JPH0319537B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photosensitive laminated structure having a structure in which a film is laminated on at least one side of a photoresist layer. A photoresist layer is formed on a light-transparent support such as polyethylene terephthalate film,
Further, a photosensitive laminated structure in which a protective film such as a polyolefin film is laminated thereon as necessary is well known, and an image is formed by peeling and removing the protective film from this laminated structure and then printing a photo onto a metal surface such as a copper plate. This is accomplished by stacking and pressing the resist layers so that they are in contact with each other, exposing to light, peeling and removing the support, and then developing with a developer. However, this method requires a step of peeling off the support after exposure and before development, but this process has to be performed manually, which is a bottleneck for automation. There were problems such as the problem of sticking to hands, the risk of damaging the photoresist layer when the support was peeled off, and the lack of oxygen barrier properties of the support resulting in longer exposure times. . Therefore, in order to investigate a method of dissolving and removing the support after exposure instead of peeling off the support after exposure, the present inventors developed a photoresist layer that can be developed with water or an alkaline aqueous solution. For this purpose, research has been conducted using polyvinyl alcohol films that are soluble in water or alkaline aqueous solutions, but using ordinary polyvinyl alcohol films makes it difficult to coat and form a photoresist layer. It is not easy to roll this up into a roll, and the finished coated laminate has a poor finish, resulting in a significant yield drop during the process of polymerizing and adhering to metal surfaces such as copper plates. Since the properties of the photoresist layer were not satisfactory, there was a problem that the photoresist layer could not be developed smoothly. However, as a result of further research, the present inventors found that a photoresist layer B was formed on a film A (hereinafter simply referred to as film A/photoresist layer B, or A/B). It has a layer structure B in which a photoresist layer B is formed on top of the photoresist layer B, and a film C is formed on top of the photoresist layer B (hereinafter simply referred to as film A/photoresist layer B/film C, or A/B/C). In the case of (2), leave it as it is; in the case of (2), peel off C, then polymerize and adhere closely so that B comes into contact with the metal surface, and after exposing A through A, dissolve A with water or an alkaline aqueous solution and dissolve B at the same time. In the type of laminated structure to be developed, (i) glycerin or dipropylene glycol is used as A.
Polymerization degree 500-2500 containing 10% by weight, saponification degree
A polyvinyl alcohol-based material consisting mainly of 75 to 97 mol% polyvinyl alcohol, (ii) a minimum dissolution temperature in water of 20°C or less, and (iii) an elongation deformation (load elongation of 100 g/10 mm width) of 2% or less. When using a film, the difficulties associated with conventional support peeling methods are overcome;
Furthermore, the present inventors have discovered that the difficulties encountered when using a normal polyvinyl alcohol film in a film dissolving method using water or an aqueous alkaline solution can be overcome, leading to the completion of the present invention. The present invention provides the following excellent effects. (1) Since the support can be removed after exposure using water or an alkaline aqueous solution, the process can be automated. (2) Trouble associated with charging during support peeling work is completely eliminated. (3) The problem of the photoresist layer being damaged when the support is peeled off is completely resolved. (4) Exposure time is short due to excellent oxygen barrier properties. (5) It is not susceptible to environmental influences such as working conditions, and has good lamination workability such as coating accuracy. (6) Excellent solubility in water or alkaline aqueous solutions. In the present invention, the polyvinyl alcohol film constituting film A is as described above.
All conditions (i) to (iii) are required to be met. (i) Degree of polymerization is 500 to 2500, degree of saponification is 75 to 97 mol%,
Preferably, it is mainly composed of 85 to 95 mol% polyvinyl alcohol. If the degree of polymerization is less than 500, the strength will be insufficient and lamination workability will be poor, while if it exceeds 2500, the solubility in water or aqueous alkaline solutions will be poor. If the saponification degree is less than 75 mol%, the solubility in water or alkaline aqueous solution will be poor, and it will be easily attacked by the solvent or high-boiling point copolymerizable monomer in the photoresist layer. If it exceeds the desired solubility with water or aqueous alkali solution, it will not be possible to obtain the desired solubility. Here, polyvinyl alcohol includes not only polyvinyl alcohol which is a saponified product of a homopolymer of vinyl acetate, but also copolymerized modified polyvinyl alcohol and modified polyvinyl alcohol. One type of polyvinyl alcohol may be used, or two or more types of polyvinyl alcohols having different degrees of polymerization, saponification, modification, etc. may be mixed to form a film. The expression "based on polyvinyl alcohol" includes not only polyvinyl alcohol alone but also a mixture of polyvinyl alcohol and other water-soluble natural or synthetic polymers. When other water-soluble polymers are used in combination, the amount used should be at most equal to or less than the weight of polyvinyl alcohol, and usually less than 30% by weight. (ii) The minimum dissolution temperature in water is 20°C or lower, preferably 10°C or lower, and more preferably 5°C or lower. The temperature of water or alkaline aqueous solution during development is usually 35
Since it is around 40℃, it is expected that the minimum melting temperature of polyvinyl alcohol film should be below that temperature, but in reality, polyvinyl alcohol film must be a special product with a minimum melting temperature of 20℃ or less. I discovered that it must be true. The reason why it is necessary to use a material with a minimum melting temperature considerably lower than the temperature during development is as follows.
Dissolution and removal of the film relies on dissolution and diffusion only from one side while the film is in close contact with the photoresist layer, so even if water or alkaline aqueous solution is sprayed onto the film during development using a jet stream or an ultrasonic stream, the temperature will be lower than that temperature. This is believed to be because it is necessary to select and use a film with a fairly low minimum melting temperature. Here, the minimum melting temperature is 0.
Prepare water 2 at ℃ and fix it with specified metal fittings.
This is the temperature at which no undissolved matter can be seen with the naked eye when a 50 mm piece of film is introduced and the temperature of the aqueous solution is raised at a rate of 1°C/min under strong stirring using a magnetic stirrer. (iii) Elongation deformation (100g/10mm width load elongation) is 2% or less, preferably 1% or less. If the elongation deformation exceeds 2%, the accuracy of the coating film thickness of the photoresist layer decreases and lamination work cannot be performed smoothly. The elongation deformation of a typical water-soluble polyvinyl alcohol film is 2.5 to 5%. In order to obtain a film with low elongation deformation, it is effective to use polyvinyl alcohol with a particularly high degree of saponification (98 mol% or more) or to heat-treat the film. The melting temperature would be considerably high, making it unsuitable for the purpose of the present invention. Therefore, we use glycerin or dipropylene glycol, which are commonly used as plasticizers for polyvinyl alcohol films, and reduce the amount added as much as possible (usually 2 to 2 to
10%) and film forming (reducing the amount of plasticizer makes film production difficult, and handling this film also requires a certain amount of skill), the desired film can be obtained. It will be done. Here, elongation deformation refers to the test speed using an autograph on a sample with a length of 100 mm (between chucks) and a width of 10 mm that was conditioned for 24 hours at 20℃ and 65% RH.
100mm/min, chart speed 1000mm/min,
When tested under the conditions of a maximum load of 1000g, the elongation (%) of the film is expressed when a load of 100g is applied per 10mm width. The thickness of such a polyvinyl alcohol film can be selected from various thicknesses, but it is usually appropriate to set it to 7 to 40 γ.If it is too thin, it will lack strength and will cause problems during lamination, while if it is too thick, it will deteriorate the resolution and be economical. It will also be disadvantageous. Next, as the photoresist layer B in the present invention, any material that can be developed with water or an alkaline aqueous solution can be used. For example, there is a layer of a composition in which an acrylic or styrene copolymer copolymerized with α,β-ethylenically unsaturated carboxylic acid is mixed with an active hydrogen-containing acrylic monomer, a photoinitiator, a dye, a solvent, etc. . Film C in the present invention serves as a protective layer or support layer for photoresist layer B, and includes polyethylene film, polypropylene film, paper laminated with polyethylene or polypropylene, polyester film,
Examples include cellulose film and nylon film. This film may be a stretched film. Biaxially stretched polyvinyl alcohol films can also be used for this purpose. It is required that these films C do not strongly adhere to the photoresist layer B. The layer structure of the laminated structure of the present invention is basically film A/photoresist layer B layer structure (a), but from the viewpoint of storage, transportation, handling, etc., film A/photoresist layer B/film C layer is usually used. Composition (b) It is often made into a three-layer structure. For the layer structure (a), a solvent solution of the photosensitive resin composition may be applied onto the film A by any method such as casting, spraying, roll coating, or extrusion coating, and then dried. Regarding the layer structure (b), a method is adopted in which a photoresist layer B is formed on a film A, and then a film C is laminated thereon.
A method may also be adopted in which a photoresist layer B is formed thereon and then a film A is laminated thereon. The thus obtained laminated structure is deposited or rolled and stored, transported, and put to practical use. A typical example of how to use the photosensitive laminate structure of the present invention will be described below. 1. For layer configuration (a), leave as is; for layer configuration (b), first peel off film C. Next A/
A laminate made of B is stacked on a metal surface such as a copper-clad laminate so that the B side is in contact with the metal surface, and bonded under pressure. At this time, pressure bonding is usually performed using a heated roll. 2 Place the original picture on film A and expose it to active light. 3. After exposure, film A is dissolved using water or an alkaline aqueous solution, and the unexposed areas of photoresist layer B are dissolved and removed for development. Water temperature is 30-45
It is often set as °C. Usually, dissolving A and developing B are done at the same time, but first dissolve A,
This may be done in stages, such as developing B next. Note that there is no problem even if the water or alkaline aqueous solution contains a solvent. 4 Perform copper plating, solder plating, resist peeling, copper etching, etc. in accordance with conventional methods. The invention will now be further explained by way of example. Example 1 A: Film formed by casting from an aqueous solution consisting of 100 parts of polyvinyl alcohol (degree of polymerization 1400, degree of saponification 90 mol%), 4 parts dipropylene glycol and 400 parts water, water dissolution temperature 0°C, elongation deformation. (100g/
10mm width load elongation) 0.36%, 20μ thick polyvinyl alcohol film B: Alkali-soluble acrylic copolymer photoresist C: 30μ thick polyethylene terephthalate film Apply the methyl ethyl ketone solution of B onto C using a roll coater. and dried. The thickness of B after drying was 25μ. Next, A from above B of B/C
A three-layered structure of A/B/C was obtained by overlapping and pressing together, and this was rolled. After C was peeled off from the three-layer structure, A/B were stacked on the copper-clad laminate so that B was in contact with the copper surface, and bonded by heating and pressing at a temperature of 100°C. Next, an original sheet was placed on side A and exposed using an exposure machine (exposure amount: 90 millijoules). After that, A was treated for 3 minutes with a developer consisting of a 2% aqueous solution of sodium carbonate at 35°C without peeling.
A was completely dissolved, and the unexposed part of B was also easily eluted. The results are shown in Table 1. Control example 1 Instead of polyvinyl alcohol film A in Example 1, a normal water-soluble polyvinyl alcohol film (degree of polymerization 1700, degree of saponification 95 mol%, containing 12% glycerin as a plasticizer, water dissolution temperature 25°C, elongation deformation) The experiment was conducted in the same manner as in Example 1, except that 3.2%) was used. The results are also shown in Table 1. Control Example 2 In place of polyvinyl alcohol film A in Example 1, a polymerization degree of 800, a saponification degree of 98 mol%, a glycerin content of 4% as a plasticizer, a water dissolution temperature of 45°C, an elongation deformation of 0.7%, and a developer were used. The experiment was conducted in the same manner as in the example except that the temperature was 50°C. The results are shown in Table 1.

【table】

[Table] Examples 2-3 Example 1 except that the following were used as A, B, and C.
An experiment was conducted in the same manner. The results are shown in Table 2. Example 2 A: Water dissolution temperature obtained by casting a film from an aqueous solution consisting of 85 parts of polyvinyl alcohol (degree of polymerization 1700, degree of saponification 88 mol%), 15 parts modified starch, 5 parts dipropylene glycol, and 400 parts water. 2°C, elongation deformation 0.20%, thickness 25μ polyvinyl alcohol film B: B used in Example 1 C: Biaxially stretched polypropylene film 25μ thick Example 3 A: Polyvinyl alcohol (polymerization degree 1400, saponification degree 88 mol%) ) 75 parts Sodium allylsulfonate modified polyvinyl alcohol, (Sodium allylsulfonate content 2 mol%, degree of saponification of vinyl acetate component)
Polyvinyl alcohol film B having a water dissolution temperature of 0°C, an elongation deformation of 0.45%, and a thickness of 27μ obtained by casting from an aqueous solution consisting of 25 parts of 92 mol%), 3 parts of glycerin, and 350 parts of water: used in Example 1 B C: Polyethylene terephthalate film example 4 having a thickness of 25 μm The methyl ethyl ketone solution of B in Example 1 was applied onto the film A of Example 1 using a roll coater and dried. The thickness of B after drying was 25μ. This A/B two-layer structure is placed on the copper-clad laminate board
were stacked so as to be in contact with a metal surface, and adhered by heating and pressing at a temperature of 100°C. Exposure and development were carried out in the same manner as in Example 1. The results are shown in Table 2. Control Example 3 An experiment was conducted in the same manner as in Example 4, except that the polyvinyl alcohol film of Control Example 1 was used as the film. The results are shown in Table 2.

【table】

Claims (1)

[Scope of Claims] 1 Layer structure A in which a photoresist layer B is formed on a film A, or layer structure B in which a photoresist layer B is formed on a film A and a film C is further formed thereon. In case A, leave it as it is; in case B, peel off film C, then polymerize and adhere to the metal surface so that photoresist layer B comes into contact with the metal surface, and after exposure through film A, apply water or alkali without peeling off film A. In a laminated structure of the type in which film A is dissolved in an aqueous solution and photoresist layer B is developed, film A contains (i) 2 glycerin or dipropylene glycol;
It is mainly composed of polyvinyl alcohol with a degree of polymerization of 500 to 2,500 and a degree of saponification of 75 to 97 mol% containing ~10% by weight, (ii) the minimum dissolution temperature in water is 20℃ or less, and (iii) elongation deformation (100g/10mm). Width load elongation) is 2%
A photosensitive resin laminate structure characterized by using the following polyvinyl alcohol film. 2. Claim 1, in which a photoresist layer B is provided on a film A, and then a film C is laminated on the photoresist layer B to form a layer structure B.
Laminated structure as described in section. 3. A laminated structure according to claim 1, wherein a photoresist layer B is provided on a film C, and then a film A is laminated thereon to form a layer structure B.