JP3045127B2 - Method for manufacturing lead frame for semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing an etching lead frame for a semiconductor device.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view for explaining an exposure step in a conventional method for manufacturing an etching lead frame for a semiconductor device. As shown in FIG. 3, the resist 2 is exposed by sandwiching a lead frame material 3 having resist 2 applied on both front and back surfaces with a pattern mask 16 in which a lead frame shape is drawn from both front and back surfaces and irradiating light from both sides. A glass plate is usually used as the material of the pattern mask 16, and a laser plotter or the like is used for drawing a lead frame shape. The drawn lead frame shape is
Normally, the shape is corrected in consideration of the etching property due to the shape in the etching process, not the shape of the lead frame that is ultimately required.

[0003] As an exposure technique used for a semiconductor element, for example, Japanese Patent Application Laid-Open No. 61-212843 discloses a method of manufacturing a reticle serving as an original plate when a device pattern is transferred onto a wafer. This manufacturing method will be described with reference to FIG.

In FIG. 2, reference numeral 12 denotes a fixed base, on which an XY movable base 11 movable in the X-axis and Y-axis directions is disposed. Reference numeral 5 denotes light emitted from a mercury lamp 5 serving as a light source, which is applied to a reticle 15 via a condenser lens 7. The reticle mounting table 6 can be moved in the X and Y axis directions so that the reticle 15 can be set and adjusted to a predetermined position by a reticle position control signal from the reticle position control unit 4.

Next, reticle design data, that is, pattern data for each process corresponding to the type is input to a memory of a design data input unit 14, and a pattern signal generation unit is generated based on the design data signal from the design data input unit 14. 13
Generates a pattern signal, and a predetermined voltage is applied to the X-axis transparent electrode and the Y-axis transparent electrode of the corresponding liquid crystal cell 15 by the pattern signal. Thereby, a mask pattern is formed. This mask pattern can be created using a single liquid crystal cell 15, and there is no need to replace it every process.

[0006]

However, the above-mentioned conventional method of manufacturing an etched lead frame has the following problems.

The first problem is that it takes a lot of man-hours to manufacture a pattern mask and the cost is high. For example, for each type of lead frame, it usually takes a construction period of one week and a cost of several hundred thousand yen.

The reason is that, after designing a lead frame shape for each type of lead frame, a step of drawing the shape on a glass plate is required.

A second problem is that a storage space and man-hours are required to store the manufactured pattern mask.

The reason is that for each type of lead frame,
This is because two pattern masks are created on the front and back sides, and a large number of types are required to store them.

[0011] Further, the storage of the pattern mask requires temperature control so as not to distort the shape of the lead frame due to heat. Further, if dust adheres or scratches on the pattern mask, problems such as pinholes occur during etching. Due to the possibility, storage in a clean room is essential.

The third problem is that every time the type of the lead frame is switched, the number of steps required to replace the pattern masks for the front and back two sheets is required. That is, the rate decreases.

The reason for this is that, unlike a reticle, a pattern mask for a lead frame requires two front and back pattern masks for each type of lead frame, and each time a lead frame type is switched, two pattern masks are required. ,
This is because it is necessary to replace it with the pattern mask of the exposing machine attached at that time.

As described above, the conventional manufacturing of an etching lead frame requires two glass mask patterns, one on the front and the other on the back, and this mask pattern is manufactured using a laser plotter or the like after the completion of the lead frame design. A pattern fabrication period was required.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a manufacturing method which eliminates the need for producing a mask pattern which has been conventionally required, and which can shorten a construction period. is there.

It is another object of the present invention to provide a manufacturing method which does not require replacement of a glass mask pattern every time a lead frame type is different at the time of exposure during the manufacture of an etching lead frame.

It is still another object of the present invention to provide a manufacturing method in which storage of a mask pattern is stored in an electronic file and maintenance cost can be reduced particularly.

[0018]

In order to achieve the above object, a method for manufacturing a lead frame for a semiconductor device according to the present invention is summarized as follows. A liquid crystal panel is used as a pattern mask on the front and back surfaces of a lead frame material. The pattern is exposed through exposure. The present invention is, in the exposure step of the production of etching the lead frame, and applied so as to wrap the entire front and back surfaces of the lead frame material with a resist, the Le
Established the LCD panel on the front and back of the lead frame coated to wrap in resist, the pattern is screen reads the pattern of the desired lead frame shape on the liquid crystal panel installed on the front and back of the lead frame, before
Light is radiated through each of the liquid crystal panels installed on the front and back of the lead frame to expose the resist to a mask pattern.

[Summary of the Invention] The present invention uses a liquid crystal panel capable of forming patterns on the front and back surfaces of a lead frame of any type.

According to the present invention, since the pattern is formed on the front and back of the lead frame using the liquid crystal panel, the same pattern is displayed on the front and back of the screen, so that it is not necessary to perform a correction operation. Also, the lead frame mask design work period is shortened, and the pattern storage space and management costs (temperature and humidity, etc.) are reduced.

[0021]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view for explaining a manufacturing method according to an embodiment of the present invention.

The lead frame 3 itself uses a general material. The entire lead frame 3 is applied so as to be wrapped with the resist 2, the liquid crystal panel 1 is set on the front and back surfaces, and light is irradiated to form a pattern.

Next, the operation of the embodiment of the present invention will be described with reference to FIG.

Using a general lead frame 3, the resist 2 is applied so as to be wrapped by a coating machine. Thereafter, the liquid crystal panel 1 is set on the front and back of the lead frame 3, and an arbitrary pattern is read from the CAD data into the liquid crystal panel 1 and displayed on a screen. The liquid crystal panel 1 is irradiated with light to form a mask pattern.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to describe the above-mentioned embodiment of the present invention in more detail, an embodiment of the present invention will be described.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIG. The lead frame 3 itself is made of a general material, preferably a Cu alloy or Fe-N
An i alloy is used. The entire front and back of the lead frame material 3 is applied so as to be wrapped with the resist 2, and the liquid crystal panel 1 is installed on the front and back of the lead frame 3.
A desired pattern is read from D and displayed on the screen. The mask pattern is exposed on the resist 2 by irradiating the liquid crystal panel 1 with light. The liquid crystal panel 1 is connected to a CAD device, and can display a lead frame shape designed by the CAD device on the liquid crystal panel 1.

As the resist 2 applied to the lead frame material 3, a photosensitive resin is used, for example, an ultraviolet curing polyimide resin.

[Embodiment 2] A second embodiment of the present invention will be described with reference to FIG.

The lead frame 3 itself is made of a general material, and a Cu alloy or an Fe-Ni alloy is used as in the above embodiment. The entire front and back surfaces of the lead frame material 3 are applied so as to be wrapped with the resist 2, the liquid crystal panel 1 is set on the front and back surfaces, and light is irradiated to expose the resist.

The liquid crystal panel 1 is connected to a PC in an etching process, and the liquid crystal panel 1 can display a lead frame shape whose lead shape correction value has been changed by the PC in the etching process.

As described above, in the second embodiment of the present invention, the liquid crystal panel 1 is connected to the PC in the etching process, and the lead frame shape whose lead shape correction value is changed in the PC in the etching process is changed to the liquid crystal. By displaying on the panel 1, the workmanship of the lead frame confirmed in the etching step can be fed back to the lead frame shape at the time of exposure.

Unlike the transfer of a pattern onto a wafer, the lead frame requires a pattern mask not only on the front surface, but also on the back surface. However, if the workmanship of the frame is fed back, the influence of the displacement of the mask is eliminated.

[0033]

As described above, according to the present invention, the following effects can be obtained.

The first effect of the present invention is that, since the lead frame is designed and the exposure process is immediately carried out, the construction period (usually one week) is greatly reduced, and the mask pattern manufacturing cost (usually several hundred thousand yen) Can be particularly reduced.

The reason is that, in the present invention, the data designed from the CAD or the like for designing the lead frame shape is displayed on the liquid crystal panel, so that the production of the pattern mask on the glass plate becomes unnecessary. .

A second effect of the present invention is that a storage space for a pattern mask and management man-hours are not required.

The reason is that, in the present invention, a pattern mask for each lead frame type is not required, and the storage of the pattern mask is performed by a CA designed with the lead frame shape.
This is because it becomes possible by electronically storing the file in D or the like.

The third effect of the present invention is that the type change in the exposure step can be performed only by the time required for the data transfer from the CAD to the liquid crystal panel. It is possible to improve the operation rate of the machine.

The reason is that, in the present invention, the man-hour for replacing a pattern mask on a glass plate for displaying data designed from a CAD or the like for designing a lead frame shape on a liquid crystal panel becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional exposure apparatus.

FIG. 3 is a cross-sectional view for explaining a conventional exposure technique for an etching lead frame.

[Explanation of symbols]

 Reference Signs List 1 liquid crystal panel 2 resist 3 lead frame 4 reticle position control unit 5 mercury lamp 6 reticle mounting table 7 condenser lens 8 wafer 9 fixing member 10 1/10 reduction lens 11 XY moving table 12 fixing table 13 pattern signal generating unit 14 design data input Part 15 Liquid crystal panel (reticle) 16 Pattern mask

Claims (4)

(57) [Claims] In an exposure step of manufacturing an etching lead frame, the entire front and back surfaces of a lead frame material are coated so as to be wrapped with a resist, and a liquid crystal panel is placed on the front and back of the lead frame coated so as to be wrapped with the resist. A desired lead frame-shaped pattern is read into the liquid crystal panel installed on the front and back of the lead frame, the pattern is displayed on a screen, and light is irradiated through each of the liquid crystal panels installed on the front and back of the lead frame to irradiate the resist. A method for manufacturing a lead frame, comprising: exposing a mask pattern to a lead frame. 2. The lead frame according to claim 1, wherein a desired lead frame shape pattern is read from the CAD data into the liquid crystal panels installed on the front and back of the lead frame, and the pattern is displayed on a screen. Production method. Wherein said liquid crystal panel, a manufacturing method of a lead frame according to claim 1 or claim 2, wherein the leading shape correction value screen displaying the changed leadframe shape of the etching process. 4. The effect of mask displacement between the liquid crystal panels installed on the front and back of the lead frame by feeding back to the screen display the lead frame shape whose lead shape correction value has been changed in the etching step. 4. The method for manufacturing a lead frame according to claim 3, wherein: