Lead frame exposure method

Abstract

The invention provides a lead frame exposure method, which comprises the following steps of: putting a lead frame raw material roll material coated with an induction film into a discharging station, and arranging an energy ruler on the upper surface of a material head of the roll material; the coil stock head is conveyed to an exposure machine, and the exposure machine exposes the energy ruler; conveying the coil stock head carrying the exposed energy ruler to a developing machine, and carrying out online developing treatment; judging the energy level of the energy ruler, and then setting the exposure energy required by the lead frame on the exposure machine according to the judgment result; and according to the set exposure energy, the exposure machine exposes the whole roll material of the lead frame raw material except the material head of the roll material. According to the invention, the energy ruler is arranged at the material head of the coil stock, and the exposed energy ruler is conveyed to the developing machine, so that online exposure and online development of the energy ruler are realized, the waiting time of energy test development is greatly shortened, and the production efficiency and the product quality of the exposure process of the lead frame are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of lead frame manufacturing, and in particular to a lead frame exposure method. Background Art

[0002] Lead frame is an important basic material in the electronic information industry. Lead frame is required in most semiconductor integrated circuits. Its quality is directly related to the working reliability and service life of semiconductors and integrated circuits.

[0003] Exposure and development are the core steps in the lead frame production process. Exposure is to expose the induction film on the lead frame substrate according to the board pattern, and polymerization occurs during the exposure process. Then during the development process, the unexposed part can be washed away with a developer, while the part that undergoes polymerization after exposure cannot be washed away. However, when the lead frame is not exposed enough, it is easy to cause the edge of the line of the board pattern to become jagged, affecting the quality and performance of the lead frame. Therefore, the lead frame exposure process needs to be tested for exposure energy before production to determine the required exposure of the lead frame.

[0004] The traditional exposure process is to test the exposure energy by cutting off the energy ruler with scissors after the exposure is completed, and then transferring the exposed energy ruler to the development process for development. After development, the energy level is determined, and after the determination is completed, the material and the traction belt need to be reconnected. In this process, the energy ruler is developed offline, and the exposure process is in a long waiting state, which increases the time cost. The reconnection of materials is very likely to cause deformation and dirt.

[0005] The Chinese invention patent with application publication number CN103698981A adopts the method of embedding a black film in the exposure energy scale to change the position of the exposure scale on the PCB board without repeatedly pasting the exposure scale. However, this method still requires taking out the exposure scale for development, and does not solve the problem of long time consumption of offline development. Summary of the invention

[0006] In view of the defects in the prior art, an object of the present invention is to provide a lead frame exposure method.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention provides a lead frame exposure method, comprising:

[0009] Place the lead frame raw material coil covered with the induction film into the unwinding station, and set an energy ruler on the upper surface of the coil head;

[0010] The coil head is transferred to an exposure machine, and the exposure machine exposes the energy ruler;

[0011] The coil head carries the exposed energy ruler and transmits it to the developer for online development processing;

[0012] Determine the energy level of the energy ruler, and then set the exposure energy required for the lead frame on the exposure machine according to the determination result;

[0013] According to the set exposure energy, the exposure machine exposes the entire roll of the lead frame raw material except the roll head.

[0014] Furthermore, the exposure machine exposes the energy ruler, wherein: the exposure time of the energy ruler is 1 second to 300 seconds.

[0015] Furthermore, the web head carries the exposed energy ruler and transmits it to a developer, wherein the developer is arranged at the outlet of the exposure machine.

[0016] Furthermore, the online development process includes: developing the energy ruler with a developer, followed by washing and drying.

[0017] Furthermore, the energy ruler is developed with a developer, wherein the developing time is 30 seconds to 300 seconds.

[0018] Furthermore, the subsequent washing and drying comprises: washing with deionized water.

[0019] Furthermore, the subsequent washing and drying may take place for 30 to 600 seconds.

[0020] Furthermore, the product is subsequently washed with water and dried, wherein the drying temperature is 30°C to 120°C.

[0021] Furthermore, the product is subsequently washed and dried, wherein the drying time is 10 seconds to 600 seconds.

[0022] Furthermore, after the exposure machine exposes the entire roll of lead frame raw material except the roll head, the method includes: removing the roll head that has passed the exposure energy test, and then transferring the lead frame to a receiving station.

[0023] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0024] 1. The present invention adds an energy ruler to the head of the whole roll material and transmits the exposed energy ruler to the developer, thereby realizing online exposure, online development of the energy ruler after exposure, and online determination of the energy level of the energy ruler, eliminating the testing steps of cutting the energy ruler, circulating the energy ruler, and reconnecting the material and the traction belt, reducing the steps of exposure energy testing, saving the waiting time for energy testing and development, and thus greatly improving the production efficiency of the lead frame exposure process.

[0025] 2. The present invention adopts the method of online exposure and development energy scale, which does not require cutting and offline development energy scale, nor does it require reconnecting materials and traction belts. It can avoid deformation and dirt problems of the lead frame during material turnover and reconnection, and avoid the risk of pollution during material turnover, thereby improving the quality and yield rate of lead frame products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0027] Figure 1 Schematic diagram of the process of a lead frame exposure method in one embodiment of the present invention. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0029] Reference Figure 1 FIG. 1 is a schematic diagram of a lead frame exposure method according to an embodiment of the present invention. The method comprises:

[0030] S1. Pretreatment: Place the lead frame raw material coil covered with the induction film into the unwinding station, and set an energy ruler on the upper surface of the coil head;

[0031] S2, Exposure energy ruler: The coil head is transferred to the exposure machine, and the exposure machine exposes the energy ruler;

[0032] S3, online development: The coil head carries the exposed energy ruler and transmits it to the developer for online development processing;

[0033] S4. Determine exposure energy: Determine the energy level of the energy ruler in the inspection window, and then set the exposure energy required for the lead frame on the exposure machine according to the determination result;

[0034] S5. Expose the lead frame: According to the set exposure energy, the exposure machine exposes the entire roll of the lead frame raw material except the roll head.

[0035] In some embodiments, the energy scale includes 21 and 41 level energy scales, etc., which are pasted on the surface of the coil head to form a scaled film optical mask. The intensity of ultraviolet irradiation can be used to determine the corresponding energy level according to the scale lines after development.

[0036] In some embodiments, in step S2, the exposure machine exposes the energy ruler, and the longer the exposure time, the higher the energy, wherein: the exposure time of the energy ruler is 1 second to 300 seconds to meet the exposure energy requirement. In some other embodiments, the energy can be increased by increasing the power to reduce the exposure time and improve production efficiency.

[0037] In some embodiments, in step S3, the developing machine is a micro developing machine, which is disposed at the discharge port of the exposure machine to display the scale, thereby realizing online development.

[0038] In some embodiments, in step S3, an online development process is performed, which includes development, washing and drying in sequence, that is, the energy ruler is developed with a developer, and then washed and dried.

[0039] In some embodiments, the developing time is 30 seconds to 300 seconds to ensure that the scale can be displayed. To avoid oxidation of the surface, it is washed with deionized water for 30 seconds to 600 seconds to accurately read the scale data. The drying temperature is 30°C to 120°C, and the drying time is 10 seconds to 600 seconds. The drying temperature and time are matched with the exposure speed to ensure that the material is not oxidized so that the scale data can be accurately read.

[0040] In step S4, for the sensing film on the surface of the lead frame, when the sensing film has different components and thicknesses, the energy required for exposure of the lead frame is different. The higher the energy level, the stronger the required exposure energy. Therefore, it is necessary to pre-determine the energy level of the energy ruler after exposure, so as to determine the exposure energy required for the lead frame.

[0041] In some embodiments, after the exposure machine exposes the entire roll of lead frame raw material except the roll head, it also includes removing the roll head and collecting the material, that is, removing the roll head that has passed the exposure energy test, and then transferring the lead frame to the collecting station.

[0042] The method of the above embodiment of the present invention, by setting an energy ruler on the material head of the lead frame, transmits the exposed energy ruler to the developer, realizes online exposure and online development of the energy ruler, and effectively reduces the steps of exposure energy testing. On the one hand, it can greatly shorten the waiting time for energy test development, thereby improving the production efficiency of the lead frame exposure process; on the other hand, it can also avoid the risk of contamination during material turnover, and can effectively improve the quality of lead frame products.

[0043] In a specific embodiment, Figure 1 As shown, a method for testing exposure energy of an exposure machine includes the following steps:

[0044] Step 1: Place the lead frame pure copper strip coil covered with the induction film into the unwinding station, and set the 21-level energy ruler on the upper surface of the pure copper strip head.

[0045] Step 2: The pure copper thin strip coil head of the first step is transferred to the roll-to-roll exposure machine, and the exposure machine exposes the energy ruler, and the exposure time of the energy ruler is 5 seconds.

[0046] Step 3: The pure copper thin strip coil head carries the exposed energy ruler to the micro developer at the discharge port of the exposure machine, and the energy ruler is developed online with a developer, and then cleaned and dried online with deionized water. The developing time is 100 seconds, the cleaning time is 500 seconds, the drying time is 180 seconds, and the drying temperature is 60°C.

[0047] Step 4: Observe the scale line of the energy scale after development in the inspection window, and determine that the energy level of the energy scale is level 10. Set the exposure energy required for the lead frame on the exposure machine to: 194mJ / cm 2 , down light 240mJ / cm 2 .

[0048] Step 5: According to the exposure energy set in step 4, the roll-to-roll exposure machine exposes the entire lead frame pure copper strip roll except the material head.

[0049] Step 6: Remove the lead frame head that has passed the exposure energy test, and then transfer the lead frame pure copper strip to the receiving station.

[0050] Compared with the existing exposure method of manually cutting and developing energy scales offline, the exposure method of the exposure machine in the above embodiment of the present invention effectively reduces the steps of exposure energy testing, shortens the time required for the lead frame exposure process by 40%, and increases the yield rate by 12%.

[0051] The above-mentioned embodiment of the present invention realizes online exposure, online development of the energy ruler after exposure, and online determination of the energy level of the energy ruler by adding an energy ruler to the material head of the whole roll of material and transmitting the energy ruler after exposure to the developer, thereby eliminating the testing steps of cutting the energy ruler, rotating the energy ruler, and reconnecting the material and the traction belt, reducing the steps of exposure energy testing, saving the waiting time for energy testing and development, and thus greatly improving the production efficiency of the lead frame exposure process.

[0052] The above-mentioned embodiment of the present invention adopts the method of online exposure and development energy scale, which does not require cutting and offline development energy scale, nor does it require reconnecting materials and traction belts. It can avoid deformation and dirt problems of the lead frame during material turnover and reconnection, and avoid the risk of contamination during material turnover, thereby improving the quality and yield rate of lead frame products.

[0053] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications or variations within the scope of the claims, which does not affect the essence of the present invention. The above preferred features can be used in any combination without conflicting with each other.

Claims

1. A lead frame exposure method, characterized in that: include: Place the lead frame raw material coil covered with the induction film into the unwinding station, and set an energy ruler on the upper surface of the coil head; The coil head is transferred to an exposure machine, and the exposure machine exposes the energy ruler; The coil head carries the exposed energy ruler and transmits it to the developer for online development processing; Determine the energy level of the energy ruler, and then set the exposure energy required for the lead frame on the exposure machine according to the determination result; According to the set exposure energy, the exposure machine exposes the entire roll of the lead frame raw material except the roll head.

2. The lead frame exposure method according to claim 1, characterized in that: The exposure machine exposes the energy ruler, wherein: the exposure time of the energy ruler is 1 second to 300 seconds.

3. The lead frame exposure method according to claim 1, characterized in that: The coil head carries the exposed energy ruler and transmits it to the developer, wherein the developer is arranged at the discharge port of the exposure machine.

4. The lead frame exposure method according to claim 1, characterized in that: The online developing process comprises: developing the energy ruler with a developer, followed by washing and drying.

5. The lead frame exposure method according to claim 4, characterized in that: The energy ruler is developed with a developer, wherein the developing time is 30 seconds to 300 seconds.

6. The lead frame exposure method according to claim 4, characterized in that: The method is then washed with water and dried, wherein: the washing is carried out with deionized water.

7. The lead frame exposure method according to claim 4, characterized in that: The method is then washed with water and dried, wherein the washing time is 30 seconds to 600 seconds.

8. The lead frame exposure method according to claim 4, characterized in that: The product is then washed with water and dried, wherein the drying temperature is 30°C to 120°C.

9. The lead frame exposure method according to claim 4, characterized in that: The method is then washed with water and dried, wherein the drying time is 10 seconds to 600 seconds.

10. The lead frame exposure method according to claim 1, characterized in that: After the exposure machine exposes the entire roll of the lead frame raw material except the roll head, the method includes: removing the roll head that has been tested for exposure energy, and then transferring the lead frame to a receiving station.

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