Method for Forming WB Metal Wire and Straight Metal Bonding Wire

Abstract

The present invention provides a WB metal wire and a method for forming a straight metal bonding wire. The WB metal wire includes a metal wire notch that extends from the surface of the WB metal wire towards the radial direction of the WB metal wire, so as to reduce the radial dimension of the WB metal wire through the metal wire notch. Thus, when performing the wire bonding process, only one solder joint can be formed, and then through stretching, the WB metal wire is disconnected from the metal wire notch to form a straight metal bonding wire, improving the UPH of the manufacturing process and the product quality.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and particularly to a method for forming a WB metal wire and a straight metal bonding wire. Background Art

[0002] As the functions of integrated circuits become more powerful, and their performance and integration level become higher, packaging technology plays an increasingly important role in integrated circuit products. Lower cost, more reliable, faster, and higher density circuits are the goals pursued by integrated circuit packaging.

[0003] In the existing semiconductor packaging process, the wire bonding process (WB) is one of the most important and challenging process steps. Considering the requirements of the special functions of the package, the bonding wires located in the package usually need to be designed as straight lines. However, the bonding wires currently used in the industry are formed by multiple draws of wire columns to have a certain wire diameter and a smooth surface. And when performing wire bonding, it is necessary to use the method of making the second bond (2nd Bond), that is, by using a special wire bonder, first semi-cut the bonding wire by the 2nd Bond method, and then stretch and cut the bonding wire to form the required wire shape. But using the 2nd Bond wire bonding process, the UPH of the process is low, and since the bonding wire is bent, a straight bonding wire that meets the requirements cannot be formed after stretching, and during the stretching process of the bonding wire, quality problems such as poor bonding of the bonding wire are likely to occur.

[0004] In recent years, the development and production technologies of semiconductor chips have developed very rapidly. The number of internal connections in a single chip is increasing and becoming more complex, and the area allowed for welding each internal connection is also shrinking accordingly. The changes in all these key technical parameters mean that the wire bonding process technology needs a comprehensive improvement and enhancement to meet the new requirements. Among them, the comprehensive improvement and enhancement of the wire bonding process will include the improvement of the corresponding wire bonding raw materials, the optimization of process parameters, and the overall quality control.

[0005] Therefore, it is necessary to provide a new type of WB metal wire and a method for forming a straight metal bonding wire. Summary of the Invention

[0006] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a WB metal wire and a method for forming a straight metal bonding wire, which are used to solve the problems of UPH and quality caused by forming a straight bonding wire in the prior art.

[0007] To achieve the above object and other related objects, the present invention provides a WB metal wire, wherein the WB metal wire includes a metal wire notch, and the metal wire notch extends from the surface of the WB metal wire to the radial direction of the WB metal wire to reduce the radial dimension of the WB metal wire through the metal wire notch.

[0008] Optionally, the metal wire incision includes a groove, and the cross-sectional morphology of the groove includes one or a combination of V-shaped, U-shaped, square, and trapezoidal shapes.

[0009] Optionally, when there is only 1 such groove in a radial cross-section of the WB metal wire, the range of the percentage of the depth of the groove to the diameter of the WB metal wire includes 20% to 80%.

[0010] Optionally, the WB metal wire includes N≥2 such grooves in a radial cross-section, and the N grooves are symmetrically distributed.

[0011] Optionally, the metal wire incision includes an annular groove, and the cross-sectional morphology of the annular groove includes one or a combination of V-shaped, U-shaped, square, and trapezoidal shapes.

[0012] Optionally, the metal wire incision includes a through hole penetrating the WB metal wire, and the cross-sectional morphology of the through hole includes one or a combination of circular and polygonal shapes.

[0013] Optionally, in the axial direction of the WB metal wire, there is an equal spacing between adjacent metal wire incisions.

[0014] Optionally, the WB metal wire includes one of Cu wire, Au wire, Cu alloy wire, Au alloy wire, and Cu / Au alloy wire.

[0015] The present invention also provides a method for forming a straight metal bonding wire, including the following steps:

[0016] Providing any one of the above-mentioned WB metal wires;

[0017] Providing a chip, the surface of the chip includes bonding pads;

[0018] Connecting the WB metal wire to the bonding pad to form a solder joint;

[0019] Stretching the WB metal wire from the solder joint so that the WB metal wire breaks at the metal wire incision.

[0020] Optionally, the range of the angle between the straight metal bonding wire and the surface of the chip includes 45° to 90°.

[0021] Optionally, it further includes the steps of forming a packaging layer covering the chip and the straight metal bonding wire, and thinning the packaging layer to expose the straight metal bonding wire.

[0022] As described above, in the method for forming the WB metal wire and the straight metal bonding wire of the present invention, the WB metal wire includes a metal wire notch, and the metal wire notch extends from the surface of the WB metal wire to the radial direction of the WB metal wire, so as to reduce the radial size of the WB metal wire through the metal wire notch. Thus, when performing the bonding wire process, only one solder joint can be formed, and then through stretching, the WB metal wire is disconnected from the metal wire notch to form a straight metal bonding wire, improving the UPH of the manufacturing process and the product quality can also be improved. Description of the Drawings

[0023] Figures 1a to 1d It shows an axial sectional structural schematic diagram of a WB metal wire including a groove in the present invention.

[0024] Figure 2 It shows Figure 1a an enlarged structural schematic diagram of the A-A' cross-section in

[0025] Figure 3 It shows an axial sectional structural schematic diagram of the WB metal wire in the present invention.

[0026] Figures 4a to 4c It shows Figure 3 an enlarged structural schematic diagram of the B-B' cross-section in

[0027] Figure 5 It shows an axial sectional structural schematic diagram of a WB metal wire including a through hole in the present invention.

[0028] Figure 6 It shows Figure 5 an enlarged structural schematic diagram of the C-C' cross-section in

[0029] Figure 7 It shows a process flow schematic diagram of the method for forming the straight metal bonding wire in the present invention.

[0030] Figure 8 It shows a schematic diagram of the formation process of the straight metal bonding wire in the present invention.

[0031] Figure 9 It shows a structural schematic diagram after forming the encapsulation layer in the present invention.

[0032] Figure 10 It shows a structural schematic diagram after thinning the encapsulation layer in the present invention.

[0033] Description of Component Labels

[0034] 100 WB metal wire

[0035] 101 Metal wire notch

[0036] 200 Chip

[0037] 201 Pad

[0038] 300 Solder Joint

[0039] 400 Straight Metal Bonding Wire

[0040] 500 Bonding Tool

[0041] 600 Encapsulation Layer

[0042] X - Axis Direction

[0043] Y - Radial Direction

[0044] D - Running Direction

[0045] θ - Included Angle Specific Embodiment

[0046] The following uses specific examples to illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0047] Please refer to Figure 1~ Figure 10 . It should be noted that the illustrations provided in this embodiment only schematically illustrate the basic concept of the present invention. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0048] This embodiment provides a WB metal wire. The WB metal wire includes a metal wire notch that extends from the surface of the WB metal wire to the radial direction of the WB metal wire to reduce the radial size of the WB metal wire through the metal wire notch. Thus, when performing the wire bonding process subsequently, only one solder joint can be formed, and then through stretching, the WB metal wire is broken at the metal wire notch to form a straight metal bonding wire, thereby improving the UPH of the manufacturing process and improving the product quality.

[0049] Specifically, as Figure 1a, a WB metal wire 100 is provided. The WB metal wire 100 includes an axial direction X and a radial direction Y. The WB metal wire 100 includes a wire incision 101. The wire incision 101 extends from the surface of the WB metal wire 100 towards the radial direction Y of the WB metal wire 100 to reduce the radial dimension of the WB metal wire 100 through the wire incision 101. Among them, the specific wire diameter of the WB metal wire 100 can be selected as needed, and no limitation is made here. The formation method of the wire incision 101 can be selected as needed, such as the laser method, mechanical cutting method, etc., and no limitation is made here.

[0050] As a further embodiment of this embodiment, the wire incision 101 includes a groove. The cross-sectional morphology of the groove includes one or a combination of V-shaped, U-shaped, square-shaped, and trapezoidal shapes.

[0051] Specifically, such as Figures 1a to 1d and Figure 2 , among which, Figure 2 schematically shows Figure 1a an enlarged structural schematic diagram of the A-A' cross-section in. Among them, the WB metal wire 100 may include only 1 such groove in a radial Y cross-section, and the cross-sectional morphology of the groove may include V-shaped (such as Figure 1a ), U-shaped (such as Figure 1b ), square-shaped (such as Figure 1c ), and trapezoidal (such as Figure 1d ). Along the axial direction X of the WB metal wire 100, preferably the grooves have the same morphology. Of course, the grooves may also include one of the combinations formed by V-shaped, U-shaped, square-shaped, and trapezoidal shapes, and no excessive limitation is made here.

[0052] As a further embodiment of this embodiment, when the WB metal wire 100 includes only 1 such groove in a radial Y cross-section, the range of the percentage of the depth of the groove to the diameter of the WB metal wire includes 20% to 80%.

[0053] Specifically, when the percentage is 20%, the stability of the WB metal wire 100 can be improved, the probability of breakage of the WB metal wire 100 can be reduced, so as to reduce the time for threading the split blade consumed due to the breakage of the WB metal wire 100; when the percentage is 80%, the process difficulty of disconnecting the WB metal wire 100 from the wire incision 101 subsequently can be reduced. Combining the process requirements, in this embodiment, it is preferred that the percentage of the depth of the groove to the diameter of the WB metal wire 100 is 50% to reduce the process difficulty of disconnecting the WB metal wire 100 on the premise of meeting the stability of the WB metal wire 100. The value of this ratio is not limited to this, and can be selected according to the specific material and size of the WB metal wire 100, such as 30%, 45%, 60%, etc.

[0054] As a further embodiment of this embodiment, the WB wire 100 may include N≥2 of the grooves in a radial Y cross-section, and the N grooves are symmetrically distributed.

[0055] Specifically, such as Figure 3 , Figure 4a and Figure 4b , where Figure 4a and Figure 4b are shown as Figure 3 two enlarged schematic structural diagrams of the B-B' cross-section in

[0056] As a further embodiment of this embodiment, the wire incision 101 includes an annular groove, and the cross-sectional morphology of the annular groove includes one or a combination of V-shaped, U-shaped, square, and trapezoidal shapes.

[0057] Specifically, such as Figure 3 and Figure 4c , Figure 4c are shown as Figure 3 another enlarged schematic structural diagram of the B-B' cross-section in Figure 3 In

[0058] As a further embodiment of this embodiment, the wire incision 101 includes a through hole penetrating the WB wire 100, and the cross-sectional morphology of the through hole includes one or a combination of circular and polygonal shapes.

[0059] Specifically, such as Figure 5 and Figure 6, when the metal wire incision 101 is a through hole penetrating the WB metal wire 100, the maximum distance of the through hole in the radial direction Y of the WB metal wire 100 needs to be less than the diameter of the WB metal wire 100, and its percentage can include 20% to 80%, preferably 50%, and can be specifically selected according to needs.

[0060] As a further embodiment of this embodiment, on the axial direction X of the WB metal wire 100, there is an equal spacing between adjacent metal wire incisions 101.

[0061] Specifically, the spacing between adjacent metal wire incisions 101 determines the length of the subsequent formed straight metal bonding wire. The setting of the spacing between adjacent metal wire incisions 101 can be selected according to specific needs and is not overly limited here.

[0062] As a further embodiment of this embodiment, the WB metal wire 100 can include one of Cu wire, Au wire, Cu alloy wire, Au alloy wire, and Cu / Au alloy wire, but is not limited thereto.

[0063] Such as Figure 7 , this embodiment also provides a method for forming a straight metal bonding wire. When forming the straight metal bonding wire, the WB metal wire 100 is used. After forming a solder joint, by stretching, the WB metal wire 100 is disconnected from the metal wire incision 101 to form the straight metal bonding wire, thereby improving the UPH of the process and the product quality.

[0064] Specifically, such as Figure 8 , provide the WB metal wire 100 described in any of the above, and mount the WB metal wire 100 on the split blade 500; provide the chip 200, and the surface of the chip 200 includes the pad 201; connect the WB metal wire 100 with the pad 201 to form the solder joint 300; stretch the WB metal wire 100 from the solder joint 300 along the required running direction D, so that the WB metal wire 100 is disconnected from the metal wire incision 101 to form the straight metal bonding wire 400. This embodiment only forms one solder joint 300, and by stretching, the WB metal wire 100 is disconnected from the metal wire incision 101, and the straight metal bonding wire 400 can be formed, thereby improving the UPH of the process and the product quality.

[0065] As a further embodiment of this embodiment, the range of the angle between the straight metal bonding wire and the surface of the chip 200 includes 45° to 90°.

[0066] Specifically, Figure 8In this case, the running direction D of the split blade 500 is perpendicular to the surface of the chip 200. Therefore, the included angle θ between the formed linear metal bonding wire 400 and the surface of the chip 200 is 90°, but it is not limited thereto. For example, Figure 9 In this case, the range of the included angle θ between the linear metal bonding wire 400 and the surface of the chip 200 can preferably be between 45° and 90°, including 45°. The included angle θ can also be selected as a value such as 60° to facilitate setting the electrical lead-out of the linear metal bonding wire as needed.

[0067] As a further embodiment of this embodiment, it further includes the steps of forming a packaging layer 600 covering the chip 200 and the linear metal bonding wire 400, and thinning the packaging layer 600 to expose the linear metal bonding wire 400.

[0068] Specifically, for example, Figure 9 , the packaging layer 600 covers the surface of the chip 200 and the linear metal bonding wire 400. Among them, the packaging layer 600 can include one of a polyimide packaging layer, a silicone packaging layer, and an epoxy resin packaging layer. The method of forming the packaging layer 600 can include one of compression molding, transfer molding, liquid encapsulation molding, vacuum lamination, and spin coating. After that, for example, Figure 10 , the packaging layer 600 can be thinned to expose the linear metal bonding wire 400 located in the packaging layer 600. Among them, the method of thinning the packaging layer 600 can include chemical mechanical polishing, but it is not limited thereto.

[0069] In summary, in the method for forming the WB metal wire and the linear metal bonding wire of the present invention, the WB metal wire includes a metal wire notch. The metal wire notch extends radially from the surface of the WB metal wire to reduce the radial size of the WB metal wire through the metal wire notch. Thus, during the wire bonding process, only one solder joint can be formed, and then through stretching, the WB metal wire is disconnected from the metal wire notch to form a linear metal bonding wire, improving the UPH of the manufacturing process and the product quality. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0070] The above embodiments are only illustrative of the principles and effects of the present invention and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for forming a straight metal bonding wire, characterized in that, Comprising the following steps: Providing a WB wire, the WB wire including a wire incision that extends radially from the surface of the WB wire into the WB wire to reduce the radial dimension of the WB wire through the wire incision, the wire incision including a through hole penetrating the WB wire; Providing a chip, the surface of the chip including pads; Connecting the WB wire to the pads to form solder joints; Stretching the WB wire from the solder joints to break the WB wire at the wire incision.

2. The method for forming a linear metal bonding wire according to claim 1, wherein: The range of the angle between the straight metal bonding wire and the surface of the chip includes 45° to 90°.

3. The method for forming a straight metal wire bond according to claim 1, wherein: It further includes the steps of forming a packaging layer covering the chip and the straight metal bonding wire, and thinning the packaging layer to expose the straight metal bonding wire.

4. The method for forming a linear metal bonding wire according to claim 1, characterized in that: The cross-sectional morphology of the through hole includes one or a combination of a circle and a polygon.

5. The method for forming a straight metal bonding wire according to claim 1, wherein: Axially of the WB wire, equal spacing exists between adjacent wire incisions.

6. The method for forming a straight metal bonding wire according to claim 1, wherein: The WB wire includes one of a Cu wire, an Au wire, a Cu alloy wire, an Au alloy wire, and a Cu / Au alloy wire.

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