Wire arc bonding structure of sinking base island

Abstract

The utility model relates to a wire arc bonding structure of a sinking base island, which comprises a chip and a pin, a bonding wire is connected between the chip and the pin, and the bonding wire is composed of a plurality of wire arcs. The included angles between the adjacent wire arcs are the same, the bonding wire is sequentially composed of a first-section wire arc, a middle wire arc and a tail-section wire arc, one end of the first-section wire arc is connected with the chip, one end of the tail-section wire arc is connected with the pin, the included angle between the first-section wire arc and the chip is x, the included angle between one end of the tail-section wire arc and the pin is z, and the included angle between the adjacent wire arcs is theta. According to the utility model, the shock resistance is improved; and a bending structure is additionally arranged, so that line arc deflection is prevented.

Description

Technical Field

[0001] The utility model belongs to the technical field of chip manufacturing and relates to a wire arc bonding structure of a sinking base island. Background Art

[0002] Chip bonding is an important step in chip packaging. The chip will generate heat during use. In order to improve the heat dissipation performance of the packaging structure, the deep island circuit came into being. However, the problem of wire arc in the operation of the deep island circuit needs to be solved. If the wire arc is too loose, it will cause the wire arc to deviate during the plastic packaging operation. Figure 3 As shown, a tight wire arc will lead to a higher risk of wire breakage, so the wire arc and bonding parameters need to be redesigned.

[0003] Causes of vibration: 1. The lead frame pins are made of elastic materials, which will shake up and down when subjected to force; 2. The lead frame will expand and contract when heated, generating stress. When vibration occurs, the pins will shake up and down to create a gap, and the wire arc will be tightened and broken. Summary of the invention

[0004] The utility model aims to provide a wire arc bonding structure of a sinking base island, which can solve the above-mentioned problems and prevent the wire arc from deflecting.

[0005] According to the technical solution provided by the utility model: a wire arc bonding structure of a sunken base island includes a chip and a pin, a welding wire is connected between the chip and the pin, and the welding wire is composed of several wire arcs; the angles between adjacent wire arcs are the same.

[0006] As a further improvement of the utility model, the welding wire is composed of a first arc segment, a middle arc segment and a last arc segment in sequence.

[0007] As a further improvement of the utility model, one end of the first arc is connected to the chip.

[0008] As a further improvement of the utility model, one end of the last arc is connected to the pin.

[0009] As a further improvement of the utility model, the angle between the first arc segment and the chip is x, the angle between one end of the last arc segment and the pin is z, and the angle between adjacent arc segments is θ, sin(x):2sin(θ / 2):2sin(θ / 2):2sin(θ / 2):sin(z)=1:2:2:2:1.

[0010] As a further improvement of the present invention, the angle range of x is 85°-90°.

[0011] As a further improvement of the present invention, the angle range of z is 90°-95°.

[0012] As a further improvement of the present invention, the number of the intermediate arcs is 3, and the angle θ is 165°. The positive and progressive effects of the present application are:

[0013] The utility model improves the anti-seismic ability and adds a bending structure to prevent the arc from falling. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model.

[0015] Figure 2 It is a schematic diagram of the arc generation process of the utility model.

[0016] Figure 3 This is an X-Raθ photograph of the inverted arc in the prior art.

[0017] Figure 4 This is an X-Raθ photo of the normal arc of the utility model.

[0018] Figure 1-Figure 4 In the figure, it includes chip 1, pin 2, welding wire 3, wire arc 3-1, etc. DETAILED DESCRIPTION

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] In order to enable those skilled in the art to better understand the solution of the utility model, the following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the utility model described herein. In addition, similar terms such as "including" and "having" mean that in addition to those contents already listed in "including" and "having", other contents that have not been listed can also be "included" and "having"; for example, a process, method, system, product or device that can include a series of steps or units is not necessarily limited to those steps or units that have been clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0022] Due to the angle of the drawing, some components may not be drawn, but their positions and connection relationships can be partially understood based on the text expression.

[0023] like Figure 1 As shown, the utility model is a wire arc bonding structure of a sunken base island, comprising a chip 1 and a pin 2, a bonding wire 3 connecting the chip 1 and the pin 2, and the bonding wire 3 is composed of several wire arcs 3-1.

[0024] In order to ensure uniform distribution of force and achieve the best anti-deflection effect, the angles between adjacent arcs 3-1 are the same.

[0025] The bonding wire 3 is composed of a first arc segment, a middle arc segment, and a last arc segment in sequence. One end of the first arc segment is connected to the chip 1 , and one end of the last arc segment is connected to the pin 2 .

[0026] In arc design, half of the angle is used as the ratio to ensure uniform distribution of arc length and angle. This is because the relationship between arc length and angle is nonlinear, and arcs of different lengths can have different shapes even if the angle is the same. By using half of the angle θ as the ratio, the parameters of the sine function can be controlled within the range of 0° to 90°, which ensures that the value range of the sine function is between 0 and 1, that is, sin(θ / 2) in the formula. The benefit of this design is that the value of the sine function can be used as the ratio of the length of each part of the arc, thereby achieving a more uniform length distribution.

[0027] When designing the length ratio of the middle sections, it is hoped that the arc's anti-deflection ability can be enhanced by properly allocating the length. When the length ratio of the middle sections is set to 2, it means that the length of the arc is distributed more concentratedly, making the length of the middle sections longer than the first and last sections. This design allows the middle sections to have more material to withstand external stress, thereby enhancing the arc's anti-deflection ability.

[0028] Therefore, relative to a length ratio of 1, increasing the length ratio of the middle segments to 2 will make the arc more resistant to deflection, because the middle segments can better share the external stress and reduce deformation and deflection of the arc.

[0029] Assume that each bending angle is θ, since the angle between the first arc and chip 1 is x, the angle range of x is 85°-90°, the angle between one end of the last arc and pin 2 is z, the angle range of z is 90°-95°, and the angle between adjacent arcs 3-1 is θ, since the angles x and z are fixed. Then the length ratio of each of the five arcs can be approximated as:

[0030] sin(x):2sin(θ / 2):2sin(θ / 2):2sin(θ / 2):sin(z)=1:2:2:2:1. According to the actual chip and wire bonding data, the angle of θ can be obtained.

[0031] This design helps to balance the stress distribution at each bending point and improve the overall anti-deflection effect.

[0032] In this embodiment, the number of the intermediate arcs is 3, and the angle θ is 165°.

[0033] The working process of the utility model is as follows:

[0034] The splitter moves from the first solder joint A of the chip to the first moving point B, the second moving point C, the third moving point D, the fourth moving point E, the fifth moving point F, the sixth moving point G, the seventh moving point H, the eighth moving point I, the ninth moving point J, the tenth moving point K, the eleventh moving point L, and the second solder joint M on the pin. The specific path is as follows Figure 2 shown.

[0035] A: First welding point;

[0036] B: first moving point;

[0037] C: second moving point;

[0038] D: third moving point;

[0039] E: fourth moving point;

[0040] F: fifth moving point;

[0041] G: Sixth moving point;

[0042] H: Seventh moving point;

[0043] I: Eighth moving point;

[0044] J: Ninth moving point;

[0045] K: tenth moving point;

[0046] L: eleventh moving point;

[0047] M: second welding point;

[0048] L: The highest point of the cleaver;

[0049] P: height difference between the first solder joint and the second solder joint, X≤80mils;

[0050] L1: The height of the first lift after the wedge is bonded to the first solder joint;

[0051] L2: Horizontal distance traveled by the reverse displacement of the riving cutter;

[0052] L3: The height at which the cleaver is lifted for the second time;

[0053] L4: The cleaver is raised for the third time;

[0054] L5: The cleaver is raised for the fourth time;

[0055] L6: The cleaver is raised for the fifth time;

[0056] L7: The cleaver is raised for the sixth time;

[0057] CD-CE: When the riving knife is lifted for the second time, it is simultaneously deflected in the reverse direction by a set angle α;

[0058] EF-EG: When the riving knife is lifted for the third time, it is simultaneously deflected in the reverse direction by a set angle β;

[0059] GH-GI: When the riving knife is lifted for the fourth time, it is simultaneously deflected in the reverse direction by a set angle γ;

[0060] IJ-IK: When the riving knife is lifted for the fifth time, it is simultaneously deflected in the reverse direction by a set angle θ.

[0061]

[0062] The utility model technology can improve the line arc break rate from 2000ppm to less than 100ppm, ensure the line arc deflection rate of the plastic sealing project is less than 7%, and is suitable for sinking base island circuits.

[0063] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A wire arc bonding structure with a sunken base island, comprising a chip (1) and a lead (2), characterized in that: A welding wire (3) is connected between the chip (1) and the pin (2), and the welding wire (3) is composed of a plurality of line arcs (3-1); and the angles between adjacent line arcs (3-1) are the same.

2. The wire arc bonding structure of the sunken base island according to claim 1, characterized in that: The welding line (3) is composed of a first arc segment, a middle arc segment, and a last arc segment in sequence.

3. The wire arc bonding structure of the sunken base island according to claim 1, characterized in that: One end of the first arc is connected to the chip (1).

4. The wire arc bonding structure of the sunken base island according to claim 1, characterized in that: One end of the last wire arc is connected to pin (2).

5. The wire arc bonding structure of the sunken base island according to claim 1, characterized in that: The angle between the first arc and the chip (1) is x, the angle between one end of the last arc and the pin (2) is z, and the angle between adjacent arcs (3-1) is θ, sin(x): 2sin(θ / 2): 2sin(θ / 2): 2sin(θ / 2): sin(z) = 1:2:2:2:

1.

6. The wire arc bonding structure of the sunken base island according to claim 5, characterized in that: The x angle ranges from 85° to 90°.

7. The wire arc bonding structure of the sunken base island according to claim 5, characterized in that: The z angle ranges from 90° to 95°.

8. The wire arc bonding structure of the sunken base island according to claim 1, characterized in that: The number of intermediate arcs is 3, and the angle θ is 165°.

Images