Low-temperature welding method for isolated conductor of chip shell

Abstract

The invention provides a low-temperature welding method for isolated conductors of a chip shell, and belongs to the technical field of welding. The method comprises the six steps of wire bending, brazing filler metal coating, wire assembling, oil discharging and oxide removing, pulse precise cold welding and dust wiping. Effective connection between the isolated conductor of the chip shell and the wire can be achieved, the shell temperature is lower than 80 DEG C in the welding process, the technology is simple, and cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of welding isolated conductors of chip shells, and in particular to a low-temperature welding method for isolated conductors of chip shells. Background Art

[0002] Satellite-borne products must be larger than 3cm 2 The isolated conductor chip must be grounded, that is, grounded by adding wires or gold wires and copper tapes.

[0003] The composition of the chip shell coating was analyzed by energy dispersive spectrometer (EDS), and it was found that the main component was Ni, accounting for 93.1%, followed by C, accounting for 6.5%, and the remaining elements were Ta and S, accounting for 0.3% and 0.1% respectively. In actual operation, we found that the traditional electric soldering iron and soldering process could not connect the silver-plated copper wire to the chip shell, that is, the two could not be soldered using traditional low-temperature soldering technology.

[0004] At present, the grounding connection is mainly achieved by bonding metal sheets (with welding holes at the tail end for welding wires) with conductive glue. However, this process has defects. The conductive glue tends to powder over time, thus forming excess metal and posing a risk of short circuit.

[0005] Traditional processes such as thermocompression bonding and thermosonic bonding can also be used to connect isolated conductors of chip shells to wires, but their operating temperature is generally required to be above 200°C. In order to ensure that the chip performance is not affected by the temperature of the welding process, the chip shell temperature is required to be lower than 80°C during the welding process. Therefore, it is necessary to study the welding method of isolated conductors and find a process that can achieve low-temperature welding to achieve the welding of isolated conductors and better serve satellite-borne products. Summary of the invention

[0006] Aiming at the problem that the existing technology cannot realize the low-temperature connection between the isolated conductor of the chip shell and the wire, an innovative low-temperature welding technology for the isolated conductor of the chip shell is proposed. The present invention can realize the effective connection between the isolated conductor of the chip shell and the wire, and the shell temperature is lower than 80℃ during the welding process, the process is simple, and the cost is saved.

[0007] The present invention adopts the following technical solutions to solve the above technical problems:

[0008] A low temperature welding method for isolated conductors of a chip shell comprises the following steps:

[0009] Step 1, bending the wire, the wire is divided into a part to be welded and a conducting part, and the two are bent at a certain angle;

[0010] Step 2, coating solder, using an electric soldering iron to melt a layer of low melting point solder on the part of the wire to be welded;

[0011] Step 3, assembling the wires, placing the parts of the wires to be welded on the welding points of the test chip for subsequent welding.

[0012] Step 4: Remove oil and oxides. Before welding, wipe the chip shell surface and the parts to be welded with acetone to remove oil, and then polish with emery cloth to remove oxides on the surface of the weldment.

[0013] Step 5: pulse precision cold welding, using pulse precision cold welding to connect the chip housing and the wire;

[0014] Step 6: Wipe off the dust. During the metal welding process, the overheated metal evaporates and falls back to the weld surface under the action of the protective airflow, forming a black dust layer, which can be removed by lightly wiping it after welding.

[0015] Optimally, in step 1), the conductor is a multi-strand flexible copper wire with a silver-plated surface.

[0016] Optimally, in step 1), the bending angle of the wire ranges from 90° to 180°.

[0017] Optimally, in the step 2), a layer of Sn63Pb37 solder is melt-coated on the surface of the wire at the position to be welded by using an electric soldering iron.

[0018] Optimally, in step 3), the part of the wire to be welded is closely attached to the surface of the chip housing, and the plane where the conducting part of the wire and the welding part are located is perpendicular to the plane where the surface of the chip housing is located.

[0019] Optimally, in step 3), the tungsten needle of the welding gun is placed directly above the to-be-welded portion of the wire whose surface is clad with Sn63Pb37 solder, and the inclination angle is 30 to 60 degrees.

[0020] Optimally, in step 3), the distance between the tungsten needle of the welding gun and the part of the wire to be welded is 0 to 1 mm.

[0021] Optimized, in step 5), the pulse precision cold welding adopts the automatic function of the equipment, and the current is 50-200A.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects: effective connection between the isolated conductor of the chip shell and the wire can be achieved, and the shell temperature is lower than 80° C. during welding, the process is simple, and the cost is saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the wire assembly structure in an embodiment of the present invention.

[0024] In the figure: the part of the wire to be welded 1, the conducting part of the wire 2, and the tungsten needle for the welding gun 3. DETAILED DESCRIPTION

[0025] The present invention provides a chip shell isolated conductor low temperature welding technology, which includes the following contents:

[0026] 1) Bending the wire, the wire is divided into a welding part 1 and a conducting part 2, and the two are bent at a certain angle;

[0027] 2) Apply solder, using an electric soldering iron to melt a layer of low melting point solder on the part of the wire to be welded;

[0028] 3) Assemble the wires and place the parts of the wires to be welded on the welding points of the test chip for subsequent welding.

[0029] 4) Remove oil and oxides. Before welding, wipe the surface of the chip shell and the parts to be welded with acetone to remove oil, and then polish with emery cloth to remove oxides on the surface of the weldment.

[0030] 5) Pulse precision cold welding, use pulse precision cold welding to connect the chip shell and the wire;

[0031] 6) Wipe off the dust. During the metal welding process, the overheated metal evaporates and falls back to the weld surface under the action of the protective airflow, forming a black dust layer, which can be removed by lightly wiping it after welding.

[0032] Optimally, in step 1), the conductor is a multi-strand flexible copper wire with a silver-plated surface.

[0033] Optimally, in step 1), the bending angle range of the wire is 90°.

[0034] Optimally, in the step 2), a layer of Sn63Pb37 (tin-lead) solder is melt-coated on the surface of the wire at the position to be welded by using an electric soldering iron.

[0035] Optimally, in step 3), the part of the wire to be welded is closely attached to the surface of the chip housing, and the plane where the conducting part of the wire and the welding part are located is perpendicular to the plane where the surface of the chip housing is located.

[0036] Optimally, in step 3), the tungsten needle of the welding gun is placed just above the to-be-welded portion of the wire whose surface is clad with Sn63Pb37 solder, and the inclination angle is 60 degrees.

[0037] Optimally, in step 3), the distance between the tungsten needle of the welding gun and the part of the wire to be welded is 1 mm.

[0038] Optimized, in step 5), the pulse precision cold welding adopts the automatic function of the equipment, and the current is 200A.

[0039] Before welding, two temperature measuring points were placed on the surface of the chip shell, and the displayed temperature was 17.2°C. During the welding process, the highest temperature of the temperature measuring points was 20.3°C, that is, the maximum temperature rise was 3.1°C.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low temperature welding method for isolated conductors of a chip housing, characterized in that: The following steps are involved: Step 1, bending the wire, the wire is divided into a part to be welded and a conducting part, and the two are bent at a certain angle; Step 2, using an electric soldering iron to melt a layer of low melting point solder on the part of the wire to be welded; Step 3, placing the part of the wire to be welded on the welding point of the test chip for subsequent welding; Step 4: Before welding, wipe the surface of the chip shell and the part to be welded of the wire with acetone to remove oil, and then polish with emery cloth to remove the oxide on the surface of the weldment; Step 5, using pulse precision cold welding to connect the chip housing and the wire; Step 6. Wipe to remove dust.

2. A chip housing isolated conductor low temperature welding method according to claim 1, characterized in that: In step 1, the conductor is a multi-strand flexible copper wire with a silver-plated surface.

3. A chip housing isolated conductor low temperature welding method according to claim 1, characterized in that: In step 1, the bending angle of the wire is in the range of 90° to 180°.

4. A chip housing isolated conductor low temperature welding method according to claim 1, characterized in that: In the step 2, a layer of Sn63Pb37 solder is melt-coated on the surface of the wire at the position to be welded by using an electric soldering iron.

5. The low temperature welding method for isolated conductors of a chip housing according to claim 1, characterized in that: In step 3, the part of the wire to be welded is closely attached to the surface of the chip shell, and the plane where the conducting part of the wire and the welding part are located is perpendicular to the plane where the surface of the chip shell is located.

6. A chip housing isolated conductor low temperature welding method according to claim 1, characterized in that: The tungsten needle of the welding gun is placed just above the to-be-welded part of the wire whose surface is clad with Sn63Pb37 solder, and the inclination angle is 30 to 60 degrees.

7. A chip housing isolated conductor low temperature welding method according to claim 1, characterized in that: The distance between the tungsten needle of the welding gun and the part to be welded of the wire is 0 to 1 mm.

8. The low temperature welding method for isolated conductors of a chip housing according to claim 1, characterized in that: The pulse precision cold welding adopts the automatic function of the equipment, and the current is 50~200A.

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