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Island-free lead frame structure prefilled with plastic encapsulating material, plated firstly and etched later and production method thereof

A technology of pre-filling plastic encapsulation and lead frame, applied in electrical components, electric solid devices, circuits, etc., can solve the problems of inability to use, complicated lead frame manufacturing procedures, increase in lead frame cost, etc., so as to reduce the process cost and quality cost. , the effect of reducing the risk of misalignment and reducing complexity

Active Publication Date: 2013-03-06
JCET GROUP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 1. A layer of high temperature resistant adhesive film is attached to the bottom of the metal lead frame, which increases the cost of the lead frame by at least 50%;
[0005] 2. The adhesive film attached to the bottom of the metal lead frame is a soft organic substance, so in the subsequent packaging process of chip loading and wire bonding operations, volatile pollution of organic substances will be generated due to high-temperature baking, which will directly pollute The bonding between the front of the chip and the front of the lead frame and the wire bonding will even affect the failure of the bonding ability with the plastic encapsulant during the subsequent packaging process between the front of the chip and the front of the lead frame (commonly known as delamination);
[0006] 3. Because the soft organic adhesive film is attached to the bottom of the lead frame, part of the bonding force is absorbed by the soft organic adhesive film during the subsequent wire bonding operation in the packaging process, increasing the wire Difficulty in bonding, resulting in instability of wire bonding yield, which may cause reliability problems;
[0007] 4. Because the soft organic adhesive film is attached to the bottom of the lead frame, the metal wire material is limited to soft and expensive gold wire during bonding, instead of hard and low-cost copper and aluminum. quality or other low-cost wire or strip;
[0009] 6. Usually, QFN products must have a metal base island before they can be mounted. Sometimes it will bring some troubles to the circuit board design, because it is necessary to prevent the short circuit between the line and the metal base island.
[0011] 1. The production process of the lead frame is too complicated, resulting in an increase in the cost of the lead frame;
[0012] 2. The etching of the lead frame is divided into upper and lower etching once, which is easy to cause misalignment due to repeated positioning errors of the upper and lower etching positions

Method used

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  • Island-free lead frame structure prefilled with plastic encapsulating material, plated firstly and etched later and production method thereof
  • Island-free lead frame structure prefilled with plastic encapsulating material, plated firstly and etched later and production method thereof
  • Island-free lead frame structure prefilled with plastic encapsulating material, plated firstly and etched later and production method thereof

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Experimental program
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Embodiment Construction

[0058] The invention relates to a base-less island pre-filled molding compound, which is first plated and then engraved with a lead frame. The production method is as follows:

[0059] Step 1. Take the metal substrate

[0060] see figure 1 1. Take a metal substrate 9 with a suitable thickness. The material of the metal substrate 9 can be changed according to the functions and characteristics of the chip, such as copper, aluminum, iron, copper alloy, stainless steel or nickel-iron alloy.

[0061] Step 2, film pasting operation

[0062] see figure 2 , using a film-attaching device to respectively paste photoresist films 10 and 11 that can be exposed and developed on the front and back of the metal substrate 9 that has been plated with a metal layer. The photoresist films 10 and 11 can be dry films or wet films. membrane.

[0063] Step 3. Remove part of the photoresist film on the front and back of the metal substrate

[0064] see image 3 , using the exposure and develop...

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Abstract

A method for manufacturing an islandless lead frame structure (100) for semiconductor packaging includes providing a metal substrate, forming a first photoresist film on the top surface of the metal substrate, and forming a top surface plating pattern in the first photoresist film using photolithography. The metal also includes performing a plating process on the top surface and the back surface of the metal substrate to form a first metal layer (5) on the top surface and a second metal layer (6) on the back surface. Further, the method includes performing an etching process on the top surface and the back surface of the metal substrate simultaneously using a top surface etching pattern and a back surface etching pattern as the respective masks to form etched regions in the metal substrate and a plurality of leads (2), without forming any island. Further, the method includes removing the third photoresist film and the fourth photoresist film, and pre-encapsulating the etched metal substrate using a molding compound (4) to form the pre-encapsulated lead frame structure.

Description

technical field [0001] The invention relates to a lead frame structure and a production method thereof, belonging to the technical field of semiconductor packaging. Background technique [0002] There are two main types of traditional lead frame structures: [0003] One is the four-sided flat no-lead package (QFN) lead frame. In order to prevent the lead frame from being sealed on the front side of the lead frame, the back of the lead frame will produce overflow of the plastic packaging compound, so the lead frame is attached to the back of the lead frame. with an expensive high temperature adhesive film (such as Figure 14 shown), this lead frame structure has the following disadvantages: [0004] 1. A layer of high temperature resistant adhesive film is attached to the bottom of the metal lead frame, which increases the cost of the lead frame by at least 50%; [0005] 2. The adhesive film attached to the bottom of the metal lead frame is a soft organic substance, so in t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L23/495H01L21/48
CPCH01L24/97H01L23/49861H01L21/48H01L2224/45144H01L21/4828H01L23/49582H01L2224/97H01L2224/73265H01L2224/32245H01L23/495H01L2224/48247H01L24/73H01L2924/181
Inventor 梁志忠谢洁人吴昊耿丛正夏文斌郁科峰
Owner JCET GROUP CO LTD
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