Welding structure for processing and fixing QFP (quad flat package) chip and PCB (printed circuit board)
A novel soldering structure integrates a heat spreader plate beneath the QFP chip on the PCB board to address heat dissipation challenges in confined spaces by effectively dissipating heat from both chip surfaces.
Patent Information
- Application Number
- CN202422333920.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-24
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-09-24
AI Technical Summary
It is difficult to install an independent heat sink for the QFP packaged chip in a narrow space. In the prior art, the heat dissipation effect from the top of the chip is limited, and the heat at the bottom of the chip cannot be effectively reduced.
A card slot is installed on the PCB board body, a heat sink is embedded and heat dissipated under the chip, and a support ring is used to fix the heat sink, heat is transmitted through the heat conduction medium, and heat dissipation fins are extended below the PCB board for heat dissipation.
It effectively reduces the working temperature of the chip, especially radiates heat from the bottom of the chip, improves heat dissipation efficiency, and is suitable for household appliances and digital products with limited space.
Smart Images
Figure CN223110254U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of printed circuit board production design, and particularly relates to a welding structure for processing and fixing a QFP package chip and a PCB board. Background Art
[0002] The QFP package, also known as the quad flat package technology, is a commonly used package form for very large scale integrated circuits. Chips of this type of package usually do not require an independent heat sink. However, with the gradual complexity of modern chip functions, the number of pins and heat generation of the chips are also gradually increasing. Many QFP package chips also need to be equipped with an independent heat sink to ensure their normal operation.
[0003] Since the heat generation of QFP package chips is not particularly large, higher power chips often use PGA packages or BGA packages. Regarding the problem of heat dissipation for QFP package chips, the common practice in the prior art is only to install a small passive heat sink on the top of the chip.
[0004] However, in some household electrical appliances and 3C digital products, the space for setting the PCB board is relatively narrow, making it difficult to set up an independent heat sink. Summary of the Utility Model
[0005] The purpose of the utility model is to overcome the problem that it is inconvenient to set up an independent heat sink for QFP package chips in a small space, and provides a welding structure for processing and fixing a QFP package chip and a PCB board. A heat sink is provided on the PCB board body, the chip is pressed on the heat sink, and several solder joints are arranged around the heat sink, and the solder joints are connected to the pins of the chip.
[0006] A slot for installing the heat sink is opened on the PCB board body, and the heat sink is arranged in the slot; the top of the heat sink is horizontal, a heat conduction medium is filled in the gap between the top of the heat sink and the chip, and the bottom of the heat sink is provided with heat dissipation fins extending downward; a relief hole penetrating the PCB board body is opened at the bottom of the slot, and the heat dissipation fins pass through the relief hole and extend below the PCB board body.
[0007] A support ring is arranged around the top edge of the heat sink, the bottom of the support ring is pressed on the PCB board body, and the top of the support ring supports the bottom surface of the chip.
[0008] In some embodiments, the outer peripheral surface of the support ring is stuck at the edge of the slot, and the inner peripheral surface of the support ring is closely attached to the top edge of the heat sink; the bottom of the support ring is pressed on the bottom surface of the slot, and the support ring is adhesively fixed to the bottom surface of the slot.
[0009] In some embodiments, the material of the support ring is an elastic material.
[0010] In some embodiments, the area on the PCB board where the pad structure is located is an avoidance area, and the wiring on the PCB board avoids the pad structure.
[0011] In some embodiments, the bottom of the card slot is provided with a blocking structure, and the blocking structure supports the heat sink upward.
[0012] In some embodiments, positioning holes are provided at the bottom of the card slot, fixing screw holes are provided at the top of the heat sink, and fixing bolts pass through the positioning holes from the bottom and are screwed into the fixing screw holes.
[0013] In some embodiments, the projection of the heat sink on the chip is located within the contour range of the chip itself.
[0014] In some embodiments, the support ring is arranged along the edge of the chip.
[0015] Applying the above technical solutions of the present invention to a welding structure for processing and fixing a QFP package chip and a PCB board has the following effects:
[0016] Since the pins of the QFP package chip are all located around the chip, there is no wiring structure on its top and bottom surfaces. Radiating heat from the top surface of the chip or from the bottom surface of the chip can achieve the effect of reducing the working temperature of the chip.
[0017] In the prior art, heat dissipation from the top of the chip is very simple, and only a heat sink needs to be arranged on the top of the chip. And in reality, since the bottom of the chip is closely attached to the PCB board, the heat radiation from the bottom of the chip is limited. Therefore, there is almost no design for heat dissipation from the bottom of the chip in the prior art.
[0018] In the present invention, a heat dissipation system is integrated on the pad structure to perform heat dissipation processing from below the chip. Specifically, a card slot is provided directly below the chip, and the card slot is located in the middle of the solder joints. A radiator is arranged in the card slot, and the heat dissipation fins of the radiator dissipate heat from the back surface of the PCB board.
[0019] Other features and advantages of the present invention will be described in detail in the subsequent specific embodiments section. Description of the Drawings
[0020] Figure 1 is a schematic diagram of the welding structure for processing and fixing a QFP package chip and a PCB board of the present invention.
[0021] Description of the Reference Numerals
[0022] 1 - PCB board, 1a - conductor layer, 1b - basic layer; 2 - chip, 2a - pins; 3 - heat sink; 3a - heat dissipation fins; 4 - support ring; 5 - heat conductive medium. Specific Embodiments
[0023] The following is a detailed description of the specific embodiments of the present utility model. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present utility model, and are not intended to limit the present utility model.
[0024] In the present utility model, unless otherwise stated, the orientation terms such as "upper" and "lower" generally refer to the orientation in the assembled and used state. "Inner" and "outer" refer to the inner and outer of the contour of each component itself.
[0025] It should be noted that the terms "first", "second", etc. in the description and claims of the present utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so as to implement the embodiments of the present utility model described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.
[0026] In the present utility model, a welding structure for processing and fixing a QFP package chip and a PCB board is provided. A heat sink 3 is provided on the PCB board body 1, the chip 2 is pressed on the heat sink 3, and a plurality of solder joints are arranged around the heat sink 3, and the solder joints are connected to the pins 2a of the chip 2.
[0027] The chip 2 in QFP package is usually in the shape of a square thin sheet, and pins 2a are arranged at intervals along its edge. The number of pins 2a of the chip 2 is numerous, about more than a hundred, and the intervals between the pins 2a are small. A pad structure is provided on the PCB board body 1 for installing the chip 2, and the pad structure includes solder joints arranged in one-to-one correspondence with the pins 2a of the chip 2. The pins 2a of the chip 2 are fixed to the solder joints by brazing. In the present utility model, the chip 2 is fixed to the PCB board body 1 by connecting the pins 2a to the solder joints.
[0028] The PCB board body 1 includes a wire layer 1a and a base layer 1b. The wire layer 1a is made of copper, and copper wires are formed by removing excess materials through processes such as etching and pickling. The base layer 1b is an insulating material. The base layer 1b and the wire layer 1a are arranged at intervals in sequence to form a multi-layer PCB board body 1. The number of layers of the PCB board body 1 refers to the number of wire layers 1a. Usually, it is 2-6 layers. The one in the present utility model Figure 1 is a three-layer board; the attached drawings only represent a specific embodiment, and the number of layers of the PCB board body 1 does not affect the implementation of the technical solution of the present utility model.
[0029] The PCB board body 1 is provided with a slot for installing the heat sink 3, and the heat sink 3 is arranged in the slot; the top of the heat sink 3 is horizontal, and the gap between the top of the heat sink and the chip 2 is filled with a heat-conducting medium 5; the bottom of the heat sink 3 is provided with heat dissipation fins 3a extending downward; a relief hole penetrating the PCB board body 1 is opened at the bottom of the slot, and the heat dissipation fins 3a pass through the relief hole and extend below the PCB board body 1.
[0030] The present utility model designs a brand-new setting method for the heat sink 3, as Figure 1 shown in. A slot is opened on the PCB board body 1, and the heat sink 3 is arranged in the slot. The heat sink 3 contacts the lower surface of the chip 2 and dissipates heat from below the chip 2. It should be noted that the heat dissipation capacity of the heat dissipation method of the present application is limited and can only cope with the situation of relatively small heat generation; if the chip 2 generates too much heat, other heat dissipation methods in the prior art should be adopted. Usually, the heat generation of the QFP package chip 2 is not particularly large, and the heat dissipation method of the present application can dissipate heat from most QFP package chips 2.
[0031] A support ring 4 is arranged around the top edge of the heat sink 3. The bottom of the support ring 4 presses on the PCB board body 1, and the top of the support ring 4 supports the bottom surface of the chip 2. The support ring 4 can position the heat sink 3 on the one hand and prevent the heat-conducting medium 5 from leaking on the other hand. The specific setting method of the support ring 4 is as Figure 1 shown. The outer peripheral surface of the support ring 4 is stuck at the edge of the slot, and the inner peripheral surface of the support ring 4 closely adheres to the top edge of the heat sink 3. Through the above settings, the support ring 4 is used to limit the heat sink 3 to prevent the heat sink 3 from moving.
[0032] The bottom of the support ring 4 presses on the bottom surface of the slot. The support ring 4 is adhesively fixed to the bottom surface of the slot, and the top of the support ring 4 contacts the chip 2. By adjusting the height of the support ring 4, the gap between the chip 2 and the PCB board body 1 can be adjusted.
[0033] The heat-conducting medium 5 between the heat sink 3 and the chip 2 can be thermal grease, phase change heat-conducting material, heat-conducting adhesive or heat-conducting gasket. Among them, thermal grease is more commonly used in engineering. The thermal grease material presents a viscous grease-like shape, and as the chip 2 and the heat sink 3 are gradually pressed tightly, the thermal grease will seep out from the edge. Therefore, the material of the middle support ring 4 of the present utility model is an elastic material. It can be rubber material, or plastics with strong deformation ability, such as polyurethane, polyethylene and silicone rubber. The present utility model utilizes the deformation ability of the support ring 4 to make the top of the support ring 4 closely fit the bottom surface of the chip 2, thereby reducing the leakage of the internal heat-conducting medium 5.
[0034] The area on the PCB board body 1 where the above-mentioned pad structure is located is an avoidance area, and the wiring on the PCB board body 1 avoids the pad structure. A heat sink 3 is provided directly below the chip 2 of the present utility model, and the heat dissipation fins 3a on the heat sink 3 need to pass through the PCB board body 1. The area aligned with the chip 2, that is, the area where the pad structure is located, is no longer suitable for wiring. Therefore, when designing the PCB board body 1, wiring is avoided at the position where the pads are located.
[0035] The bottom of the card slot is provided with a blocking structure, and the blocking structure supports the heat sink 3 upwards. There are two implementation manners for the blocking structure.
[0036] Implementation manner 1: Avoidance holes need to be opened at the bottom of the card slot, and the heat dissipation fins 3a pass through the avoidance holes and extend below the PCB board body 1. The avoidance holes and the heat dissipation fins 3a correspond one by one. The remaining part after opening the avoidance holes at the bottom of the card slot forms the blocking structure.
[0037] Implementation manner 2: The card slot is set in a stepped form. The top contour of the heat sink 3 is larger than that of the heat dissipation fins 3a. The top of the heat sink 3 is stuck at the stepped part of the card slot, so that the stepped part forms the blocking structure.
[0038] The present utility model also provides an optional fixing method for the heat sink 3. It includes that positioning holes are provided at the bottom of the card slot, fixing screw holes are provided at the top of the heat sink 3, and fixing bolts pass through the positioning holes from the bottom and are screwed into the fixing screw holes.
[0039] Since the heat sink 3 needs to avoid contacting the pins 2a of the chip 2. Therefore, in this application, the projection of the heat sink 3 on the chip 2 is located within the contour range of the chip 2 itself. The pins 2a of the chip 2 will bend downwards, so even if the projection area is larger than the chip 2 when the heat sink 3 is provided on the top of the chip 2, it will not contact the pins 2a of the chip 2. The heat sink 3 of the present utility model is provided at the bottom of the chip 2. In order to avoid the heat sink 3 contacting the pins 2a, the projection area of the heat sink 3 is set within the contour range of the chip 2, and a support ring 4 is provided at the edge of the heat sink 3. The support ring 4 separates the heat sink 3 from the pins 2a of the chip 2. Preferably, the support ring 4 is arranged along the edge of the chip 2.
[0040] The preferred implementation manners of the present utility model have been described in detail above. However, the present utility model is not limited to the specific details in the above implementation manners. Within the scope of the technical concept of the present utility model, various simple modifications can be made to the technical solutions of the present utility model, and these simple modifications all belong to the protection scope of the present utility model.
[0041] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present utility model will not separately describe various possible combination methods.
[0042] Furthermore, any combination can be made among the various different embodiments of the present utility model, as long as it does not violate the idea of the present utility model, and it should equally be regarded as the content disclosed by the present utility model.
Claims
1. A welding structure for processing and fixing a QFP package chip and a PCB board, characterized in that It includes a heat sink (3) arranged on a PCB board body (1), a chip (2) is pressed on the heat sink (3), and a number of solder joints are arranged around the heat sink (3), and the solder joints are connected to the pins (2a) of the chip (2). A slot for installing the heat sink (3) is opened on the PCB board body (1), and the heat sink (3) is arranged in the slot; the top of the heat sink (3) is horizontal, and a heat-conducting medium (5) is filled in the gap between the top of the heat sink and the chip (2), and the bottom of the heat sink (3) is provided with heat dissipation fins (3a) extending downward; a relief hole penetrating the PCB board body (1) is opened at the bottom of the slot, and the heat dissipation fins (3a) pass through the relief hole and extend below the PCB board body (1). A support ring (4) is arranged around the top edge of the heat sink (3), the bottom of the support ring (4) is pressed on the PCB board body (1), and the top of the support ring (4) supports the bottom surface of the chip (2).
2. The soldering structure for processing and fixing a QFP package chip and a PCB board according to claim 1, wherein The outer peripheral surface of the support ring (4) is stuck at the edge of the slot, and the inner peripheral surface of the support ring (4) is closely attached to the top edge of the heat sink (3); the bottom of the support ring (4) is pressed on the bottom surface of the slot, and the support ring (4) is adhesively fixed to the bottom surface of the slot.
3. The soldering structure for processing and fixing a QFP package chip and a PCB board according to claim 1, characterized in that, The material of the support ring (4) is an elastic material.
4. The soldering structure for processing and fixing a QFP package chip and a PCB board according to claim 1, characterized in that The area where the pad structure is located on the PCB board body (1) is an avoidance area, and the wiring on the PCB board body (1) avoids the pad structure.
5. The soldering structure for processing and fixing a QFP package chip and a PCB board according to claim 1, characterized in that The bottom of the slot is provided with a blocking structure, and the blocking structure supports the heat sink (3) upward.
6. The welding structure for processing and fixing a QFP package chip and a PCB board according to claim 1, wherein The bottom of the slot is provided with a positioning hole, and the top of the heat sink (3) is provided with a fixing screw hole, and a fixing bolt passes through the positioning hole from the bottom and is screwed into the fixing screw hole.
7. The welding structure for processing and fixing a QFP package chip and a PCB board according to claim 1, wherein The projection of the heat sink (3) on the chip (2) is located within the contour range of the chip (2) itself.
8. The soldering structure for processing and fixing a QFP package chip and a PCB board according to claim 1, characterized in that, The support ring (4) is arranged along the edge of the chip (2).