阅读说明：本技术 一种提升引线键合精度的楔形劈刀结构 (Wedge-shaped cleaver structure for improving lead bonding precision ) 是由 贾斌 王辉 庞婷 文泽海 张平升 董东 李慧 李悦 徐榕青 毛小红 董江 伍泽 于 2021-07-27 设计创作，主要内容包括：本发明涉及微电子封装技术领域,具体公开了一种提升引线键合精度的楔形劈刀结构,包括刀柄、与刀柄一端连接的刀头；所述刀头上设置有键合引线过孔,所述键合引线过孔包括设置在刀头侧面的导向孔、与导向孔连通的椭圆通孔。本发明有效的限制键合引线水平方向可移动的范围,避免键合引线在键合引线过孔中发生偏移；可使键合过程中键合引线始终处于劈刀刀头端面正中；有效的提升键合引线键合的精度。(The invention relates to the technical field of microelectronic packaging, and particularly discloses a wedge-shaped riving knife structure for improving lead bonding precision, which comprises a knife handle and a knife head connected with one end of the knife handle; the cutter head is provided with a bonding lead through hole, and the bonding lead through hole comprises a guide hole arranged on the side surface of the cutter head and an oval through hole communicated with the guide hole. The invention effectively limits the movable range of the bonding lead in the horizontal direction and avoids the bonding lead from deviating in the bonding lead through hole; the bonding lead can be always positioned in the center of the end surface of the cutter head of the riving knife in the bonding process; the bonding precision of the bonding wire is effectively improved.)

1. A wedge-shaped riving knife structure for improving the lead bonding precision comprises a knife handle and a knife head connected with one end of the knife handle; the tool bit is characterized in that a bonding lead through hole is formed in the tool bit and comprises a guide hole formed in the side face of the tool bit and an oval through hole communicated with the guide hole.

2. The wedge-shaped riving knife structure for improving the wire bonding precision of claim 1, wherein the tool bit is wedge-shaped, and one end of the tool bit, which is far away from the tool holder, is provided with a bonding surface, a bottom surface and a groove arranged in front of the bottom surface and the bonding surface; and the bottom surface is provided with a side of the bonding lead through hole far away from the tool shank.

3. The wedge-shaped riving knife structure for improving the bonding accuracy of a wire as claimed in claim 2 wherein said groove includes a first inclined surface connected to the bottom surface, a second inclined surface connected to the bonding surface; one end of the oval through hole, which is far away from the guide, is arranged on the first inclined plane, and the long-sleeve direction of the oval through hole is vertical to the bottom surface.

4. The wedge-shaped riving knife structure for improving the bonding accuracy of a wire as claimed in claim 1, wherein the length of the minor axis of the elliptical through hole is 1.5-2 times the diameter of the bonding wire.

5. The wedge-shaped riving knife structure for improving the wire bonding precision of claim 4, wherein the length of the major axis of the elliptical through hole is 3-4 times the diameter of the bonding wire.

6. The wedge-shaped riving knife structure for improving the bonding accuracy of a lead as claimed in claim 1, wherein the guiding hole is trumpet-shaped, and the small end of the guiding hole is communicated with the oval through hole.

7. The wedge-shaped riving knife structure of claim 6 wherein the pilot hole is coaxial with the elliptical through hole.

Technical Field

The invention relates to the technical field of microelectronic packaging, in particular to a wedge-shaped riving knife structure for improving wire bonding precision.

Background

In the field of microelectronic packaging, bonding wire bonding is generally adopted to realize electrical interconnection between unpackaged integrated circuit chips and between chips and peripheral circuits, and a wedge-shaped welding process has the characteristics of high welding density, small welding spot size, low-radian interconnection, deep-cavity welding, small parasitic effect and the like, and is one of the commonly used bonding wire bonding methods. The wedge cleaver is an important tool in the wedge bonding process and directly determines the density of bonding wires and the quality of a bonded product.

The wedge-shaped riving knife is used for bonding, in order to ensure bonding precision and bonding quality, a bonding lead is positioned in the center of the end face of the riving knife head in the bonding process, the bonding precision is affected when the bonding lead deviates from the center of the end face of the riving knife head, and bonding welding spots exceed a bonding pad when the bonding lead is serious. After passing through the bonding wire through hole, the bonding wire is positioned at the end face of the cutter head of the riving knife, and in order to ensure that the wire is smoothly threaded for the first time and the wire is smoothly discharged in the bonding process, the size of the bonding wire through hole (bonding wire through hole) is usually twice of the diameter of the bonding wire. In the bonding process, the riving knife pulls the bonding wire to move, and the bonding wire moves (mainly horizontally swings) in the through hole due to the fact that the diameter of the through hole of the bonding wire is far larger than that of the bonding wire, so that the bonding wire deviates from the center of the end face of the tool bit of the riving knife, and welding precision is affected. If the bonding wire through hole is reduced, the wire threading difficulty and the unsmooth wire feeding in the bonding process can be caused.

Chinese patent CN 107052557A discloses a welded ceramic chopper with a coating, which prevents the inner surface of the ceramic chopper from being adhered with a bonding lead by adding the coating on the inner surface of the ceramic chopper; chinese patent CN107275243A discloses a welded chopper and a preparation method thereof, wherein the ultrasonic transmission efficiency is improved by arranging a passage of a cylindrical groove and a conical groove at the middle part of the chopper, and a groove is designed at the position of a knife mouth to avoid material residue; chinese patent CN 107710394A discloses a welding chopper, which realizes the purposes of improving bonding strength, improving filament truncation and inhibiting abrasion by the precise design of the end of the chopper; chinese patent CN108389806A discloses a ceramic cleaver for improving bonding strength of a bonding wire, and the surface structure of the cleaver is designed to improve bonding effect and bonding stability; chinese patent CN 109332901A discloses a ceramic cleaver, a manufacturing method and application thereof, and the service life and welding effect of the cleaver are improved by laser bombardment treatment.

The structure and the performance of the wedge chopper are improved, the service life of the wedge chopper and the welding effect are improved compared with the prior art, but the improvement of the wedge chopper bonding precision is not involved.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a wedge-shaped riving knife structure for improving the bonding precision of a lead; the movable range of the bonding lead in the horizontal direction is effectively limited, and the bonding lead is prevented from shifting in the bonding lead through hole; the bonding lead can be always positioned in the center of the end surface of the cutter head of the riving knife in the bonding process; the bonding precision of the bonding wire is effectively improved.

The technical problem to be solved by the invention is as follows:

a wedge-shaped riving knife structure for improving the lead bonding precision comprises a knife handle and a knife head connected with one end of the knife handle; the cutter head is provided with a bonding lead through hole, and the bonding lead through hole comprises a guide hole arranged on the side surface of the cutter head and an oval through hole communicated with the guide hole.

Compared with the prior art, the circle center through hole is replaced by the oval through hole, in the bonding process of the bonding lead, the bonding lead correspondingly bears a downward or upward force in the upward or downward movement process of the chopper, the bonding lead is positioned below or above the bonding lead through hole, the upper and lower directions of the oval through hole are gradually narrowed, the horizontal swinging of the bonding lead in the oval through hole in the bonding process can be effectively avoided, the bonding lead is always positioned in the center of the end face of the cutter head of the chopper, the bonding error caused by the swinging of the bonding lead is prevented, and the bonding precision of the lead can be effectively improved.

In some possible embodiments, the tool bit is in a wedge-shaped structure, and one end of the tool bit, which is far away from the tool shank, is provided with a bonding surface, a bottom surface and a groove arranged in front of the bottom surface and the bonding surface; and the bottom surface is provided with a side of the bonding lead through hole far away from the tool shank.

In some possible embodiments, the groove includes a first slope connected to the bottom surface, a second slope connected to the bonding surface; one end of the oval through hole, which is far away from the guide, is arranged on the first inclined plane, and the long-sleeve direction of the oval through hole is vertical to the bottom surface.

In some possible embodiments, the length of the minor axis of the elliptical through hole is 1.5 to 2 times the diameter of the bonding wire.

In some possible embodiments, the length of the major axis of the elliptical through hole is 3-4 times the diameter of the bonding wire.

In some possible embodiments, the pilot hole is flared, the small end of which communicates with the oval through hole.

In some possible embodiments, the pilot hole is coaxial with the elliptical through hole.

Compared with the prior art, the invention has the beneficial effects that:

the oval through hole is arranged, so that the swinging distance of the bonding lead in the horizontal direction in the oval through hole in the bonding process is effectively avoided, and the bonding lead is always positioned in the middle of the end face of the cutter head of the riving knife; the bonding precision is effectively improved;

the invention effectively limits the length of the major axis and the length of the minor axis of the elliptical through hole, thereby effectively avoiding the wire clamping in the bonding process;

the invention can effectively guide the bonding lead by arranging the guide hole into the horn shape.

Drawings

FIG. 1 is a schematic cross-sectional view of a cutting head according to the present invention;

FIG. 2 is a schematic view showing a structural relationship between an oval through hole, a first inclined surface, a bottom surface and a bonding wire according to the present invention;

FIGS. 3 and 4 are schematic views showing relative positions of bonding wires and elliptical through holes when bonding the bonding wires according to the present invention;

wherein: 1. a cutter head; 11. a first inclined plane; 12. a bottom surface; 2. bonding a lead; 3. an elliptical through hole; 4. and (4) a guide hole.

Detailed Description

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; either directly or indirectly through intervening media, either internally or in any other relationship. Reference herein to "first," "second," and similar words, does not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. In the implementation of the present application, "and/or" describes an association relationship of associated objects, which means that there may be three relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In the description of the embodiments of the present application, the meaning of "a plurality" means two or more unless otherwise specified. For example, the plurality of positioning posts refers to two or more positioning posts. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The present invention will be described in detail below.

As shown in fig. 1-4:

a wedge-shaped riving knife structure for improving the bonding precision of a lead comprises a knife handle and a knife head 1 connected with one end of the knife handle; the tool bit 1 is provided with a bonding lead 2 through hole, and the bonding lead 2 through hole comprises a guide hole 4 arranged on the side surface of the tool bit 1 and an oval through hole 3 communicated with the guide hole 4.

In some possible embodiments, the tool bit 1 has a wedge-shaped structure, and one end of the wedge-shaped structure, which is far away from the tool shank, is provided with a bonding surface, a bottom surface 12 and a groove arranged in front of the bottom surface 12 and the bonding surface; and the bottom surface 12 is provided with one side of the bonding lead 2 through hole far away from the tool shank.

In some possible embodiments, the groove comprises a first bevel 11 connected to the bottom surface 12, a second bevel connected to the bonding surface; one end of the oval through hole 3, which is far away from the guide, is arranged on the first inclined plane 11, and the long-sleeve direction of the oval through hole is perpendicular to the bottom plane 12.

Preferably, the included angle formed by the oval through hole 3 and the extending surface of the end surface bonding surface side facing the bottom surface 12 of the tool bit 1 is 45 degrees.

In some possible embodiments, the length of the minor axis of the elliptical through hole 3 is 1.5 to 2 times the diameter of the bonding wire 2.

In some possible embodiments, the length of the major axis of the elliptical through hole 3 is 3 to 4 times the diameter of the bonding wire 2.

The size of the oval through hole 3 is limited, so that the wire clamping condition can be effectively guaranteed not to occur in the bonding process.

In some possible embodiments, the pilot hole 4 is flared, the small end of which communicates with the oval through hole 3.

In some possible embodiments, the guide hole 4 is coaxial with the elliptical through hole 3.

Compared with the prior art, the circle center through hole is replaced by the oval through hole, in the bonding process of the bonding lead 2, the bonding lead 2 correspondingly bears a downward or upward force in the upward or downward movement process of the chopper, the bonding lead 2 is positioned below or above the oval through hole 3, the upper and lower sides of the oval through hole 3 are gradually narrowed, the horizontal swinging of the bonding lead 2 in the oval through hole 3 in the bonding process can be effectively avoided, the bonding lead 2 is always positioned in the middle position of the end face of the chopper bit 1, the bonding error caused by the swinging of the bonding lead 2 is prevented, and the bonding precision of the lead can be effectively improved.

As shown in fig. 3, after the chopper completes the bonding of the first solder joint on the substrate, the chopper starts to move upward to make the bonding wire 2 form a certain radian, and at this time, the bonding wire 2 is positioned below the elliptical through hole 3, and the elliptical structure can effectively limit the horizontal swing of the bonding wire 2;

as shown in fig. 4, when the chopper moves upward to form an arc of the bonding wire 2, the chopper starts to drive the bonding wire 2 to move downward, and moves to another substrate to bond and complete a second welding point, and in the downward movement process of the chopper, the bonding wire 2 is located above the elliptical through hole 3, and the elliptical structure can effectively limit the horizontal swing of the bonding wire 2.

According to the analysis, in the whole riving knife bonding motion process, the bonding lead 2 is always positioned above or below the oval through hole 3, and the oval through hole 3 can effectively limit the swing of the bonding lead 2 in the horizontal direction, so that the bonding lead 2 is always positioned in the center of the end face of the riving knife head 1, and the bonding precision can be effectively improved.

When the bonding wire 2 is bonded by adopting the method, under the condition that other structures are the same and only the center of a circle is used for replacing the through hole 3, compared with a cleaver adopting the center of a circle is used for passing through the through hole, the welding precision of the method is improved from +/-10 microns to +/-6 microns, and the effect of improving the bonding precision is obvious.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.