JPS622642A - Manufacture of lead frame with supporting body - Google Patents

Abstract

PURPOSE:To reduce the amount of noble metal used, by forming a thin film comprising gold with a thickness of 5-10mum at the tip part of an inner lead, then lightly etching the thin film, and protruding a bump by 10-30mum. CONSTITUTION:On one surface of a metal foil 1, a supporting film 2, in which a semiconductor-device inserting hole 3 is provided, is laminated. Positive type photoresist films 4 and 5 are formed on the upper and lower surfaces of the metal foil 1. An exposing plate is applied on the surface of a photoresist film 4 and exposure is carried out. After development, a first resist pattern 6 is formed. Then alloy is electrodeposited on the surface of the metal foil 1, which is exposed through holes 7, to a thickness of 10-30mum. A second resist pattern 9 is similarly formed. The, the unnecessary part of the metal foil 1 is etched away. After the first resist pattern is removed, the surface of the exposed metal foil is lightly etched and the electrodeposited part is protruded from the inner lead part other than the electrodeposited part by 10-30mum. Finally, the remaining resist film is dissolved and removed, then the device is washed with water.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing a lead frame with a support. [Prior art] The pads of semiconductor chips transmit and receive electrical signals from the outside.
Usually, a ζ nichrome layer is formed on the base of the aluminum wiring circuit by vapor deposition to a thickness of 500 to 1,000 A, and then copper is formed on top of it by vapor deposition to a thickness of 500 to 1,000 A. Overwriting = gold layer 1 by electrodeposition etc.
0 to 20) It is manufactured by forming it to a thickness of 1 m. Then, bonding with gold wire is performed to the pads produced in this way. As mentioned above, conventionally, the fine area C of a semiconductor chip:
Since multiple layers of heavy metals must be formed using a steaming method or an electric method, it takes a long time to manufacture pads for semiconductor chips, and the large number of steps can easily lead to a decrease in yield. There was a point. In addition, the tips of the inner leads of semiconductor lead frames were formed long enough to reach the pads of the semiconductor chip, and were bonded directly to the semiconductor chip without wire bonding. For example, in the case of solder bonding, a titanium layer and a lead layer each have a thickness of 50 to 1
．． It was necessary to form the pad to a thickness of 0.000 h and raise the pad. [◆Problems to be Solved by the Invention] Therefore, the problems to be solved by the present invention are to provide a lead with a support that enables bonding between a semiconductor chip and a lead frame without the need for bulges on the pads of the semiconductor chip. It is an object of the present invention to provide a method for manufacturing a frame, to reduce the number of steps in the process of manufacturing a frame, and to improve the yield. [Means for Solving the Problems] As a result of research to solve the above problems, the present inventor laminated a supporting film with holes for inserting two semiconductor devices on one side of metal foil, and then supported it on the metal foil. A positive photoresist is applied to both sides of the laminated film, and then applied to the support film side (positive photoresist). After applying an exposure master plate to the M side and exposing it, it is developed to form the bump formation area at the tip of the inner lead. Form a first Lujist pattern with an opening in the portion corresponding to C2, and apply gold, silver,
Lead or an alloy consisting of gold, silver, tin, lead, chromium, etc. is electrodeposited to a thickness of 5 to 10 μm, and after the electrodeposition, the metal foil side (
= After exposing the surface of the coated positive photoresist film to light, it is developed to open the area other than the area corresponding to the inner lead flake R1 of the chip carrier tape or the semiconductor lead frame. A second resist pattern is formed, etched from the second resist pattern side to remove unnecessary metal foil portions by corrosion, and after removing the unnecessary metal foil portions, the entire surface is exposed from the second resist pattern side, and then developed. The exposed metal foil surface is lightly etched to make the part where the gold or the like is electrodeposited protrude by 10 to 60 μm from the rest of the inner lead part, and finally the remaining resist film is peeled off to form the inner lead. We have discovered that it is possible to easily obtain a lead frame with a support, which has a bump (protrusion) at the tip and can be bonded even if the pad part of a semiconductor chip is not raised, with a small number of steps, and we have developed this knowledge. The present invention has been completed based on the above.The method for producing a lead frame with a support according to the present invention includes the steps of laminating a support film with a hole for inserting a semiconductor device on one side of a metal foil, and laminating a support film on the metal foil. A process of covering both sides with positive photoresist, applying an exposure master plate to the surface of the positive photoresist film coated on the support film side, exposing it, and developing it to remove the bumps at the tips of the inner leads. Formation location: A process of forming a first Lujist pattern with openings in the corresponding portions, and applying gold, silver, lead, or gold, silver, tin, lead, 5 alloys made of chromium etc.
After the process of electrodeposition to a thickness of ~10 μm and the electrodeposition by cutting, an original plate for exposure is applied to the metal foil side (the surface of the positive photoresist film formed on the two-wheeled cloth) to form a layer, and then developed to form the inner layer of the chip carrier tape. A step of forming a male 2 resist pattern with openings in areas other than the area corresponding to the lead frame or semiconductor lead frame, a step of etching from the second resist pattern side to remove unnecessary metal foil portions, and an unnecessary process. After removing the metal foil portion, the entire surface is exposed to light from the first resist pattern side, and then developed, the exposed metal foil surface is lightly etched, and the portion where the gold etc. has been electrodeposited is exposed more than the other inner lead portion. 10-50
The process consists of a step of oozing out micrometers and a step of peeling off the remaining resist film. In the present invention, the metal foil is 0.015 to 0.0.
30 years of good electrical conductors mainly made of copper, or mainly made of copper and other metals (zinc, iron, tin, lead, etc.)
alloys, or iron, nickel, tin, zinc, aluminum,
A metal foil made of a metal such as tantalum or a clad type between the above-mentioned metals can be used. Next, as the material for the support film, the thickness is 20 to 2.000μ.
Polyimide, polyester, glass fiber-filled epoxy resin, and triazine resin may be used. Next, as a positive photoresist, a quinone diazide photoresist such as 0FPR-800 (manufactured by Tokyo Ohka) or AZ-1350 (manufactured by Hoechst Java) can be used. Next, in the present invention, after removing the unnecessary metal foil portion (= fully exposed from the second resist pattern side, then developing, the exposed metal foil surface is lightly etched and the portion where caps, silver, etc. are electrodeposited) The protrusion height of the bump is 1 to make the bump protrude 10 to 30 μm higher than the other inner lead parts.
This is because if it is less than 0 μm, the bonding with the pad portion of the semiconductor chip will not be successful, and on the other hand, it is not economical to make it protrude more than 30 μm. In addition, if the protruding portion (bump) is too high, it may bend laterally when bonding the pad portion of the semiconductor chip and the inner lead portion with the bump.
This is because excessive melting may occur, causing it to protrude and adversely affect other wiring. Next, in the present invention, a metal such as gold or silver is electrodeposited, and then a second resist pattern is formed, followed by a corrosion removal process of unnecessary metal foil parts, and a second resist after removing unnecessary gold TF4 foil parts. The process of exposing the entire surface from the pattern side, then developing, and then etching the exposed metal foil surface will corrode the metal foil, but the electrical parts of metals such as gold and silver will not corrode, or will corrode only slightly. No corrosive liquid,
It is necessary to perform this depending on the plating conditions. [Function] The positive photoresist film coated and formed on the metal foil side in the sheet of the present invention functions as a plating mask when plating metals such as gold and silver, and also functions as a plating mask when exposed and developed. After the resist pattern is formed, it functions as an etching mask. [Example] Hereinafter, examples of the present invention will be described in detail with reference to the drawings. First, as shown in the first diagram, a good electrical conductor with a thickness of 0.015 to 0.60 mm and mainly composed of copper;
- alloys with other metals (zinc, iron, tin, lead, etc.), or metals such as iron, nickel, tin, zinc, aluminum, dantal, or cladding types between the above metals.
IAffi (thickness 20 mm with a semiconductor device insertion hole (3) for inserting a semiconductor/chip etc. on one side of 11)
~2,000 μm polyimide, polyester, glass fiber filled Evo film (laminated with two layers. Then, as shown in the second figure, the metal foil (1) is laminated with the support film (2), and a positive photoresist is applied on the front and back sides of the film. , for example, quinone φ diazide photoresist (
AZ-1350, manufactured by Hoechst Japan) is applied and dried to form a positive photoresist film (41(5)).Next, a positive photoresist film (4) coated on the support film (2) side is coated. After the exposure master is applied and exposed, it is developed to form a second resist pattern (6) in which the portion corresponding to the bump formation location at the end of the inner lead portion is open as shown in FIG. 6. (7) shows the opening of the $ resist pattern. Next, as shown in the fourth figure, metal w3 (11
Electrodeposit gold, silver, lead, or an alloy of gold, silver, tin, chromium, etc. on the surface to a thickness of 10 to 30 μm to form an electrodeposited portion (8) of metal such as gold or silver. . For electrodeposition, for example, when electrodepositing gold on copper foil, use a gold plating solution such as Tenbe Regis 7'r (manufactured by Nippon Kojundo Kagaku) as a plating solution, and apply a current of 80゛C±1''C%. The process is carried out under the condition of a density of 5A±α5*/am'. Next, an exposure master plate is applied to the surface of the positive photoresist film (9) formed on the metal foil (1) side, exposed to UV light, and then developed. Then, as shown in Figure 5, a tJS2 resist pattern (9) is formed in which areas other than the area corresponding to the inner lead frame of the TEP carrier tape or the semiconductor lead frame are open.Next, it is etched to form a gold fR foil. (1) Unnecessary parts are corroded and removed as shown in Figure 6. Metal foil

[1]Thickness 35μ
An example of etching conditions when using shoulder copper foil is etching solution;
f1 Eclipse temperature; 70~so”c, souffle pressure; t O~
t5111/C11l, corrosion time; z5 to 3 minutes. Next, as shown in Figure 7, the entire surface is exposed to ultraviolet light from the first resist pattern side, and then developed to remove the first resist pattern.The exposed metal foil surface is then lightly etched to electrodeposit gold or the like. This portion is made to protrude 10 to 30 μm from the other inner lead portions. Finally, as shown in Fig. 8, the remaining resist film is dissolved and peeled off using a film stripping solution, and washed with water. can be done.In addition, figure N49,
and in FIG. 10 (IG indicates an inner lead l indicates a bump. FIG. 11 shows a state in which a semiconductor chip is mounted using a lead frame with a support obtained by the manufacturing method of the present invention. As described in detail above, according to the present invention, the bonding between the pad part (to) and the inner lead can be performed even without the embankment of the pad part 0 of the semiconductor chip (2). The photoresist (IIQ) provided on the foil side was first used as a plating mask when plating gold, silver, etc., and then the photoresist film was patterned and used as a resist pattern for etching, for two purposes. The overall number of steps was reduced by using it together with the pattern as a corrosion-resistant material during etching, and the bumps were removed by forming a thin film of 5 to 10 μm of gold or the like on the tip of the inner lead and then lightly etching it. By forming bumps in a short plating time by protruding 10 to 30 μm, the tip of the inner lead can be formed with fewer steps and less time, and with less precious metals such as gold and silver. A lead frame with a support having bumps can be obtained.

[Brief explanation of drawings]

1 to 8 are cross-sectional views of the manufacturing process of the manufacturing method of the present invention, FIGS. 9 and 10 are plan views of a supported frame manufactured by the manufacturing method of the present invention, and FIG. The figure is a cross-sectional view of a lead frame (with a two-handed conductor chip mounted on it. 1. Metal foil 2.
・・・・・・・・・・・・・・・・Support film 3・・
・・・・・・・・・・・・・・・Semiconductor device insertion hole 4.5・・・・・・・・・Positive photoresist film 6・・・・・・・・・・・・・・・・・・First resist pattern 7・・・・・・・・・・・・・・・
・・・Opening 8・・・・・・・・・・・・・・・・・・
Metals such as gold and silver 9・・・・・・・・・・・・・・・
...Second resist pattern patent applicant Dai Nippon Printing Co., Ltd. Agent Atsumi Konishi, patent attorney Figure 1 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] A process of laminating a support film with a hole for semiconductor device insertion on one side of the metal foil, a process of applying a positive photoresist to both sides of the laminated support film on the metal foil, and a process of applying a positive photoresist coated on the side of the support film. A step of applying an exposure master plate to the surface of the mold photoresist film, exposing it to light, and then developing it to form a first resist pattern in which a portion corresponding to the bump formation location at the tip of the inner lead is opened; and an opening in the first resist pattern. A step of electrodepositing gold, silver, lead, or an alloy of gold, silver, tin, lead, chromium, etc. to a thickness of 5 to 10 μm on the more exposed surface of the metal foil, and after the electrodeposition, a step of electrodepositing gold, silver, lead, or an alloy consisting of gold, silver, tin, lead, chromium, etc. After applying an exposure master plate to the surface of the positive photoresist film and exposing it to light, it is developed to form the inner lead frame of the chip carrier tape.
Alternatively, a step of forming a second resist pattern in which a region other than the region corresponding to the semiconductor lead frame is open, a step of etching from the second resist pattern side to remove unnecessary metal foil portions, and a step of removing unnecessary metal foil. After removing the foil portion, the entire surface is exposed from the first resist pattern side, and then developed, and then the exposed metal foil surface is lightly etched so that the portion where the gold or the like is electrodeposited is 10 to 30 μm thicker than the other inner lead portion. A method for producing a lead frame with a support, comprising the steps of protruding the lead frame and peeling off the remaining resist film.