TWI487046B - Method of welding a solder wire - Google Patents

Description

Welding method of welding wire

The invention relates to a welding method for a welding wire, in particular to a welding method capable of strengthening the bonding force between the welding ball and the welding pad.

As electronic products move toward a thinner and lighter trend, and the technology of semiconductor manufacturing is changing with each passing day, the distance between the lines of wafers or semiconductor devices is getting smaller and smaller, so that the size of the pad as an input/output (I/O) is gradually reduced. The wiring of the semiconductor package also moves from a fine pitch to an ultra fine pitch.

However, due to the reduction in the size of the pad, it is easy to cause the solder ball or the solder joint to fall off from the pad, resulting in a product failure and a considerable manufacturing cost.

FIG. 1 is a schematic plan view showing a contact area A in which solder balls 10 are soldered to pads 11 in the prior art. As shown, a solder ball 10 such as a circular wire is soldered to, for example, a square pad 11 by a bonding wire, and the contact area between the solder ball 10 and the pad 11 is A.

Due to the reduction in the size of the pad 11, that is, the length L and the width W of the pad 11 become smaller, the contact area A of the solder ball 10 soldered to the pad 11 is also reduced. The solder ball 10 and the pad 11 The bonding force is lowered, and the solder ball 10 is easily detached from the solder pad 11, resulting in product failure and increased manufacturing cost.

Therefore, how to overcome the problems of the above-mentioned prior art has become a problem that is currently being solved.

In view of the above-mentioned various deficiencies of the prior art, the present invention provides a method of soldering a bonding wire, comprising: forming a soldering wire by a soldering pin; soldering the solder ball to at least one corner region by the soldering pin And soldering the ball to a corner region of the solder pad to enlarge the contact area of the solder ball on the solder pad;

It can be seen from the above that the soldering method of the bonding wire of the present invention mainly uses a soldering pin to push a part of the solder ball to at least one corner of the soldering pad to increase the contact area between the solder ball and the soldering pad. Thereby, the invention can strengthen the bonding force between the solder ball and the soldering pad to prevent the solder ball from falling off from the soldering pad, thereby avoiding product failure and increasing manufacturing cost.

10‧‧‧ solder balls

11‧‧‧ solder pads

20‧‧‧Wire welding machine

201‧‧‧welding part

21‧‧‧ welding needle

211‧‧‧ head

22‧‧‧welding line

221‧‧‧End

222‧‧‧ solder balls

23‧‧‧ solder pads

231‧‧‧ upper surface

241‧‧‧First corner

242‧‧‧second corner

243‧‧‧ third corner

244‧‧‧fourth corner

251‧‧‧First corner area

252‧‧‧second corner area

253‧‧‧ Third Corner Area

254‧‧‧Four Corner Area

26‧‧‧ center point

271‧‧‧First connection

272‧‧‧Second connection

273‧‧‧ third connection

274‧‧‧ fourth connection

A‧‧‧Contact area

A1‧‧‧First contact area

A2‧‧‧second contact area

A3‧‧‧ third contact area

A4‧‧‧4th contact area

L‧‧‧ length

W‧‧‧Width

SS‧‧ ‧ line segment

Θ1‧‧‧ first angle

Θ2‧‧‧second angle

1 is a top plan view showing a contact area of a solder ball soldered on a solder pad in a conventional technique; FIG. 2A is a perspective view showing a solder ball soldered to a solder pad by a soldering machine of the present invention; 2B is a schematic side view showing the welding ball of the welding wire welded to the welding pad by the welding pin according to the welding part of FIG. 2A; FIG. 3A is a drawing of the line according to the line SS of FIG. 2B; The invention discloses a contact area for soldering a solder ball on a solder pad and a top view of the first to fourth corner regions 3B is a top plan view showing the solder balls of the first and second connecting portions of the present invention to the first and second corner regions according to FIG. 3A; and FIG. 3C is according to FIG. 3B. A schematic plan view of the solder balls to the third and fourth corner regions of the third and fourth connecting portions of the present invention is shown.

The other embodiments of the present invention will be readily understood by those skilled in the art from this disclosure.

It is to be understood that the structure, the proportions, the size, and the like of the present invention are intended to be used in conjunction with the disclosure of the specification, and are not intended to limit the invention. The conditions are limited, so it is not technically meaningful. Any modification of the structure, change of the proportional relationship or adjustment of the size should remain in this book without affecting the effects and the objectives that can be achieved by the present invention. The technical content disclosed in the invention can be covered.

At the same time, the terms "upper", "one", "first", "second", "connection" and "corner area" as quoted in this manual are for convenience only, not for use. To the extent that the invention can be implemented, the relative changes or adjustments of the present invention are also considered to be within the scope of the invention.

2A is a view showing the welding of the present invention by the welding pin 21 of the wire bonding machine 20. A perspective view of the ball 222 soldered to the pad 23, and FIG. 2B shows the solder ball 222 of the wire 22 soldered to the pad 23 by the soldering pin 21 according to the soldering portion 201 of FIG. 2A. See the schematic.

As shown in FIG. 2A to FIG. 2B, the bonding wire 22 (such as a tin wire, a copper wire or a gold wire) is first held by the welding pin 21 of the wire bonding machine 20, and the end portion 221 of the bonding wire 22 is exposed to the welding. Below the head 211 of the needle 21, the end 221 of the wire 22 is brought into contact with or in contact with the upper surface 231 of the pad 23. Next, the end portion 221 of the bonding wire 22 is sintered to form a solder ball 222 such as a circular shape, and the solder ball 222 is soldered to the upper surface 231 of the bonding pad 23 by the soldering pin 21.

Furthermore, as shown in FIG. 2A, after the soldering pin 21 solders the solder ball 222 to the solder pad 23 to form a solder joint, the wire bonding machine 20 can be along the first connection line 271 and the second line. The wire 272, the third wire 273, and/or the fourth wire 274 move the welding pin 21, so that the welding pin 21 pushes the portion of the solder ball 222 to the first to fourth corner regions of the pad 23 at least One is to enlarge the contact area of the solder ball 222 on the pad 23.

FIG. 3A is a top plan view showing the contact area A and the first to fourth corner regions 251-254 of the solder ball 222 soldered to the solder pad 23 according to the line segment SS of FIG. 2B. FIG. 3B is a schematic diagram according to the third embodiment. 3A is a top plan view showing the solder balls 222 of the present invention along the first and second connecting lines 271-272, respectively, to the first and second corner regions 251-252, and FIG. 3C is shown according to FIG. 3B. The present invention is a top plan view of the solder balls 222 to the third and fourth corner regions 253-254 along portions of the third and fourth links 273-274, respectively.

As shown in FIG. 3A, the solder ball 222 is soldered to the pad 23 The surface 231, and the contact area between the solder ball 222 and the solder pad 23 is A, and the center point 26 of the solder ball 222 can be the same as the center point 26 of the upper surface 231 of the solder pad 23.

In this embodiment, the pad 23 is square or rectangular, and has four corner regions, including a first corner region 251 and a second corner region 252 respectively opposite to the first corner 241 and the second corner 242. And a third corner region 253 and a fourth corner region 254 having opposite third corners 243 and fourth corners 244, respectively. However, it is not limited thereto. In other embodiments, the pad 23 may have various shapes or have less than or more than four corner regions and four corners. It should be understood that the corner regions indicated by the dashed lines in the drawings are not intended to limit the scope or area thereof.

As shown in Figure 3B, please refer to Figures 2A through 2B and Figure 3A at the same time. After the soldering pin 21 solders the solder ball 222 to the upper surface 231 of the solder pad 23 to form a solder joint, the wire bonding machine 20 passes along the center point 26 of the solder ball 222 and the first corner 241. The first connecting line 271, and/or the second connecting line 272 of the second corner 242 moves the soldering pin 21, so that the soldering pin 21 pushes the portion of the solder ball 222 to the solder pad 23 A corner region 251 and/or a second corner region 252 expand the contact area A of the solder ball 222 on the pad 23.

In detail, in the embodiment, when the pad 23 is square, taking the XY coordinate as an example, the first angle θ1 of the X-axis to the first connection 271 is equal to 45 degrees, and the X-axis to the second The angle of the line 272 is equal to 225 degrees (45 degrees of the first angle θ1 plus 180 degrees); and when the pad 23 is rectangular, the first angle θ1 is greater than or less than 45 degrees, and the X axis is to the first Erlian The angle of line 272 is greater than or less than 225 degrees. The soldering pin 21 is separated from the center point 26 along the first connecting line 271 and the second connecting line 272, and a part of the solder balls 222 are respectively pushed to the first corner area 251 and the second corner area 252. The first contact area A1 and the second contact area A2 are increased to increase the contact area between the solder ball 222 and the pad 23 to A+A1+A2.

However, in other embodiments, for example, when the pad 23 has only one of the first corner region 251 and the second corner region 252, the soldering pin 21 may also follow the first connection from the center point 26. 271 or the second connection 272, the portion of the solder ball 222 is pushed to the first corner region 251 or the second corner region 252, thereby increasing the first contact area A1 or the second contact area A2, so that the solder ball The contact area between 222 and the pad 23 is enlarged to A+A1 or A+A2.

As shown in Figure 3C, please refer to Figures 2A to 2B and Figures 3A to 3B at the same time. After the soldering pin 21 moves a portion of the solder ball 222 to the first corner region 251 and/or the second corner region 252 of the solder pad 23, the wire bonding machine 20 is along the center point 26 of the solder ball 222. The third wire 273 of the third corner 243 and/or the fourth wire 274 of the center point 26 and the fourth corner 244 move the soldering pin 21, so that the soldering pin 21 pushes the portion of the solder ball 222 to The third corner region 253 and/or the fourth corner region 254 of the pad 23 expands the contact area A of the solder ball 222 on the pad 23.

In detail, in the embodiment, when the pad 23 is square, taking the XY coordinate as an example, the second angle θ2 of the X-axis to the third connection 273 is equal to 135 degrees, and the X-axis to the fourth. The angle of the line 274 is equal to 315 degrees (135 degrees of the second angle θ2 plus 180 degrees). The first corner 241 and the first The connection of the two corners 242 is orthogonal to the connection of the third corner 243 and the fourth corner 244, that is, the first connection line 271 and the second connection line 272 are connected to the third connection line 273 and the The fourth connecting lines 274 are each 90 degrees apart, indicating that the angle between the first connecting line 271 and the third connecting line 273 and the angle between the second connecting line 272 and the fourth connecting line 274 are both 90 degrees.

When the pad 23 is rectangular, the second angle θ2 is greater than or less than 135 degrees, and the angle from the X axis to the fourth wire 274 is greater than or less than 315 degrees; the first corner 241 and the second corner The connection of the 242 is not orthogonal to the connection between the third corner 243 and the fourth corner 244, that is, the first connection 271 and the second connection 272 are connected to the third connection 273 and the first The four wires 274 are each different by more than or less than 90 degrees, indicating that the angle between the first wire 272 and the third wire 273 and the angle between the second wire 272 and the fourth wire 274 are not 90 degrees.

The soldering pin 21 is separated from the center point 26 along the third connecting line 273 and the fourth connecting line 274, and the solder balls 222 are partially pushed to the third corner area 253 and the fourth corner area 254, respectively. The third contact area A3 and the fourth contact area A4 are increased to increase the contact area between the solder ball 222 and the pad 23 to A+A1+A2+A3+A4.

However, in other embodiments, for example, the pad 23 has only one of the first corner region 251 and the second corner region 252, and one of the third corner region 253 and the fourth corner region 254. The soldering pin 21 can also move part of the solder ball 222 from the center point 26 along the first connection line 271 or the second connection line 272, and the third connection line 273 or the fourth connection line 274. The first corner area 251 or the second corner area 251, And the third corner region 253 or the fourth corner region 254, thereby increasing the first contact area A1 or the second contact area A2, and the third contact area A3 or the fourth contact area A4, so that the solder ball 222 and the solder ball 222 The contact area between the pads 23 is expanded to A+A1+A3, A+A1+A4, A+A2+A3 or A+A2+A4.

It can be seen from the above that the welding method of the bonding wire of the present invention mainly uses a welding pin to push a part of the solder balls to each corner region to increase the contact area between the solder ball and the bonding pad. Thereby, the invention can strengthen the bonding force between the solder ball and the soldering pad to prevent the solder ball from falling off from the soldering pad, thereby avoiding product failure and increasing manufacturing cost.

The above embodiments are intended to illustrate the principles of the invention and its effects, and are not intended to limit the invention. Any of the above-described embodiments may be modified by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention should be as set forth in the appended claims.

222‧‧‧ solder balls

23‧‧‧ solder pads

231‧‧‧ upper surface

241‧‧‧First corner

242‧‧‧second corner

243‧‧‧ third corner

244‧‧‧fourth corner

26‧‧‧ center point

271‧‧‧First connection

272‧‧‧Second connection

273‧‧‧ third connection

274‧‧‧ fourth connection

A‧‧‧Contact area

A1‧‧‧First contact area

A2‧‧‧second contact area

A3‧‧‧ third contact area

A4‧‧‧4th contact area

Θ1‧‧‧ first angle

Θ2‧‧‧second angle

Claims (8)

A soldering wire bonding method comprising: forming a solder ball by a soldering pin; soldering the solder ball to a solder pad having at least one corner region; and soldering the soldering pin The solder ball on the pad moves a portion of the solder ball to a corner region of the solder pad to expand a contact area of the solder ball on the solder pad through the push portion. The welding method of the welding wire according to the first aspect of the invention, wherein the welding pad has a first corner area and a second corner area, and the first corner area and the second corner area respectively have a first first a corner and a second corner, the solder pin pushing portion of the solder ball to at least one of the first corner region and the second corner region. The welding method of the welding wire according to the first aspect of the invention, wherein the welding pad has a first corner area and a third corner area, and the first corner area and the third corner area respectively have a first corner And the third corner, the soldering pin moves the solder ball to at least one of the first corner region and the third corner region. The method of welding a bonding wire according to the third aspect of the invention, wherein the solder ball is soldered to the bonding pad to form a solder joint, and the soldering point is respectively connected to the first corner and the third corner. The angle is equal to 90 degrees. The welding method of the bonding wire according to claim 3, wherein the solder ball is soldered to the bonding pad to form a solder joint, and the soldering point respectively The angle formed by the line formed by the first corner and the third corner is greater than or less than 90 degrees. The method of welding a bonding wire according to claim 3, wherein the bonding pad has a second corner region and a fourth corner region, and the second corner region and the fourth corner region respectively have a second corner and In the fourth corner, the solder pin pushes the solder ball to at least one of the first corner region to the fourth corner region. The method of welding a bonding wire according to claim 6, wherein the connection between the first corner and the second corner is orthogonal to the connection between the third corner and the fourth corner. The method of welding a bonding wire according to claim 6, wherein the connection between the first corner and the second corner is not orthogonal to the connection between the third corner and the fourth corner.