High-precision automatic alignment method with magnetic copper needle

Abstract

The invention discloses a high-precision automatic alignment method with a magnetic copper needle, which belongs to the technical field of microelectronic packaging, and comprises the following steps: providing a copper needle; the method comprises the following steps: cleaning to remove impurities and oil stains on the surface of a copper needle, adhering iron powder to one end of the copper needle, magnetizing the copper needle, slowly reducing the magnetic field intensity after the magnetization is finished, cooling the magnetized copper needle through a coolant, preparing a metal Pad, magnetizing the metal Pad, magnetizing the metal Pad, and planting the copper needle. And carrying out subsequent technological processes of normal copper needle planting. One end of the copper needle is polarized to be magnetic, the magnetic direction is fixed, the copper needle is scattered into the steel mesh, the copper needle and a magnetic field on soldering paste at a metal Pad interface generate the opposite attraction phenomenon, the copper needle and the metal Pad can be connected, the alignment effect is achieved, automatic alignment and rapid connection can be achieved, alignment is more accurate, the operation process is simplified, and the production efficiency is improved. And connection reliability is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of microelectronic packaging, and in particular relates to a high-precision automatic alignment method with a magnetic copper needle. Background Art

[0002] Most packaging technologies such as WireBond and FlipChip are single-sided connections. Now that the semiconductor industry is developing rapidly, the processing speed of such single-sided connected chips obviously cannot keep up with our needs. Therefore, we propose to use the subsequent technology of copper-copper needles to implant copper needles into the metal interface of the product for packaging to achieve chip interconnection packaging. This packaging can significantly improve computing efficiency, reduce the overall area and power consumption of the chip, reduce signal delay, reduce power consumption and high-speed communication, and increase the number and bandwidth of I / O interfaces. Summary of the invention

[0003] In view of the above situation, in order to overcome the defects of the prior art, the present invention polarizes one end of the copper needle to make it magnetic and fix the magnetic direction, and then sprinkles it into the steel mesh, so that the magnetic field on the solder paste at the interface of the metal pad produces an opposite attraction phenomenon, so that the two can be connected to achieve the effect of alignment.

[0004] In order to achieve the above object, the following technical solution is adopted: The present invention provides a high-precision automatic alignment method with a magnetic copper needle, comprising:

[0005] Copper needles are provided;

[0006] Remove impurities and oil stains on the surface of the copper needle by cleaning;

[0007] Adhering iron powder to one end of the copper needle specifically includes:

[0008] Use conductive silver paste to apply to the part of the copper needle where the iron powder needs to be adhered, then sprinkle the iron powder evenly on the surface of the copper needle to ensure that the iron powder is evenly distributed, and wait for it to dry or solidify naturally;

[0009] The copper needle is subjected to magnetization treatment, which specifically comprises:

[0010] Fix the copper needle on a fixture with a recess by a fixture, and place the fixture in an energized solenoid;

[0011] Next, the magnetic field parameters, such as magnetic field strength, frequency and processing time, are adjusted, and then the magnetic field processing is performed;

[0012] After the treatment, use a detection tool such as a magnetometer to detect the magnetization effect of the copper needle;

[0013] After the copper needle is magnetized, the magnetic field strength is slowly reduced, and the magnetized copper needle is cooled by a coolant;

[0014] Prepare the metal pad;

[0015] The metal Pad is magnetized, specifically comprising:

[0016] Applying solder paste mixed with magnetic powder to the metal pad interface;

[0017] Before the solder paste is completely dry, place the N pole of the permanent magnet close to the surface of the product coated with solder paste for a while to allow the magnetic powder to fully absorb the magnetism of the magnet;

[0018] Gently remove the magnet and observe whether the magnetic powder in the solder paste is arranged in the direction of the magnet's polarity;

[0019] Then use the same pole of the permanent magnet to adsorb the solder paste again to strengthen the arrangement direction of the fixed magnetic powder so that the S pole of the magnetic powder faces upward;

[0020] After the magnetization of the metal pad is completed, copper needle implantation is performed, which specifically includes:

[0021] Fix the copper needle product on the vibrating plate, move the porous screen above the product, sprinkle the magnetic copper needle on the porous screen with a slightly larger aperture, place the end with iron powder downward, and make the metal interface of the product with the S pole facing upward;

[0022] The vibration plate is turned on to vibrate, and the copper needles in the screen fall from the holes as they vibrate. The magnetic N pole at the downward end of the copper needle is opposite to the magnetic field on the solder paste, and the two poles attract each other to complete automatic alignment.

[0023] Perform reflow soldering to fix the copper needle;

[0024] Make sure that all metal pad interfaces have implanted pins, and then follow the normal copper implantation process.

[0025] Furthermore, the conductive silver paste is a paste composed of silver powder and an organic solvent.

[0026] Furthermore, the coolant includes but is not limited to liquid nitrogen.

[0027] The beneficial effects of the present invention are as follows: the present invention polarizes one end of the copper needle to make it magnetic and fix the magnetic direction, and then sprinkles it into the steel mesh, which produces an opposite attraction phenomenon with the magnetic field on the solder paste at the interface of the metal pad, so that the two can be connected to achieve the effect of alignment. The present invention can realize automatic alignment and quick connection, the alignment is more accurate, the operation process is simplified, and the connection reliability is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the principle of magnetizing the copper needle;

[0029] Figure 2 Schematic diagram of the structure of a single copper needle, (a) is a top view, (b) is a side view;

[0030] Figure 3 It is a structural schematic diagram of the vibration plate;

[0031] Figure 4 Schematic diagram of the principle of magnetizing the metal Pad;

[0032] Figure 5 Schematic diagram of the principles of copper needle implantation steps.

[0033] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0034] Legend: 1. A fixture with a depression; 2. A copper needle; 3. An energized solenoid; 4. Conductive silver paste that has been solidified after being sprinkled with iron powder; 5. A vibration plate; 6. A porous screen; 7. A pad interface; 8. PI glue; 9. A handle; 10. Screen holes; 11. A bolt; 12. A chuck; 13. A solder paste; 14. A permanent magnet; 15. A substrate. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0037] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0038] Example

[0039] High-precision automatic alignment method with magnetic copper needle

[0040] The method comprises:

[0041] Copper needles are provided;

[0042] Remove impurities and oil stains on the surface of the copper needle by cleaning;

[0043] Adhering iron powder to one end of the copper needle specifically includes:

[0044] Use conductive silver paste to apply to the part of the copper needle where the iron powder needs to be adhered, then sprinkle the iron powder evenly on the surface of the copper needle to ensure that the iron powder is evenly distributed, and wait for it to dry or solidify naturally;

[0045] like Figure 1 As shown, the copper needle is magnetized, and the structure of a single copper needle is as follows Figure 2 As shown, specifically including:

[0046] Fix the copper needle on a fixture with a recess by a fixture, and place the fixture in an energized solenoid;

[0047] Next, the magnetic field parameters, such as magnetic field strength, frequency and processing time, are adjusted, and then the magnetic field processing is performed;

[0048] After the treatment, use a detection tool such as a magnetometer to detect the magnetization effect of the copper needle;

[0049] After the copper needle is magnetized, the magnetic field strength is slowly reduced, and the magnetized copper needle is cooled by a coolant;

[0050] Prepare the metal pad;

[0051] like Figure 4 As shown, magnetizing the metal Pad specifically includes:

[0052] Applying solder paste mixed with magnetic powder to the metal pad interface;

[0053] Before the solder paste is completely dry, place the N pole of the permanent magnet close to the surface of the product coated with solder paste for a while to allow the magnetic powder to fully absorb the magnetism of the magnet;

[0054] Gently remove the magnet and observe whether the magnetic powder in the solder paste is arranged in the direction of the magnet's polarity;

[0055] Then use the same pole of the permanent magnet to adsorb the solder paste again to strengthen the arrangement direction of the fixed magnetic powder so that the S pole of the magnetic powder faces upward;

[0056] After the magnetization of the metal pad is completed, Figure 5 As shown, copper needle implantation is performed, specifically including:

[0057] Fix the copper needle product on the vibration plate. The structure of the vibration plate is as follows: Figure 3 As shown, the porous screen is moved above the product, and the copper needles with magnetic properties are sprinkled in the porous screen with a slightly larger aperture than the diameter of the product. The end with the iron powder is placed downward, so that the metal interface of the product has the S pole facing upward.

[0058] The vibration plate is turned on to vibrate, and the copper needles in the screen fall from the holes as they vibrate. The magnetic N pole at the downward end of the copper needle is opposite to the magnetic field on the solder paste, and the two poles attract each other to complete automatic alignment.

[0059] Perform reflow soldering to fix the copper needle;

[0060] Make sure that all metal pad interfaces have implanted pins, and then follow the normal copper implantation process.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0062] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. High-precision automatic alignment method with magnetic copper needles, Features: include: Copper needles are provided; Remove impurities and oil stains on the surface of the copper needle by cleaning; Adhere iron powder to one end of the copper needle; Magnetizing the copper needle; After the treatment, use a detection tool such as a magnetometer to detect the magnetization effect of the copper needle; After the copper needle is magnetized, the magnetic field strength is slowly reduced, and the magnetized copper needle is cooled by a coolant; Prepare the metal pad; The metal pad is magnetized. After the magnetization of the metal pad is completed, copper needle implantation is performed, which specifically includes: Fix the copper needle product on the vibrating plate, move the porous screen above the product, sprinkle the magnetic copper needles on the porous screen with a slightly larger aperture, place the end with iron powder downward, and make the metal interface of the product with the S pole facing upward; The vibration plate is turned on to vibrate, and the copper needles in the screen fall from the holes as they vibrate. The magnetic N pole at the downward end of the copper needle is opposite to the magnetic field on the solder paste, and the two poles attract each other to complete automatic alignment. Perform reflow soldering to fix the copper needle; Make sure that all metal pad interfaces have implanted pins, and then follow the normal copper implantation process.

2. The high-precision automatic alignment method with a magnetic copper needle according to claim 1, Features: The step of adhering iron powder to one end of the copper needle specifically includes: Use conductive silver paste to apply to the part of the copper needle where the iron powder needs to adhere, then sprinkle the iron powder evenly on the surface of the copper needle to ensure that the iron powder is evenly distributed, and wait for it to dry or solidify naturally.

3. The high-precision automatic alignment method with a magnetic copper needle according to claim 1, Features: The copper needle is subjected to magnetization treatment, which specifically comprises: Fix the copper needle on a fixture with a recess by a fixture, and place the fixture in an energized solenoid; Then the magnetic field parameters such as magnetic field strength, frequency and processing time are adjusted, and then the magnetic field processing is performed.

4. The high-precision automatic alignment method with a magnetic copper needle according to claim 1, Features: Magnetizing the metal Pad specifically includes: Applying solder paste mixed with magnetic powder to the metal pad interface; Before the solder paste is completely dry, place the N pole of the permanent magnet close to the surface of the product coated with solder paste for a while to allow the magnetic powder to fully absorb the magnetism of the magnet; Gently remove the magnet and observe whether the magnetic powder in the solder paste is arranged in the direction of the magnet's polarity; Then, the same pole of the permanent magnet is used again to adsorb the solder paste to strengthen the arrangement direction of the fixed magnetic powder so that the S pole of the magnetic powder faces upward.

5. The high-precision automatic alignment method with a magnetic copper needle according to claim 1, Features: The copper implant needle specifically comprises: Use conductive silver paste to apply to the part of the copper needle where the iron powder needs to be adhered; Then sprinkle the iron powder evenly on the surface of the copper needle, make sure the iron powder is evenly distributed, and wait for it to dry or solidify naturally.

6. The high-precision automatic alignment method with a magnetic copper needle according to claim 1, Features: The conductive silver paste is a paste composed of silver powder and an organic solvent.

7. The high-precision automatic alignment method with a magnetic copper needle according to claim 1, Features: The coolant includes, but is not limited to, liquid nitrogen.

8. The high-precision automatic alignment method with a magnetic copper needle according to claim 1, Features: The method described is limited to chip packages that are not affected by magnetic fields.

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