CN116727961A - Welding jig and welding set - Google Patents

Abstract

The application provides a welding fixture and a welding device, which are used in a wire bonding process of a device. The welding fixture is composed of a double-layer hollow pressing plate, an air passage capable of allowing air to circulate is formed in the inner space of the welding fixture, and air outlets and air inlets at different positions are designed by utilizing the upper surface and the lower surface of the pressing plate, so that the welding fixture has the clamping function in a thermal welding process and also has the function of blowing air, and therefore the effect of simultaneously providing protective air for different areas to reduce thermal oxidation of welding devices is achieved.

Description

Welding jig and welding set

Technical Field

The application relates to the technical field of semiconductor packaging, in particular to a welding fixture and a welding device used in a wire bonding process.

Background

Along with the continuous change of market product demands, the requirements on PCB circuit refinement and function integration are also higher and higher, and in order to meet the product function and quality demands, the cost is reduced, the efficiency is improved, and many PCB products need to adopt Wire Bonding (WB) during SMT, also known as Wire Bonding, chip Wire Bonding and the like, and the name is to adopt a Wire to connect the PCB and the PCBA. Wire bonding processes have higher reliability than Surface Mount Technology (SMT), and with the increasing packing density of system in SIP, the probability of wire bonding is increasing.

Referring to fig. 1, fig. 1 is a schematic diagram of a conventional Wire Bonding (WB) apparatus. In the related art, it is necessary to expose the semiconductor chip 11 to be soldered using the jig 3 and then perform wire bonding by the bonding head 5. The process is characterized in that enough temperature is required to act on the surface of the frame/chip/wire rod during welding, so that protective gas is required to be continuously blown through the gas blowing pipe 4 in a welding line area during the operation of a welding station machine, thereby maintaining the surface of the copper wire/frame/chip in the welding process, reducing the possibility of oxidation to the greatest extent and ensuring the welding reliability.

However, the welding area of the WB machine 1 is composed of three parts, i.e., a preheating area, a welding area, and an annealing area, which respectively correspond to the pre-welded chip 12, the chip 11 to be welded, and the welded chip 13, and the three areas have a continuous high temperature. Conventionally, only one air duct is used to blow nitrogen gas on the surface of the welding wire area, and the preheating area and the defervescing area are not protected by the nitrogen gas, so that two main risks are provided:

1. when the preheating area heats the chip/frame, the chip/frame is oxidized, so that the welding area in the next step cannot be welded normally, and the welding-off condition occurs;

2. the surface of the welded product frame in the heat release area is baked at high temperature for a long time, and oxidation discoloration occurs due to no nitrogen protection, so that layering is abnormal in the subsequent plastic packaging.

Disclosure of Invention

Accordingly, the present application is directed to a new welding fixture, which can solve the problem of poor welding caused by that the preheating zone and the defervescing zone are easily oxidized by oxygen without protection of nitrogen in the existing thermal welding wire bonding process.

Based on the above problems, the present application provides a welding fixture for use in a wire bonding process of a device, the welding fixture comprising:

the hollow area is arranged on the corresponding device to be welded in working and exposes the device to be welded;

the shielding area is arranged on at least one adjacent device of the device to be welded in operation and covers the adjacent device;

the transition area is in slope transition from the shielding area at a high point to the hollowed-out area at a low point;

an air inlet passage arranged inside the welding fixture and extending from the shielding region to the transition region,

at least one air inlet arranged at one end of the air inlet channel located in the shielding area;

at least one first air outlet which is arranged at the other end of the air inlet channel, which is positioned at the transition area, and is arranged towards the device to be welded;

and at least one second air outlet is arranged at the middle section of the air inlet channel, which is positioned in the shielding area and/or the transition area, and the second air outlet is arranged towards the adjacent device.

Preferably, the welding fixture is a hollow pressing plate, the shielding area and the transition area form a main body of the hollow pressing plate, and the hollow area is an opening formed in the hollow pressing plate.

Preferably, the space between the upper surface and the lower surface of the hollow pressing plate forms the air inlet pipeline, the air inlet is arranged on the upper surface of the hollow pressing plate, and the second air outlet is arranged on the lower surface of the hollow pressing plate.

Preferably, the adjacent devices include a soldered device and a pre-soldered device, and the shielding region includes a soldered region and a pre-soldered region, which are disposed corresponding to the soldered device and the pre-soldered device, respectively.

Preferably, the number of second air outlets in the pre-welded zone is greater than the number of second air outlets in the welded zone.

Preferably, the welded area and the pre-welded area are respectively provided with an air inlet, and the air inlet flow rate in the pre-welded area is larger than that in the pre-welded area.

Preferably, a part of the bottom of the transition region is a horizontal extension Shen Duan, and the hollowed-out region is surrounded by the extension section.

Preferably, the first air outlet is located at an end of the extension.

The application also provides a welding device for welding a plurality of devices to a substrate by a wire bonding process, comprising

The welding fixture is arranged on the substrate, at least 1 device to be welded is exposed to perform a wire bonding process, and adjacent devices of the device to be welded are shielded;

the gas source device is connected to the welding fixture through a gas pipe and provides protective gas for the welding fixture;

and the welding head is used for conducting wire bonding on the device to be welded.

Preferably, the machine comprises

The welding area is used for providing a welding station of the device to be welded;

the preheating zone is used for preheating unwelded devices;

a heat removal zone for removing heat from the soldered device;

wherein at least one of the unwelded device and the soldered device is adjacent to the device to be soldered.

The welding fixture disclosed by the application is composed of the hollow pressing plate, the air channel pipeline is arranged in the hollow pressing plate, and the surface of the pressing plate is respectively provided with the plurality of air blowing ports, so that air can be blown to the preheating zone and the defervescing zone simultaneously, the whole process of a chip in the welding process is protected by the protective gas, the problem of oxidization in the preheating zone and the defervescing zone is avoided, and the welding yield of the chip is improved.

Drawings

Fig. 1 is a schematic diagram of a prior art wire bonding apparatus.

Fig. 2 is a schematic operation diagram of the welding apparatus according to the first embodiment of the present application.

Fig. 3 is a schematic operation view of a welding apparatus according to a second embodiment of the present application.

Detailed Description

The present application will be described in detail below with reference to the specific embodiments shown in the drawings, but these embodiments are not limited to the present application, and structural, method, or functional modifications made by those skilled in the art based on these embodiments are included in the scope of the present application.

As pointed out in the background art by the applicant, in the existing wire bonding process, a device to be welded needs to be exposed through a fixture to perform wire bonding, and during welding, a protective gas such as nitrogen needs to be blown to an operation area of the device, so that the problems of cold joint or poor contact and the like caused by oxidation of a metal wire caused by high temperature are avoided. However, due to the presence of the clamp, the areas around the device to be soldered are blocked, i.e. the protective gas cannot be pushed against the devices in these areas. The devices in these areas correspond to high temperature areas such as a preheating area and an annealing area on the machine, so that the risk of oxidization still exists.

In order to solve the problems, the application provides a brand new welding fixture, which can not only expose the devices to be welded, but also blow protective gas to the devices in the shielded preheating area and the shielded defervescing area, so that the devices in the two high-temperature areas can be protected by the protective gas, the probability of oxidizing the devices is reduced, and the welding yield of the devices is improved. And in the future application of welding wires on the surface of the bare copper frame, a good welding gas protection environment can be provided, and the problem of oxidization in the welding process of the bare copper frame is avoided.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings.

Referring to fig. 2, fig. 2 is a schematic diagram illustrating the operation of the welding apparatus according to the first embodiment of the present application. The bonding apparatus is used for bonding a plurality of semiconductor chips to a substrate through a wire bonding process, and includes a bonding jig 100, a machine 200, a bonding head 300, and a gas source apparatus and a necessary gas pipe (not shown). The machine 200 is provided with a substrate placing station for processing a substrate. The gas source device is connected to the welding fixture 100 through a gas pipe and provides protective gas for the welding fixture; the bonding head 300 is used for wire bonding of devices to be bonded, where the devices include chips, lead frames, wires, etc. that are bonded by a wire bonding process, and a semiconductor chip is taken as an example, and a bonding fixture and a working method thereof in the present application are described below.

Referring to fig. 2 again, a heating device 201 is disposed under the substrate, and the heating device 201 heats the substrate to achieve the required ambient temperature for wire bonding. Further, the apparatus 200 may be divided into a preheating zone 210, a soldering zone 220 and an annealing zone 230, wherein stations above the preheating zone 210 may preheat the semiconductor chips that are not soldered in preparation for subsequent soldering. The bonding region 220 provides a bonding station for wire bonding of the semiconductor die to be bonded. And a station above the heat removal zone 230 provides heat removal to the die that has been soldered. The welding area needs to be heated to finish welding of the device, and the preheating area and the defervescing area are arranged at lower temperature relative to the welding area to finish preheating and defervescing of the device. Wherein at least one of the unwelded semiconductor chip and the soldered semiconductor chip is adjacent to the semiconductor chip to be soldered.

It should be noted that the preheating zone 210, the soldering zone 220 and the annealing zone 230 may be set according to specific functions of the working state, rather than the inherent structural design of the whole soldering apparatus, for example, according to the soldering sequence of the chips, if the semiconductor chip is moved in one direction after being soldered, the next station corresponding to the moving direction of the soldering station is the annealing zone 230, and the last station corresponding to the moving direction of the soldering station is the preheating zone 210 may be positioned to distinguish the setting of the corresponding working area.

In a preferred embodiment, the preheating zone 210 and the abatement zone 230 may provide different temperatures. Typically, since the chips in the preheating zone 210 are about to enter the soldering station for soldering, and the chips in the annealing zone 230 are already soldered, the chips need to be gradually annealed to enter the next process, and thus the temperature set in the preheating zone 210 is greater than the temperature set in the annealing zone 230.

In the present application, the welding fixture 100 is changed from a conventional single-plate fixture into a double-layer hollow pressing plate, so that the inner space of the welding fixture 100 forms an air passage capable of allowing air to flow, and therefore, the upper and lower surfaces of the pressing plate can be utilized to design air outlets and air inlets at different positions, so that the welding fixture 100 of the present application has the function of clamping and simultaneously has the function of blowing air, thereby realizing the effect of simultaneously providing shielding air for different areas.

Specifically, the welding fixture 100 includes a hollowed-out area 110, a shielding area 120, and a transition area 130. The shielding region 120 and the transition region 130 form the main body of the hollow platen, and the hollowed-out region 110 is an opening formed in the hollow platen. When in operation, the hollowed-out area 110 is arranged on a corresponding semiconductor chip to be soldered and exposes the semiconductor chip to be soldered, and the hollowed-out area 110 is, for example, a hole hollowed out on the hollow pressing plate, and the hole has a preset size and can expose the whole semiconductor chip to be soldered. The shielding region 120 is disposed at a higher position relative to the hollowed-out region, so that the shielding region 120 can cover the adjacent region around the semiconductor chip to be soldered when the hollowed-out region 110 clamps the semiconductor chip to be soldered, thereby forming a shielding effect. Further, the shielding region 120 is divided into a pre-bonding region 121 and a bonded region 122, wherein the pre-bonding region 121 is used for shielding the pre-bonded semiconductor chips in the preheating region 210, and the bonded region 122 is used for shielding the bonded semiconductor chips in the heat-release region 230.

The transition area 130 is formed by slope transition from the shielding area 110 at a high point to the hollowed-out area 120 at a low point, the slope transition is similar to a bowl shape, the shielding area 110 is positioned on the plane of the bowl mouth, and the hollowed-out area 120 is positioned on the plane of the bowl bottom. In particular, the transition region 130 extends partially into the plane of the hollowed-out region 120, so that a portion of the transition region 130 is in the horizontal direction, and the hollowed-out region 120 is surrounded by the extension section.

Referring back to fig. 2, in the present application, the welding jig 100 has an air inlet passage 140 inside the pressing plate due to the hollow pressing plate. As can be seen from the sectional view of fig. 2, the air inlet channel 140 extends from the shielding region 120 to the transition region 130 inside the welding jig 100, i.e. both ends of the air inlet channel 140 are respectively provided on the shielding region 120 and the transition region 130, wherein the end on the shielding region 120 constitutes an air inlet 141 of the air inlet channel 140, and the end on the transition region 130 constitutes a first air outlet 142 of the air inlet channel 140, and the shielding gas is introduced through the air inlet 141 and is blown out from the first air outlet 142 after passing through the entire air inlet channel 140. Since the first gas outlet 142 mainly blows the shielding gas toward the semiconductor chips to be soldered in the present application, the outlet direction is provided toward the semiconductor chips to be soldered, and as shown in the drawing, the first gas outlet 142 is located at the end of the horizontal extension of the transition zone 130 and blows the shielding gas in the horizontal direction.

On the other hand, in the present application, a plurality of second gas outlets 143 are also provided at the intermediate section of the gas inlet passage 140, and these second gas outlets 143 are mainly used to blow the shielding gas to the semiconductor chips located in the preheating zone 210 and/or the defervescing zone 230, so that these second gas outlets 143 are provided at the lower surface of the hollow platen with their outlet directions being provided toward the semiconductor chips located in these zones. Specifically, as can be seen from the figure, the second air outlets 143 may be disposed on the area where the shielding area 210 is located, and these second air outlets 143 may blow downward; or may be disposed in the area of the transition zone 230, where the second air outlets 143 may blow air obliquely downward. In this way, the chips in the preheating zone 210 and the heat removal zone 230 are always in the atmosphere of the shielding gas during the whole soldering process, so that the problem of oxidization caused by high temperature can be avoided.

Further, the number of the second gas outlets 143 may be plural or one, and the gas flow rates in the preheating zone 210 and the defervescing zone 230 may be adjusted by adjusting the number of the second gas outlets 143. Referring to fig. 3, fig. 3 is a schematic operation diagram of a welding device according to a second embodiment of the present application. As shown in the drawing, in the second embodiment, the number of the second air outlets 143 provided in the pre-welding zone 121 is greater than the number of the second air outlets 143 of the welded zone 122, so that the flow rate of the shielding gas blown to the preheating zone 210 is greater than the flow rate of the shielding gas blown to the heat removal zone 230 with the same intake flux. Since the semiconductor chip in the preheating region 210 is in a preheating state, the preheating temperature is often higher, and the pins or pads exposed on the surface are more easily oxidized, which may cause poor contact in the subsequent wire bonding. The temperature of the heat rejection area 230 is relatively low, and the semiconductor chip after soldering is required to be subjected to heat rejection treatment, so that the flow requirement of the shielding gas is relatively low.

In another embodiment, the number of the second air outlets arranged in the pre-welding area and the welded area may be the same, and at this time, air inlets are respectively arranged in the welded area and the pre-welding area, and the flow of the air inlets in the pre-welding area is greater than that of the air inlets in the welded area by controlling the flow of the air inlets at the two different positions, so that the same effect as that of the second embodiment is achieved.

The welding fixture disclosed by the application is composed of the hollow pressing plate, the air channel pipeline is arranged in the hollow pressing plate, and the surface of the pressing plate is respectively provided with the plurality of air blowing ports, so that air can be blown to the preheating zone and the defervescing zone simultaneously, the whole process of a chip in the welding process is protected by the protective gas, the problem of oxidization in the preheating zone and the defervescing zone is avoided, and the welding yield of devices is improved.

The above disclosure is illustrative of the preferred embodiments of the present application, but it should not be construed as limiting the scope of the application as will be understood by those skilled in the art: changes, modifications, substitutions, combinations, and simplifications may be made without departing from the spirit and scope of the application and the appended claims, and equivalents may be substituted and still fall within the scope of the application.

Claims (10)

1. A bonding fixture for a wire bonding process, the bonding fixture comprising:

the hollow area is arranged on the corresponding device to be welded in working and exposes the device to be welded;

the shielding area is arranged on at least one adjacent device of the device to be welded in operation and covers the adjacent device;

the transition area is in slope transition from the shielding area at a high point to the hollowed-out area at a low point;

an air inlet passage arranged inside the welding fixture and extending from the shielding region to the transition region,

at least one air inlet arranged at one end of the air inlet channel located in the shielding area;

at least one first air outlet which is arranged at the other end of the air inlet channel, which is positioned at the transition area, and is arranged towards the device to be welded;

and at least one second air outlet is arranged at the middle section of the air inlet channel, which is positioned in the shielding area and/or the transition area, and the second air outlet is arranged towards the adjacent device.

2. The welding jig of claim 1 wherein the welding jig is a hollow platen, the shielding region and the transition region comprise a body of the hollow platen, and the hollowed-out region is an opening provided in the hollow platen.

3. The welding jig of claim 2, wherein a space between upper and lower surfaces of the hollow platen constitutes the air intake duct, the air inlet is provided at the upper surface of the hollow platen, and the second air outlet is provided at the lower surface of the hollow platen.

4. The bonding fixture of claim 2, wherein the adjacent devices comprise a bonded device and a pre-bonded device, and the shielded region comprises a bonded region and a pre-bonded region disposed in correspondence with the bonded device and the pre-bonded device, respectively.

5. The welding fixture of claim 4, wherein a number of second air outlets in the pre-weld zone is greater than a number of second air outlets in the welded zone.

6. The welding fixture of claim 4, wherein air inlets are provided on the welded zone and the pre-welded zone, respectively, and wherein the air inlet flow rate in the pre-welded zone is greater than the air inlet flow rate of the welded zone.

7. The welding jig of claim 2 wherein the transition zone has a partially horizontally extending section at the bottom and the hollowed-out zone is surrounded by the extending section.

8. The welding fixture of claim 7, wherein the first air outlet is located at an end of the extension.

9. A bonding apparatus for bonding a plurality of devices to a substrate by a wire bonding process, comprising: comprising

The welding fixture is arranged on the substrate, at least 1 device to be welded is exposed to perform a wire bonding process, and adjacent devices of the device to be welded are shielded;

the gas source device is connected to the welding fixture through a gas pipe and provides protective gas for the welding fixture;

and the welding head is used for conducting wire bonding on the device to be welded.

10. The welding apparatus of claim 9, wherein the machine comprises:

a welding area for providing a welding temperature required by the device to be welded;

a preheating zone to provide a desired preheating temperature for the unwelded device;

a heat removal zone to provide a desired heat removal temperature for the soldered device;

wherein at least one of the unwelded device and the soldered device is adjacent to the device to be soldered.