JPH0336904B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is applicable to an etching process that is continuously transported by a transport device, for example, in an etching process during the production of printed wiring boards, color cathode ray tube shadow masks, etc. The present invention relates to a method for controlling the degree of etching of a thin plate-shaped workpiece in etching, in which the workpiece is exposed to an etching solution and the surface of the workpiece is corroded (ie, etched) in a desired pattern.

[Conventional technology]

The following are known as conventional control methods and devices of this type.

(1) Japanese Patent Application Laid-Open No. 59-100587 discloses that a laser beam scanning device installed between a first etching chamber and a second etching chamber is used to determine the width of a monitor pattern on a printed circuit board by light reflection. and measure
A method and apparatus are described for determining etching conditions, such as etching chamber conveyor speed, depending on the measurement results.

(2) Japanese Patent Publication No. 44-10371 discloses that an etching state detecting means, such as a photoelectric detecting means or a conductivity detecting means, is provided in the etching apparatus, and the etching state is detected by this etching state detecting means. A metal etching apparatus is disclosed in which the conveyance speed of a workpiece can be directly controlled.

(3) Japanese Patent Publication No. 46-19262 provides an etching opening size sensing means at the rear of the etching device, and when the etching opening size detected by this sensing means exceeds the allowable upper and lower limits. discloses a method in which the conveying speed of the metal strip is corrected and the next speed correction is not performed until the portion of the metal strip that has undergone the speed correction reaches the etching opening size sensing means. There is.

[Problem that the invention seeks to solve]

In the "Method and Apparatus for Etching Printed Wiring Boards" described in JP-A-59-100587, a monitor pattern width measuring means is disposed between the first etching chamber and the second etching chamber,
In order to control the transport speed of the second etching chamber, it is impossible to transport the metal strip continuously from the first etching chamber to the second etching chamber for etching.

In the "metal etching apparatus" described in Japanese Patent Publication No. 44-10371, an etching state detection means is installed in the etching apparatus, so that during the etching process,
The etching condition can be detected and the conveyance speed of the workpiece can be directly controlled, but the etching liquid attached to the surface of the workpiece or the etching liquid sprayed from the nozzle adheres to the surface of the etching condition detection means, making it difficult to accurately detect the etching condition. The problem is that it cannot be detected.

In the "automatic control device for the diameter of corrosion pores in a continuous metal strip" described in Japanese Patent Publication No. 46-19262, an etching hole size sensing means is arranged after the metal strip passes through an etching device. , there is no error caused by the etching solution, but when the output of the etching hole size sensing means exceeds the allowable upper and lower limits of the etching hole size,
Correcting the conveyance speed of the metal strip, and etching the metal strip portion that has undergone the speed correction,
Since the next speed correction is not made until the etching opening size sensing means is reached, the speed correction of the conveyance speed of the metal strip is as follows.
This process is extremely gradual, and is unsatisfactory in terms of uniform quality and improved productivity, which are required in recent high-precision etching processes.

The purpose of the present invention is to solve all the above problems,
The object of the present invention is to perform high-quality, uniform etching processing by steplessly and accurately controlling the conveyance speed of the object to be processed.

[Means for solving problems]

In order to achieve the above object, the present invention is configured as follows.

An etching control method that controls etching by controlling a conveyance speed based on the difference between an etching rate measured on a workpiece that is continuously conveyed by a conveyance device and a preset etching rate, the method comprising: At times, the conveyance speed is measured multiple times at appropriate time intervals and the average value is calculated, and after etching, the etching rate of the etched workpiece is calculated by calculating the average value of the above-mentioned conveyance speed, and the etching rate of the etched object is measured. Based on the difference between the measured etching rate and a preset standard etching rate, a correction value for the average value of the conveyance speed is determined, and the conveyance speed of the workpiece being etched is adjusted to the average value of the conveyance speeds. An etching control method characterized in that the etching control method is controlled to match a value obtained by adding the correction value to the above-mentioned correction value.

Further, the etching control method uses an average value of the etching rates of objects to be processed that have been processed prior to the object to be measured as a measurement value of the etching rate of the object to be etched.

An etching chamber equipped with a transport means for transporting the object to be processed, an etching liquid supply means for supplying an etching solution to the surface of the object to be processed, and an etching chamber connected to the etching chamber for cleaning and drying the surface of the object to be processed. a cleaning/drying chamber for performing etching, an etching rate measuring means installed after the cleaning/drying chamber for measuring the etching rate of the object to be processed, and a difference between the value measured by the etching rate measuring means and a preset desired etching rate. An etching control device comprising: a conveying speed control means for controlling the conveying speed of the conveying means based on the value, a speed detecting means for detecting the conveying speed of the object to be processed in the etching chamber at appropriate time intervals;
A storage means for storing a plurality of conveyance speed values detected by the speed detection means is provided, and a control means for controlling the conveyance speed of the conveyance means is configured to adjust the conveyance speed of the etched workpiece stored in the speed storage means. From this value, calculate the average value of the transport speed during etching of the workpiece, and calculate the difference between the etching rate of the etched workpiece for which the average value of the drying speed was calculated and the desired etching rate set in advance. An etching control device characterized in that the etching control device is a conveyance means that controls the conveyance speed of the workpiece during etching so that the conveyance speed of the workpiece being etched becomes a value obtained by adding the previous correction value to the average value of the conveyance speed.

[Effect]

In the present invention, the average value of the conveyance speed of the workpiece during etching is measured, and the measured value is
The amount of correction obtained from the difference between the etching rate measured after the etching process and the desired etching rate set in advance is added to the etching rate so that the value is equal to the conveyance speed of the workpiece during the etching process. This controls the conveyance speed.

In other words, the desired transport speed during the etching process is constantly and continuously determined based on the difference between the set etching rate and the actual etching rate, based on the average value over time of the transport speed when etching the workpiece. Can be set automatically.

The etching rate of the workpiece sent out after the etching process gradually approaches the desired etching rate compared to the workpiece sent out from the etching process.

Therefore, according to the method of the invention, for example:
Etching conditions due to deterioration of etching solution, etc.
Even if the changes are minute and slow, it can be sensitively handled and etching can be performed with high precision.

〔Example〕

An example of an etching apparatus for carrying out the method of the present invention is shown in FIG.

This device manufactures shadows by etching a metal strip, and includes an etching chamber 2 in which a transport roller 4 is rotatably disposed, and a required number of nozzles 5 for ejecting etching liquid from above and below. , and washing/peeling/drying device 3
The metal strip 1, which is the object to be treated, is placed approximately in the center of the
is placed on a conveying roller 4 and is pulled and conveyed to the right in FIG.

A cutter 7 is installed after the nip roller 6, and the shadow mask 1' cut into a predetermined size from the metal strip 1 is placed on the conveyor 11 to adjust the light transmittance of the light emitting element 8' and the light receiving element 8''. The transmittance is detected by the transmittance detection device 8, and then the guide plate 10
They are guided by and stacked and stored in the storage container 9.

In FIG. 2, instead of the metal strip 1 as the object to be treated,
Another example of an etching apparatus is shown in which a plurality of thin plate-shaped substrates 1'', such as printed wiring boards, are transported one by one into an etching chamber 2 at regular intervals.
In this case, the transport roller 4 that horizontally transports the substrate 1''
Each of them and the driving means are connected to each other by a suitable linking device (not shown).

The other configurations are the same as those shown in the first diagram,
The same reference numerals are given to them, and the explanation thereof will be omitted.

FIG. 3 is a block diagram of the main configuration of the present invention;
4a and 4b are flowcharts of an embodiment of the present invention, and FIG. 5 is an explanatory diagram for explaining the operation when carrying out the method of the present invention using the apparatus shown in FIG. 1.

In FIG. 5, the surface of the metal strip 1 has been previously subjected to surface treatment by exposing and developing a pattern such as a shadow mask at regular intervals. In the etching chamber 2, a large number of fine holes are opened by etching according to each pattern, and then cut by a cutter 7 to form individual shadow masks.

The transport speed of the metal strip 1 by the nip roller 6 when the shadow mask (hereinafter simply referred to as mask) M _i which is a part of the metal strip 1 in FIG. 5 is at the position P ₀ of the light transmittance detection device 8 is S Let it be _i .

The conveyance speed of the metal strip 1 when the mask M _i is at the position P ₁ is the transport speed of the metal strip _{1 which is etched one mask earlier than the mask M i (} although not shown, it is faster than the mask M _i) . Since the conveyance speed is the same as the conveyance speed when the position (one position to the right on the paper) is at the position _P0 , it is set as S _i-1 .

Similarly, when this mask M _i passes through the position P ₁₂ near the entrance of the etching chamber 2, the metal strip 1
Assume that the conveying speed of is S _i-12 , the speed at positions P ₁₁ ..., S _i-11 ..., and the speed at position P ₆ near the outlet of the corrosion chamber 2 is S _i-6 . In addition, each position
The intervals between P ₁₂ ...P ₀ shall be equal intervals.

The average speed at which the mask M _i on the surface of the metal strip 1 passes through predetermined positions P ₁₂ , P ₁₁ ...P ₆ in the etching chamber 2 is _i = (S _i-12 ) + (S _i-11 ) + ...+(S _i-6 )/7.

When the mask M _i is at the position P ₀ , the detected light transmittance is T _i , and a value k (T _i − _{T 0} ) proportional to the difference from the set light transmittance T ₀ is added to the average speed _i , SP The driving means 11 of the nip rolls 6 may be controlled so that SP(i) given by the formula (i)= _i +k(T _i −T ₀ ) becomes a new conveyance speed. Here, (k) is an appropriate coefficient, a value determined experimentally, and varies depending on the structure of the device, etc.

Next, if the conveyance speed when the first etched mask M _i+1 of the masks M _i moves to the position P ₀ is S _i+1 (≒SP(i)), then the mask M _{i+ 1} is the position P ₁₂ in the etching chamber 2,
The speed when passing P ₁₁ ,...P ₆ is respectively
S _i-11 , S _i-10 ,...S _i-5 , and their average speed is _i+1 = (S _i-11 ) + (S _i-10 ) +... + (S _i-5 )/7. , if the light transmittance of the mask M _i+1 at position P ₀ is T _i+1 , the new speed control value is SP( _i+1 )= _i+1 +k(T _i+1 −T ₀ ).

In this way, the conveyance speed of the metal strip 1 is continuously controlled.

In FIG. 3, the arithmetic control means controls a driving means such as a pulse motor, which rotates the nip roller 6 in conveying the metal strip 1 shown in FIG. Second
In conveying the substrate 1'' shown in the figure, all conveyance rollers 4' are rotated.

In addition, as shown in the block diagram in Figure 3, the mask
The light transmittance _{T i measured} at the position P ₀ is stored by the storage means, and the mask M _i including the mask M _i
The average light transmittance _i of the required number of masks preceding
It is possible to perform more accurate speed control by determining the average light transmittance and using the average light transmittance in the arithmetic expression for the conveyance speed control value, SP(i)= _i + k(T _i +T ₀ ).

In the above embodiment, in FIG. 5, when calculating the average value of the transport speed of the masks M _i ... passing through the etching chamber, a number of points corresponding to the number of masks that can be placed in the etching chamber (in the above embodiment, The conveyance speed when the mask M _i ... passed through the seven locations (P ₆ to _{P 12} ) was calculated arithmetically and averaged to determine the average speed _i in the etching chamber.

However, it is not always necessary to calculate the average value based on the transport speed at a number of points corresponding to the number of masks that can be placed in the etching chamber.
The conveying speed at three or four points may be averaged.

Figures 4a and 4b show a flowchart of this example.

First, power on the control means P ₁ and set the required data P ₂ . For example, when the mask (or substrate) is transported in the etching chamber, the number of times the transport speed S _i is measured, the number of integrated light transmittances for averaging the light transmittances, etc. are set. Furthermore, if necessary, the light transmittance may also be integrated at regular intervals.

Next, turn on the start switch of the control means P ₃ .

P ₄ The conveyance speed SP (0) of the object to be processed, such as a metal strip or a substrate, being conveyed within the etching chamber is set using a digital switch.

The nip roller 6 in FIG. 1 or the conveyance roller 4' in FIG. 2 is rotated by the driving means, and the object to be processed is conveyed at a conveyance speed SP(0).

While each workpiece (for example, one shadow mask) is transported from the entrance to the exit of the corrosion chamber, the transport speed is stored in the storage device a preset number _of times for each workpiece.P5 .

After leaving the etching chamber, the object to be processed is measured for light transmittance P ₇ and stored in a storage device P ₈ .

Measure the light transmittance T _i of a predetermined number N ₁ of objects to be processed.
P ₉ , the average thereof is calculated by the arithmetic control means, P ₁₀ , and then the new conveyance speed SP(1)=SP(0)+k( _i +T ₀ )
Calculate P ₁₁ .

The drive means in FIG. 3 is configured such that a desired pulse command signal is given by the control means to a pulse motor, for example, so that the transport speed of the new object to be processed entering the etching chamber becomes SP (1 ₎ . .

From flowchart P ₁₂ , a steady and controlled state is reached, and flowcharts (P ₆ ), (P ₇ ), (P ₈ )
and (P ₉ ), as well as flowchart (P ₁₃ ),
(P ₁₄ ), (P ₁₅ ) and (P ₁₇ ) follow, during which the transport speed of the object to be processed passing through the etching chamber is measured at preset intervals and stored (P ₁₆ ).

The arithmetic control means constantly calculates the average light transmittance T _i and the average speed S _i , and calculates the new transport speed SP(N)=S _i
P ₂₀ to calculate +k( _i −T ₀ ).

In this way, the transport speed of a new workpiece brought into the etching chamber can be set based on the difference between the average transport speed of the workpiece within the etching chamber, the average light transmittance, and the set light transmittance. Can be done.

In this example, the etching rate of the processed object was measured by detecting the light transmittance of the processed object, but the etching rate of the processed object could also be measured using the light reflectance of the processed object. Needless to say, you can do that too.

Furthermore, the etching rate of the object to be processed can also be measured by detecting conductivity or other indicators indicating the etching rate.

〔Effect of the invention〕

According to the present invention, the following effects can be achieved.

(1) The desired conveyance speed during the etching process is set based on the average value of the conveyance speed when etching the workpiece, so etching can be controlled continuously with high precision. be able to.

(2) Since the conveyance speed of the processed material is controlled steplessly, continuously, and with high precision, it is particularly effective against minute and slow changes in etching conditions due to etching solution deterioration or fatigue, for example. However, it is possible to respond sensitively to these changes and prevent any adverse effects on the object to be processed due to such changes.

(3) Since the etching rate is measured after the etching process, there is no risk of the etching solution adhering to the etching rate measuring device and causing erroneous measurements.
The etching rate can be measured accurately and the etching can be controlled accurately and reliably.

(4) It can be carried out not only when forming a uniform pattern on a metal strip, but also when processing thin plate-like substrates such as glass substrates and printed wiring boards continuously at regular intervals.

(5) This can be carried out not only by opening a large number of micropores in the object to be processed, but also by detecting the etching rate, such as light reflectance or electrical conductivity, depending on the surface processing conditions.

In addition to being based on the temporal average value of the conveyance speed of the processed material, the corrosion rate of the processed material is also calculated based on the
By determining the correction amount based on the average value of the etching rates of the object to be processed and an appropriate range of objects that precede it, etching control can be carried out more continuously and with high precision.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional view showing an example of an etching apparatus for carrying out the present invention, and FIG. 2 is a schematic longitudinal sectional view showing another example of the etching apparatus.
FIG. 3 is a block diagram showing the mutual relationship of the main components used in carrying out the present invention, and FIG. 4 a, b
is a flowchart showing an embodiment of the present invention, No. 5
The figure is an operation explanatory view for explaining the operation when implementing the method of the present invention using the apparatus shown in the first figure. 1...Metal strip, 1'...Mask, 1'...Substrate, 2...Etching chamber, 3...Water washing/peeling/drying device, 4, 4'...Transport roller, 5...Nozzle,
6... Nip roller, 7... Cutter, 8... Light transmittance detection device, 8'... Light emitting element, 8''... Light receiving element, 9... Storage container, 10... Guide plate, S _i ,
S _i-5 ...S _i-12 , S _i+1 , SP (0), SP (1), SP (N)...
...Conveyance speed, M _i , M _i+1 ... M _i+14 ... Shadow mask (mask), P ₀ , P ₁ ... P ₁₂ ... Position, T ₀ , T _i ,
T _i+1 ...light transmittance (corrosion rate), k...coefficient.

Claims (1)

[Claims] 1. Etching in which etching is controlled by controlling the transport speed based on the difference between the etching rate measured on the workpiece that is continuously transported by a transport device and a preset etching ratio. In this control method, the conveyance speed is measured multiple times at appropriate time intervals during etching, and the average value is calculated, and after etching, the etched workpiece is The etching rate is measured, and based on the difference between the measured etching rate and a preset standard etching rate, a correction value for the average value of the conveyance speed is determined, and the conveyance speed of the workpiece being etched is determined. . An etching control method, characterized in that control is performed to match a value obtained by adding the correction value to the average value of the conveyance speed. 2. The method according to claim 1, wherein the average value of the etching rates of the workpieces processed prior to the workpiece to be measured is applied as the measured value of the etching rate of the etched workpiece. Etching control method. 3. An etching chamber equipped with a transport means for transporting the object to be processed, and an etching solution supply means for supplying an etching solution to the surface of the object to be processed, which is connected to the etching chamber and cleans the surface of the object to be processed;
A cleaning and drying chamber for drying, an etching rate measuring means installed after the cleaning and drying chamber to measure the etching rate of the object to be processed, and a difference between a value measured by the etching rate measuring means and a preset desired etching rate. an etching control device comprising: a conveying speed control means for controlling the conveying speed of the conveying means based on the value of , a speed detecting means for detecting the conveying speed of the workpiece in the etching chamber at appropriate time intervals;
A storage means for storing a plurality of conveyance speed values detected by the speed detection means is provided, and a control means for controlling the conveyance speed of the conveyance means is configured to adjust the conveyance speed of the etched workpiece stored in the speed storage means. From this value, calculate the average value of the transport speed during etching of the workpiece, and calculate the difference between the etching rate of the etched workpiece for which the average value of the drying speed was calculated and the desired etching rate set in advance. 1. An etching control device characterized in that the etching control device is a conveyance means for controlling the conveyance speed of a workpiece during etching so that the conveyance speed of a workpiece being etched becomes a value obtained by adding an earlier correction value to an average value of the earlier conveyance speed.