CN214588746U

CN214588746U - Wedge-shaped cleaver suitable for superfine-spacing wire bonding process

Info

Publication number: CN214588746U
Application number: CN202120246332.3U
Authority: CN
Inventors: 汤闵枫; 李唯韬; 郭东红; 彭福生; 刘军
Original assignee: XIAMEN HONGLU TUNGSTEN MOLYBDENUM INDUSTRY CO LTD
Current assignee: XIAMEN HONGLU TUNGSTEN MOLYBDENUM INDUSTRY CO LTD
Priority date: 2021-01-28
Filing date: 2021-01-28
Publication date: 2021-11-02
Anticipated expiration: 2031-01-28

Abstract

The utility model relates to a wedge chopper suitable for superfine spacing lead bonding technology, including cylindrical pole body, the bottom of pole body is wedge-shaped weld part, a welding boss has on the free end terminal surface of weld part, the setting is extended toward the direction of keeping away from the weld part free end to the axis direction of welding boss edge pole body, the width of welding boss is less than the width of weld part free end terminal surface, the breach portion of seting up along the length direction of this pole body has on the welding boss terminal surface, breach portion forms a lateral wall that is roughly parallel with the axial of pole body on the bottom of pole body, the working face has on the free end surface of welding boss, the pole body has along its axial follow the first wire feed hole of the top of pole body runs through to breach portion to and from the second wire feed hole that runs through to the working face of lateral wall slope.

Description

Wedge-shaped cleaver suitable for superfine-spacing wire bonding process

Technical Field

The utility model relates to a semiconductor package technical field specifically relates to a wedge chopper suitable for superfine spacing lead bonding technology.

Background

The lead bonding of the IC package is realized by fixing the leads on the bonding pads of the substrate by a cleaver in a thermosonic welding mode and conducting heat and ultrasonic energy, thereby realizing the tight connection of the leads. The wedge welding is the mainstream bonding mode in the high and new field because the welding spot is small and the fine-pitch lead bonding can be realized.

With the development of the chip industry, the arrangement pitch of leads on a chip is smaller and smaller, the ultra-fine pitch arrangement is generally defined as the pad center distance of 100 μm or less, the use of the traditional wedge-shaped chopper structure is often difficult to complete or easily causes problems, and the following defects exist:

1. in the lead bonding process, in order to ensure that the lead is connected with two welding spots with certain strength and is not easy to break and lose efficacy, the welded leads need to be arranged in an arch bridge manner. The transition mode of the traditional wedge-shaped riving knife structure from the rod body to the tip working face is to remove materials in a chamfering mode, so that the tip of the riving knife is conical, occupies more space above a bonding pad during bonding, and is difficult to reach an ultra-fine gap.

2. The traditional wedge-shaped cleaver structure which is conical occupies too large space above a chip, has no problem when the planar lead is bonded, but has the problem that the traditional wedge-shaped cleaver structure cannot stretch into the bottom of a deep cavity and a groove to be bonded in substrate structures such as the deep cavity and the groove, and has great limitation.

3. The wire penetrating part structure of the traditional wedge-shaped chopper lead consists of a first wire penetrating hole penetrating through a chopper rod body and a second wire penetrating hole forming a certain angle with a working surface.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a wedge riving knife suitable for superfine spacing lead bonding technology.

The specific scheme is as follows:

the wedge-shaped riving knife comprises a columnar knife body, wherein the bottom of the knife body is a wedge-shaped welding part, a welding boss is arranged on the end face of the free end of the welding part, the welding boss extends in the direction far away from the free end of the welding part along the axis direction of the knife body, the width of the welding boss is smaller than that of the end face of the free end of the welding part, a notch part which is arranged along the length direction of the knife body is arranged on the end face of the welding boss, the notch part forms a side wall which is approximately parallel to the axial direction of the knife body on the bottom end of the knife body, a working face is arranged on the free end face of the welding boss, a first wire penetrating hole which penetrates through the notch part from the top of the knife body along the axial direction of the knife body is arranged on the knife body, and a second wire penetrating hole which penetrates through the working face from the side wall in an inclined mode.

Furthermore, a third wire passing hole which is coaxial with the first wire passing hole is formed in one side, close to the notch portion, of the first wire passing hole, the inner diameter of the third wire passing hole is smaller than that of the first wire passing hole, and the first wire passing hole is in transitional connection with the third wire passing hole through a conical hole.

Further, the inner diameter of the third wire through hole is 3-5 times of the diameter of the lead.

Further, the surface roughness value of the inner wall of the third wire through hole is not more than Ra0.4.

Furthermore, the included angle between the second wire penetrating hole and the working surface is 45-52 degrees.

Furthermore, a square limiting groove communicated with the second wire feeding hole is formed in the position, close to the outlet of the second wire feeding hole, of the working surface, the cross section of the limiting groove is rectangular, and the width of the limiting groove is smaller than that of the working surface.

Furthermore, the width of the limiting groove is 1.5-2.5 times of the diameter of the lead.

Further, the length of the welding boss extending along the axial direction of the shaft is 70-100 μm.

The utility model provides a wedge chopper compares with prior art and has following advantage: the utility model provides a wedge chopper forms a welding boss on the weld part, and this welding boss has less width for current wedge chopper, therefore its applicable wire bonding that carries out on superfine interval pad, and pad centre-to-centre spacing (Wr) can reach 50 mu m and below.

Drawings

FIG. 1 shows a schematic perspective view of a wedge-shaped riving knife.

FIG. 2 shows an enlarged view of the weld of the wedge-shaped riving knife of FIG. 1.

FIG. 3 shows a schematic cross-sectional view of a wedge-shaped riving knife in one view.

FIG. 4 shows an enlarged view of the weld of the wedge-shaped riving knife of FIG. 3.

FIG. 5 shows a schematic cross-sectional view of a wedge-shaped riving knife in another view orientation.

FIG. 6 shows an enlarged view of the weld of the wedge-shaped riving knife of FIG. 5.

Detailed Description

To further illustrate the embodiments, the present invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

The present invention will now be further described with reference to the accompanying drawings and detailed description.

As shown in fig. 1-6, the wedge-shaped riving knife suitable for the ultra-fine pitch wire bonding process is provided in this embodiment, and includes a column-shaped shaft 10, where the bottom of the shaft 10 is a wedge-shaped welded portion, a welding boss 11 is provided on an end face of a free end of the welded portion, the welding boss 11 extends along an axial direction of the shaft 10 in a direction away from the free end of the welded portion, a length of the welding boss 11 extending along the axial direction of the shaft 10 is greater than a maximum height (Wh) of a wire, and the length may be designed according to actual working conditions, and is generally 70-100 μm, and may correspond to one specification per 10 μm.

And the width of the welding boss 11 is smaller than that of the free end face of the welding part, that is, a step structure is formed between the free end face of the welding part and the side face of the welding boss 11, so that the side wall of the welding boss 11 is retracted, the welding boss 11 can have a smaller width, and a smaller pad center distance (Wr) can be realized in the welding process.

The end face of the welding boss 11 is provided with a notch part 12 which is opened along the length direction of the shaft 10, the notch part 12 forms a side wall 121 which is approximately parallel to the axial direction of the shaft 10 on the bottom end of the shaft 10, and the free end face of the welding boss 11 is provided with a working face 110.

The shaft 10 has a first threading hole 101 penetrating from the tip of the shaft 10 to the cut-out portion 12 in the axial direction thereof, and a second threading hole 102 penetrating from the side wall 121 to the working surface 110 at an angle. In the present embodiment, the first threading hole 101 and the second threading hole 102 are through holes each having a circular cross section.

In the welding process of the wedge-shaped riving knife provided by the embodiment, the welding boss 11 has smaller width compared with the existing wedge-shaped riving knife, so that the wedge-shaped riving knife can be suitable for carrying out wire bonding on ultra-fine-pitch welding pads, and the center distance (Wr) of the welding pads can reach 50 mu m or below.

In this embodiment, a third wire passing hole 103 is disposed on a side of the first wire passing hole 101 close to the notch portion 12, the third wire passing hole 103 being coaxial with the first wire passing hole 101, and an inner diameter of the third wire passing hole 103 is smaller than an inner diameter of the first wire passing hole 101, so as to limit a moving range of the lead, so that the lead is led out to the notch portion 12 and then is closer to the side wall 121, thereby preventing the lead from being suspended outside the riving knife and interfering with other leads or structures on the chip to cause wire breakage.

Preferably, the inner diameter of the third threading hole 103 is designed according to the selected diameter of the lead, and the inner diameter thereof is preferably 3 to 5 times of the selected diameter of the lead, in order to prevent damage to the lead, more preferably, the surface roughness value of the inner wall of the third threading hole 103 should not exceed ra0.4, and the first threading hole 101 and the third threading hole 103 are transited by a tapered hole to prevent unsmooth threading.

In this embodiment, the included angle between the second wire hole 102 and the working surface 110 is preferably selected to be 45 ° to 52 °, so that the wire can be closer to the side wall 121 after passing through the third wire hole 103, so as to avoid wire breakage caused by the wire being suspended outside the riving knife and interfering with other wires or structures on the chip.

In this embodiment, the working surface 110 is provided with a square limiting groove 104 communicating with the second wire feeding hole 102 at a position close to the outlet of the second wire feeding hole 102, the cross section of the limiting groove 104 is substantially rectangular, the width of the limiting groove 104 is smaller than the width of the working surface 110, preferably 1.5-2.5 times the diameter of the lead, and the limiting groove 104 can limit the moving range of the lead at the working surface to prevent the problem of wire breakage caused by interference between leads with ultra-fine pitches.

It should be understood that, although the wedge-shaped chopper provided by the present invention is more advantageous in the ultra-fine pitch wire bonding process (the pad center distance is 100 μm or less), it can also be applied to the wire bonding process in which the pad center distance exceeds 100 μm.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A wedge-shaped cleaver suitable for a superfine spacing wire bonding process is characterized in that: including columnar pole body, the bottom of pole body is wedge-shaped weld part, a welding boss has on the free end terminal surface of weld part, the setting is extended toward the direction of keeping away from the weld part free end along the axis direction of pole body to welding boss, the width of welding boss is less than the width of weld part free end terminal surface, have the breach portion of seting up along the length direction of this pole body on the welding boss terminal surface, breach portion forms a lateral wall that is roughly parallel with the axial of pole body on the bottom of pole body, working face has on the free end surface of welding boss, have on the pole body along its axial follow the first wire feed hole of the top of pole body run through to breach portion to and from the slope of lateral wall run through to the second wire feed hole on the working face.

2. The wedge riving knife of claim 1 wherein: one side of the first wire penetrating hole, which is close to the notch portion, is provided with a third wire penetrating hole which is coaxial with the first wire penetrating hole, the inner diameter of the third wire penetrating hole is smaller than that of the first wire penetrating hole, and the first wire penetrating hole is in transitional connection with the third wire penetrating hole through a conical hole.

3. The wedge riving knife of claim 2 wherein: the inner diameter of the third wire through hole is 3-5 times of the diameter of the lead.

4. The wedge riving knife of claim 2 wherein: the surface roughness value of the inner wall of the third wire penetrating hole is not more than Ra0.4.

5. The wedge riving knife of claim 1 wherein: the included angle between the second wire penetrating hole and the working surface is 45-52 degrees.

6. The wedge riving knife of claim 1 wherein: the working face is provided with a square limiting groove communicated with the second wire penetrating hole at a position close to the outlet of the second wire penetrating hole, the cross section of the limiting groove is rectangular, and the width of the limiting groove is smaller than that of the working face.

7. The wedge riving knife of claim 6 wherein: the width of the limiting groove is 1.5-2.5 times of the diameter of the lead.

8. The wedge riving knife of claim 1 wherein: the length of the welding boss extending along the axial direction of the shaft body is 70-100 mu m.