CN113395837A

CN113395837A - Wet laser forming method for nano metal circuit and structure

Info

Publication number: CN113395837A
Application number: CN202110625035.4A
Authority: CN
Inventors: 杨冠南; 曾宇杰; 崔成强; 张昱
Original assignee: Guangdong University of Technology
Current assignee: Guangdong University of Technology
Priority date: 2021-06-04
Filing date: 2021-06-04
Publication date: 2021-09-14
Anticipated expiration: 2041-06-04
Also published as: CN113395837B

Abstract

The invention relates to the technical field of integrated circuits, in particular to a wet laser forming method of a nano metal circuit and a nano metal structure, which comprises the following steps: s1, presetting a circuit on a carrier plate to form a carrier plate to be formed with the circuit, and then coating a nano metal paste in a wet state on the surface of the carrier plate to be formed with the circuit; s2, modifying the surface of the nano metal paste on the circuit to-be-formed carrier plate to form a pre-sintering neck; irradiating the surface of the nano metal paste on the circuit to-be-formed carrier plate for at least one time by adopting laser to complete circuit sintering to obtain a circuit forming carrier plate; s3, cleaning the circuit forming support plate; and S4, carrying out surface treatment on the cleaned circuit forming carrier plate to obtain the circuit carrier plate. The invention can control the appearance of the circuit, optimize the quality of the circuit and improve the forming efficiency of the circuit.

Description

Wet laser forming method for nano metal circuit and structure

Technical Field

The invention relates to the technical field of integrated circuits, in particular to a wet laser forming method of a nano metal circuit and a structure.

Background

With the development of electronic and electric products towards ultra-large scale integration, digitization and batch, the traditional printed circuit manufacturing process method comprises a chemical method and a template (or silk screen) missing printing method, and large errors are easily caused to high-density and high-precision printed circuit boards due to more manufacturing procedures in the process of printing the circuit boards; the minimum line width and the line spacing are greatly limited, and the line breakage often occurs in the corrosion process, particularly in a high-density multilayer printed board adopted in a large-scale motor computer, because the wiring density is high, the printed lines are thin, and the corrosion and the line breakage at individual positions are more easily caused, so that the waste of a large amount of precious metals and working hours of the board is caused.

With the rapid development of the laser printing technology, the application field of the laser printing technology is wider and wider, the purpose of rapidly forming a circuit can be achieved by coating metal particles on a part to be formed of a broken line and performing laser forming by applying the laser printing technology, and the method is simple to operate, low in cost and short in time consumption, and is considered to be the most effective method at present.

However, in the current laser forming process of metal circuits, the line width and the surface quality of the circuits are difficult to be effectively controlled. The large temperature fluctuation during the sintering process causes the problem that the surface of the formed circuit is difficult to keep flat. Furthermore, laser formed lines still lack effective line cleaning means: after the circuit is formed by laser, the residual unsintered nano metal particles can cause the faults of short circuit and the like of the existing circuit. However, the conventional ultrasonic cleaning method can disperse the nano metal particles into the whole line, and further increases the risk of faults such as short circuit.

Chinese patent publication No. CN110753454B discloses a method for forming and repairing a fine line, which comprises the following steps: step 1, depositing a thin copper layer on a first surface of a light-transmitting plate by a physical vapor deposition method, and then increasing the thickness of the thin copper layer to a required thickness by electroplating; step 2, turning over the light-transmitting plate, and covering the first surface of the light-transmitting plate on the circuit carrier plate; and 3, adjusting the focal length of the laser transmitter to enable laser emitted by the laser transmitter to be focused on the thin copper layer on the first surface of the light-transmitting plate, irradiating the thin copper layer by the laser through the light-transmitting plate according to a preset track, and cladding the thin copper metal on the track on the circuit carrier plate by the laser. And 4, removing the light-transmitting plate from the circuit carrier plate, cleaning the surface of the circuit carrier plate, and removing residual copper at the unsintered part to finish fine circuit molding.

However, in the above scheme, the copper layer is firstly coated by a physical vapor deposition method, and the thickness is also increased by an electroplating method, so that the operation is complicated.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a wet laser forming method of a nano metal circuit and a structure, which can control the appearance of the circuit, optimize the quality of the circuit and improve the forming efficiency of the circuit.

In order to solve the technical problems, the invention adopts the technical scheme that:

a wet laser forming method of nano metal circuit and structure is provided, which comprises the following steps:

s1, presetting a circuit on a carrier plate to form a carrier plate to be formed with the circuit, and then coating a nano metal paste in a wet state on the surface of the carrier plate to be formed with the circuit;

s2, modifying the surface of the nano metal paste on the circuit to-be-formed carrier plate to form a pre-sintering neck; irradiating the surface of the nano metal paste on the circuit to-be-formed carrier plate for at least one time by adopting laser to complete circuit sintering to form a circuit forming carrier plate;

s3, cleaning the circuit forming support plate;

and S4, carrying out surface treatment on the cleaned circuit forming carrier plate to obtain the circuit carrier plate.

The invention relates to a wet laser forming method of a nano metal circuit and a structure, which directly coats a nano metal paste in a wet state on a circuit to-be-formed support plate, can shorten the coating time and improve the forming efficiency of the support plate; then, the surface of the nano metal paste on the circuit carrier plate to be formed is modified to form a pre-sintering neck, so that the flowability of the nano metal paste can be reduced; and sintering the surface of the nano metal paste at high power to obtain the final circuit carrier plate. The invention can control the appearance of the circuit, optimize the quality of the circuit and improve the forming efficiency of the circuit.

Further, in step S2, the modification process includes any one of the following steps:

a. irradiating the circuit to-be-formed support plate by adopting an area flashing light source to volatilize a solvent in the nano metal paste, and primarily sintering nano particles to form a pre-sintering neck;

b. irradiating the circuit to-be-formed support plate by adopting laser to volatilize a solvent in the nano metal paste, and primarily sintering nano particles to form a pre-sintering neck;

c. and (3) heating the circuit to-be-formed support plate wholly or locally by adopting a pre-drying device to volatilize the solvent in the nano metal paste, and primarily sintering the nano particles to form a pre-sintering neck.

Further, before modification treatment, macromolecular long-chain organic matters are added into the nano metal paste to form a nano metal organic mixture.

Further, the macromolecular long-chain organic matter comprises any one or more of epoxy resin, hydroxyl resin and ethyl acrylate.

Further, the content of the macromolecular long-chain organic matter in the nano metal organic mixture is 0.01-10% by mass, and the content of the nano metal paste is 90-99.99%.

Further, the step b comprises any one of the following steps:

b1. irradiating the circuit to-be-formed support plate by adopting single laser;

b2. irradiating the circuit to-be-formed support plate by adopting a plurality of laser beams; setting a main laser to irradiate the circuit on the circuit carrier plate to be formed; and then at least two auxiliary lasers are arranged on two sides of the main laser, and the auxiliary lasers irradiate areas on two sides of the circuit on the carrier plate to be formed on the circuit, so that the solvent in the nano metal paste is volatilized, and the nano particles are primarily sintered to form a pre-sintering neck.

Further, in step b1, the single laser is any one of the following:

laser with the light spot size being 1-10 times of the line width and the pulse being more than 20 ns; or a continuous laser.

Further, when the modification process is performed in step S2, the temperature of the nano metal paste does not exceed 300 ℃.

Further, in step S1, after the coating of the nano metal paste is completed, a glass plate is covered on the circuit board to be formed, and a groove structure having the same shape as the circuit is formed on the glass plate.

Further, in step S4, the surface treatment specifically includes: and spraying organic solution on the surface of the cleaned circuit forming carrier plate to form an anti-oxidation layer on the surface, and then obtaining the circuit carrier plate.

Compared with the prior art, the invention has the beneficial effects that:

Drawings

Fig. 1 is a flow chart of a wet laser forming method of a nano metal line and structure according to the present invention.

Fig. 2 is a schematic structural diagram illustrating the step S2 according to the present invention.

Fig. 3 is a schematic structural diagram after step S2 is completed.

Fig. 4 is a schematic structural diagram after step S3 is completed.

Fig. 5 is a schematic structural diagram of the case where multiple lasers are used in embodiment 2 of the present invention.

Fig. 6 is a schematic structural diagram of the case where multiple lasers are used in embodiment 3 of the present invention.

Fig. 7 is a schematic structural diagram of a laser with a thick spot and a long pulse in embodiment 4 of the present invention.

Fig. 8 is a schematic view of a laser scanning direction in embodiment 4 of the present invention.

Fig. 9 is a schematic structural diagram of embodiment 5 of the present invention.

Fig. 10 is a schematic structural diagram of embodiment 8 of the present invention.

The graphic symbols are illustrated as follows:

1-nano metal paste, 2-circuit to-be-formed carrier plate, 3-laser, 4-sintered circuit and 5-glass plate.

Detailed Description

The present invention will be further described with reference to the following embodiments. Wherein the showings are for the purpose of illustration only and are shown by way of illustration only and not in actual form, and are not to be construed as limiting the present patent; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. based on the orientation or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms may be understood by those skilled in the art according to specific circumstances.

Example 1

Fig. 1 to 4 show a first embodiment of a wet laser forming method for nano metal lines and structures according to the present invention, which includes the following steps:

s1, a circuit is preset on a carrier plate to form a carrier plate 2 to be formed, and then a nano metal paste 1 in a wet state is coated on the surface of the carrier plate 2 to be formed. Specifically, the coating thickness of the nano metal paste 1 is 1-200 μm, and the nano metal paste 1 is a nano copper paste.

S2, after the step S1, carrying out modification treatment on the surface of the nano metal paste 1 on the circuit carrier plate 2 to be formed to form a pre-sintering neck;

wherein the modification treatment is specifically as the following step a: and irradiating the range of the area near the circuit on the circuit-to-be-formed carrier plate 2 by adopting an area flash lamp light source to volatilize the solvent in the nano metal paste 1, and primarily sintering the nano particles to form a presintering neck. It should be noted that the range of the area near the circuit refers to a range of 1 to 10 times the width of the circuit preset on the carrier board. In addition, the temperature of the nano metal paste 1 is maintained at not more than 300 ℃ during the modification treatment.

After the presintering neck is formed, irradiating the surface of the nano metal paste 1 on the circuit to-be-formed carrier plate 2 for at least one time by using a laser 3 to complete circuit sintering so as to obtain a sintered circuit 4 and obtain a circuit forming carrier plate; wherein, the laser emitted by the laser 3 is adjusted to be a fine light spot and a short pulse laser; specifically, the fine light spot and short pulse laser refers to laser with the light spot size being 0.5-1 time of the width of a preset line on the carrier plate and the single pulse time being 1-100 ns.

And S3, cleaning the line forming carrier plate to remove residual metal particles.

S4, carrying out surface treatment on the cleaned line forming carrier plate to obtain a circuit carrier plate; wherein the surface treatment specifically comprises: and spraying organic solution on the surface of the cleaned circuit forming carrier plate to form an anti-oxidation layer on the surface, and then obtaining the circuit carrier plate. Specifically, the organic solution is any one of imidazole, PVP, PEG, and CTAB.

Example 2

This embodiment is similar to embodiment 1, except that the following steps are included:

s1, a circuit is preset on a carrier plate to form a carrier plate 2 to be formed, and then a nano metal paste 1 in a wet state is coated on the surface of the carrier plate 2 to be formed.

S2, modifying the surface of the nano metal paste 1 on the circuit carrier plate to be formed to form a pre-sintering neck; meanwhile, the surface of the nano metal paste 1 on the carrier plate 2 to be formed of the circuit is irradiated at least once by laser to complete the circuit sintering, and then the carrier plate for forming the circuit is obtained.

Specifically, the laser used for the modification treatment and the line sintering may be irradiated with the same laser 3, and a laser beam splitter or a laser diffractor may be provided in the laser 3 so that the laser 3 can emit the main laser for the line sintering and the sub-laser for the modification treatment; the sub laser beam is positioned in front of the main laser beam, and front refers to a front direction along the laser scanning direction, as shown in fig. 5.

Example 3

This embodiment is similar to embodiment 2 except that, in the modification processing and the line sintering in step S2, a coarse spot is set, the long pulse laser is subjected to the modification processing in the front, and a fine spot, the short pulse laser is set, and the line sintering is performed in the rear, as shown in fig. 6. The thick light spot and long pulse laser refer to laser with light spot size 1-10 times the width of a preset line on the carrier plate and pulse length more than 20 ns; the thin light spot and short pulse laser refers to laser with the light spot size being 0.5-1 time of the width of a preset line on the carrier plate and the single pulse time being 1-100 ns.

Example 4

This example is similar to example 1, except that in step S2, the modification process is specifically as in step b: and irradiating the carrier plate to be formed on the circuit by adopting laser to volatilize the solvent in the nano metal paste, and primarily sintering the nano particles to form a pre-sintering neck. In this embodiment, step b1 is executed: the carrier plate to be formed is irradiated with a single laser beam line to form a pre-sintering neck, as shown in fig. 7 and 8.

Specifically, the single laser may be: coarse light spot, long pulse laser; the thick light spot and the long pulse laser refer to lasers with light spot size 1-10 times of the width of a preset circuit on the carrier plate and pulse length more than 20 ns.

In particular, the single laser may also be a continuous laser.

The light spot of the single laser is any one of a circle, an ellipse and a rectangle, the long axis of the laser light spot is perpendicular to the direction of the line, and the length of the long axis of the laser light spot is 1-10 times of the width of the preset line on the carrier plate. When laser irradiation scanning is used, the scanning method is to perform a plurality of superimposed scans in parallel or perpendicular to the line direction.

Example 5

In this embodiment, similar to embodiment 4, in step S2, the modification process is specifically as in step b: and irradiating the carrier plate to be formed on the circuit by adopting laser to volatilize the solvent in the nano metal paste, and primarily sintering the nano particles to form a pre-sintering neck. The difference is that the present embodiment executes step b 2:

adopting a plurality of laser irradiation lines to irradiate the carrier plate 2 to be formed; wherein, a main laser is arranged to irradiate the circuit on the circuit carrier plate to be formed; then at least two secondary lasers are arranged at the two sides in front of the main laser, the secondary lasers irradiate the area range near the circuit on the carrier plate to be formed on the circuit, so that the solvent in the nano metal paste 1 is volatilized, and the nano particles are primarily sintered to form a pre-sintering neck; as shown in fig. 9.

The range of the nearby area means that the maximum distance of the laser center of the secondary laser is 1-10 times of the width of the preset line on the carrier plate, and the size of a laser spot is 1-10 times of the width of the preset line on the carrier plate.

Example 6

This example is similar to example 1, except that in step S2, the modification process is specifically as in step c: and (3) heating the circuit to-be-formed carrier plate 2 wholly or locally by adopting a pre-drying device to volatilize the solvent in the nano metal paste, and primarily sintering the nano particles to form a pre-sintering neck. Specifically, the pre-drying device is any one of an infrared heating device, a directional radiation heating device, a directional high-temperature inert heating device and a reducing gas blowing heating device.

Example 7

This example is similar to examples 1 to 6, except that a nanometal organic mixture was formed by adding a macromolecular long-chain organic substance to the nanometal paste 1 before the modification treatment. Wherein, the macromolecular long-chain organic matter comprises any one or more of epoxy resin, hydroxyl resin and ethyl acrylate. Specifically, the content of the macromolecular long-chain organic matter in the nano metal organic mixture is 0.01-10% by mass, and the content of the nano metal paste is 90-99.99%. Therefore, when modification treatment is carried out, the solvent in the nano metal paste is volatilized through light source irradiation, the nano metal organic mixture is heated and shrunk, and the nano particles are primarily sintered to form a pre-sintering neck.

Example 8

This embodiment is similar to embodiments 1 to 7, except that in step S1, after the coating of the nano-metal paste 1 is completed, the glass plate 5 is covered on the circuit board to be formed; wherein, the glass plate 5 is provided with a groove structure with a shape similar to that of the circuit; as shown in fig. 10. Specifically, the similarity between the groove structure and the shape of the circuit means that the width of the groove structure is 1-10 times of the width of a preset circuit on the carrier plate, and the thickness of the groove structure is the same as the thickness of the circuit. After the glass plate 5 is covered, the groove structure can distinguish the nano metal paste 1 at the line position from the nano metal paste 1 at other positions, and the nano metal paste 1 is prevented from flowing directionally in the line sintering process.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A wet laser forming method for nano metal lines and structures is characterized by comprising the following steps:

s2, modifying the surface of the nano metal paste on the circuit to-be-formed carrier plate to form a pre-sintering neck; irradiating the surface of the nano metal paste on the circuit to-be-formed carrier plate for at least one time by adopting laser to complete circuit sintering to obtain a circuit forming carrier plate;

s3, cleaning the circuit forming support plate;

2. The method of claim 1, wherein in step S2, the modification process comprises any one of the following steps:

3. The wet laser forming method of claim 2, wherein the nanometal paste is added with macromolecular long-chain organic substances before modification to form a nanometal-organic mixture.

4. The wet laser forming method of nano metal lines and structures according to claim 3, wherein the macromolecular long-chain organic substance comprises any one or more of epoxy resin, hydroxyl resin and ethyl acrylate.

5. The wet laser forming method of nano metal lines and structures as claimed in claim 3, wherein the nano metal organic mixture comprises 0.01-10% by mass of the macromolecular long-chain organic substance and 90-99.99% by mass of the nano metal paste.

6. The wet laser forming method of nano-metal lines and structures as claimed in claim 2, wherein the step b comprises any one of the following steps:

7. The wet laser forming method of nano-metal lines and structures as claimed in claim 6, wherein in step b1, the single laser is any one of the following:

laser with the light spot size being 1-10 times of the line width and the pulse being more than 20 ns;

and (4) continuous laser.

8. The wet laser forming method of nano-metal lines and structures as claimed in claim 1, wherein the temperature of the nano-metal paste does not exceed 300 ℃ when the modification process is performed in step S2.

9. The wet laser forming method for nano-metal lines and structures as claimed in claim 1, wherein in step S1, after the coating of nano-metal paste is completed, a glass plate is coated on the carrier board to be formed with the lines, and the glass plate is provided with a groove structure similar to the shape of the lines.

10. The wet laser forming method for nano-metal lines and structures as claimed in claim 1, wherein in step S4, the surface treatment specifically comprises: and spraying organic solution on the surface of the cleaned circuit forming carrier plate to form an anti-oxidation layer on the surface, and then obtaining the circuit carrier plate.