Welding method for copper stranded wire connecting piece

Abstract

The invention provides a welding method for a copper stranded wire connecting piece, which comprises the following two steps of: 1, welding a molybdenum terminal and a copper stranded wire, heating through a high-frequency induction coil, melting local part of the copper stranded wire and copper powder by using a centralized heating mold, then reliably welding the copper stranded wire and the molybdenum terminal, and turning the molybdenum terminal into a required shape; and 2, welding the copper terminal and the copper stranded wire, heating through a high-frequency induction coil, melting the local part of the copper stranded wire and the whole molybdenum terminal by utilizing a centralized heating mold, so that the copper stranded wire and the molybdenum terminal are reliably welded, and turning the copper terminal into a required shape. The beneficial effects are that the two ends of the copper stranded wire are respectively welded with the molybdenum terminal and the oxygen-free copper terminal through two steps, the contact resistance at the joint is small, the tensile strength is large, and the manufacturing of the electrostatic chuck for semiconductor equipment is positively promoted.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology applications, and specifically relates to a welding method for copper stranded wire connectors. Background Art

[0002] During the manufacturing process of electrostatic chucks for semiconductor equipment, flexible copper stranded wires with excellent electrical conductivity (about 10 mm in length) are required to reliably connect molybdenum terminals and oxygen-free copper terminals. Since the copper stranded wires are relatively short, after soldering with solder, the solder will flow along the copper stranded wires, causing the copper stranded wires to become hard. Currently, cold pressing is mainly used in China to separately press the molybdenum terminals and oxygen-free copper terminals to connect them to the copper stranded wires. However, the cold pressing method has a large contact resistance and poor tensile strength at the joint. Especially for molybdenum terminals, due to brittleness, the tensile strength is even lower, unable to meet the reliability requirements of electrostatic chucks. Summary of the Invention

[0003] The purpose of the present invention is to provide a highly reliable welding method for copper stranded wire connectors. This method connects both ends of the copper stranded wire to a molybdenum terminal and an oxygen-free copper terminal respectively, with a small contact resistance and large tensile strength at the joint.

[0004] The present invention adopts the following technical solutions: A welding method for copper stranded wire connectors is mainly divided into two steps. The first step is the welding of the molybdenum terminal and the copper stranded wire. Through high-frequency induction coil heating, using a concentrated heating mold to melt the local part of the copper stranded wire and copper powder to form a reliable weld with the molybdenum terminal, and turning the molybdenum terminal into the required shape. The second step is the welding of the copper terminal and the copper stranded wire. Through high-frequency induction coil heating, using a concentrated heating mold to melt the local part of the copper stranded wire and the whole molybdenum terminal, so that the two form a reliable weld, and turning the copper terminal into the required shape.

[0005] In the above first step, copper powder is added to the blind hole of the columnar molybdenum terminal. One end of the copper stranded wire is inserted into the blind hole of the columnar molybdenum terminal. After being fixed by a support mold and a fixing mold, it is placed in a concentrated heating mold and a coil. Through high-frequency induction concentrated heating, the copper powder and the copper stranded wire inserted into the columnar molybdenum terminal are melted, and the columnar molybdenum terminal is welded to the copper stranded wire. After welding, the columnar molybdenum terminal is machined into a cap-shaped molybdenum terminal by mechanical processing; In the above second step, the copper terminal and the copper stranded wire inserted into the copper terminal are fixed by a support mold, a copper terminal support mold, and a copper terminal fixing mold and then placed in a concentrated heating mold and a coil. Through high-frequency induction concentrated heating, the copper terminal and the copper stranded wire inserted into the copper terminal are melted, and the copper terminal is welded to the copper stranded wire. After welding, the copper terminal is machined into a convex platform copper terminal by mechanical processing.

[0006] The coil is attached to a hollow copper tube, and deionized water is passed through the inside of the copper tube. The coil is placed in a hydrogen atmosphere during operation.

[0007] The centralized heating mold is made of metal materials such as oxygen-free copper. The inner diameter of the small hole in the centralized heating mold is 1-2 mm larger than the outer diameter of the columnar molybdenum terminal and the outer diameter of the copper terminal support mold.

[0008] The molybdenum terminal is made of high-density molybdenum material.

[0009] The copper stranded wire, copper powder, and copper terminal are made of oxygen-free copper material to ensure that their melting points are basically the same.

[0010] The fixing mold and the copper terminal fixing mold are made of high-temperature resistant and non-conductive materials such as ceramics and talc.

[0011] The support mold is made of high-strength, high-temperature resistant, and non-conductive materials such as ceramics. It is composed of two symmetrical halves and is provided with an observation window. The height of the observation window is the distance between the cap-shaped molybdenum terminal and the copper terminal. When the support mold is in use, the side with the observation window is placed downward and tied with semi-rigid high-temperature resistant materials such as fine copper wire.

[0012] The copper terminal support mold is made of high-temperature resistant and non-bonding conductive materials such as blackened stainless steel and high-density graphite.

[0013] The beneficial effects of the present invention: By welding the two ends of the copper stranded wire to the molybdenum terminal and the oxygen-free copper terminal respectively in two steps, the contact resistance at the joint is small and the tensile strength is large, which plays a positive role in promoting the manufacture of electrostatic chucks for semiconductor equipment. Description of the Drawings

[0014] Figure 1 It is a schematic diagram of the welding of the molybdenum terminal and the copper stranded wire; Figure 2 It is a schematic diagram before precision turning of the connecting piece between the molybdenum terminal and the copper stranded wire; Figure 3 It is a schematic diagram after precision turning of the connecting piece between the molybdenum terminal and the copper stranded wire; Figure 4 It is a schematic diagram of the welding of the copper terminal and the copper stranded wire; Figure 5 It is a schematic diagram before precision turning of the connecting piece between the copper terminal and the copper stranded wire; Figure 6 It is a schematic diagram after precision turning of the connecting piece between the copper terminal and the copper stranded wire; Figure 7 It is a schematic diagram of the support mold.

[0015] Explanation of each mark in the above drawings: 100 - columnar molybdenum terminal, 101 - cap-shaped molybdenum terminal, 200 - copper stranded wire, 300 - copper terminal, 301 - convex copper terminal, 400 - copper powder, 500 - support mold, 501 - copper terminal support mold, 600 - fixing mold, 601 - copper terminal fixing mold, 700 - centralized heating mold, 800 - coil. Detailed Embodiment

[0016] To illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments and the accompanying drawings.

[0017] Figure 1 It is a schematic diagram of the welding of a molybdenum terminal and a copper stranded wire. The columnar molybdenum terminal 100 is cylindrical on the outside and has a blind hole in the center. An appropriate amount of copper powder 400 is poured into the columnar molybdenum terminal 100. The copper stranded wire 200 is inserted into the columnar molybdenum terminal 100, and the copper stranded wire 200 is fixed with a support mold 500. The assembly formed by the columnar molybdenum terminal 100, the copper powder 400, the copper stranded wire 200, and the support mold 500 is placed on a fixed mold 600. Finally, the component formed by the columnar molybdenum terminal 100, the copper powder 400, the copper stranded wire 200, the support mold 500, the fixed mold 600, and the centralized heating mold 700 is placed in a coil 800. The coil 800 is placed in a hydrogen atmosphere and water is passed through the cooling circulating water copper pipe. Subsequently, an electric current is passed through the coil 800, and local welding is performed by high-frequency induction heating. The welding effect is that the part of the copper powder 400 and the copper stranded wire 200 inserted into the columnar molybdenum terminal 100 are melted and form a reliable connection with the columnar molybdenum terminal 100. The centralized heating mold 700 is cylindrical, with an opening at the upper part, and the opening is used to accommodate the passage of the columnar molybdenum terminal 100. The fixed mold 600 is a block with a blind hole in the middle, and the blind hole is used to place the columnar molybdenum terminal 100.

[0018] Figure 2 It is a schematic diagram before precision turning of the connector of the molybdenum terminal and the copper stranded wire. Through precision machining, the columnar molybdenum terminal 100 is turned into the shape of a cap-shaped molybdenum terminal 101, as Figure 3 shown.

[0019] Figure 4 It is a schematic diagram of the welding of a copper terminal and a copper stranded wire. The Figure 3 part after precision turning of the connector of the molybdenum terminal and the copper stranded wire shown is inserted into the copper terminal 300. The copper terminal 300 is sleeved with a copper terminal support mold 501. The copper stranded wire 200 is fixed with a support mold 500. The formed assembly is placed on a copper terminal fixed mold 601. Finally, the above components are placed together with the centralized heating mold 700 in a coil 800. The coil 800 is placed in a hydrogen atmosphere and water is passed through the cooling circulating water copper pipe. Subsequently, an electric current is passed through the coil 800, and local welding is performed by high-frequency induction heating. The welding effect is that the part of the copper stranded wire 200 inserted into the copper terminal 300 and the copper terminal 300 are melted and form a reliable connection. The copper terminal support mold 501 is cylindrical, and its diameter can just pass through the upper opening of the centralized heating mold 700. The copper terminal fixed mold 601 has the same shape as the fixed mold 600 but different heights. The blind hole in the middle is used to place the copper terminal support mold 501. The copper terminal 300 is placed in the inner hole of the copper terminal support mold 501, and the bottom of the copper terminal 300 also contacts the bottom of the blind hole in the middle of the copper terminal fixed mold 601. Figure 5 It is a schematic diagram before precision turning of the connector between the copper terminal and the copper stranded wire. Through precision machining, the copper terminal 300 is turned into the shape of the boss copper terminal 301. Figure 6 It is a schematic diagram after precision turning of the connector between the copper terminal and the copper stranded wire.

[0020] Figure 7 It is a schematic diagram of the support mold 500. In order to observe the melting condition of the copper stranded wire 200 and fix and support it, the support mold 500 is set into two symmetrical halves and provided with an observation window.

[0021] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A copper stranded wire connector welding method, characterized in that: Copper powder (400) is added to the blind hole of the columnar molybdenum terminal (100), one end of the copper stranded wire (200) is inserted into the blind hole of the columnar molybdenum terminal (100), and the terminal is fixed by a supporting mold (500) and a fixing mold (600), and then placed in a centralized heating mold (700) and a coil (800), and the copper powder (400) and the copper stranded wire (200) inserted into the columnar molybdenum terminal (100) are melted by high-frequency induction centralized heating, and the columnar molybdenum terminal (100) and the copper stranded wire (200) are welded, and after welding, the columnar molybdenum terminal (100) is machined into a cap-shaped molybdenum terminal (101); The copper terminal (300) and the copper stranded wire (200) inserted into the copper terminal (300) are fixed by means of a supporting mold (500), a copper terminal supporting mold (501), and a copper terminal fixing mold (601), and then placed in a centralized heating mold (700) and a coil (800). The copper terminal (300) and the copper stranded wire (200) inserted into the copper terminal (300) are melted by high-frequency induction centralized heating, and the copper terminal (300) and the copper stranded wire (200) are welded. After welding, the copper terminal (300) is machined into a boss copper terminal (301).

2. The method for welding a copper stranded wire connector according to claim 1, wherein: The coil (800) is attached to a hollow copper tube, deionized water flows into the interior of the copper tube, and the coil (800) is placed in a hydrogen atmosphere when working.

3. The method for welding a copper stranded wire connector according to claim 1, wherein: The centralized heating mold (700) is made of metal material, and the inner diameter of the small hole of the centralized heating mold (700) is 1-2 mm larger than the outer diameter of the columnar molybdenum terminal (100) and the outer diameter of the copper terminal supporting mold (501).

4. The method for welding a copper stranded wire connector according to claim 1, wherein: The copper stranded wire (200), copper powder (400) and copper terminal (100) are made of oxygen-free copper materials.

5. The method for welding a copper stranded wire connector according to claim 1, wherein: The fixing mold (600) and the copper terminal fixing mold (601) are made of high temperature resistant and non-conductive materials.

6. The method for welding a copper stranded wire connector according to claim 1, characterized in that: The support mold (500) is made of high-strength, high-temperature-resistant, non-conductive material and is composed of two symmetrical halves. An observation window is provided, and the height is the distance between the cap-shaped molybdenum terminal (101) and the copper terminal (301). When the support mold (500) is used, the observation window is arranged on one side facing downwards and is bound with a semi-rigid high-temperature-resistant filament material.

7. The method for welding a copper stranded wire connector according to claim 1, characterized in that: The copper terminal supporting mold (501) is a conductive material that is resistant to high temperatures and does not adhere to oxygen-free copper.

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