A line forming process based on high-speed high-precision roll-to-roll resist film punching

Abstract

The present application belongs to the technical field of printed circuit board precision line forming, and particularly relates to a line forming process based on high-speed and high-precision roll-to-roll resist film punching, which comprises the following steps: a mark hole punching process, in which mark holes with the same interval and coinciding positions are punched on the acid-resistant film and copper foil; an acid-resistant film punching process, in which the acid-resistant film is semi-punched, and the acid-resistant film in the non-line area is flattened; a pattern transfer process, in which the acid-resistant film and the copper foil are respectively aligned by using a CCD machine vision system, and the punched acid-resistant film is transferred to the copper foil by means of movable rollers, rubber rollers and heating rollers; and an etching and film stripping process, in which the copper foil with the acid-resistant film is sequentially soaked in an acid solution and an alkaline solution, and the line forming is completed. The present application reduces the material cost and saves the equipment cost, and is easier to control than the traditional exposure and development process, with a yield of 99.9%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of printed circuit board precision circuit forming, and particularly relates to a circuit forming process based on high-speed and high-precision roll-to-roll resist film punching. BACKGROUND

[0002] With the continuous development of science and technology, electronic products are increasingly developing towards miniaturization, intelligence, high performance and high reliability. The packaging substrate is transitioning from FPC to COF, and the PITCH value of the COF substrate is becoming smaller and smaller, and the pins in the packaging are becoming more and more dense and precise. The integrated circuit packaging not only directly affects the performance of the integrated circuit, electronic module and even the whole machine, but also restricts the miniaturization, low cost and reliability of the whole electronic system. In the increasingly competitive market, reducing production costs is a problem that COF enterprises have to face.

[0003] For example, large-screen mobile phones sold in the market, in order to pursue a larger screen ratio, most of them use COF technology, because COF products have high bending resistance and can achieve 180° bending, so that the IC on the substrate can be bent to the back of the screen, increasing the screen ratio. In the COF process, precision circuit forming is a crucial step. In the traditional process, the copper foil needs to go through dry film pasting, pattern transfer, development, etching and film stripping. Among them, in the dry film pasting, pattern transfer and development processes, the product needs to be kept in a non-ultraviolet light irradiation environment, which has strict requirements on the working environment. The production process is complex, increasing the difficulty of process control, and at the same time, for roll-to-roll production products, it is impossible to control the defects produced in the pattern transfer or development process, resulting in low production yield and high cost. SUMMARY

[0004] To overcome the above technical problems, the present application provides a process for forming a circuit by pasting an acid-resistant film on a copper foil, then transferring a pattern, etching and stripping the film to achieve the purpose of reducing cost and improving production efficiency.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] A circuit forming process based on high-speed and high-precision roll-to-roll resist film punching, comprising a mark hole punching process, an acid-resistant film punching process, a pattern transfer process, an etching process and a film stripping process; wherein,

[0007] The mark hole punching process: according to the size of the product pattern, set the hole spacing, punch mark holes with the same spacing and position coinciding on the acid-resistant film and the copper foil;

[0008] Acid-resistant film punching process: according to the product pattern, the acid-resistant film is semi-punched, only the acid-resistant film is punched off; the non-wire area is punched by using a mold, and the acid-resistant film in the non-wire area is flattened;

[0009] Pattern transfer process: the mark points on the acid-resistant film and the copper foil are recognized by using a CCD machine vision system respectively, the acid-resistant film and the copper foil are aligned, the movable roller holds up the acid-resistant film and contacts the rubber roller, the heating roller holds up the copper foil and contacts the rubber roller, and the rubber roller transfers the punched acid-resistant film to the copper foil;

[0010] Etching process: the copper foil with the acid-resistant film is transferred to an acid solution pool, the copper foil without the acid-resistant film covering area is etched away, and the line spacing is formed;

[0011] Film stripping process: the etched copper foil is transferred to an alkaline solution pool, the acid-resistant film is stripped off, and the circuit forming is completed.

[0012] Further, the acid-resistant film and the copper foil are subjected to the mark hole punching process and are wound on the reel for use; the reels of the acid-resistant film and the copper foil after the mark hole punching are respectively installed at the acid-resistant film unwinding end and the copper foil unwinding end of the film attaching equipment, and the ends of the acid-resistant film and the copper foil are respectively connected to the reels at the acid-resistant film winding end and the copper foil winding end, so as to perform the acid-resistant film punching process and the pattern transfer process.

[0013] Further, in the acid-resistant film punching process, the mold has a heating function, and the temperature control is controlled at 30-120 DEG C.

[0014] Further, in the pattern transfer process, the movable roller has a cooling function, and the temperature control is controlled at 0-20 DEG C; the heating roller has a heating function, and the temperature control is controlled at 30-120 DEG C; and the pressure between the movable roller, the rubber roller and the heating roller is controlled at 10.0-50.0 N.

[0015] Further, between the acid-resistant film punching process and the pattern transfer process, there is also a punching inspection process, the punched MAP is transmitted to the PLC, the punched acid-resistant film is compared with the reference template, and the defective products are recorded.

[0016] After the pattern transfer process, the CCD machine vision system is installed, whether the mark holes of the attached acid-resistant film and the copper foil overlap is checked, if not, the equipment stops and alarms.

[0017] The acid-resistant film of the present application replaces the dry film in the traditional process, and the light type does not need to be controlled, only the acid resistance is required, the material cost is reduced, and the equipment cost is saved;

[0018] The punching and film pasting process of the present application replaces the film pasting, exposure and development processes of the traditional process, and the process control of the punching and film pasting process is easier than that of the traditional exposure and development process.

[0019] The present application can remove defective products during punching, and the product yield is improved to 99.9%. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 : Schematic diagram of acid-resistant film structure;

[0021] Figure 2 : Schematic diagram of copper foil marking hole;

[0022] Figure 3 : Schematic diagram of acid-resistant film marking hole;

[0023] Figure 4 : Schematic diagram of acid-resistant film after punching;

[0024] Figure 5 : Schematic diagram of process flow of the present application;

[0025] Figure 6 : Schematic diagram of product after etching;

[0026] Figure 7 : Schematic diagram of product after film removal. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described clearly and completely in combination with embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0028] The present application provides a line forming process based on high-speed and high-precision roll-to-roll etching film punching, which is based on the principle that the acid-resistant film 12 is pasted to the copper foil 13 to form a line area, and the non-pasted area of the copper foil 13 is a non-line area; the exposed copper foil 13 in the non-line area is etched by using an acidic solution to form a line distance, and the copper foil 13 in the line area does not react with the acidic solution due to the protection of the acid-resistant film 12; the acid-resistant film 12 is stripped by using an alkaline solution in the line area of the copper foil 13 to realize line forming.

[0029] The acid-resistant film 12 and the copper foil 13 are both market-purchased products, wherein the lower surface of the acid-resistant film 12 is attached with a release film 14, as shown in Figure 1 .

[0030] The basic scheme of the present application: first, the acid-resistant film 12 and the copper foil 13 are punched to mark holes, then the acid-resistant film 12 is punched, and the punched acid-resistant film 12 is transferred by the weakly adhesive rubber roller 7, and the acid-resistant film 12 is attached to the copper foil 13. Because the acid-resistant film 12 is resistant to acid, then etched by an acidic solution, the copper foil 13 area not covered by the acid-resistant film is etched, and finally the film stripping process is carried out by an alkaline solution, the acid-resistant film 12 is corroded and peeled off, and the purpose of circuit forming is achieved.

[0031] Wherein:

[0032] Punching mark holes: as shown in Figure 2 and Figure 3 The acid-resistant film 12 and the copper foil 13 are punched to mark holes, the copper foil mark hole 131 is a φ0.7mm round hole, and the hole spacing can be 1mm-1000mm, the selection range depends on the size of the product pattern; the acid-resistant film mark hole 121 is a φ0.5mm round hole, and the hole spacing needs to be the same as that on the copper foil 13. The acid-resistant film 12 and the copper foil 13 are attached to each other.

[0033] After punching the mark holes, the acid-resistant film 12 and the copper foil 13 are put into the reel for use.

[0034] Acid-resistant film punching: as shown in Figure 4 According to the product pattern, the acid-resistant film 12 is semi-punched, only the acid-resistant film 12 is punched off, and the release film 14 is not punched off, to ensure the integrity of the release film 14. In this process, the die 2 punches the non-circuit area, flattens the acid-resistant film 12 of the non-circuit area, which is thinner than the circuit area, and is more conducive to pattern transfer. After this process, the circuit area and the non-circuit area of the acid-resistant film 12 have been separated, the acid-resistant film 12 that is not transferred is connected with the release film 14, and the acid-resistant film of the non-circuit area will not be stuck up during pattern transfer. The upper die 2 in this process can have a heating function, and the temperature control can be controlled at 30-120℃ according to the characteristics of the acid-resistant film, which facilitates the die 2 demolding and prevents the acid-resistant film 12 from being lifted.

[0035] After the acid-resistant film punching is completed, in order to improve the yield and reduce the cost, the punching inspection 3 is carried out: the punched acid-resistant film is compared with the reference template to check whether the punched acid-resistant film 12 has defective products. The punched MAP is transmitted to the PLC, and the defective products are recorded. During pattern transfer, only good products are attached, and defective products are excluded. The purpose of improving yield and reducing cost can be achieved.

[0036] Pattern transfer: as shown in Figure 5As shown, the mark points on the acid-resistant film 12 and the copper foil 13 are identified respectively using the CCD machine vision system 4, the mark points are aligned according to the installation position of the CCD machine vision system 4, and the acid-resistant film is attached in the pattern transfer area. There is a movable roller 5 under the acid-resistant film, which supports the acid-resistant film 12 and contacts the rubber roller 7. When the defective product passes through this area, the PLC controls the movable roller 5 to lower, so that the acid-resistant film 12 is separated from the rubber roller 7 and does not attach, and is directly wound. At the same time, the PLC controls the copper foil 13 to stop conveying, and waits for the good product to pass through, and then the pattern transfer is performed again. The movable roller 5 has a cooling function, and the temperature is controlled at 0-20°C. Reducing the temperature can reduce the adhesion of the glue, and facilitate the separation of the punched acid-resistant film 12 and the release film 14 for pattern transfer. There is a weakly adhesive rubber roller 7 above the movable roller 5, which separates the punched acid-resistant film 12 and the release film 14 and transfers them to the copper foil 13. The rubber roller 7 contacts the high-viscosity dust roller 8 during operation to achieve foreign matter cleaning and prevent foreign matter from causing defects. There is a heating roller 9 behind the copper foil 13, which can heat the copper foil 13. The temperature can be controlled at 30-120°C. Heating can increase the adhesion of the glue, and the acid-resistant film 12 is more reliable after being attached to the copper foil 13. There is a certain pressure between the rubber roller 7, the movable roller 5 and the heating roller 9, which improves the reliability of pattern transfer. The pressure can be controlled between 10.0N-50.0N.

[0037] In order to timely find the displacement of the copper foil 13 and the acid-resistant film 12 during pattern transfer, a CCD machine vision system 4 is installed at the copper foil winding end 11 to check whether the mark holes after attachment overlap. If the acid-resistant film mark hole is not within the range of the copper foil 13 mark hole, the equipment stops and alarms, and the parameters are adjusted in time to continue the attachment.

[0038] Etching: The copper foil 13 with the attached acid-resistant film is transferred to an acid solution pool, and an acid solution (such as hydrochloric acid, copper chloride solution, etc.) is used to soak the copper foil 13. Since the acid-resistant film 12 is resistant to acid, the acid solution will etch away the copper foil 13 without the acid-resistant film covering area, forming a line distance, as shown in Figure 6 .

[0039] Film stripping: The etched copper foil 13 is transferred to an alkaline solution pool, and an alkaline solution (such as sodium hydroxide solution, etc.) is used to soak the copper foil 13. The acid-resistant film 12 reacts with the alkaline solution, and finally the acid-resistant film 12 is stripped off to achieve the purpose of circuit forming, as shown in Figure 7 .

[0040] As shown in Figure 5As shown, the process flow of the embodiment: according to the size of the product pattern, set the hole spacing, mark the hole of acid-resistant film 12 and copper foil 13, the mark hole spacing of acid-resistant film 12 and copper foil 13 is the same, the position is coincident, which is convenient for the alignment of acid-resistant film 12 and copper foil 13 when pasting. After marking the hole, the acid-resistant film 12 and copper foil 13 are put into the reel for use. The reel of acid-resistant film 12 which has completed the marking hole is installed at the acid-resistant film winding-out end 1 of the film pasting equipment, and the end of the acid-resistant film 12 is connected to the reel at the acid-resistant film winding-in end 6. Similarly, the reel of copper foil 13 which has completed the marking hole is installed at the copper foil winding-out end 10 of the film pasting equipment, and the end of the copper foil 13 is connected to the reel at the copper foil winding-in end 11.

[0041] The reels at the acid-resistant film winding-in end 6 and the copper foil winding-in end 11 rotate to drive the acid-resistant film 12 and the copper foil 13 to move. When the acid-resistant film 12 passes through the punching die 2, it is half-punched to cut off the acid-resistant film 12 and ensure the integrity of the release film 14. The die 2 flattens the acid-resistant film in the non-wiring area, which is thinner than the wiring area, completing the acid-resistant film punching process. After the acid-resistant film punching is completed, the punching inspection 3 is performed to compare the punched acid-resistant film with the reference template to check whether there is any defective product in the punched acid-resistant film. The punched MAP is transmitted to the PLC for checking the defective product and recording.

[0042] In the pattern transfer process, the CCD machine vision system 4 is used to identify the mark points on the acid-resistant film 12 and the copper foil 13, and the alignment of the acid-resistant film 12 and the copper foil 13 is completed. The acid-resistant film 12 and the copper foil 13 are pasted in the pattern transfer area, and there is a movable roller 5 under the acid-resistant film 12, which lifts the acid-resistant film 12 to contact with the rubber roller 7. The heated roller 9 lifts the copper foil 13 to contact with the rubber roller 7. The rubber roller 7 transfers the punched acid-resistant film 12 to the copper foil 13, completing the pattern transfer process. When the defective product recorded by the PLC passes through the pattern transfer area, the PLC controls the movable roller 5 to lower, so that the acid-resistant film 12 is separated from the rubber roller 7, and the pasting is not performed, and the product is directly wound; at the same time, the PLC controls the copper foil winding-in end 11 to stop rotating, and waits for the good product to pass through, and then the pattern transfer is performed.

[0043] After the pattern transfer process, the CCD machine vision system 4 is installed at the copper foil winding-in end 11 to check whether the mark holes after pasting are overlapped. If the mark hole of the acid-resistant film 12 is not within the range of the mark hole of the copper foil 13, the equipment stops and alarms, and the parameters are adjusted in time to continue pasting.

[0044] After the whole roll of copper foil 13 completes the pattern transfer, the copper foil 13 with the pasted acid-resistant film is transferred to the acid solution pool, and the copper foil 13 is soaked in the acid solution to etch away the copper in the area without the acid-resistant film coverage, forming a line distance, completing the etching process. Figure 6The copper foil 13 after etching is transferred to a pool of alkaline solution, and the copper foil is soaked in the alkaline solution to peel off the acid-resistant film 12, thus forming the circuit and completing the film peeling process. Figure 7

[0045] While some specific embodiments of the disclosure have been described in detail by way of example with reference to the drawings, it should be understood that the examples are for illustrative purposes only and are not intended to limit the scope of the disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the disclosure. The scope of the disclosure is defined by the appended claims.​

Claims

1. A high-speed high-precision roll-to-roll resist film punching-based line forming process, characterized in that: The method comprises a punch mark hole process, an acid-proof film punching process, a pattern transfer process, an etching process and a film stripping process. The punch mark hole process: according to the size of the product pattern, set the hole spacing, and punch the same spacing and position coinciding mark holes on the acid-proof film (12) and the copper foil (13); The acid-proof film punching process: according to the product pattern, semi-punch the acid-proof film (12), wherein the lower surface of the acid-proof film (12) is attached with a release film (14), and the acid-proof film (12) is only punched off during semi-punching, but the release film (14) is not; use the mold (2) to punch the non-wiring area, and flatten the acid-proof film (12) in the non-wiring area; The pattern transfer process: use the CCD machine vision system (4) to identify the mark points on the acid-proof film (12) and the copper foil (13) respectively, complete the alignment of the acid-proof film (12) and the copper foil (13), the movable roller (5) holds up the acid-proof film (12) and contacts with the rubber roller (7), the heating roller (9) holds up the copper foil (13) and contacts with the rubber roller (7), and the rubber roller (7) transfers the punched acid-proof film (12) to the copper foil (13); The etching process: transfer the copper foil (13) with the attached acid-proof film to the acid solution pool, etch away the copper foil (13) without the acid-proof film covering area, and form the line spacing; The film stripping process: transfer the etched copper foil (13) to the alkaline solution pool, strip off the acid-proof film (12), and complete the circuit forming.

2. The process according to claim 1, wherein the process is a high speed and high precision roll-to-roll resist film punching process. Perform the punch mark hole process on the acid-proof film (12) and the copper foil (13), and collect them in the reel for use; Install the reels of the acid-proof film (12) and the copper foil (13) after completing the punch mark hole process on the acid-proof film (12) and the copper foil (13) in the acid-proof film roll-out end (1) and the copper foil roll-out end (10) of the film attaching equipment respectively, connect the ends of the acid-proof film (12) and the copper foil (13) to the reels in the acid-proof film roll-in end (6) and the copper foil roll-in end (11) respectively, and perform the acid-proof film punching process and the pattern transfer process.

3. The process according to claim 1 or 2, wherein the process is a high speed and high precision roll-to-roll resist film punching process. In the acid-proof film punching process, the mold (2) has a heating function, and the temperature is controlled at 30-120°C.

4. The process of claim 3, wherein the process is characterized by: In the pattern transfer process, the movable roller (5) has a cooling function, and the temperature is controlled at 0-20°C; the heating roller (9) has a heating function, and the temperature is controlled at 30-120°C; the pressure between the movable roller (5), the rubber roller (7) and the heating roller (9) is controlled at 10.0-50.0N.

5. The process according to claim 1 or 2, wherein the process is a high speed and high precision roll-to-roll resist film punching process. There is also a punching inspection process between the acid-proof film punching process and the pattern transfer process, the punched MAP is transmitted to the PLC, the punched acid-proof film (12) is compared with the reference template, and the defective products are recorded.

6. The process of claim 5, wherein the process is a high speed and high precision roll-to-roll resist film punching process. Install the CCD machine vision system (4) after the pattern transfer process, check whether the mark holes of the acid-proof film (12) and the copper foil (13) after attachment overlap, and if not, stop the equipment and alarm.

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