Carrier for chemical plating of single chip and method for chemical plating by using carrier

Abstract

The invention discloses a carrier for chemical plating of a single chip and a method for chemical plating by using the carrier. The carrier for chemical plating of the single chip comprises a retainer, a lower limiting piece, an upper limiting piece and a pressing plate, wherein the retainer is used for placing the chip and limiting plane movement of the chip; the lower limiting piece is used for limiting the chip from falling from the lower part of the retainer; the upper limiting piece is used for limiting the chip from falling from the upper part of the retainer; the base is used for fixing the lower limiting piece and containing the holder, the hook is used for being connected with the base and hung on a plating solution tank, the holder is arranged in the base and is provided with a holding cavity penetrating through the holder, the holding cavity is used for placing a chip, the lower limiting piece is provided with a lower flow channel communicated with the holding cavity, and the lower flow channel is communicated with the holding cavity. The upper limiting piece is provided with an upper flow channel communicated with the maintaining cavity, the pressing plate is provided with an upper channel communicated with the upper flow channel, and the pressing plate is detachably installed on the base. According to the carrier for chemical plating of the single chip and the method for carrying out chemical plating by using the carrier, chemical plating can be carried out on the single chip.

Description

Technical Field

[0001] The present invention relates to the technical field of chip lead-out terminal coating, and in particular to a carrier for chemical plating of a single chip and a method for performing chemical plating using the carrier. Background Art

[0002] Electroless plating of the chip's I / O terminals, coating them with metals such as nickel, palladium, and gold, improves reliability and solderability. For mass-produced chips, this process typically uses a wafer-level electroless plating process, where the wafer itself is the primary substrate for electroless plating.

[0003] Due to R&D projects or small chip requirements, a panelization method is often used during tapeout. Different chips have different processing techniques, resulting in some chips on the same wafer requiring chemical plating while others do not. Such wafers cannot use the existing wafer-level chemical plating process, and the current chemical plating equipment is for the entire wafer. For panelized chips or single chips, the existing equipment cannot be used, resulting in the inability to carry out chemical plating process on panelized chips and single chips, and thus the inability to carry out post-ball planting based on under-bump metallization based on chemical plating process. This also leads to the reliability of the subsequent gold wire bonding process being unstable and the inability to improve the solderability of the chip. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a carrier for chemical plating of a single chip which can carry a single chip for chemical plating and a method for chemical plating using the carrier.

[0005] In order to solve the above problems, the present invention provides a carrier for chemical plating of a single chip, the carrier for chemical plating of a single chip includes a retaining frame for placing the chip and limiting the planar movement of the chip, a lower limit member for limiting the chip from falling from below the retaining frame, an upper limit member for limiting the chip from falling from above the retaining frame, a pressure plate for limiting the upper limit member to the top surface of the retaining frame, a base for fixing the lower limit member and accommodating the retaining frame, and a hook for connecting to the base and hanging on the plating tank, the retaining frame is placed in the base, the retaining frame has a retaining cavity passing through the retaining frame, the retaining cavity is used to place the chip, the lower limit member has a lower flow channel connected to the retaining cavity, the plating liquid in the plating tank directly or indirectly enters the retaining cavity through the lower flow channel, the upper limit member has an upper flow channel connected to the retaining cavity, the pressure plate has an upper channel connected to the upper flow channel, and the pressure plate is detachably mounted on the base.

[0006] Furthermore, the base has an accommodating cavity whose upper and lower ends are both connected to the outside world, the retaining frame is located in the accommodating cavity, and the lower limit member is located at the lower end of the accommodating cavity; or the base has a lower channel for connecting the outside world with the lower flow channel.

[0007] Furthermore, the pressing plate is provided with an upper through hole for the plating solution in the plating solution tank to flow, and the upper through hole is an upper channel.

[0008] Furthermore, the pressing plate is mounted on the base by interference fit, screw connection or clip connection.

[0009] Furthermore, the lower limit member and the upper limit member each have a plurality of meshes, the meshes of the lower limit member and the upper limit member are woven from silk threads, the meshes of the lower limit member are used as a lower flow channel, and the meshes of the upper limit member are used as an upper flow channel.

[0010] Furthermore, the height of the holding cavity is greater than the thickness of the chip, and the height of the holding cavity is less than the length of the short side of the chip.

[0011] Furthermore, the retaining frame is provided with a taking hole or a rod for applying force when taking.

[0012] Furthermore, the hook includes a hanging part for hanging with the plating liquid tank and a connecting rod for connecting the hanging part and the base, and the hanging part is screwed on the connecting rod.

[0013] Furthermore, the base includes an outer frame seat for connecting to the hook and an inner frame seat for fixing to the outer frame seat, the lower limit member is clamped and fixed between the inner frame seat and the outer frame seat, and the inner frame seat and the outer frame seat are connected by screwing, interference fit or snapping.

[0014] The present invention also provides a method for chemical plating using the above-mentioned carrier, comprising the following steps:

[0015] S1. Place the holder in the base, and then place the chip in the holding cavity of the holder;

[0016] S2. Place the upper limit member on the retaining frame and assemble the pressure plate on the base;

[0017] S3. Use a hook to hook the entire carrier into the plating solution tank, so that the chip, base, pressure plate, upper limit member and lower limit member are immersed in the plating solution to complete the chemical plating of the chip;

[0018] S4, taking out the carrier from the plating tank;

[0019] S5. Disassemble the pressure plate, then take out the upper limit piece and the retaining frame, and finally take out the chip after chemical plating.

[0020] The present invention provides a carrier for chemical plating of a single chip and a method for chemical plating using the carrier. The single chip can be confined in the holder by means of a holder, an upper limit member and a lower limit member, and the holder and the chip in the holder are placed in a plating solution tank by means of a hook for chemical plating, thereby realizing the chemical plating process of the single chip. Therefore, for the assembled wafer or the single chip, post-ball planting of under-bump metallization based on the chemical plating process can be carried out, which can improve the reliability of the subsequent gold wire bonding process and improve the solderability of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a carrier for chemical plating of a single chip according to the present invention.

[0022] Figure 2 It is an exploded view of a carrier for chemical plating of a single chip according to the present invention.

[0023] Figure 3 It is a cross-sectional view of a carrier for chemical plating of a single chip according to the present invention.

[0024] Figure 4 It is a structural diagram of the base.

[0025] Figure 5 It is a structural diagram of the cage.

[0026] Figure 6 It is a structural diagram of the pressure plate.

[0027] Figure 7 It is a structural schematic diagram of another embodiment of the pressing plate.

[0028] Figure 8 It is a method of chemically plating a single chip using a carrier.

[0029] Figure 9 It is a structural schematic diagram of another embodiment of the base.

[0030] Figure 10 It is a structural schematic diagram of another embodiment of the base.

[0031] The meanings of the reference numerals in the accompanying drawings are:

[0032] Retaining frame 1, retaining cavity 11, taking hole 12, lower limit member 2, upper limit member 3, pressure plate 4, upper channel 40, connecting part 41, limiting part 42, buckle groove 43, base 5, accommodating cavity 501, lower channel 502, inner frame seat 51, outer frame seat 52, mounting part 521, hook 6, hanging part 61, connecting rod 62. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings.

[0034] Example 1

[0035] like Figures 1 to 3 As shown, a preferred embodiment of a carrier for chemical plating of a single chip of the present invention includes a holder 1 for placing the chip and limiting the planar movement of the chip, a lower limiter 2 for limiting the chip from falling from below the holder 1, an upper limiter 3 for limiting the chip from falling from above the holder 1, a pressure plate 4 for pressing the upper limiter 3 against the top surface of the holder 1, a base 5 for fixing the lower limiter 2 and accommodating the holder 1, and a hook 6 for connecting to the base 5 and hanging on the plating tank. The holder 1 is placed in the base 5, and the holder 1 has a holding cavity 11 that passes through the holder 1. The chip to be chemically plated is placed in the holding cavity 11. The shape of the holding cavity 11 is adapted to the shape of the chip, that is, the holding cavity 11 is a quadrilateral to ensure that the chip does not rotate in the holding cavity 11. The lower limit member 2 is located on the bottom surface of the retaining frame 1, and the lower limit member 2 is used to limit the chip in the retaining cavity 11 from falling from the lower end of the retaining cavity 11. The plating liquid in the plating tank can pass through the base 5 and the lower limit member 2 into the retaining cavity 11. The upper limit member 3 is placed on the top surface of the retaining frame 1, and the upper limit member 3 is used to limit the chip in the retaining cavity 11 from falling out from the upper end of the retaining cavity 11; in other embodiments, as shown in the figure, the upper limit member 3 can also be fixed on the pressure plate 4. The pressure plate 4 is detachably mounted on the base 5, and the pressure plate 4 presses the upper limit member 3 against the top surface of the retaining frame 1, so that the upper limit member 3 fits the top surface of the retaining frame 1. The plating liquid in the plating tank can pass through the pressure plate 4 and the lower limit member 2 into the retaining cavity 11, thereby allowing the chip in the retaining cavity 11 to undergo chemical plating.

[0036] like Figure 4 As shown, the base 5 has a receiving cavity 501 with both the upper and lower ends connected to the outside world. The retaining frame 1 is located in the receiving cavity 501, and the lower limit member 2 is located at the lower end of the receiving cavity 501. The base 5 is usually made of plastic, such as polytetrafluoroethylene, so that the base 5 remains absolutely inert in the chemical plating solution, does not react with the plating solution, and protects the solution from contamination. The base 5 includes an inner frame seat 51 and an outer frame seat 52. The inner frame seat 51 and the outer frame seat 52 are fixed by interference fit. The inner frame seat 51 is located within the outer frame seat 52. The inner frame seat 51 and the outer frame seat 52 fix the lower limit member 2 by clamping. The outer frame seat 52 is provided with a mounting portion 521, and the hook 6 is fixed to the mounting portion 521. The inner frame seat 51 and the outer frame seat 52 are both tubular. It should be known that the interference fit between the inner frame seat 51 and the outer frame seat 52 is not easily released by human power, thereby ensuring a stable connection between the inner frame seat 51 and the outer frame seat 52; of course, in other embodiments, the inner frame seat 51 and the outer frame seat 52 can also be screwed or snapped together.

[0037] like Figure 5 As shown, there are multiple retaining cavities 11, each of which extends through the retaining frame 1 in the thickness direction. Thus, the height of each retaining cavity 11 is the same as the thickness of the retaining frame 1. The retaining cavities 11 are evenly distributed on the retaining frame 1. Providing multiple retaining cavities 11 allows for chemical plating of multiple chips at once. The thickness of the retaining frame 1 is less than the short side of the chip, meaning that the height of the retaining cavity 11 is less than the short side of the chip. Even if the chip is flipped around the center of its short side, it will be restrained by the upper and lower stoppers 3 and 2, preventing it from flipping within the retaining cavity 11. The thickness of the retaining frame 1 is greater than the thickness of the chip, meaning that the height of the retaining cavity 11 is greater than the thickness of the chip, effectively preventing friction between the chip within the retaining cavity 11 and the upper and lower stoppers 3. The outer diameter of the retaining frame 1 is adapted to the inner diameter of the inner frame seat 51, ensuring that the retaining frame 1 does not abut against the end face of the inner frame. When the pressure plate 4 presses the limiter 3, the inner frame is not subjected to the thrust of the pressure plate 4, thus ensuring the stability of the interference fit between the inner and outer frames. The holder 1 is provided with two access holes 12, which facilitate placement and removal of the holder 1 into or from the base 5 using tools such as tweezers. In other embodiments, a lever may be provided on the holder 1, with corresponding clearance holes or slots provided on the upper limit member 3 and the pressure plate 4. The holder 1 is typically made of a plastic, such as polytetrafluoroethylene, to ensure absolute inertness in the chemical plating solution, preventing reaction and contamination.

[0038] The lower limit member 2 has a lower flow channel, which is connected to the holding chamber 11. The plating liquid in the plating tank enters the holding chamber 11 through the flow channel. Since the lower limit member 2 is located on the end face of the base 5, the plating liquid in this embodiment directly enters the holding chamber 11 through the lower flow channel. The lower limit member 2 has a plurality of mesh holes, which makes the lower limit member 2 mesh-shaped. The mesh holes are used as the lower flow channel. The mesh is usually made of plastic, such as polytetrafluoroethylene, so that the lower limit member 2 remains absolutely inert in the chemical plating solution, does not react with the plating solution, and protects the solution from being contaminated. It should be known that those skilled in the art can select a mesh with a suitable mesh size according to their needs to ensure that the chip and the plating solution can fully react, that is, the reaction between the chip and the plating solution is not affected. The mesh holes of the lower limit member 2 are usually formed by weaving plastic silk threads.

[0039] The upper limit member 3 has an upper flow channel, and the plating liquid in the plating liquid tank enters the holding cavity 11 through the flow channel. The upper limit member 3 is placed on the retaining frame 1. The upper limit member 3 has a plurality of mesh holes so that the upper limit member 3 is mesh-shaped, and the mesh holes are used as lower flow channels. The mesh is usually made of plastic, such as polytetrafluoroethylene, so that the upper limit member 3 remains absolutely inert in the chemical plating solution, does not react with the plating solution, and protects the solution from being contaminated. It should be known that those skilled in the art can select a mesh with an appropriate mesh size according to their needs to ensure that the chip and the plating solution can fully react, that is, the reaction between the chip and the plating solution is not affected; the mesh holes of the upper limit member 3 are usually woven from plastic silk threads.

[0040] like Figure 6 As shown, the pressure plate 4 and the base 5 are installed by interference fit. It should be noted that the interference fit between the pressure plate 4 and the base 5 can be disassembled or assembled by a person using relatively light force, which makes disassembly and assembly convenient and easy to use. In other embodiments, the pressure plate 4 and the base 5 can also be connected in other detachable ways such as screw connection or snap connection. The pressure plate 4 has an upper channel 40 for the plating solution to pass through. The upper channel 40 is connected to the upper flow channel to ensure that the plating solution can smoothly enter the upper flow channel. An upper through hole is provided in the center of the pressure plate 4. The upper through hole is the upper channel 40. The through hole can cover all the holding cavities 11 on the retaining frame 1; in other embodiments, such as Figure 7 As shown, a plurality of upper perforations can also be provided on the pressing plate 4, each of which corresponds to a holding cavity 11. The pressing plate 4 is usually made of plastic, such as polytetrafluoroethylene, so that the pressing plate 4 remains absolutely inert in the chemical plating solution, does not react with the plating solution, and protects the solution from being contaminated. The pressing plate 4 has a buckle groove 43, which allows a hand to be inserted into the buckle groove 43 for easy application when removing the pressing plate 4. Of course, the buckle groove 43 can also be the position for applying force to a tool. Specifically, the pressing plate 4 includes a connecting portion 41 and a limiting portion 42. The connecting portion 41 is interference-fitted with the base 5 and simultaneously presses the limiting member 3. The limiting portion 42 is located at the upper end of the connecting portion 41 and is formed by extending outward from the upper end of the connecting portion 41. The buckle groove 43 is provided on the limiting portion 42. The limiting portion 42 is used to prevent the connecting portion 41 from moving too much downward, thereby avoiding squeezing the lower limiting member 2 and causing the lower limiting member 2 to fall off.

[0041] The hook 6 includes a hanging member 61 and a connecting rod 62. The hanging member 61 is used to hang on the plating tank. The lower end of the connecting rod 62 is fixed to the base 5, and the upper end of the connecting rod 62 is connected to the hanging member 61. The connecting rod 62 connects the hanging member 61 and the base 5 to form a whole. To facilitate adjustment of the height of the base 5, the hanging member 61 is provided with a threaded hole. The upper end of the connecting rod 62 is provided with an external thread, and the connecting rod 62 is screwed into the threaded hole.

[0042] like Figure 8 As shown, the method for chemical plating using a carrier includes the following steps:

[0043] S1. Place the chip. Specifically, first place the holder 1 in the base 5, and then place the chip in the holding cavity 11 of the holder 1;

[0044] S2. Fix the chip. Specifically, place the upper limit member 3 on the holder 1 and assemble the pressure plate 4 on the base 5.

[0045] S3. The carrier is placed in a plating tank for chemical plating. Specifically, the entire carrier is hooked into the plating tank using a hook 6, so that the chip, base 5, pressure plate 4, upper limit member 3 and lower limit member 2 are immersed in the plating solution to complete the chemical plating of the chip.

[0046] S4, removing the carrier from the plating tank, specifically: removing the entire electroless plating carrier from the plating tank after the electroless plating is completed;

[0047] S5. Take out the chip. Specifically, disassemble the pressing plate 4, then take out the upper limit member 3 and the retaining frame 1, and finally take out the chip after chemical plating.

[0048] The electroless plating process for a single chip is realized. Therefore, for a single chip, post-balling with under-bump metallization (UBM) based on the electroless plating process can be performed, which can improve the reliability of the subsequent wire bonding process and the chip's solderability. The assembled wafer can be divided into individual chips for electroless plating. The retaining frame 1 is removable and replaceable, and the appropriate retaining cavity 11 can be selected according to the chip size. By replacing the retaining frame 1, electroless plating can be performed on individual chips of various specifications, thus providing a wide range of applications.

[0049] Example 2

[0050] like Figure 9 As shown, the difference between this embodiment and the first embodiment is that the inner frame seat 51 of the base 5 has a lower channel 502, and the inner frame seat 51 is provided with a plurality of through holes, which serve as the lower channel 502. In this case, the inner diameter of the inner frame seat 51 is the same as the inner diameter of the outer frame seat 52. Of course, in other embodiments, such as Figure 10 As shown, the inner frame seat 51 can also be annular, that is, the inner frame seat 51 has a hole with a larger diameter that can cover the entire holding cavity 11.

[0051] The above are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure made using the contents of the present invention's description and drawings, directly or indirectly applied to other related technical fields, is also within the patent protection scope of the present invention.

Claims

1. A carrier for chemical plating of a single chip, characterized by: It includes a holder for placing chips and limiting the planar movement of the chips, a lower limiter for limiting the chips from falling from below the holder, an upper limiter for limiting the chips from falling from above the holder, a pressure plate for limiting the upper limiter to the top surface of the holder, a base for fixing the lower limiter and accommodating the holder, and a hook for connecting with the base and hanging on a plating tank. The holder is placed in the base, and the holder has a holding cavity that passes through the holder, and the holding cavity is used to place chips. The lower limiter has a lower flow channel connected to the holding cavity, and the plating liquid in the plating tank directly or indirectly enters the holding cavity through the lower flow channel. The upper limiter has an upper flow channel connected to the holding cavity, and the pressure plate has an upper channel connected to the upper flow channel. The pressure plate can be detachably mounted on the base.

2. A carrier for chemical plating of a single chip as claimed in claim 1, characterized in that: The base has an accommodating cavity whose upper and lower ends are both connected to the outside, the retaining frame is located in the accommodating cavity, the lower limit member is located at the lower end of the accommodating cavity, or the base has a lower channel for connecting the outside with the lower flow channel.

3. A carrier for chemical plating of a single chip as claimed in claim 1, characterized in that: The pressing plate is provided with an upper through hole for the plating solution in the plating solution tank to flow, and the upper through hole is an upper channel.

4. A carrier for chemical plating of a single chip as claimed in claim 1, characterized in that: The pressing plate is mounted on the base by interference fit, screw connection or clamping.

5. A carrier for chemical plating of a single chip as claimed in claim 1, characterized in that: The lower limit member and the upper limit member both have a plurality of meshes, the meshes of the lower limit member and the upper limit member are formed by weaving silk threads, the meshes of the lower limit member are used as a lower flow channel, and the meshes of the upper limit member are used as an upper flow channel.

6. A carrier for chemical plating of a single chip as claimed in claim 1, characterized in that: The height of the holding cavity is greater than the thickness of the chip, and the height of the holding cavity is less than the length of the short side of the chip.

7. A carrier for chemical plating of a single chip as claimed in claim 1, characterized in that: The retaining frame is provided with a taking hole or a rod for applying force when taking.

8. A carrier for chemical plating of a single chip as claimed in claim 1, characterized in that: The hook comprises a hanging part for hanging with the plating liquid tank and a connecting rod for connecting the hanging part and the base, and the hanging part is screwed on the connecting rod.

9. A carrier for chemical plating of a single chip as claimed in claim 1, characterized in that: The base includes an outer frame seat connected to the hook and an inner frame seat fixed to the outer frame seat, the lower limit member is clamped and fixed between the inner frame seat and the outer frame seat, and the inner frame seat and the outer frame seat are connected by screwing, interference fit or snapping.

10. A method for chemical plating using the carrier according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, placing the holder in the base, and then placing the chip in the holding cavity of the holder; S2, placing the upper limit member on the retaining frame, and assembling the pressure plate on the base; S3, using a hook to hook the entire carrier into the plating solution tank, so that the chip, base, pressure plate, upper limit piece and lower limit piece are immersed in the plating solution to complete the chemical plating of the chip; S4, taking out the carrier from the plating tank; S5. Disassemble the pressing plate, then take out the upper limit piece and the retaining frame, and finally take out the chip after chemical plating.

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