CN102638947B - Production technology of silver paste over-line printed circuit board - Google Patents

Abstract

The invention relates to a silver paste cross-line printed circuit board production process. The process steps include material cutting-edge grinding-NC drilling-deburring-pre-printing treatment-printing reverse solder resist ink, UV curing-printing graphic ink, UV curing—etching, ink removal—solder resist printing pretreatment—printing front solder resist ink, UV curing—printing front text, UV curing—printing reverse text, UV curing—preprinting treatment—printing insulating layer 1 ink, UV curing— Printing insulation layer 2 ink, UV curing - silver paste cross-line printing pretreatment - printing silver paste cross-line - silver paste hot air curing - pre-printing treatment - printing silver paste protective layer 1 ink, UV curing - printing silver paste protective layer 2 ink , Hot air curing - hot air leveling with lead - punching - open circuit detection - low resistance detection - finished product inspection - packaging, shipping.

Description

Silver paste cross-line printed circuit board production process

Technical field:

The invention relates to a production process of a silver paste cross-line printed circuit board.

Background technique

The traditional double-sided metallized hole is to use double-sided copper-clad laminates. Through the production process of drilling, chemical copper formation and electroplating copper, the copper lines on different sides of the substrate are connected into a loop. It requires double-sided copper-clad laminates, and the chemical And the electroplating production process will produce toxic waste liquid and pollute the environment. In addition, the production cost is high, the production cycle is long, and the production efficiency is low.

Contents of the invention

In order to overcome the above-mentioned defects, the object of the present invention is to provide a production process of a silver paste cross-line printed circuit board, which can be used to form a double-layer conductive circuit on a single-sided copper-clad board, that is, printed with silver paste to form a cross-line Multiple non-adjacent loops are connected into a loop with almost the same potential, and the silver paste jumper and the underlying copper wire have a relatively high insulation resistance, which can meet the requirements of the original design of the circuit.

In order to achieve the above object, the present invention adopts the following technical scheme: silver paste cross-line printed circuit board production process, which is: material cutting - edge grinding - NC drilling - deburring - pre-printing treatment - printing reverse solder resist ink, UV Curing—printing graphics ink, UV curing—etching, ink removal—solder mask printing pretreatment—printing front solder mask ink, UV curing—printing front text, UV curing—printing reverse text, UV curing—printing pretreatment—printing insulating layer 1 ink, UV curing - printing insulation layer 2 ink, UV curing - silver paste cross-line printing pretreatment - printing silver paste cross-line - silver paste hot air curing - pre-printing treatment - printing silver paste protective layer 1 ink, UV curing - printing Silver paste protective layer 2 ink, hot air curing - hot air leveling with lead - punching - open circuit detection - low resistance detection - finished product inspection - packaging, shipping.

In order to reduce the surface stress of the insulating layer, the light energy when the first layer of insulating ink is cured is actually controlled at 650-750mj/cm ² , so that the ink is in a semi-cured state, and the pencil hardness is between HB-1H, which improves the The adhesion between the silver paste and the insulating layer eliminates the separation of the silver paste and the insulating layer.

The cured UV light energy of the ink on the second insulating layer is controlled at a semi-cured state of 700-800mj/cm ² , which enhances the bonding force between the insulating layer and the silver paste cross-line.

Silver paste cross-line: adopt single-sided PCB screen printing process, select 170-mesh screen and 40μm thick film that can meet the resistance requirements of silver paste cross-line to make printing screen, so that the thickness of silver paste cross-line printed each time Keep relatively consistent to maintain the stability of the resistance value of the product's silver paste across the line.

The UV light energy of the first layer of silver paste cross-line protective layer ink is controlled at a semi-cured state of 700-800mj/cm ² to enhance the bonding force between the insulating layer and the silver paste cross-line.

1. Use American Acheson 976-SSHV (or Korean Sun NS-FSP04) silver paste with low resistivity as the cross-line printing material to ensure that the lines connected by the cross-line have a relatively low potential difference;

2. Select Shanghai Xiangle Tiancun USR-11G-11 UV-curable solder resist ink with low pencil hardness as the insulating layer ink and silver paste protective layer between the two conductive layers, and control the light energy process parameters of ink curing, It can not only ensure the insulation, but also achieve good adhesion between the insulating layer and the silver paste across the line;

3. Select the cleaning solution and water washing combination with degreasing and deoxidation of copper foil as the pre-treatment process for cross-line printing of silver paste to ensure strong adhesion between silver paste and copper plate and reduce the contact resistance between silver paste and copper plate.

4. Use heat-curing solder resist ink as the last silver paste cross-line protective layer ink to better protect the silver paste cross-line and improve the thermal shock resistance of the product. The product has undergone lead hot air leveling, reflow soldering and wave peak After the high-temperature impact of soldering, the resistance value of the silver paste across the line has a small change rate.

The silver paste cross-line printed circuit board of the present invention is compared with the metallized hole double-sided board: the production technology of the silver paste cross-line printed circuit board is to form a double-layer circuit board on a single-sided copper-clad sheet through a screen printing process. Compared with the metallized hole double-sided process, the production cycle is shorter, the efficiency is higher, and it is more suitable for mass production of products; the most important thing is that it does not use chemical plating

process, there is no waste liquid that damages the environment, and it saves 50% of copper raw materials compared with metallized double-sided panels, and also greatly reduces product drilling costs. It conforms to the concept of clean production and has positive significance for environmental protection.

Detailed ways

Further explanation below:

A SIIC N300 printed circuit board product is used in automobile dashboards. This circuit board is produced by the production technology of silver paste cross-line single-sided printed circuit board.

Silver paste cross-line printed circuit board production process: it is: material cutting - edge grinding - NC drilling - deburring - pre-printing treatment - printing reverse solder resist ink, UV curing - printing graphic ink, UV curing - etching, deburring Ink—solder resist printing pretreatment—printing front solder resist ink, UV curing—printing front text, UV curing—printing reverse text, UV curing—printing pretreatment—printing insulating layer 1 ink, UV curing—printing insulating layer 2 ink, UV curing - silver paste cross-line printing pretreatment - printing silver paste cross-line - silver paste hot air curing - pre-printing treatment - printing silver paste protective layer 1 ink, UV curing - printing silver paste protective layer 2 ink, hot air curing - lead Hot air leveling - punching - open circuit detection - low resistance detection - finished product inspection - packaging, shipment.

In order to reduce the surface stress of the insulating layer, the light energy when the first layer of insulating ink is cured is actually controlled at 650-750mj/cm ² , so that the ink is in a semi-cured state, and the pencil hardness is between HB-1H, which improves the The adhesion between the silver paste and the insulating layer eliminates the separation of the silver paste and the insulating layer, and solves a key problem.

The cured UV light energy of the ink on the second insulating layer is controlled at a semi-cured state of 700-800mj/cm ² , which enhances the bonding force between the insulating layer and the silver paste cross-line.

Silver paste cross-line: adopt single-sided PCB screen printing process, select 170-mesh screen and 40μm thick film that can meet the resistance requirements of silver paste cross-line to make printing screen, so that the thickness of silver paste cross-line printed each time Keep relatively consistent to maintain the stability of the resistance value of the product's silver paste across the line.

The UV light energy of the first layer of silver paste cross-line protective layer ink is controlled at a semi-cured state of 700-800mj/cm ² to enhance the bonding force between the insulating layer and the silver paste cross-line.

1. In the printing and curing process of the insulating layer ink in the production process, we use Shanghai Xiangle Tiancun USR-11G-11 solder resist ink, and through the special control of the ink curing light energy, the contact between the silver paste cross-line and the insulating layer is improved. Adhesion eliminates the separation of silver paste and insulating layer, which solves a key problem.

2. The second key issue is to ensure that the silver paste and the copper plate have a good bonding force, so that the contact resistance between the silver paste and the copper plate is ≤20mΩ, and after the product is leveled by hot air with lead, the resistance of the silver paste cross-line circuit The value change rate should be ≤30%, which is the most critical. For this reason, in the pre-treatment process of silver paste cross-line printing, we use a cleaning solution with the effect of degreasing and removing copper foil oxidation and an optimized combination of water washing, so that the product has a clean copper surface before printing silver paste across the line. After testing, the actual contact resistance between the silver paste and the copper plate is less than 15mΩ. After the product is leveled by hot air with lead, the actual change rate of the resistance of the silver paste cross-line circuit is ≤20%.

3. In order to make the circuit connected by the silver paste across the line in the product have a relatively "zero" potential, we choose the American Acheson 976-SSHV (or Korean Sun NS-FSP04) conductive silver paste, and use the appropriate The silver paste is printed on the screen to ensure that the printed silver paste has a certain thickness across the line and finally meets the requirement of low resistance value. After testing, the actual square resistance of the silver paste cross-line on our products is <20mΩ (the product square resistance standard is ≤40mΩ).

4. In order to keep the resistance of the silver paste cross-line circuit relatively stable after the product is leveled with lead hot air, we chose heat-curing solder resist ink as the final silver paste cross-line protective layer, which improved the thermal shock resistance of the product , After testing, after the product is leveled with lead hot air, the resistance value change rate of the silver paste cross-line circuit is <20%.

Claims (3)

1. single side printed wiring board production technology: it is: sawing sheet-edging-NC boring-deburring-printing pre-treatment-printing reverse side solder mask, UV solidification-printed pattern ink, UV solidification-etching, removal ink-welding resistance printing pre-treatment-printing front solder mask, UV solidifies-prints front word, UV solidifies-prints reverse side word, UV solidifies-prints pre-treatment-printing ground floor dielectric ink, UV solidifies-prints second layer dielectric ink, UV solidification-Yin starches cross-line printing pre-treatment-printing silver slurry cross-line-Yin slurry hot blast and solidifies-print pre-treatment-printing ground floor silver slurry protective layer ink, UV solidifies-prints second layer silver slurry protective layer ink, hot blast solidifies-has plumbous hot air leveling-die-cut-break-make road detection-low resistance detection-product inspection-packaging, shipment, light energy working control when ground floor dielectric ink is solidified is at 650 ~ 750mj/cm ², make ink be in semi-cured state, make its pencil hardness between HB ~ 1H, improve the adherence of silver slurry cross-line and insulating barrier, eliminate silver slurry and insulating barrier segregation phenomenon, the UV light energy of second layer dielectric ink solidification controls at 700 ~ 800mj/cm ², make ink be in semi-cured state, reinforced insulation layer starches the adhesion of cross-line with silver.

2. single side printed wiring board production technology according to claim 1, it is characterized in that: silver slurry cross-line: adopt one side PCB silk-screen printing technique, printing screen plate made by the 170 order silk screens selecting the resistance that can meet silver slurry cross-line to require and 40 μm of thickness films, the silver slurry cross-line thickness of each printing is made to keep relatively consistent, to keep product silver slurry cross-line resistance stability.

3. single side printed wiring board production technology according to claim 1, is characterized in that: the UV light energy of ground floor silver slurry protective layer ink controls at 700 ~ 800mj/cm ², make ink be in semi-cured state, reinforced insulation layer starches the adhesion of cross-line with silver.