed plates, which was previously difficult.

This variable pattern mask is a two-dimensional plane consisting of a large number of pixels, and compared to a point light source such as a laser beam, the exposed area per unit time is wider and productivity is better, so it can be used for direct exposure to printed circuit boards. It is practical even for medium volume production.

For printed boards whose dimensions are larger than the area exposed once using this variable pattern mask, a table that supports the exposed object and moves in two orthogonal axes is installed, and the movement of this table can be controlled and the exposure pattern can be changed. By reversing, it is possible to expose the entire area to light, and this is automatically carried out by one or more control computers, which has great practical effects.

[Brief explanation of the drawing]

An explanatory diagram of the manufacturing process, Figure 3 is an explanatory diagram showing the basic configuration of a general liquid crystal, B is an explanatory diagram when it is in operation, B is an explanatory diagram when it is not in operation, and Figure 4 is an explanatory diagram showing the basic configuration of a general liquid crystal. An explanatory diagram showing the counter electrodes separately; FIG. 5 is an explanatory diagram showing the liquid crystal counter electrodes in a matrix configuration overlaid; FIG. 6 is a timing diagram of the control voltage applied to the liquid crystal counter electrode in the matrix configuration; Figure 7 is a diagram of the operating characteristics of the liquid crystal, Figure 8 is a plan view of a printed board showing the case where the entire surface of one printed board is exposed with multiple exposures, and Figure 9 is the exposure when multiple exposures are performed. FIG. 3 is a plan view of the printed board showing an overlapping state. 1...Light source, 2...Shutter, 3.
...Variable pattern mask, 11...Liquid crystal control circuit, 13...Control computer, 14...
···Storage device. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
4 more colors "---51! jv11"'15p times 41j--g fin ε
4- πY, /l;goshij 8 Figure Figure 9

Claims (3)

[Claims] (1) A light source for exposure, a variable pattern mask with a large number of liquid crystal pixels arranged on a two-dimensional plane, and an object to be exposed are arranged in the above order on the same optical path, and the object to be exposed has a pattern to be exposed. A storage device that stores data; a liquid crystal control circuit that performs light transmission/blocking control for each liquid crystal pixel of the variable pattern mask; and a liquid crystal control circuit that reads necessary pattern data from the storage device and sends it to the liquid crystal control circuit based on this data. A pattern exposure apparatus equipped with a control computer that sends control information. (2) A light source for exposure, a variable pattern mask with a large number of liquid crystal pixels arranged on a two-dimensional plane, and an object to be exposed are arranged in the above order on the same optical path, and are orthogonal to each other with the object to be exposed placed thereon. A table movable in two axes, a drive unit for this table, a control computer that sends control information to this drive unit, a storage device that stores data of a pattern to be exposed on the coated exposure object, and the variable pattern mask. A pattern comprising: a liquid crystal control circuit that performs light transmission/blocking control for each liquid crystal pixel; and a control computer that reads necessary pattern data from the storage device and sends control information to the liquid crystal control circuit based on this data. Exposure equipment. (3) A light source for exposure, a variable pattern mask having a large number of liquid crystal pixels arranged on a two-dimensional plane, and an object to be exposed are arranged in the above order on the same optical path, and a pattern to be exposed to the object to be exposed is arranged. A storage device that stores data; a liquid crystal control circuit that performs light transmission/blocking control for each liquid crystal pixel of the variable pattern mask; and a liquid crystal control circuit that reads necessary pattern data from the storage device and sends it to the liquid crystal control circuit based on this data. A control computer for transmitting control information, further provided with a shutter for transmitting and blocking light between the exposure light source and the variable pattern mask, and a shutter drive circuit for controlling opening/closing of this shutter. The pattern exposure apparatus is configured such that the drive circuit receives a signal from the control computer to open the shutter during exposure.