Graphite jig for chip packaging

Abstract

The utility model discloses a graphite jig for chip packaging, the graphite jig for chip packaging adopts a seat plate and a detachable and replaceable seat block on the seat plate, and a first rectangular hole arranged on the seat plate limits a welding area for only placing a welding sheet with a fixed size. A second rectangular hole arranged on the seat block limits a welding area for placing chips and soldering lugs of other different sizes, and a third rectangular hole separated by the seat block on the inverted-T-shaped hole on the seat plate limits a welding area for placing chips and soldering lugs of fixed sizes. According to the utility model, a plurality of areas of different welding conditions on the packaging substrate can be limited at the same time, and the welding limiting of chips with different sizes can be realized by replacing the seat block, and in addition, polytetrafluoroethylene layers are arranged on the back surfaces of the seat plate and the seat block which are in direct contact with the packaging substrate, so that the reliability of the welding limiting is improved. And the problem of oxidation caused by the fact that the graphite jig absorbs moisture to be saturated and then releases the moisture to the surfaces of the packaging substrate and the welding element is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of chip packaging, and particularly to a graphite fixture for chip packaging. Background Art

[0002] Graphite fixtures are widely used in semiconductor manufacturing, especially in chip packaging, due to their excellent properties such as high temperature resistance, corrosion resistance, high thermal conductivity, light weight, and high hardness. There is an existing chip packaging process flow that requires using a graphite fixture to limit multiple areas with different welding conditions on a packaging substrate at the same time. Among these areas, some only need to place solder pads of fixed sizes and pre-weld them to prepare for the welding of other components in subsequent process flows, and some need to place chips and solder pads to weld the chips to the packaging substrate. The chips to be welded include not only those with fixed sizes but also those with other different sizes. However, the existing graphite fixtures in the prior art cannot meet the functional requirements of the above process flow. Summary of the Utility Model

[0003] In order to overcome the deficiencies of the above prior art, the utility model provides a graphite fixture for chip packaging, which can limit multiple areas with different welding conditions on a packaging substrate at the same time and is applicable to the welding limit of chips with different sizes by replacing components.

[0004] To achieve the above object, the technical solution adopted by the utility model to solve its technical problems is that a graphite fixture for chip packaging includes a base plate and a number of base blocks. The base plate is provided with a number of convex-shaped holes and a number of first rectangular holes. The convex-shaped hole is composed of a large rectangular part and a small rectangular part connected. A number of base blocks can be fitted into the large rectangular part. The base block is provided with a second rectangular hole, and the sizes of the second rectangular holes in different base blocks are different. A rectangular notch is provided on one side of the base block adjacent to the small rectangular part. When the base block is fitted into the large rectangular part, the rectangular notch and the small rectangular part communicate to form a third rectangular hole. The back surfaces of the base plate and the base blocks are both covered with a polytetrafluoroethylene layer.

[0005] In some embodiments, the polytetrafluoroethylene layer is a Teflon tape.

[0006] In some embodiments, at least one positioning block extends outward from one side of the base plate.

[0007] In some embodiments, relief holes are provided at the four corners of the first rectangular hole, the second rectangular hole, and the third rectangular hole, and the relief holes are cylindrical.

[0008] In some embodiments, the upper parts of the inner walls on the four sides of the first rectangular hole are inclined to form slopes.

[0009] In some embodiments, the upper parts of the inner walls on the three sides of the second rectangular hole except the side adjacent to the rectangular notch are inclined to form slopes.

[0010] In some embodiments, on the upper parts of the two inner walls of the third rectangular hole that are perpendicular to one side where the notch on the seat block is located, slopes are formed obliquely.

[0011] In some embodiments, when the seat block is fitted into the large rectangular part, the upper end of the seat block protrudes above the upper wall of the seat plate, and on the upper ends of the three sides of the seat block except the side where the rectangular notch is located, flanges extend outward.

[0012] In some embodiments, rounded corners are adopted for all four end corners of the large rectangular part and the seat block.

[0013] In some embodiments, the convex-shaped holes and the first rectangular holes are each provided in pairs and are symmetrically distributed on the seat plate.

[0014] Due to the application of the above technical solutions, the present utility model has the following beneficial effects compared with the prior art:

[0015] The present utility model adopts a seat plate and a seat block that can be detachably replaced on the seat plate. Among them, the first rectangular hole opened on the seat plate limits the welding area for only placing solder pads of a fixed size, the second rectangular hole opened on the seat block limits the welding area for placing other chips and solder pads of different sizes, and the third rectangular hole separated by the seat block from the convex-shaped hole on the seat plate limits the welding area for placing chips and solder pads of a fixed size, realizing the limitation of multiple areas with different welding conditions on the packaging substrate at the same time, and being applicable to the welding limitation of chips of different sizes by replacing the seat block. In addition, the present utility model also provides a polytetrafluoroethylene layer on the back surfaces of the seat plate and the seat block that are in direct contact with the packaging substrate, avoiding the problem that the graphite fixture absorbs moisture until it reaches saturation and then releases it to the surfaces of the packaging substrate and the welding components, resulting in oxidation. Description of the Drawings

[0016] Figure 1 It is the front view of the first embodiment of the graphite fixture for chip packaging proposed by the present utility model.

[0017] Figure 2 It is the front view of the seat plate in the first embodiment of the graphite fixture for chip packaging proposed by the present utility model.

[0018] Figure 3 It is the three-dimensional view of the seat plate and a pair of seat blocks thereon in the first embodiment of the graphite fixture for chip packaging proposed by the present utility model.

[0019] In the figure: 1 - seat plate; 2 - seat block; 3 - convex-shaped hole; 4 - first rectangular hole; 5 - large rectangular part; 6 - small rectangular part; 7 - second rectangular hole; 8 - rectangular notch; 9 - third rectangular hole; 10 - positioning block; 11 - relief hole; 12 - slope; 13 - flange. Detailed Embodiment

[0020] The following further elaborates on the content of the present utility model in conjunction with specific embodiments:

[0021] Combined with Figures 1 to 3 , Embodiment 1 of the graphite fixture for chip packaging proposed by the present utility model includes a base plate 1 and two pairs of seat blocks 2. The base plate 1 is generally rectangular, and a positioning block 10 extends outward from one side thereof. The positioning block 10 is used to connect to an external mechanism to limit and fix itself on the packaging substrate. A pair of convex-shaped holes 3 and two pairs of first rectangular holes 4 are provided on the base plate 1. The pair of convex-shaped holes 3 and the two pairs of first rectangular holes 4 are symmetrically arranged on the base plate 1 respectively, forming a double welding station. The convex-shaped hole 3 is composed of a large rectangular part 5 and a small rectangular part 6 connected. The first pair of seat blocks 2 are respectively fitted into a pair of large rectangular parts 5, and a pair of second rectangular holes 7 provided thereon have the same size. The second pair of seat blocks 2 are located outside the seat blocks 2, and a pair of second rectangular holes 7 provided thereon and a pair of rectangular holes on the first pair of seat blocks 2 have different sizes. The seat blocks 2 adopt an anti-fooling design and are symmetric left and right. Rectangular notches 8 are provided on one side of the seat blocks 2 adjacent to the small rectangular part 6. When the seat blocks 2 are fitted into the large rectangular parts 5, the rectangular notches 8 and the small rectangular part 6 communicate to form a third rectangle with a fixed size. The back surfaces of the base plate 1 and the seat blocks 2 are both covered with a polytetrafluoroethylene layer (not shown in the drawings due to its too thin thickness). Among them, the first rectangular holes 4 are used to place solder chips of a fixed size, the second rectangular holes 7 are used to place other chips and solder chips of different sizes, and the third rectangular hole 9 is used to place chips and solder chips of a fixed size.

[0022] In Embodiment 1 and other embodiments of the present utility model:

[0023] The shape, size, and quantity distribution of the base plate 1, the seat blocks 2, and the various holes, protruding blocks, and notches thereon are determined by the requirements of the actual chip packaging process flow and can be flexibly adjusted. Preferably, the convex-shaped holes 3 and the first rectangular holes 4 are each provided in pairs and are symmetrically distributed on the base plate 1 to form a double welding station;

[0024] Both the base plate 1 and the seat blocks 2 are made of graphite, and their back surfaces are in direct contact with the packaging substrate. After the graphite is treated at high temperature, a nano-scale pore structure will be generated on the surface. These void structures have a strong absorption effect on various gas molecules, organic molecule, and metal ion molecules. When the solder chips in the holes melt, carbon monoxide, carbon dioxide, oxygen, hydrogen, nitrogen, water vapor, and a small amount of metal vapor and slag vapor will be generated. Among them, the main thing to guard against is water vapor. After the graphite absorbs water to saturation and releases it to the surface of the packaging substrate and the welding components, oxidation will occur, resulting in a reduction in the yield. Therefore, a polytetrafluoroethylene layer with excellent properties such as high temperature resistance, corrosion resistance, good waterproofness, and ultra-thin thickness is provided on the back surfaces of the base plate 1 and the seat blocks 2 to block water molecules. Among them, the polytetrafluoroethylene layer is preferably Teflon (another name for polytetrafluoroethylene) tape, which is directly pasted, with low cost and convenient production. It can also be coated with a protective film layer by spraying to achieve a better protection effect;

[0025] Preferably, relief holes 11 are provided at the four end corners of the first rectangular hole 4, the second rectangular hole 7, and the third rectangular hole 9. The relief holes 11 are cylindrical. The seat plate 1 and the seat block 2 are integrally formed by machining with a precision machine tool, and the relief holes 11 are milled by a machine tool cutter head, ensuring that there is sufficient space at the four end corners of the first rectangular hole 4, the second rectangular hole 7, and the third rectangular hole 9 to accommodate the four right-angled end corners of the solder pad and / or the chip;

[0026] Preferably, upper portions of the inner walls of the four sides of the first rectangular hole 4, upper portions of the inner walls of the three sides of the second rectangular hole 7 except for the side adjacent to the rectangular notch 8, and upper portions of the inner walls of the two sides of the third rectangular hole 9 perpendicular to the side where the notch on the seat block 2 is located are inclined to form slopes 12, facilitating the smooth placement of the solder pad and / or the chip and avoiding clamping damage;

[0027] Preferably, when the seat block 2 is fitted into the large rectangular portion 5, the upper end of the seat block 2 protrudes above the upper wall of the seat plate 1. Three sides of the seat block 2 except for the side where the rectangular notch 8 is located extend outward to form wing edges 13, facilitating the taking and replacement of the seat block 2;

[0028] Preferably, the four end corners of the large rectangular portion 5 and the seat block 2 are all rounded, which is beautiful and safe, and also facilitates the smooth fitting and separation of the two.

[0029] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it. It is not intended to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A graphite fixture for chip packaging, characterized in that, It includes a seat board (1) and several seat blocks (2). A plurality of convex-shaped holes (3) and a plurality of first rectangular holes (4) are formed on the seat board (1). The convex-shaped holes (3) are composed of a large rectangular part (5) and a small rectangular part (6) connected together. A plurality of the seat blocks (2) can be fitted into the large rectangular part (5). A second rectangular hole (7) is formed on the seat block (2), and the sizes of the second rectangular holes (7) in different seat blocks (2) are different. A rectangular notch (8) is provided on one side of the seat block (2) adjacent to the small rectangular part (6). When the seat block (2) is fitted into the large rectangular part (5), the rectangular notch (8) and the small rectangular part (6) communicate to form a third rectangular hole (9). The back surfaces of the seat board (1) and the seat blocks (2) are both covered with a polytetrafluoroethylene layer.

2. The graphite fixture for chip packaging according to claim 1, wherein The polytetrafluoroethylene layer is a Teflon tape.

3. The graphite fixture for chip packaging according to claim 1, wherein, At least one positioning block (10) extends outward from one side of the seat board (1).

4. The graphite fixture for chip packaging according to claim 1, wherein, Relief holes (11) are provided at the four end corners of the first rectangular hole (4), the second rectangular hole (7), and the third rectangular hole (9), and the relief holes (11) are cylindrical.

5. The graphite jig for chip packaging according to claim 1, wherein, The upper parts of the inner walls on the four sides of the first rectangular hole (4) are inclined to form slopes (12).

6. The graphite jig for chip packaging according to claim 1, characterized in that, The upper parts of the inner walls on the three sides of the second rectangular hole (7) except for the side adjacent to the rectangular notch (8) are inclined to form slopes (12).

7. The graphite jig for chip packaging according to claim 1, wherein The upper parts of the inner walls on the two sides of the third rectangular hole (9) perpendicular to the side where the notch of the seat block (2) is located are inclined to form slopes (12).

8. The graphite jig for chip packaging according to claim 1, characterized in that, When the seat block (2) is fitted into the large rectangular part (5), the upper end of the seat block (2) protrudes above the upper wall of the seat board (1), and the upper ends of the three sides of the seat block (2) except for the side where the rectangular notch (8) is located extend outward to form wing edges (13).

9. The graphite fixture for chip packaging according to claim 1, characterized in that The four end corners of the large rectangular part (5) and the seat block (2) are all rounded.

10. The graphite fixture for chip packaging according to claim 1, wherein, The convex-shaped holes (3) and the first rectangular holes (4) are each provided in pairs and are symmetrically distributed on the seat board (1).

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