CN103021883A - Flat package part manufacturing process based on corrosion plastic package body - Google Patents

Abstract

The invention relates to a manufacturing process of a flat package based on a corroded plastic package, and belongs to the technical field of integrated circuit packaging. The present invention adopts different from the previous plastic sealing process. After the grooves are formed on the frame by corrosion method, an effective anti-drag structure is formed between the frame and the primary plastic sealing compound and the secondary plastic sealing compound by the method of secondary plastic sealing, which greatly Reduce the probability of package delamination, greatly improve product reliability, better than the plastic sealing effect of traditional AQQFN products.

Description

A manufacturing process of flat package based on corroded plastic package

technical field

The invention relates to a manufacturing process of a flat package based on a corroded plastic package, and belongs to the technical field of integrated circuit packaging.

Background technique

Integrated circuits are the core of the information industry and high-tech, and the foundation of economic development. Integrated circuit packaging is the main component of the integrated circuit industry, and its development has been accompanied by the increase in its functions and device count. Since the 1990s, it has entered the development track of multi-pin count, narrow pitch, and miniaturization. Carrierless grid array package (AAQFN) is a new packaging form born to adapt to the rapid development of electronic products, and it is an indispensable product for the realization of miniaturization, light weight and networking of electronic machines.

There are no carrier grid array package components, no solder balls at the bottom, and the pins are directly connected to the PCB board when soldering. The electrical and mechanical connection to the PCB is through printing solder paste on the PCB pads, and the solder joints formed by the SMT reflow process. to achieve. This technology package can realize multi-pin, high-density, small and thin package under the same size condition, and has the characteristics of heat dissipation, electrical performance and good coplanarity.

AAQFN packaging products are suitable for packaging of large-scale and ultra-large-scale integrated circuits. Most of the AAQFN packaged devices are used in high-end consumer markets such as mobile phones, network and communication equipment, digital cameras, microcomputers, notebook computers and various flat panel displays. Mastering its core technology and having mass production capacity will greatly narrow the gap between the domestic integrated circuit industry and the international advanced level. This product has a broad market application prospect.

However, due to limitations such as technical difficulties, it is currently difficult to promote AAQFN products in the market, especially in terms of reliability, which directly affects the use and life of products, and has become a technical difficulty for AAQFN packages.

Contents of the invention

In order to overcome the above-mentioned problems in the prior art, the present invention provides a flat package manufacturing process based on corroded plastic packages, which makes the combination of the integrated circuit frame and the plastic package more firm, free from the influence of the external environment, and directly improves the packaging reliability of the product , and reduce costs to a certain extent.

The technical scheme adopted in the present invention: a flat package manufacturing process based on corroded plastic packaging, specifically carried out according to the following steps:

The first step, thinning: the thinning thickness is 50 μm to 200 μm;

The second step, dicing: the wafer above 150μm adopts the ordinary QFN dicing process, and the wafer with the thickness below 150μm uses a double-knife dicing machine and its process;

The third step, core: use adhesive film to glue the core;

The fourth step, pressure welding;

The fifth step, one-time plastic sealing: use traditional plastic sealing compound for plastic sealing;

The sixth step, frame etching groove: use ferric chloride solution to do partial window half-etching on the back of the frame to form a groove, and the depth is controlled within half of the thickness of the frame;

The seventh step, reflow soldering;

The eighth step, secondary plastic sealing: the secondary plastic sealing is filled with plastic sealing compound with a particle size of 30~32um;

The ninth step, corrode the plastic package: corrode the plastic package with a mixture of sulfuric acid and fuming nitric acid;

The tenth step is post-curing, grinding, tinning, printing, product separation, inspection, and packaging.

In the third step of the above-mentioned steps, the adhesive film (DAF) can be used instead of the adhesive film; the fourth, fifth, seventh, and tenth steps of the above-mentioned steps are all the same as the conventional AAQFN process.

Beneficial effects of the present invention: In the present invention, grooves are first formed on the frame by means of corrosion, the first plastic sealing is to fill the grooves with plastic sealing compound, after the back is etched, then the balls are planted, and finally the secondary plastic sealing is performed, which can effectively reduce the The overall thickness of the product meets the needs of development; especially, the plastic sealing compound of the second plastic sealing can form a more effective anti-drag structure with the plastic sealing compound of the first plastic sealing and the frame, which significantly improves the reliability of the package, and this method is easy to implement ,high productivity.

Description of drawings

Figure 1 Sectional view of the lead frame;

Figure 2 Sectional view of the product after core loading;

Figure 3 Cross-sectional view of the product after pressure welding;

Figure 4 Product profile after one-time plastic sealing;

Figure 5 Product profile after etching on the back of the frame;

Figure 6 Product profile after reflow soldering with solder paste;

Figure 7 Product profile after secondary plastic sealing;

Figure 8 Sectional view of the product after corrosion;

Figure 9 Profile of the finished product.

In the figure: 1-lead frame, 2-adhesive, 3-chip, 4-bonding wire, 5-first plastic package, 6-etching groove, 7-solder ball, 8-second plastic package .

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, so as to facilitate the understanding of technical personnel.

As shown in Figures 1-9: the method of the present invention is used for single-chip packaging, and the product includes a lead frame 1, a die-bonding glue 2, a chip 3, a bonding wire 4, the first plastic package 5, and an etching groove 6. Solder balls 7, the second plastic package 8; wherein the chip 3 is connected to the lead frame 1 through the adhesive 2, and the bonding wire 4 is directly hit from the chip 3 to the lead frame 1, and the lead frame 1 is the adhesive 2. Chip 3 is on the adhesive 2, and the bonding wire between the solder joint on the chip 3 and the inner pin is the bonding wire 4. The plastic package 5 surrounds the lead frame 1, the adhesive 2, and the chip 3 for the first time. , the bonding wire 4, the etching groove 6, and the solder ball 7 constitute the whole circuit, and the first plastic package 5 plays a role of supporting and protecting the bonding wire 4 and the solder ball 7 of the chip 3, and the chip 3, bonding The wire 4, the lead frame 1 and the solder ball 7 constitute the power supply and signal channel of the circuit.

A flat package manufacturing process based on corroded plastic packaging. First, grooves are formed on the frame by corrosion. The first plastic packaging is to fill the grooves with plastic compound. After the back is etched, ball planting is performed, and finally the second Plastic sealing, specifically follow the steps below;

Example 1

The first step, thinning: the thinning thickness is 50 μm to 200 μm;

The second step, dicing: use a wafer with a thickness of 100 μm, use a double-knife dicing machine and its process;

The third step, core: use adhesive 2 to core;

The fourth step, pressure welding: the same as the conventional AAQFN process;

The fifth step, one-time plastic sealing: use traditional plastic sealing compound 9920 for plastic sealing, which is the same as the conventional AAQFN process;

The sixth step, frame etching groove: use ferric chloride solution to do partial window half-etching on the back of the frame to form a groove, and the depth is controlled within half of the thickness of the frame;

The seventh step, reflow soldering: the same as the conventional AAQFN process;

The eighth step, secondary plastic sealing: the secondary plastic sealing is filled with 30um particle size plastic sealing compound;

The ninth step, corroding the plastic package: corrode the plastic package with a mixture of sulfuric acid and fuming nitric acid, the solution will not react with the solder ball. This method can better protect the solder balls and improve the packaging yield;

The tenth step, post-curing, grinding, tinning, printing, product separation, inspection, and packaging are the same as the conventional AAQFN process.

Example 2

The first step, thinning: the thinning thickness is 50 μm to 200 μm;

The second step, dicing: use a wafer with a thickness of 130 μm, use a double-knife dicing machine and its process;

The third step, core: use adhesive 2 to core;

The fourth step, pressure welding: the same as the conventional AAQFN process;

The fifth step, one-time plastic sealing: use traditional plastic sealing compound 9920 for plastic sealing, which is the same as the conventional AAQFN process;

The sixth step, frame etching groove: use ferric chloride solution to do partial window half-etching on the back of the frame to form a groove, and the depth is controlled within half of the thickness of the frame;

The seventh step, reflow soldering: the same as the conventional AAQFN process;

The eighth step, secondary plastic sealing: the secondary plastic sealing is filled with 31um particle size plastic sealing compound;

The ninth step, corroding the plastic package: corrode the plastic package with a mixture of sulfuric acid and fuming nitric acid, the solution will not react with the solder ball. This method can better protect the solder balls and improve the packaging yield;

The tenth step, post-curing, grinding, tinning, printing, product separation, inspection, and packaging are the same as the conventional AAQFN process.

Example 3

The first step, thinning: the thinning thickness is 50 μm to 200 μm;

The second step, dicing: use a wafer with a thickness of 170 μm, which is the same as the ordinary QFN scribing process;

The third step, core: use adhesive 2 to core;

The fourth step, pressure welding: the same as the conventional AAQFN process;

The fifth step, one-time plastic sealing: use traditional plastic sealing compound 9920 for plastic sealing, which is the same as the conventional AAQFN process;

The sixth step, frame etching groove: use ferric chloride solution to do partial window half-etching on the back of the frame to form a groove, and the depth is controlled within half of the thickness of the frame;

The seventh step, reflow soldering: the same as the conventional AAQFN process;

The eighth step, secondary plastic sealing: the secondary plastic sealing is filled with 32um particle size plastic sealing compound;

The ninth step, corroding the plastic package: corrode the plastic package with a mixture of sulfuric acid and fuming nitric acid, the solution will not react with the solder ball. This method can better protect the solder balls and improve the packaging yield;

The tenth step, post-curing, grinding, tinning, printing, product separation, inspection, and packaging are the same as the conventional AAQFN process.

The present invention is described through a specific implementation process. Without departing from the scope of the present invention, various transformations and equivalent substitutions can also be made to the patent of the present invention. Therefore, the patent of the present invention is not limited to the disclosed specific implementation process, but should be All embodiments falling within the scope of the patent claims of the present invention are included.

Claims (3)

1. A flat package manufacturing process based on corroded plastic seals, characterized in that: specifically follow the steps below: The first step, thinning: the thinning thickness is 50 μm to 200 μm; The second step, dicing: the wafer above 150μm adopts the ordinary QFN dicing process, and the wafer with the thickness below 150μm uses a double-knife dicing machine and its process; The third step, core: use adhesive film to glue the core; The fourth step, pressure welding; The fifth step, one-time plastic sealing: use traditional plastic sealing compound for plastic sealing; The sixth step, frame etching groove: use ferric chloride solution to do partial window half-etching on the back of the frame to form a groove, and the depth is controlled within half of the thickness of the frame; The seventh step, reflow soldering; The eighth step, secondary plastic sealing: the secondary plastic sealing is filled with plastic sealing compound with a particle size of 30~32um; The ninth step, corrode the plastic package: corrode the plastic package with a mixture of sulfuric acid and fuming nitric acid; The tenth step is post-curing, grinding, tinning, printing, product separation, inspection, and packaging. 2 . The manufacturing process of a flat package based on corroded plastic package according to claim 1 , characterized in that: in the third step of the steps, an adhesive film (DAF) can be used instead of the adhesive. 3. A kind of flat package manufacturing process based on corroded plastic package according to claim 1, it is characterized in that: the fourth step, the fifth step, the seventh step and the tenth step in the described steps are all the same as the conventional AAQFN The process is the same.

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