JPH1018058A - Etching solution flow rate control method in photoetching equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to avoid non-uniformity in the etching quantity attributable to the clogging in a spray nozzle or a spray piping. SOLUTION: A spray piping 2 on which a plurality of spray nozzles 3 are mounted performs etching on a sheet to be etched by a plurality of rows of photoetching equipment parallel to the advancing direction of the sheet 1 to be etched. The flow rate and the pressure of the etching solution to be fed to each spray piping are measured for each spray piping, and when the relationship between the flow rate and the pressure is deviated from the predetermined range, feeding of the etching solution to each spray piping is stopped and the operation of the etching equipment is stopped. Alternatively, non-uniformity of the etching quantity can be avoided by forcibly increasing the flow rate in the piping deviated from the predetermined range. More rapid treatment can be taken by installing an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the flow rate of an etching solution in a photo-etching apparatus used for manufacturing an IC lead frame, a shadow mask of a cathode ray tube, and other electronic parts.

[0002]

2. Description of the Related Art A photo-etching apparatus is used for performing fine processing on the surface of a material to be etched as a base material, and is indispensable for manufacturing IC lead frames, CRT shadow masks, and other electronic components. It has become.

FIG. 1 is a view showing a schematic process of a photo-etching process. As shown in the figure, a sheet-like material to be etched (hereinafter, referred to as “etching sheet”) 1 is washed and dried, and a resist is applied (in this example, applied by a dip coating method), and then a predetermined amount is applied to both surfaces thereof. A mask (original plate for exposure) on which a product pattern is drawn is overlapped and brought into close contact with each other, followed by printing. Next, through the respective steps of development, water washing, and drying (post-baking), an etching solution is sprayed (sprayed) on the surface (both surfaces) in the etching tank to perform etching. Thereafter, the resist is washed and removed to obtain a product. Note that a ferric chloride solution is usually used as an etching solution.

[0004] It is known that unexpected etching nonuniformity occurs in the photoetching process.
This is due to clogging of a spray nozzle for spraying the etching liquid and clogging of a pipe (spray pipe) to which the spray nozzle is attached.

In the photoetching process, the flow rate of an etching solution sprayed on the surface of a sheet to be etched is conventionally controlled by adjusting a pressure gauge attached to a spray pipe so as to indicate a predetermined pressure (fluid pressure). It is done by. This is because there is a certain relationship between the pressure and the flow rate of the etching solution. For example, when a filled cone nozzle is used as the spray nozzle, the flow rate of the ferric chloride solution is proportional to the 1/2 power of the spray pressure. (“Surface Technology”, Vol. 43 (1992), No. 4).
10, 48-53).

However, while the spray device has been used for a long period of time, a large amount of deposits accumulates in the spray pipe, and the pressure loss when the etchant passes through the pipe increases. The value may not always represent the flow rate of the etching solution. That is, even if the etching solution is sprayed on the surface of the sheet to be etched at the same pressure, the flow rate decreases, and the amount of etching in the direction perpendicular to the conveying direction of the sheet to be etched (hereinafter referred to as the width direction of the sheet to be etched) is reduced. It becomes uneven. Also, a part of the deposits accumulated on the inner surface of the spray pipe is peeled off and clogs the spray nozzle, so that the etching amount suddenly becomes non-uniform in the width direction of the sheet to be etched, and a large number of defective products are generated. In some cases, things became extremely serious. The etching amount referred to in the present specification is a side etching amount, that is, at the time when the etching process is completed, in the direction perpendicular to the thickness direction from the end of the resist formed on the surface of the sheet to be etched. It means the distance (width) to the corroded part.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and a photo-etching apparatus provided with a plurality of rows of spray pipes to which a large number of spray nozzles are attached is applied to a sheet to be etched. It is an object of the present invention to provide a method for detecting clogging in a spray nozzle or a spray pipe at an early stage when performing an etching process, and for preventing a non-uniformity of an etching amount in a width direction caused by the clogging.

[0008]

In order to solve the above-mentioned problems, the present inventors provide a flow meter and a pressure gauge with a portion capable of measuring a flow rate and a pressure of an etching solution sent to a spray pipe (in this case, a portion capable of measuring a flow rate and a pressure). Each of the spray pipes was attached to an inlet of the etchant), and the relationship between the pressure and the flow rate of the etchant passing through the spray pipe was investigated. As a result, even when a spray nozzle without clogging was used, the relationship between the pressure and the flow rate was sometimes different, and a large amount of deposits was observed in the spray pipe showing a high pressure. In addition, the flow rate of the etching solution was also reduced by the presence of the deposit.

FIG. 4 shows an example in which the spray pipe is clogged with a large amount of deposits (hereinafter referred to as "pipe clogging"). This drawing is a drawing shown in an embodiment to be described later. Using an etching apparatus having six rows of spray pipes parallel to the width direction of the sheet to be etched, the pressure of the etching solution passing through each spray pipe is kept constant (2 kgf). / Cm
² ) shows, as an example, the flow rate deviation of the etching solution for each pipe when the sheet to be etched made of Fe-42% Ni (hereinafter, referred to as 42Ni) is subjected to the etching process, and the etching amount deviation at that time.

[0010] A pipe is clogged in the second spray pipe from the left in FIG. 4, and the flow rate of the etchant in the pipe is extremely reduced, and the etching amount in the width direction of the sheet to be etched becomes uneven. (Indicated by a circle in the figure). Although not shown, the pressure of the etchant passing through the piping also increases.

Further, when the spray nozzle itself is closed by the deposits that have fallen off from the spray pipe, the etching is performed in the width direction of the sheet to be etched as shown in FIG. The amount became non-uniform (indicated by ● in the figure).

FIG. 3 is also a view shown in an embodiment to be described later, and the flow rate of the etchant is adjusted by adjusting the pressure of the etchant passing through each spray pipe by using the same etching apparatus as in FIG. The figure shows the flow rate deviation of the etching solution for each pipe and the etching amount deviation at that time when each pipe is constant (46.5 liter / min).

The spray nozzle attached to the third spray pipe from the left in FIG. 3 is clogged (hereinafter referred to as “nozzle clogging”), so that the etching amount in the width direction of the sheet to be etched is not uniform. This has occurred (indicated by a circle in the figure).

Further, when the nozzle clogging occurs, as shown in FIG. 5, an increase in pressure (fluid pressure) was observed even when the flow rate of the etching solution was the same. FIG. 5 shows a case where a spray nozzle without nozzle clogging is used in the same etching processing apparatus as in FIGS. 3 and 4;
This is the result of investigating the relationship between the flow rate and the pressure of the etchant by performing an etching process on a sheet to be etched made of 42Ni when using a spray nozzle having clogged nozzles.

That is, as described above, the flow meter and the flow rate of the etching solution sent to the spray pipe are measured at each of the portions (in the above example, the inlet side of the etching solution of the spray pipe) which can be measured for each spray pipe. By installing and monitoring a pressure gauge and a pressure gauge, nozzle clogging and pipe clogging can be detected at an early stage. Therefore, by stopping the operation of the apparatus by stopping the flow of the etching solution to each spray pipe at the same time as finding such an abnormality, or by forcibly increasing the flow rate of the pipe in which the abnormality has occurred. It is considered possible to prevent or minimize etching nonuniformity.

The present invention has been made under such a concept, and its gist lies in the following (1) and (2) methods for controlling the flow rate of an etching solution.

(1) When performing etching on a sheet to be etched by a photo-etching apparatus in which a plurality of spray pipes having a plurality of spray nozzles attached thereto are provided in a plurality of rows in parallel with the traveling direction of the sheet to be etched.
The flow rate and pressure of the etchant sent to each spray pipe are measured for each spray pipe, and when the relationship between the measured flow rate and pressure deviates from a predetermined range, the etchant is supplied to each spray pipe. A method for controlling the flow rate of an etchant in a photo-etching apparatus, wherein the flow is stopped to stop the operation of the apparatus.

(2) When performing etching on a sheet to be etched by a photo-etching apparatus in which a plurality of spray pipes provided with a plurality of spray nozzles are provided in a plurality of rows in parallel with the traveling direction of the sheet to be etched.
The flow rate and pressure of the etching solution sent to each spray pipe are measured for each spray pipe, and when the relationship between the measured flow rate and pressure deviates from a predetermined range, the flow rate of the pipe deviates from the predetermined range. And controlling the flow rate of the etching solution in the photo-etching apparatus.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for controlling the flow rate of an etching solution according to the present invention (the methods (1) and (2),
The method of the present invention means both of these methods (1) and (2)).

FIG. 2 is a diagram schematically showing an example of the configuration of an apparatus for carrying out the method of the present invention. In the upper part and the lower part of the sheet 1 to be etched, six rows of spray pipes 2 are arranged in parallel with the traveling direction of the sheet 1 to be etched, and each pipe 2 is provided with nine spray nozzles 3. A flow meter 4 for measuring the flow rate of the etching solution passing therethrough and a valve 5 for adjusting the flow rate are installed on the entry side of the etching solution in the six rows of pipes 2. A pressure gauge 6 for measuring the pressure of the etching solution passing through the pipe 2 is provided.

When the above-described etching apparatus is used, the flow rate and pressure of the etching solution sent into each spray pipe can be measured when performing etching on the sheet to be etched.

In the method (1), when the relationship between the flow rate and the pressure of the etchant measured for each spray pipe is out of a predetermined range, the flow of the etchant to each spray pipe is stopped. This is a method of stopping the operation of the device.

For this purpose, the relationship between the flow rate and the pressure of the etching solution is previously investigated for each spray pipe in a state where neither the spray pipe nor the spray nozzle is clogged, and the etching process can be performed without any clogging. A range (that is, an allowable range in the relationship between the flow rate and the pressure) is determined in advance.

When nozzle clogging occurs during the etching process, as shown in FIG. 5, even if the flow rate of the etching solution is the same, the pressure increases, so that clogging can be detected. Therefore, when the pressure rises and the relationship between the flow rate and the pressure of the etchant deviates from a predetermined range (the allowable range), the supply of the etchant to each spray pipe is stopped to operate the etching apparatus. Stop.

Further, when the pipe is clogged, the flow rate of the etching solution sharply decreases as the pressure increases (see FIG. 4), so that the clogging can be detected. Therefore, when the flow rate decreases and the relationship between the flow rate and the pressure of the etchant deviates from a predetermined range (the allowable range), the operation of the etching processing apparatus is stopped as in the case where nozzle clogging occurs.

According to this method, nozzle clogging and pipe clogging can be detected at an early stage, and continuation of non-uniform etching can be avoided, and a large number of defective products having a variation in dimension in the width direction of the sheet to be etched. Can be prevented from occurring.

In the method (2), when the relationship between the flow rate of the etching solution and the pressure measured for each spray pipe is out of a predetermined range, the flow rate of the pipe out of the range is forcibly increased. It is.

Also in this case, the relationship between the flow rate and the pressure of the etching solution can be checked in advance for each spray pipe in a state where neither the spray pipes nor the spray nozzles are clogged, and the etching can be performed without clogging. Range (ie, allowable range in relation to flow rate and pressure)
Is defined.

When nozzle clogging occurs, as described above, clogging can be detected by an increase in pressure. Therefore, the pressure increases, and the relationship between the flow rate of the etchant and the pressure falls within a predetermined range (the above-described range). If it is out of the allowable range, forcibly increase the flow rate of the piping.

The amount of increase in the flow rate at that time is obtained based on the relationship between the flow rate deviation of the etching solution and the etching amount deviation (that is, the side etching amount deviation) which are obtained in advance.

FIG. 7 is a diagram showing an example of this relationship. The etching apparatus shown in FIG.
m, 250 μm thick sheet to be etched (42Ni
Product pattern as shown in FIG. 6 (in this case,
(Flow frame deviation when the reference flow rate is set to 46.5 liter / min) and the corresponding width direction deviation of the etching solution when the etching process is performed by allocating 20 lead frames (7). It is the result of having plotted the relationship of the etching amount deviation (deviation obtained based on the etching amount at the reference flow rate).

If the relationship between the flow rate deviation of the etching solution and the etching amount deviation is determined in advance, the etching amount deviation when the nozzle is clogged is determined, and the etching required to prevent the etching amount deviation from occurring. Since the flow rate deviation of the liquid can be obtained from the relationship shown in FIG. 7, it is sufficient to forcibly compensate for the flow rate.

When the pipe is clogged, the flow rate of the etching solution sharply decreases (see FIG. 4).
C.), The clogging can be detected, and the relationship between the flow rate and the pressure of the etching solution also deviates from a predetermined range (the allowable range). Therefore, similarly to the case where the nozzle is clogged, the flow rate of the pipe is forcibly increased. At this time, the amount of increase in the flow rate may be an amount that compensates for the decrease.

According to this method, nozzle clogging and pipe clogging can be detected at an early stage, and by forcibly increasing the flow rate of the piping, uneven etching can be minimized and the width can be reduced in the width direction. It is possible to prevent the occurrence of defective products having variations in dimensions.

Whether the method (1) or the method (2) is used may be determined according to the situation at the time of manufacturing. For example,
The deviation from the predetermined range is not so large (that is, it is estimated that the degree of clogging is slight), and it is possible to avoid unevenness in the width direction of the etching amount by increasing the flow rate of the etching solution. In the case where it is determined, for example, the method (2) can be performed to minimize the decrease in the production rate.

If the relationship between the pressure and the flow rate of the etching solution is out of a predetermined range due to the rise of the pressure of the etching solution or the rapid decrease of the flow rate as described above, an alarm is issued. It is possible to take quicker action.

[0037]

EXAMPLE The following test was conducted by using the etching apparatus having the structure shown in FIG. 2 and applying the method of the present invention. Note that a ferric chloride solution was used as an etching solution.

(Example 1) As a sheet to be etched,
As shown in FIG. 6, a product (lead frame) is formed on a sheet made of 42Ni having a size of 450 mm × 500 mm and a thickness of 250 μm.
First, the flow rate and the pressure of the etching liquid were measured by adjusting the spray pressure so that the flow rate of the etching liquid was constant (46.5 liter / min) in each row. Etching was performed while doing. "Assign product pattern"
This means that in the etching step shown in FIG. 1 described above, a photoresist film having the same pattern as the product pattern drawn on this mask is formed on the surface of the sheet to be etched by overlaying and baking and developing a mask. .

At this time, an increase in pressure is observed in the third pipe from the left in the conveying direction of the sheet to be etched,
Since the relationship between the flow rate and the pressure of the etchant was out of the predetermined range, the flow of the etchant to each spray pipe was stopped, the operation of the etching apparatus was stopped, and the distribution of the etching amount in the width direction of the sheet to be etched. Was examined.

As a result, as shown in FIG. 3, one of the spray nozzles attached to the third pipe from the left has a nozzle clogging, and the surface of the sheet to be etched corresponding to the position of the spray pipe has been clogged. The amount of etching was small in the vicinity (indicated by a black circle in the figure), and uneven etching was observed.

Therefore, the required flow rate deviation of the etching solution was determined based on FIG. 7, and the etching process was performed by adjusting the pressure of the etching solution and increasing the flow rate to the mark ○ in FIG. The uniformity was improved (in the figure,
Mark).

Example 2 Using the same sheet to be etched as in Example 1, the spray pressure was kept constant (2 kgf /
cm ² ), etching was performed while measuring the flow rate and pressure of the etching solution.

At that time, a large decrease in the flow rate was observed as the pressure increased in the second pipe from the left in the conveying direction of the sheet to be etched, and the relationship between the flow rate and the pressure was out of the predetermined range. Then, the supply of the etchant to each spray pipe was stopped, the operation of the etching apparatus was stopped, and the etching amount distribution of the sheet to be etched in the width direction was examined.

As a result, as shown in FIG. 4, pipe clogging occurred in the second pipe from the left, and non-uniform etching was observed near the surface of the sheet to be etched corresponding to the position of the spray pipe. (Indicated by ● in the figure).

Then, the deposits in the pipe which caused the clogging of the pipe were removed, and the etching process was performed with the spray pressure constant (2 kgf / cm ² ) without clogging. As described above, the partial deviation of the etching amount was improved. The amount of etching increased at both ends of the sheet to be etched, but this is because the liquid accumulated in the center of the sheet flows along with the drop of the etching solution from the periphery of the sheet. This is because the flow rate of the etching solution was increased and the flow velocity was increased, and the etching rate was increased.

[0046]

According to the method of the present invention, clogging of a spray nozzle or a spray pipe is detected at an early stage, and nonuniformity of the etching amount in the width direction caused by the clogging is avoided, thereby preventing the etching amount in the width direction of the sheet to be etched. The occurrence of defective products having variations in dimensions can be prevented or minimized.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic process of a photo-etching process.

FIG. 2 is a diagram showing a configuration of an example of a photo-etching apparatus for performing the method of the present invention.

FIG. 3 is a diagram illustrating deviations in the width direction of a flow rate and an etching amount when nozzle clogging occurs.

FIG. 4 is a diagram showing a deviation in a width direction of a flow rate and an etching amount when a pipe is clogged.

FIG. 5 is a diagram showing a relationship between a flow rate of an etching solution and a pressure when nozzle clogging occurs.

FIG. 6 is a diagram showing an example of assignment of a lead frame to a sheet to be etched.

FIG. 7 is a diagram illustrating a relationship between a flow rate deviation of an etching solution and a side etching amount deviation.

[Explanation of symbols]

 1: Sheet to be etched 2: Spray pipe 3: Spray nozzle 4: Flow meter 5: Valve 6: Pressure gauge 7: Conveying roll 8: Product pattern

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hayato Kita 4-5-33 Kitahama, Chuo-ku, Osaka-shi, Osaka Sumitomo Metal Industries, Ltd.

Claims (2)

[Claims] 1. A method according to claim 1, wherein a plurality of spray pipes provided with a plurality of spray nozzles are provided in a plurality of rows in parallel with a traveling direction of the sheet to be etched. The flow rate and pressure of the etchant sent to the spray pipe are measured for each spray pipe. If the relationship between the measured flow rate and pressure deviates from a predetermined range, the flow of the etchant to each spray pipe is stopped. And stopping the operation of said apparatus by controlling the flow rate of the etchant in the photo-etching apparatus. 2. A spray pipe having a plurality of spray nozzles attached thereto is used for etching a sheet to be etched by a photo-etching apparatus provided in a plurality of rows in parallel with a traveling direction of the sheet to be etched. The flow rate and pressure of the etchant sent to the spray pipe are measured for each spray pipe, and if the relationship between the measured flow rate and pressure deviates from a predetermined range, the flow rate of the pipe outside the range is forcibly applied. A method for controlling the flow rate of an etchant in a photoetching apparatus, comprising: