CN110565058B

CN110565058B - Magnetron sputtering method of BGA product

Info

Publication number: CN110565058B
Application number: CN201910809187.2A
Authority: CN
Inventors: 邢发军; 许伟; 马国海; 张明俊; 李全兵
Original assignee: Jiangsu Changjiang Electronics Technology Co Ltd
Current assignee: JCET Group Co Ltd
Priority date: 2019-08-29
Filing date: 2019-08-29
Publication date: 2021-07-27
Anticipated expiration: 2039-08-29
Also published as: CN110565058A

Abstract

The invention relates to a magnetron sputtering method of a BGA product, which comprises the following steps: step one, taking a BGA product, and arranging a circle of groove at the position, close to the edge, of the periphery of a solder ball of a substrate of the BGA product; step two, taking a sputtering jig, designing a circle of continuous supporting dam on the surface of the sputtering jig, and matching the position and the size of the supporting dam with the groove of the substrate; and step three, placing the BGA product on a sputtering jig for sputtering, placing the bottom groove of the product on a supporting dam of the sputtering jig, and forming an internal closed space in the tin ball area, wherein the tin ball is not contacted with the sputtering jig. The invention can realize that the product tin ball is not sputtered in the sputtering process by the structural design of the BGA substrate and the sputtering jig, has simple process, does not need adhesive tape consumables, has strong operability and saves cost.

Description

Magnetron sputtering method of BGA product

Technical Field

The invention relates to a magnetron sputtering method of a BGA product, belonging to the technical field of semiconductor packaging.

Background

The conventional BGA sputtering method comprises the following steps: sputtering was performed using a perforated double sided tape to protect the bottom of the BGA, see figure 1. The method comprises the following steps: with double-sided tape trompil 3, will foraminiferous double-sided tape 2 laminate earlier on sputter carrier 1, place double-sided tape 2 with BGA product 4 again on, the bottom edge region of BGA product 4 laminates with double-sided tape 2, BGA product 4's tin ball sinks in trompil 3, later push down the product with the pressfitting machine, make 4 bottom edges of BGA product closely laminate with the double-sided tape, prevent the excessive plating in product bottom, then carry out the sputter operation again, sputter the back with the top that has the thimble make BGA product and double-sided tape separation, and place in the material collecting tray.

The disadvantages of the conventional BGA sputtering process are as follows:

1. the distance between the solder balls of some BGA products is too small to the edge of the products, no space is provided for the solder balls to be tightly attached to the double-sided adhesive tape, and the gaps between the products and the double-sided adhesive tape can cause the products to be over-plated by adopting the traditional BGA sputtering process;

2. the double-sided tape used in the conventional BGA sputtering method described above requires a hole to be opened, which requires precise processing of the tape. Due to the material and structural characteristics of the double-sided tape, the high-precision processing cost is increased;

3. when the solder balls are embedded into the holes of the double-sided adhesive tape, once the solder balls are contacted with the hole walls of the adhesive tape, the soldering performance of the product can be influenced due to the problem of adhesion;

4. in the traditional BGA sputtering method, in the process of taking a part after sputtering, the thimble applies upward pressure on the surface of the solder ball, and meanwhile, the surface of the product is sucked by the suction nozzle, so that the solder ball has the risk of breaking and the performance of the product can be influenced;

5. when the BGA product is separated from the double-sided adhesive tape, a continuous coating between the side surface of the BGA product and the surface of the double-sided adhesive tape is broken by pulling, so that metal burrs are generated, short circuit between solder balls can be caused, and the product performance is influenced.

Disclosure of Invention

The invention aims to solve the technical problem of providing a magnetron sputtering method of a BGA product aiming at the prior art, which can protect a product tin ball in the sputtering process through the structural design of a substrate and a sputtering jig of the BGA product, has simple process, does not need adhesive tape consumables, has strong operability and saves cost.

The technical scheme adopted by the invention for solving the problems is as follows: a magnetron sputtering method of a BGA product, said method comprising the steps of:

step one, taking a BGA product, and arranging a circle of groove at the position, close to the edge, of the periphery of a solder ball of a substrate of the BGA product;

step two, taking a sputtering jig, designing a circle of continuous supporting dam on the surface of the sputtering jig, and matching the position and the size of the supporting dam with the groove of the substrate;

and step three, placing the BGA product on a sputtering jig for sputtering, placing the substrate groove on a supporting dam of the sputtering jig, forming an internal closed space in the tin ball area, and enabling the tin balls not to be in direct contact with the upper surface of the sputtering jig.

Preferably, the depth H of the groove in the first step is 10-50 μm.

Preferably, the inner walls of the two sides of the groove in the first step are inclined planes, wherein the angle a of the inner wall of the outer side ranges from 10 degrees to 60 degrees, and the angle b of the inner wall of the inner side ranges from 20 degrees to 45 degrees.

Preferably, in the second step, one surface of the upper end of the supporting dam is an inclined surface, the angle c ranges from 20 degrees to 45 degrees, and the other surface of the upper end of the supporting dam is a vertical surface.

Preferably, an inner side wall of the groove of the substrate contacts the inclined surface of the support dam, and an outer side wall of the groove does not contact the vertical surface of the support dam.

Compared with the prior art, the invention has the advantages that:

1. the matching design of the substrate groove and the supporting dam ensures that the solder ball area is sealed, sputtering atoms cannot diffuse to the solder ball area, the solder ball area is protected from being overflowed, and the condition that short circuit between the solder balls and electrical property failure are caused by overflowed plating is effectively avoided;

2. because the product is only contacted with the sputtering jig, double faced adhesive tape is not needed in the sputtering process, the production cost is low, and no pollution waste is generated; the product does not need to be contacted with the adhesive tape, and has no defects of adhesive residue and the like;

3. the longer the sputtering path, the more difficult the sputtered atoms are diffused, and the lower the thickness of the coating around the path, so that the ultra-thin coating formed in the groove of the product is very thin. After the product is sputtered and separated from the sputtering jig, burrs of the cracked plating layer can not be generated; in addition, the adhesive force of the adhesive tape is not needed to be overcome in the part taking process, the product can be taken away only by contacting the surface sealing surface of the product, and the solder ball cannot be damaged under the action of external force.

Drawings

FIG. 1 is a schematic diagram of a conventional BGA sputtering method.

FIG. 2 is a schematic diagram of the magnetron sputtering method of a BGA product of the present invention.

FIG. 3 is a schematic view of the mating relationship between the back recess and the support dam of the product of FIG. 2.

FIG. 4 is a schematic view of the mating relationship of the back recess and the support dam of the product of FIG. 2.

Wherein:

carrier 1

Double-sided adhesive tape 2

Opening 3

BGA product 4

Through-hole 5

Sputtering jig 6

Substrate 7

Solder ball 8

Groove 9

Supporting the dam 10.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

Referring to fig. 2 and 3, the invention relates to a magnetron sputtering method of a BGA product, which comprises the following steps:

step one, taking a BGA product 4, arranging a circle of groove 9 on the periphery of a solder ball 8 on the bottom surface of a substrate 7 of the BGA product 4, forming the groove 9 by laser in the preparation process of the substrate, wherein the groove 9 extends into the substrate 7, the depth H of the groove 9 is 10-50 mu m, but the design of the groove 9 does not damage the internal circuit of the substrate 7; the groove 9 is designed to be wedge-shaped, the groove 9 is provided with an outer inner wall and an inner wall, the inner walls of two sides have certain angles, wherein the angle a of the inner wall of the outer side ranges from 10 degrees to 60 degrees, and the angle b of the inner wall of the inner side ranges from 20 degrees to 45 degrees;

step two, taking a sputtering jig 6, wherein a circle of continuous supporting dam 10 is arranged on the surface of the sputtering jig 6, the upper end of the supporting dam 10 is in a wedge-shaped structure, the surface of the upper end of the supporting dam 10, which is close to the solder balls 8, is an inclined surface, the angle c range of the inclined surface is 20-45 degrees, the inclined surface is matched with the angle b of the inner wall of the inner side of the substrate groove 9 of the BGA product 4, and the surface of the upper end of the supporting dam 10, which is far away from the solder balls 8, is a vertical surface;

and thirdly, placing the BGA product 4 on a sputtering jig 6 for sputtering, wherein the groove 9 is matched with the support dam 10 in size, the groove 9 is placed on the support dam 10 of the sputtering jig 6, the inner wall of the inner side of the groove 9 is in contact with the inclined surface of the support dam 10, and a certain gap is formed between the inner wall of the outer side of the groove 9 and the vertical surface of the support dam 10, so that an inner closed space is formed in the area of the solder ball 8, and the solder ball 8 is not in direct contact with the upper surface of the sputtering jig 6.

In addition, the present invention also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. A magnetron sputtering method of BGA products, characterized in that the method comprises the following steps:

step one, taking a BGA product, and arranging a circle of groove at the position, close to the edge, of the periphery of a solder ball of a substrate of the BGA product, wherein the groove is provided with an inner side inner wall and an outer side inner wall, and the depth H of the groove ranges from 10 microns to 50 microns;

2. The magnetron sputtering method of a BGA product of claim 1, wherein: in the first step, the inner wall of the inner side and the inner wall of the outer side of the groove are both inclined planes, wherein the angle a of the inner wall of the outer side ranges from 10 degrees to 60 degrees, and the angle b of the inner wall of the inner side ranges from 20 degrees to 45 degrees.

3. The magnetron sputtering method of a BGA product of claim 1, wherein: in the second step, one surface of the upper end of the supporting dam is an inclined surface, the angle c ranges from 20 degrees to 45 degrees, and the other surface of the upper end of the supporting dam is a vertical surface.

4. A magnetron sputtering method for BGA products as claimed in claim 3, wherein: the inner wall of the inner side of the groove of the substrate contacts the inclined surface of the supporting dam, and the inner wall of the outer side of the groove does not contact the vertical surface of the supporting dam.