TW519869B - Heat dissipation structure of lead frame encapsulation and method for increasing the heat dissipation of lead frame encapsulation - Google Patents

Abstract

The present invention provides a heat dissipation structure of a lead frame encapsulation and a method for increasing the heat dissipation performance of a lead frame encapsulation. The heat dissipation structure of a lead frame encapsulation comprises: a lead frame encapsulation; and a printed circuit board having a contact face contacting the lead frame encapsulation. The method for increasing the heat dissipation performance of a lead frame encapsulation comprises: (a) coating a flux on the printed circuit board; and (b) contacting the bottom of a lead frame encapsulation with the printed circuit board. Thus, the heat generated by the lead frame encapsulation can be dissipated to the atmosphere through the printed circuit board, thereby eliminating the cost of designing a high performance heat dissipation system, and the cost of designing a lead frame encapsulation having a higher heat dissipation efficiency, while increasing the heat dissipation efficiency of an ordinary lead frame encapsulation and a high heat dissipation efficiency lead frame encapsulation, enabling them to be used in an electric product having a higher processing speed, and extending the operation life of the chip in the lead frame encapsulation.

Description

519869 V. Description of the invention ο) [Field of the invention] The present invention applies a layer of flux to a copper exposed area on a printed circuit board, and uses a lead frame package (such as a four-sided package) as a medium through the flux. The bottom surface of the lead frame package contacts the copper exposed area on the printed circuit board, and the copper exposed area and the flux on the printed circuit board have a better thermal conductivity effect than air, and the wire is improved. The heat dissipation efficiency of the rack package allows it to be used in electronic products with faster processing speeds. [Background of the Invention] When the lead frame package of the current industry is soldered to a printed circuit board (as shown in the first and second figures), a plurality of pins 1 a of a lead frame package 1 a are soldered to the printing On the circuit board 2 a, and a bottom surface 1 2 a of the lead frame package 1 a is not in contact with an upper surface 2 1 a of the printed circuit board 2 a, so the bottom surface 1 of the lead frame package 1 a The space between 2 a and the upper surface 2 1 a of the printed circuit board 2 a is occupied by almost adiabatic air. In this way, the lead frame package 1 a sums the plurality of pins 1 1 a with gold wires. 1 4 a connected chip 1 3 a hot summer 'will not be able to be conducted to the printed circuit board 2 a through the bottom surface 1 2 a of the lead frame package 1 a, and only through the printed circuit board 2 a Heat is dissipated in the atmospheric environment, or the thermal energy of the lead frame package 1 a is conducted to the pin 11 and then conducted to the printed circuit board 2 a to dissipate heat. In addition, when the lead frame package is mounted on a printed circuit board of an electronic product with a high processing rate, it needs to be matched with a design 焉 efficient heat dissipation system 'or a high heat dissipation rate lead frame package, for example, with embedded heat dissipation. Sheet four-sided package, four-sided package with exposed embedded heat sink, and

Page 4 519869 V. Description of the invention (2) Four-sided package with exposed pads, etc. This can prevent the chip inside the lead frame package from being damaged due to excessive heat. However, the packaging cost of the above-mentioned lead frame package with high heat dissipation rate is much higher than that of a general lead frame package, and a high-performance heat dissipation system also requires a relatively large manufacturing cost. To sum up, if the conventional lead frame package is used in a high-speed electronic product, it needs to spend a lot of cost to design a high-efficiency heat dissipation system, and to design a lead frame package with high heat dissipation efficiency. It will increase the manufacturing cost of electronic products, and due to the poor heat dissipation efficiency of the conventional lead frame package, the service life of the chip inside the lead frame package will be shortened. [Objective of the Invention] The object of the present invention is to provide a heat dissipation structure of a lead frame package and a method for improving the heat dissipation efficiency of the lead frame package, so that the lead frame package contacts the exposed copper area on the printed circuit board through a flux. The thermal energy generated by the lead frame package is dissipated to the atmosphere through the printed circuit board. This can save the costly design of a high-performance heat dissipation system and a lead frame package with high heat dissipation efficiency. And improve the heat dissipation efficiency of the general lead frame package and high heat dissipation efficiency lead frame package, so that it can be used for faster processing of electronic products, and extend the service life of the chip inside the lead frame package. [Inventive Features] The present invention provides a heat dissipation structure of a lead frame package and a method for improving the heat dissipation performance of the lead frame package. The heat dissipation structure of the lead frame package includes: a lead frame package; and a printed circuit board. A contact surface is in contact with the lead frame package, and the contact surface is coated and dissipated well

519869 V. Insulation substance of invention description (3). The method for improving the heat dissipation efficiency of a lead frame package includes the steps of: a. Coating a printed circuit board with a flux: and b. Contacting a bottom surface of the lead frame package with the printed circuit board. In order for your review committee to further understand the features and technical contents of the present invention, please refer to the following detailed contents and drawings of the present invention, and hereby give a preferred and feasible embodiment and explain it in detail with the drawings. The invention should have a deep and concrete understanding. [Embodiment] The heat dissipation structure of the lead frame package (as shown in the third and fourth figures) of the present invention includes: a lead frame package 1; and a printed circuit board 2 having an exposed copper area 2 2, the The exposed copper area 22 is coated with a layer of flux 3, and the material of the flux 3 is resin or rosin. The exposed copper area 22 uses the flux 3 as a medium, and the system surface contacts the lead frame package 1. The method (shown in the fifth figure) for improving the heat dissipation efficiency of the lead frame package of the present invention includes the following steps: a. Reserve a copper exposed area 2 2 on a printed circuit board 2 to contact the lead frame package 1, A layer of flux 3 is coated on the exposed copper area 2. The material of the flux 3 may be resin or rosin, and the flux 3 on the exposed copper area 2 2 is heated to 2 2 0 — 2 6 0 °. The molten state of C; and b. The plurality of pins 11 of the lead frame package 1 are soldered to the printed circuit board 2 and at the same time, one bottom surface 1 2 of the lead frame package 1 is in contact with the flux. 3 on the exposed copper area 2 2, and the flux 3 is cooled to room temperature, and is fixedly connected to the exposed copper area 2 2

519869 V. The leadframe package 1 in the description of the invention (4). The invention provides a heat dissipation structure of a lead frame package and a method for improving the heat dissipation efficiency of the lead frame package. The heat dissipation structure of the lead frame package includes: a lead frame package; and a printed circuit board having a contact surface. It is in contact with the lead frame package. The method for improving the heat dissipation performance of a lead frame package includes the steps of: a. Coating a printed circuit board with a flux; and b. Contacting a bottom surface of the lead frame package with the printed circuit board. In this way, the overall heat dissipation efficiency of the lead frame package can be improved, so that the heat generated by the chip in the lead frame package can be conducted to the printed circuit board through the bottom surface of the lead frame package, and dissipated to the atmospheric environment through the printed circuit board; A numerical simulation experiment (Experiment 1 and Experiment 2) and an actual measurement experiment (Experiment 3 and Experiment 4) are performed with the bottom surface of the lead frame package (such as a four-sided package) filled with flux and when the bottom surface only has air. ), The conclusion is as follows: Experiment 1 · Take a four-sided package with a thickness of 1.4 mm and 208 pins and place it on a double-layer printed circuit board. When the average heating power of the wafer inside it is 2.2 W, And when the bottom surface of the four-sided package is filled with flux, the center temperature of the upper surface of the four-sided package is reduced by 11.4 ° C compared to when the bottom surface of the four-sided package is filled with air, and the four-sided package is The surface-to-ambient thermal resistance is reduced by 17%. Experiment 2 · Take a four-sided package with a thickness of 1.4mm and 208 pins on a four-layer printed circuit board. When the average heating power of the wafer inside it is 2 · 2 W, and the four-sided package S '

519869 V. Description of the invention (5) The temperature of the bottom of the heart, the body-centered face, the surface of the watch, the face of the body, the face of the body, the top of the body, the top of the body, the face of the body, the face of the body, the face of the time, the time, and the agent. C welding, 9 assists, full gas, 4 fill in the blank, 1 surface is full, the bottom surface is low, and the feet are rejected. 8 ο 2% there are 4 sets of 2 m, low m, 4 drop resistance, 1 degree of heat 1 to thick 3 to take 3 to verify the electricity, 2 when the brush 2 is printed as a flux rate welding dual-function to help fill the hot filling The inner surface of the part of the package that is mounted on the surface of the flat bottom cover and the surface of the crystal is scattered when it is embedded, and when it is inside, the exposed board W is on the outside. At time C, 5 air and air 3 are filled with a warm body with a low surface and low base. The cover on the cover surface should be sealed on the cover surface. ΤγΗ The low-resistance heat environment is extended to the upper surface of the heart surface. Install the cover. 4% have electric appliance brushes and foot prints, insert four in 8 units, 2 are equipped with sealing surfaces, 4 m in 4 pieces of heat, 4 are hot and loose, 1 degree of inner thickness, 1 are exposed, and 4 are verified. 2 hours Fill the inner surface of the mounting surface of the crystal of the flat flat film for the flux rate welding to assist the heating. The four sides should be, and the upper side of the W board should be four, and the above. c Hour 7 Qi · Air 4 Full body with low surface temperature and low temperature. The cover on the front surface of the body should be sealed as shown on the cover. 6 IX The low-resistance heat-resistance environment is extended to the surface of the heart. Install the cover. 4% heat and dissipate, body lift, lift, seal, energy efficiency It is necessary to learn how to set up a multi-line rack in a sealed package as compared to the cost of the guide. The solution is to produce 1 ± son: the superior description of the electrical point is more reasonable than the following. 519869 5 Explanation of the invention (6) The problem of efficient heat dissipation system; 2 · It is not necessary to design a lead frame package with high heat dissipation efficiency, but high heat dissipation efficiency can be achieved, reducing the cost of designing a lead frame package with high heat dissipation efficiency Cost; 3 · Improve the heat dissipation efficiency of general lead frame packages and high heat dissipation efficiency lead frame packages, which can be used for faster electronic products; 4 · Extend the service life of the chip inside the lead frame package . Of course, the above is only a preferred embodiment of the present invention, and it should not be used to limit the implementation scope of the present invention. Any modification made by those skilled in the art without departing from the spirit of the present invention shall belong to the present invention. Scope, so the protection scope of the present invention should be based on the patent application scope described below.

519869 Brief Description of Drawings The first figure is a side view of a conventional lead frame package soldered to a printed circuit board. The second figure is a cross-sectional view of a conventional lead frame package soldered to a printed circuit board. The third figure is a side view of a lead frame package of the present invention soldered to a printed circuit board. The fourth figure is a sectional view of a lead frame package of the present invention soldered to a printed circuit board. The fifth figure is a flowchart of the steps of the method for improving the heat dissipation efficiency of the lead frame package according to the present invention.

Body-mounting frame lead pin piece to connect the bottom crystal / ^^ I— / 明 ^ aaa # Xi 3 rH 〇〇CO 14a Gold wire 2 a Printed circuit board 2 1a Upper surface 1 Lead frame package 2 Printed circuit board 11 pin 2 1 Top surface 12 Bottom surface 2 2 Copper exposed area 13 Wafer 3 Flux page 10

519869 Schematic illustration 14 Gold 11111

Claims (1)

519869 VI. Application Patent Scope 1. A heat dissipation structure of a lead frame package, comprising: a lead frame package; and a printed circuit board having a contact surface contacting the lead frame package, and the contact surface is coated Insulating material with good heat dissipation. 2 · The heat dissipation structure of the lead frame package according to item 1 of the scope of patent application, wherein the lead frame package is a four-sided package. 3. The heat dissipation structure of the lead frame package according to item 1 of the scope of patent application, wherein the printed circuit board is provided with an exposed copper area. 4. The heat dissipation structure of the lead frame package according to item 1 of the scope of the patent application, wherein the insulating substance is a flux. 5. The heat dissipation structure of the lead frame package according to item 4 of the scope of the patent application, wherein the flux is resin or rosin. 6-A method for improving the heat dissipation efficiency of a lead frame package, the steps include: a. Coating a printed circuit board with a flux; and b. Contacting a bottom surface of the lead frame package with the printed circuit board. 7. The method for improving the heat dissipation efficiency of the lead frame package according to item 6 of the scope of patent application, wherein step a further includes a step of preserving an exposed copper area on the printed circuit board. 8. The method for improving the heat dissipation efficiency of the lead frame package as described in item 6 of the scope of patent application, wherein step a further includes a step of melting the flux. 9 · The method for improving the heat dissipation efficiency of a lead frame package as described in item 8 of the scope of patent application, wherein the flux melting temperature of step a is 2 2 Page 12 519869 VI. Application scope 0-2 6 Ο X :. 10 · The method for improving the heat dissipation efficiency of a lead frame package as described in item 6 of the scope of patent application, wherein step b further includes a step of soldering the plurality of pins of the printed circuit board to the printed circuit board. 1 1 · The method for improving the heat dissipation efficiency of a lead frame package as described in item 6 of the scope of patent application, wherein step b further includes a step of cooling the flux to room temperature. 1 2 · The method for improving the heat dissipation efficiency of a lead frame package as described in item 6 of the scope of patent application, wherein the material of the flux is resin or rosin. 1 3 · The method for improving the heat dissipation performance of a lead frame package as described in item 6 of the scope of patent application, wherein the lead frame package is a four-sided package 0 Page 13