JPH0994686A - Method for machining metallic plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform microfabrication of a metallic plate with high precision and with ease by surely preventing dross or spatters generating in laser machining from sticking to the machined part of the metallic plate. SOLUTION: A metallic plate 9 with a film formed of casein etching resist 10, 11 is irradiated with a laser beam L by a YAG laser beam machine and formed with an opening 12 penetrated through the metallic plate 9 and the casein etching resist 10, 11. Then, a lead frame 1a is made, which consists of a product from the metallic plate 9, by stripping and removing the casein etching resist 10, 11. Since an extra laser beam energy is absorbed by the casein etching resist 10, 11, generation of dross is suppressed. In addition, spatters 13 stuck around the opening for an etching resist 9 are removed by stripping the casein etching resist 10, 11. Thus, a product from the metallic plate 9 is obtained free from dross and spatters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for finely processing a metal plate, and more particularly to a method for finely processing a relatively small metal plate such as a lead frame which is a semiconductor assembly member. It is about.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for high-density mounting of semiconductor elements, and in such a situation, a large number of lead frame pins have been developed. At present, lead frames with more than 300 pins are also manufactured. With the increase in the number of pins of the lead frame, the pitch of the inner leads of the lead frame has been the minimum of about 200 μm in the past, but is now 2
Lead frames of less than 00 μm have been developed.
As a method of manufacturing such a lead frame having a large number of pins and a fine (narrow) pitch, a manufacturing method by etching has been the mainstream. This manufacturing method by etching is easy to increase the number of pins and fine pitch as compared with the conventional manufacturing method by stamping, but when manufacturing a lead frame whose inner lead pitch is less than 200 μm, a reduction in etching factor,
Various obstacles such as the limit of the pattern correction or the deterioration of the yield are accompanied.

Under such circumstances, various studies were made on the increase in pin count and fine pitch of the lead frame by etching. First, as one means capable of coping with the increase in pin count and fine pitch, processing was performed. It is conceivable to form the metal plate as the base material from a thin plate having a small thickness. However, if the thickness of the metal plate is too thin, the strength becomes insufficient, so there is a limit to how thin the plate can be.

Further, as another means for coping with the increase in the pin count and the fine pitch of the lead frame, it is conceivable to improve the etching factor by using an additive for the etching solution. However, at present, the etching factor has not been effectively improved.

[0007] By etching a metal plate whose plate thickness cannot be made so thin by etching in which the etching factor is not improved in this way, a multi-pin lead frame of 300 pins or more and a fine pitch lead frame of 200 μm or less will be manufactured. In such a case, the outer lead portions that do not require fine processing can be penetrated by this etching, but it is difficult to penetrate the inner lead portions that require fine processing by such etching. In addition, even if the inner lead portion is penetrated, there arises a problem that the flat width of the lead and the desired narrow pitch of the lead required for wire bonding or molding cannot be secured.

Therefore, even with this manufacturing method by etching, it is difficult to reliably and sufficiently cope with the increase in the number of pins and the fine pitch of the lead frame whose inner lead pitch is less than 200 μm.

Therefore, the applicant of the present invention forms a fine pattern such as an inner lead by laser processing,
A method for processing a metal plate adapted to the increase in the pin count and the fine pitch of the lead frame is disclosed in JP-A-4-37.
Proposed in Japanese Patent No. 493.

In the method for processing a metal plate disclosed in this publication, the metal plate is subjected to etching processing, and the processed portion in the etched portion of the metal plate is finely processed by laser processing, so that fineness such as inner leads can be obtained. A pattern is formed. By using this laser processing, predetermined fine processing can be performed.

FIG. 6 and FIG. 7 are views showing a lead frame manufactured by fine processing by the metal plate processing method of this publication. In these figures, 1a and 1b are QFP (Quad Flat Package) type lead frames made of a metal plate of a predetermined thickness such as copper, copper alloy, 42 alloy, and Kovar, and 2 are arranged vertically and in parallel with each other. The paired rails 2, 2 and 4 are arranged between the pair of rails 2 and 2, and are mounted on the die pad 5 on which the semiconductor element 3 is mounted.
Is a predetermined number of inner leads arranged so as to surround the die pad 4, 6 is an outer lead continuous with the inner lead 5, 7 is a dam bar for supporting the inner lead 5 and the outer lead 6 on the rails 2, 2, and 8 is a laser It is a positioning hole for positioning the metal plate during processing. The lead frame 1a shown in FIG. 6 is manufactured by irradiating the entire surface with a laser beam during laser processing, and the lead frame 1b shown in FIG.
Is manufactured by partially irradiating a laser beam on a portion where fine processing is required.

[0010]

However, in the laser processing disclosed in this publication, the metal plate 21 is irradiated with the laser beam L as shown in FIG.
When the opening 22 is formed by laser processing 1, the dross (metal agglomerate) 23 due to metal dissolution and the spatter (metal scattering) 23 due to metal scattering adhere to the periphery of the opening 12 of the metal plate 21. There is a problem that it ends up. Since the quality of the microfabricated product is deteriorated by the dross 23 and the spatter 24, if the problem of the dross 23 and the spatter 24 is not completely solved by the microfabrication by the laser processing, the laser processing is performed on the metal plate. It is difficult to apply to the fine processing of. As described above, even by laser processing, it is still difficult to perform fine processing of a metal plate necessary for increasing the number of pins of a lead frame and achieving a fine pitch.

The present invention has been made in view of the above problems, and an object thereof is to reliably prevent dross or spatter generated during laser processing from adhering to a processed portion of a metal plate. It is an object of the present invention to provide a metal plate processing method capable of highly accurately and easily performing fine processing of a metal plate necessary for increasing the number of pins of a lead frame and achieving a fine pitch.

[0012]

In order to solve the above-mentioned problems, a method for processing a metal plate according to a first aspect of the invention is a metal plate having a photosensitive material on one or both sides and processed by a laser beam. A step of applying a possible etching resist to form a film, a step of irradiating a predetermined position of the metal plate and the etching resist with a laser beam to form an opening in the metal plate and the etching resist, and after the laser processing And a step of peeling the etching resist from the metal plate.

According to a second aspect of the present invention, a first etching resist having a predetermined pattern is made on one or both sides of the metal plate, and the metal plate is etched by using the first etching resist to obtain a total amount of processing of the metal plate. A step of half-etching by a predetermined amount; a step of applying a film of a second etching resist having a photosensitive substance and capable of being processed by a laser beam to a surface of at least the half-etching part of the metal plate to form a film; A laser beam is applied to a predetermined position of the etching processed portion of the metal plate and the second etching resist to process the remaining amount of the entire processing amount of the etching processed portion of the metal plate and the second etching resist to form an opening. The step of forming a portion, and after the laser processing, the first and second etching resists are applied to the metal plate. It is characterized by comprising the steps of al peeling.

Further, according to a third aspect of the present invention, a first etching resist having a predetermined pattern is made on one or both sides of the metal plate, and the metal plate is etched by using the first etching resist to obtain a total amount of the metal plate. A step of half-etching a predetermined amount, a step of peeling the first-time etching resist from the metal plate, and a laser beam having a photosensitive substance on at least the half-etched surface of the metal plate. A second step of applying an etching resist to form a film, and irradiating a laser beam to a predetermined position of the etching plate of the metal plate and the second etching resist to completely process the etching plate of the metal plate. Amount of remaining amount and the step of forming the opening by processing the second etching resist, The second etching resist is characterized by comprising the step of separating from the metal plate after.

Further, the invention of claim 4 is characterized in that the same etching resist is used for the first etching resist and the second etching resist. Furthermore, the invention of claim 5 provides the first etching resist and the second etching resist,
It is characterized in that different kinds of etching resists are used.

Further, the invention of claim 6 is characterized in that an etching resist having high heat resistance is used as each of the etching resists. Further, in the invention of claim 7, each of the etching resists is a casein type, a PVA type, a cyclized rubber type, an acrylic type, a novolac type, a polyimide type, a fish glue type, a vinyl acetate type, a gelatin type, and a cinnamic acid type. It is characterized in that it is one of the etching resists.

[0017]

In the method for processing a metal plate according to the first aspect of the present invention having such a structure, the laser processing is performed in a state where the etching resist is applied and formed on one surface or both surfaces of the metal plate. Here, although the mechanism by which the resist suppresses the dross is not clear, it is considered that the excess laser beam is absorbed by the etching resist due to the change of the charge of the photosensitive substance in the etching resist. Therefore, excess melting of the metal by the extra laser beam does not occur, and the dross generation is effectively suppressed.

Further, in the invention of claim 1, the etching resist is peeled off from the metal plate after the laser processing. Therefore, the spatters scattered during laser processing adhere to the etching resist, and as a result, the spatters are removed together with the peeling and removal of the etching resist, so that the work of removing the spatters becomes unnecessary and the process is shortened. In this way, according to the first aspect of the invention, a high-quality finely worked metal plate product free from dross and spatter is obtained.

Further, in the invention of claim 2, after the first etching resist is plate-formed in a predetermined pattern on one side or both sides of the metal plate and half-etching is performed, the half-etching part is further subjected to the second etching. The etching resist is applied, and in this state, the laser beam is applied to the half-etched portion. Therefore, as in the first aspect of the invention, the excess laser beam is absorbed by the photosensitive substance in the etching resist,
Excessive dissolution of metal does not occur, and dross generation is effectively suppressed. Moreover, since the half-etched portion is laser-processed, the amount of metal to be laser-processed is small. Therefore, the dross generation can be suppressed more effectively, and the laser processing can be performed in a short time. Moreover,
Similar to the invention of claim 1, after the laser processing, the first time and the second time
Since the etching resist of the second time is peeled and removed from the metal plate, the spatter is removed together with the removal and removal of the etching resist.
The process is shortened. In this way, according to the second aspect of the present invention, it is possible to obtain a finely processed metal plate having a higher quality than that of dross and spatter.

Furthermore, in the invention of claim 3, the first etching resist is plate-formed on one or both sides of the metal plate in a predetermined pattern and half-etched, and then the first etching resist is peeled off. It And further 2 in this half etching processing part
The etching resist for the second time is applied, and in this state, the half-etched portion is irradiated with the laser beam. Therefore, the invention of claim 3 has almost the same effect as that of the invention of claim 2, but in the case of the invention of claim 3, the thickness of the etching resist film is suppressed and two kinds of etching resists are used properly. Is possible. Thus, also in the third aspect of the present invention, it is possible to obtain a finely processed metal plate finer product having a higher quality in which neither dross nor spatter adheres.

Further, in the invention of claim 4, the same etching resist material is used for the etching resist used twice. Therefore, since the same coating device and the same peeling device can be used, the manufacturing cost can be suppressed and the labor of the work can be further reduced.

Further, in the invention of claim 5, different kinds of etching resists are used as the etching resists used twice. By using different etching resists in this way, a higher degree of fine processing becomes possible.

Further, in the invention of claim 6, since an etching resist having high heat resistance is used for each etching resist, even if spatter generated during laser processing adheres to the etching resist, the etching resist is not decomposed or modified. Does not happen. Therefore, as the etching resist is peeled off, the spatters are surely removed.

Further, in the invention of claim 7, an etching resist material used in a wet photoetching process is used as the etching resist. Here, when a water-soluble colloidal photoresist such as casein, PVA, fish glue or gelatin is used as the etching resist, dichromate such as potassium dichromate, chromate, diazo compound, bisazide compound, etc. The cyclized rubber photoresist is added with a diazide.

When the etching resist is composed of a molecule having a photosensitive group introduced, the molecule itself becomes a photosensitive substance. In addition, a photosensitive material such as a photoinitiator may be used depending on the type of etching resist. Thus, in the metal plate processing method of the present invention, both shortening of the metal processing step and high quality processing can be achieved.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a method for processing a metal plate according to the present invention, which is applied to a manufacturing process of the lead frame 1a shown in FIG. 6 and will be described.

In manufacturing the lead frame 1a,
First, as shown in FIG. 1B, a casein-based etching resist containing potassium dichromate as a photosensitive substance is formed on both surfaces of a metal plate 9 having a predetermined thickness shown in FIG. 1A, which is a material of the lead frame 1a. 10 and 11 are evenly applied to form a film. Next, as shown in FIG. 3C, the metal plate 9 on which the casein-based etching resists 10 and 11 have been formed is irradiated with a laser beam L by a YAG laser processing machine, as shown in FIG. Thus, the opening 12 is formed so as to penetrate the metal plate 9 and the casein-based etching resists 10 and 11. At this time, the irradiation of the laser beam L by the YAG laser beam machine is performed on the entire area shown by the hatched area in FIG. 6, that is, the area that will be the lead frame 1a. Finally, as shown in FIG. 1E, the casein-based etching resists 10 and 11 on both surfaces of the metal plate 9 are peeled and removed, whereby the lead frame 1a made of a processed product of the metal plate 9 is manufactured.

In the metal plate processing method according to the first embodiment, the casein system etching resist 1 is formed on both surfaces of the metal plate 9.
Since 0 and 11 are formed, the characteristics of these casein-based etching resists 10 and 11, that is, the charge of the photosensitive material contained therein, changes, so that the energy of the extra laser beam is increased. It is absorbed by the etching resists 10 and 11. Therefore, the generation of dross is suppressed. Therefore, the Y
Even if the laser beam L is irradiated by the AG laser beam machine, as shown in FIG. 1D, the dross as shown in FIG. 8 does not adhere to the opening 12. Further, as a result of this processing, spatters 13 adhere to the periphery of the opening 12 of the etching resist 9 as shown in FIG. 3D, but the spatters 13 are also removed by peeling off the casein etching resists 10 and 11. As a result, it is possible to obtain a high-quality processed product of the metal plate 9 in which the spatter 13 is not attached to the surface as shown in FIG.

As described above, according to the method of processing a metal plate of the present embodiment, even if laser processing is used, a finely processed product of the metal plate 9 which is finely processed with high precision without any attachment of dross or spatter is obtained. be able to. That is, according to the present embodiment, the laser processing can be easily applied to the fine processing for forming the fine pattern such as the inner leads 5 of the lead frame 1a. As a result, for example, the lead frame 1a has a large number of pins. -It will be possible to reliably handle fine pitches.

FIG. 2 shows a second embodiment of the method for processing a metal plate according to the present invention, and is a view for explaining the manufacturing process of the lead frame 1b shown in FIG. In manufacturing the lead frame 1b, first, as shown in FIG. 2A, casein-based etching resists 10 and 11 are applied to both surfaces of a metal plate 9 having a predetermined thickness, which is a material of the lead frame 1b, to form a film. At the same time, a predetermined pattern is formed on the casein-based etching resists 10 and 11. By forming this predetermined pattern, resist removal portions 10a and 11a are formed in the film of the casein-based etching resists 10 and 11. Next, using this pattern, a half etching process is performed on the portion of the inner lead 5 shown by hatching in FIG. In that case, as shown in FIG. 2B, half etching is performed on both sides of the metal plate 9 by the same amount to form the half etching portions 14 on both sides of the metal plate 9. At this time,
A portion of the lead frame 1b other than the hatched portion, that is, a portion other than the portion where the half etching process is performed, is entirely processed by only etching, and the metal plate 9 is opened. next,
After removing the casein-based etching resists 10 and 11 as shown in FIG. 6C, diazo resin as a photosensitive substance is formed on both surfaces of the metal plate 9 including the half-etched portion 14 as shown in FIG. PVA-based etching resists 15 and 16 containing an aqueous solution are applied to form a film. Then, as shown in FIG. 7E, YAG is formed on the half-etched portion 14.
A laser beam L is irradiated by a laser processing machine to form an opening 12 penetrating the metal plate 9 and the PVA type etching resists 15 and 16 as shown in FIG. Finally, as shown in FIG. 3G, the PVA on both sides of the metal plate 9 is
By removing and removing the system etching resists 15 and 16, the lead frame 1b made of a processed product of the metal plate 9 is manufactured.

In the metal plate processing method of the second embodiment, due to the characteristics of the PVA type etching resists 15 and 16 formed on both surfaces of the metal plate 9, the metal plate is processed in the same manner as in the first embodiment. Even if the laser beam L is irradiated to the beam 9, the dross does not adhere to the opening 12 as shown in FIG. In that case, in the second embodiment, since the half-etched portion 14 is laser-processed, the amount of metal to be laser-processed is reduced. Therefore, the time required for laser processing can be shortened, and the occurrence of dross can be suppressed more effectively. Further, as a result of this processing, the spatter 13 adhering to the periphery of the opening 12 of the PVA etching resist 15 as shown in FIG. 3F is also removed by peeling off the PVA-based etching resists 15 and 16. The removal work becomes unnecessary, and a high-quality processed product of the metal plate 9 without the spatter 13 adhered to the surface as shown in FIG.

As described above, the same effect as that of the first embodiment can be obtained by the processing method of the metal plate of the second embodiment, and for example, it is possible to surely cope with the increase in the number of pins and the fine pitch of the lead frame. You will be able to.

FIG. 3 shows a third embodiment of the method for processing a metal plate according to the present invention, and is a view for explaining the manufacturing process of the lead frame 1b shown in FIG. In manufacturing the lead frame 1b, first, the next step, that is, FIG.
A step of forming the casein-based etching resists 10 and 11 containing potassium dichromate as a photosensitive substance on both surfaces of the metal plate 9 shown in (a), and the metal plate 9 shown in FIG.
The step of forming the half-etched portions 14 on both surfaces of the metal plate 9 and the step of opening the metal plate 9 by performing the etching processing on the portion of the lead frame 1b other than the half-etching processing are shown in FIG. a)-(b)
It is exactly the same as the process shown in. Next, as shown in FIG. 3C, the same casein-based etching resists 15 ', 1 are again formed on the surfaces of the casein-based etching resists 10 and 11 on both surfaces of the metal plate 9 and the surface of the half-etched portion 14.
6'is applied and a film is formed. Then, as shown in FIG. 3D, the YAG laser beam machine is used to irradiate the half-etched portion 14 with the laser beam L, and as shown in FIG. 3E, the metal plate 9 and the casein-based etching resist 15 ', 1
An opening 12 is formed through 6 '. Next same figure
As shown in (f), casein-based etching resist 1
After removing 5'and 16 'by peeling and removing the casein etching resists 10 and 11 finally as shown in FIG. 3G, the lead frame 1b made of the processed product of the metal plate 9 is manufactured. It

Also in the metal plate processing method of the third embodiment, due to the characteristics of the casein type etching resists 15 'and 16' formed on both surfaces of the metal plate 9, the same metal as in the above-mentioned respective embodiments is used. Even if the plate 9 is irradiated with the laser beam L, the dross does not adhere to the opening 12 as shown in FIG. Further, by this processing, the spatter 1 adhered around the opening 12 of the etching resist 9 shown in FIG.
3 is also removed by peeling off the etching resists 15 'and 16', so that the work of removing the spatter 13 becomes unnecessary, and the spatter 13 is formed on the surface as shown in FIG.
It is possible to obtain a high-quality processed product of the metal plate 9 on which is not attached.

As described above, the same effects as those of the above-described respective embodiments can be obtained by the metal plate processing method of the third embodiment, and for example, it is possible to surely deal with the increase in the number of pins and the fine pitch of the lead frame. Will be able to.

FIG. 4 shows a fourth embodiment of the method for processing a metal plate according to the present invention, and is a view for explaining the manufacturing process of the lead frame 1b shown in FIG. In the second embodiment shown in FIG. 2 described above, the half-etched portions 14 formed on both sides of the metal plate 9 are set to have the same size, whereas in the fourth embodiment, both sides of the metal plate 9 are formed. By making the sizes of both resist removal portions 10a, 11a of the casein-based etching resists 10, 11 different from each other, the half etching portions 14 on both surfaces of the metal plate 9 are set to have different sizes. The other construction of the processing method of the metal plate 9 is exactly the same as that of the second embodiment, and the description thereof is omitted.

The same effects as those of the above-mentioned respective embodiments can be obtained by the processing method of the metal plate of the fourth embodiment.
For example, it is possible to reliably cope with the increase in the number of pins and the fine pitch of the lead frame.

FIG. 5 shows a fifth embodiment of the metal plate processing method according to the present invention, and is a view for explaining the manufacturing process of the lead frame 1b shown in FIG. In the third embodiment shown in FIG. 3 described above, the half-etched portions 14 formed on both sides of the metal plate 9 are set to have the same size, whereas in the fifth embodiment, the fourth embodiment described above is used. Similar to the example, the half-etched portions 14 on both surfaces of the metal plate 9 are set to have different sizes. The other construction of the method for processing the metal plate 9 is exactly the same as that of the third embodiment, and the explanation thereof is omitted.

The same effects as those of the above-mentioned respective embodiments can be obtained also by the method for processing a metal plate of the fifth embodiment.
For example, it is possible to reliably cope with the increase in the number of pins and the fine pitch of the lead frame.

In each of the above-mentioned embodiments, at least one of casein type and PVA type is used as the etching resist, but the method for processing the metal plate of the present invention is not limited to this, and it is not limited to this. It only needs to be an etching resist containing a reactive substance and capable of being processed and removed by a laser beam, such as cyclized rubber type, acrylic type, novolac type, polyimide type, fish glue type, vinyl acetate type, gelatin type, and cinnamon bark. Other acid-based etching resists can also be used.

Table 1 shows the sixth to ninth embodiments of the method for processing a metal plate according to the present invention in comparison with comparative examples.

In Example 6, the same method as in Example 1 was applied to 42 alloy (42% Ni-Fe alloy), and in Example 7, the same method as in Example 3 was applied. It is applied to alloys. In addition, Example 8 is a method in which the same method as in Example 1 is applied to a copper alloy, and Example 9 is
The same method as in Example 3 is applied to a copper alloy.
Further, in Comparative Examples 1 and 2, the 42 alloy and the copper alloy were processed by irradiating a laser beam with a YAG laser processing machine without coating the casein-based resist, respectively.

[0043]

[Table 1]

As is clear from Table 1, according to the sixth embodiment, the occurrence of dross and spatter can be suppressed to a sufficiently satisfactory level for 42 alloy, and good results are obtained. By incorporating half-etching as in No. 7, the generation of dross and spatter can be suppressed to a completely satisfactory level.

On the other hand, the copper alloy tends to generate more dross than the case of the 42 alloy, and according to Example 8, it is possible to reach a practicable level, and half etching is performed as in Example 9. If applied, dross and spatter can be suppressed to a sufficiently satisfactory level.

Here, an example of 42 alloy is shown, but in the case of iron-based alloy materials such as Kovar and steel, its thermal conductivity, YAG
Since there is no large difference in the reflectance of the laser light, the dross can be suppressed to the same level as the 42 alloy. Further, it is considered that a large amount of dross is generated in the copper alloy because of high thermal conductivity and high reflectance of YAG laser light.

Also, an example in which a casein-based resist containing potassium dichromate is used as an etching resist is shown, but PV which is usually used for metal etching processing is shown.
Almost the same effect can be obtained when an A-based, fish glue-based, gelatin-based, cyclized rubber-based, acrylic-based, novolac-based, vinyl acetate-based, or vinyl cinnamate-based etching resist is used.

In each of the above-mentioned embodiments, the etching resists 10, 11, 15, 16, 15 ', 16' are formed on both sides of the metal plate 9, but depending on the type of metal plate. , These etching resists are metal plates 9
It is also possible to form a film only on one surface side of.

Further, as the laser beam used for laser processing, other laser such as CO ₂ laser or excimer laser can be used instead of the YAG laser used in each of the above-mentioned embodiments. Furthermore, by using an assist gas together with the laser, it is possible to further improve the quality and processing speed of laser processing.

[0050]

As is apparent from the above description, according to the method for processing a metal plate of the first aspect of the present invention, an etching resist containing a photosensitive substance and capable of being processed by a laser beam is provided on at least one side of the metal plate. Alternatively, since the laser beam is radiated with the film formed on both sides,
Due to the characteristics of this etching resist, it is possible to prevent dross from adhering during laser processing. Moreover, since the spatter scattered during laser processing adheres to the etching resist, the spatter can be easily and surely removed by peeling and removing the etching resist from the metal plate. This eliminates the need for spatter removal work. Therefore, as compared with the conventional method for processing a metal plate, it is possible to perform a higher degree of fine processing and shorten the process, and it is possible to obtain a high-quality fine processed product of a metal plate.

According to the inventions of claims 2 and 3,
By combining the laser processing with the half-etching processing, the laser processing can be partially performed, so that the laser processing time can be significantly shortened. Moreover, by applying half etching,
Since the amount of metal dissolved by the laser beam is reduced, it is possible to more reliably and stably suppress the generation of dross, and it is possible to perform higher-level fine processing. Further, since the spatter scattered during laser processing adheres to the etching resist, the spatter can be easily and surely removed by peeling and removing the etching resist from the metal plate. This eliminates the need for spatter removal work. Therefore, as compared with the conventional method for processing a metal plate, it is possible to perform a higher degree of fine processing and shorten the process, and it is possible to obtain a high-quality fine processed product of a metal plate.

Further, since the etching resist is used twice, two kinds of etching resist can be selectively used depending on the characteristics. As a result, in this case, a higher degree of fine processing of the metal plate becomes possible. Further, according to the invention of claim 4, since the same etching resist material is used for the etching resist used twice, the same coating device and the same peeling device can be used.
Thereby, the manufacturing cost can be suppressed and the labor of the work can be further reduced.

Further, according to the fifth aspect of the invention, since the etching resists of different types are used as the etching resists used twice, the characteristics of the etching resists can be changed. As a result, a higher degree of fine processing can be performed.

Further, according to the inventions of claims 6 and 7, since the etching resist having high heat resistance is used as the etching resist, even if spatter generated during laser processing adheres to the etching resist, the etching resist is decomposed. Therefore, it is possible to surely remove spatter accompanying the removal of the etching resist without causing denaturation.

As described above, according to the metal plate processing method of the present invention, it is possible to achieve both shortening of the fine processing step and high-quality fine processing.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a first embodiment of a metal plate processing method according to the present invention.

FIG. 2 is a diagram illustrating a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a third embodiment of the present invention.

FIG. 4 is a diagram illustrating a fourth embodiment of the present invention.

FIG. 5 is a diagram illustrating a fifth embodiment of the present invention.

FIG. 6 is a view showing an example of a conventional lead frame formed by microfabrication, showing a lead frame processed by irradiating a laser beam on the entire surface.

FIG. 7 is a view showing another example of a conventional lead frame formed by fine processing, showing a lead frame processed by partially irradiating a laser beam.

FIG. 8 is a diagram showing a conventional method for processing a metal plate with a laser beam.

[Explanation of symbols]

1a, 1b ... Lead frame, 4 ... Die pad, 5 ... Inner lead, 6 ... Outer lead, 8 ... Positioning mark, 9 ... Metal plate, 10, 11 ... Casein-based etching resist, 12 ... Opening portion, 13 ... Spatter, 14 ... Half-etched part, 15,16 ... PVA-based etching resist, 15 ', 16' ... Casein-based etching resist,
L ... Laser beam

Front Page Continuation (72) Inventor Shigeyuki Sakurai 650 Kazunachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Plant

Claims (7)

[Claims] 1. A step of applying an etching resist having a photosensitive substance and capable of being processed by a laser beam to form a film on one or both sides of a metal plate, and a laser beam at a predetermined position of the metal plate and the etching resist. And a step of forming an opening in the metal plate and the etching resist, and a step of peeling the etching resist from the metal plate after the laser processing. 2. A first etching resist having a predetermined pattern is made on one or both sides of a metal plate, and the metal plate is half-etched by a predetermined amount out of the total processing amount by etching using this first etching resist. And a step of applying a second etching resist having a photosensitive substance and capable of being processed by a laser beam to a surface of at least the half-etched processed part of the metal plate to form a film, and the etched processed part of the metal plate. And a step of irradiating a predetermined position of the second etching resist with a laser beam and the remaining amount of the total processing amount of the etched portion of the metal plate and the second etching resist to form an opening. From the step of peeling the first and second etching resists from the metal plate after the laser processing A method for processing a metal plate, which comprises: 3. A first etching resist having a predetermined pattern is made on one or both sides of a metal plate, and the metal plate is half-etched by a predetermined amount out of the total processing amount by etching using this first etching resist. And a step of peeling the first-time etching resist from the metal plate, and a second-time etching resist that has a photosensitive substance on at least the half-etched surface of the metal plate and can be processed by a laser beam. A step of applying and forming a film, and irradiating a laser beam to a predetermined position of the etching processed part of the metal plate and the second etching resist and the remaining amount of the total processed amount of the etching processed part of the metal plate and the The second step of processing the etching resist to form the opening, and the second etching step after the laser processing. A method for processing a metal plate, which comprises a step of peeling a coating resist from the metal plate. 4. The method for processing a metal plate according to claim 2, wherein the same etching resist is used for the first etching resist and the second etching resist. 5. The method for processing a metal plate according to claim 2, wherein different kinds of etching resists are used for the first etching resist and the second etching resist. 6. The method for processing a metal plate according to claim 1, wherein an etching resist having high heat resistance is used as each of the etching resists. 7. Each of the etching resists is a casein type, a PVA type, a cyclized rubber type, an acrylic type, a novolac type, a polyimide type, a fish gluing type, a vinyl acetate type, a gelatin type, and a cinnamic acid type etching resist. 7. The method for processing a metal plate according to claim 6, wherein: