JP3945341B2 - Circuit board components - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit board member, and more particularly to a circuit board member using a flexible film having a highly accurate circuit pattern and excellent productivity.
[0002]
[Prior art]
As electronics products become lighter and smaller, printed circuit board patterning needs to be highly accurate. Among them, the demand for flexible film substrates is increasing because three-dimensional wiring is possible due to its flexibility and it is suitable for downsizing of electronic products. For example, TAB (Tape Automated Bonding) technology used for IC connection to a liquid crystal display panel is a long polyimide film substrate with a relatively narrow width of 35 to 70 mm, which is the finest level of fine pattern on a resin substrate. Can be obtained. However, the progress of miniaturization is approaching its limit.
[0003]
For miniaturization, there are an index represented by a line width and a space width between lines, and an index represented by a position of a pattern on a substrate. The latter index, so-called positional accuracy, is related to the alignment of the electrode pad and the circuit board pattern when connecting the circuit board and the electronic component such as an IC, and the required accuracy is severe as the number of pins of the IC increases. It has become to.
[0004]
[Problems to be solved by the invention]
In view of the above positional accuracy, the TAB (Tape Automated Bonding) technique is becoming difficult to improve. In the circuit board processing process, there are a heat treatment process such as drying and curing, and a wet process such as etching and development, and the flexible film repeatedly expands and contracts. The hysteresis at this time causes displacement of the circuit pattern on the substrate. In addition, when there are a plurality of processes that need alignment, if there is expansion or contraction between these processes, positional deviation occurs between the formed patterns.
[0005]
Deformation due to expansion and contraction of a flexible film has an even greater effect in the case of an FPC (Flexible Printing Circuit) in which processing is performed with a relatively large substrate size. In addition, the positional shift is caused by an external force such as pulling or twisting, and it is difficult to control when a thin substrate is used to increase flexibility.
[0006]
An object of the present invention is to solve the above-described problems, and specifically to provide a highly accurate and high-definition circuit board member.
[0007]
[Means for Solving the Problems]
  This problem is achieved by the following configuration. That is, the present invention provides a circuit board member in which a peelable organic layer and a flexible film having a circuit pattern are laminated in this order on a reinforcing plate, and the peelable organic layer is an island. Including anti-stick areasIn the anti-adhesion area, silicone resin or film is providedCircuit board member characterized in thatFurther, as another aspect of the present invention, there is provided a circuit board member in which a peelable organic material layer and a flexible film having a circuit pattern are laminated in this order on a reinforcing plate, A circuit board member, wherein the peelable organic layer includes an island-shaped adhesion prevention region, an electronic component is mounted on the circuit pattern, and an adhesion prevention region is provided substantially below the mounting portion. It is.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The member for a circuit board of the present invention is obtained by laminating a peelable organic layer and a flexible film having a circuit pattern on a reinforcing plate at least in this order.
[0009]
In the present invention, the flexible film can be used without limitation as long as it has flexibility. However, it is preferably a plastic film and can withstand a thermal process in a circuit pattern manufacturing process and electronic component mounting. It is desirable to have only heat resistance. For example, films such as polycarbonate, polyether sulfide, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyimide, polyamide, and liquid crystal polymer can be employed.
[0010]
Among these, a polyimide film is preferably used because it is excellent in heat resistance and chemical resistance. In addition, a liquid crystal polymer is preferably used because it has excellent electrical characteristics such as low dielectric loss. It is also possible to employ a flexible glass fiber reinforced resin plate. Examples of the resin for the glass fiber reinforced resin plate include epoxy, polyphenylene sulfide, polyphenylene ether, maleimide, polyamide, polyimide, and the like.
[0011]
The thickness of the flexible film is not particularly limited, but it is preferable to reduce the thickness of the electronic device, to reduce the size, or to form a fine via hole. On the other hand, to ensure mechanical strength and maintain flatness. In order to achieve this, a range of 7.5 μm to 125 μm is preferably used because a thicker one is preferable.
[0012]
In the present invention, a method for producing a metal layer for forming a circuit pattern is not particularly limited. For example, a metal foil such as a copper foil can be formed by adhering with an adhesive, sputtering, plating, or A combination of these can be used. Alternatively, a flexible film with a metal layer can be obtained by coating, drying, and curing a raw film resin or a precursor thereof on a metal foil such as copper.
[0013]
Examples of the material used for the reinforcing plate in the present invention include glasses such as soda lime glass, borosilicate glass, and quartz glass, metals such as stainless steel, invar alloy, and titanium, ceramics and glass such as alumina, zirconia, and silicon nitride. Fiber reinforced resin can be used. Both are preferable because of their low linear expansion coefficient and hygroscopic expansion coefficient, but they are excellent in heat resistance and chemical resistance in the circuit pattern manufacturing process, and are easy to obtain inexpensively because of their large area and high surface smoothness Inorganic glass is preferably used because it is difficult to be plastically deformed. Among these, borosilicate glass represented by aluminoborosilicate glass is particularly preferable because of its high elastic modulus and small linear expansion coefficient.
[0014]
In the case where the peelable organic layer is of a type in which the adhesive force and peel force are reduced by irradiation with ultraviolet rays, a reinforcing plate that allows passage of ultraviolet rays is preferable. A type in which a reinforcing plate is bonded to both sides of the film during the process, and when the reinforcing plate on one side is peeled off, the peelable organic layer adjacent to the reinforcing plate is reduced in adhesive strength and peeling force by UV irradiation. It is particularly preferable that the reinforcing plate is a substrate that transmits ultraviolet rays.
[0015]
When a metal or glass fiber reinforced resin is used for the reinforcing plate, it can be manufactured as a long continuous body, but the circuit board of the present invention can be manufactured as a single wafer type because it is easy to ensure positional accuracy. preferable. A sheet means a state where it is handled as an individual sheet, not a long continuous body.
[0016]
When a glass substrate is used as a reinforcing plate, if the Young's modulus is small or the thickness is small, warping and twisting will increase due to the expansion / contraction force of the flexible film, and the glass substrate will break when vacuum-adsorbed on a flat stage. Sometimes. Further, the flexible film is deformed by vacuum adsorption / desorption, and it is difficult to ensure the positional accuracy. On the other hand, when the glass substrate is thick, the flatness may deteriorate due to uneven thickness, and the exposure accuracy tends to deteriorate. In addition, the load increases during handling by a robot or the like, which makes it difficult to handle quickly and causes a decrease in productivity, and also tends to increase the transportation cost. From this point, the Young's modulus of the glass substrate used for the reinforcing plate (kg / mm²) And the cube of thickness (mm) is preferably in the range of 850 kg · mm to 860000 kg · mm, more preferably in the range of 1500 kg · mm to 190000 kg · mm, and more preferably 2400 kg · mm. A range of 110,000 kg · mm or less is particularly preferable. The Young's modulus of the glass substrate is a value determined according to JIS R1602.
[0017]
When a metal substrate is used for the reinforcing plate, if the Young's modulus of the metal substrate is small or the thickness is thin, the warp and twist of the metal substrate increase due to the expansion force and contraction force of the flexible film, and vacuum suction is performed on a flat stage. It becomes impossible to maintain the positional accuracy because the flexible film is deformed due to the warp or twist of the metal substrate. Further, if the metal substrate is bent, it becomes a defective product at that time. On the other hand, when the metal substrate is thick, the flatness may be deteriorated due to uneven thickness, and the exposure accuracy is deteriorated. In addition, the load is increased during handling by a robot or the like, which makes it difficult to handle quickly and causes a decrease in productivity, and also increases the transportation cost. From this point, the Young's modulus (kg / mm) of the metal substrate used as the reinforcing plate²) And the cube of thickness (mm) is preferably in the range of 2 kg · mm to 162560 kg · mm, more preferably in the range of 10 kg · mm to 30000 kg · mm, more preferably 15 kg · mm. The range of 20500 kg · mm or less is particularly preferable.
[0018]
The peelable organic material used in the present invention is composed of an adhesive or a pressure-sensitive adhesive, and after the flexible film is attached to the reinforcing plate via the organic material layer and processed, the flexible film is peeled off. There is no particular limitation as long as it is possible. Examples of such adhesives or pressure-sensitive adhesives include pressure-sensitive adhesives called acrylic or urethane-based re-peeling pressure-sensitive adhesives. Since the molecular design can be easily performed and the solvent resistance is excellent, what is called a cross-linking type in which a main agent of an adhesive or a pressure-sensitive adhesive and a curing agent are mixed is preferably used. A film having a sufficient adhesive force during the flexible film processing, easily peelable at the time of peeling, and having a peeling force in a region called weak adhesion that does not cause distortion of the flexible film substrate is preferably used. For example, a silicone resin may be used as a release agent, but those having tackiness can be used as a peelable organic layer in the present invention. In addition, it is also possible to use an epoxy resin having tackiness as an organic layer that can be peeled off.
[0019]
In addition, those in which the adhesive force and peeling force are reduced in a low temperature region, those in which the adhesive force and peeling force are reduced by ultraviolet irradiation, and those in which the adhesive force and peeling force are reduced by heat treatment are also preferably used. Among these, those by ultraviolet irradiation are preferable because of large changes in adhesive force and peeling force. As an example of the adhesive strength and peel strength that are reduced by ultraviolet irradiation, a two-component cross-linking acrylic pressure-sensitive adhesive can be mentioned. Moreover, as an example of what adhesive strength and peeling force reduce in a low temperature area | region, the acrylic adhesive which reversibly changes between a crystalline state and an amorphous state is mentioned.
[0020]
The thickness of the organic material layer is not particularly limited, but if it is too thin, the planarity is deteriorated, and the peeling force is greatly reduced, so that the strength of the peeling force is uneven due to the unevenness of the layer thickness. On the other hand, if it is too thick, the adhesive property of the adhesive or the pressure-sensitive adhesive on the flexible film is improved, so that the adhesive strength becomes too strong. In order to suppress the deformation of the flexible film at the end of the organic layer, it is preferable that the thickness of the organic layer is thin. From these points, the thickness of the organic layer is preferably in the range of 0.1 μm to 30 μm, and more preferably in the range of 0.3 μm to 20 μm. The organic layer may be a single layer, or organic layers having different compositions may be stacked in the thickness direction.
[0021]
In the present invention, the peeling interface may be either the interface between the reinforcing plate and the organic layer or the interface between the organic layer and the flexible film, but the step of removing the organic layer from the flexible film can be omitted. It is preferable to peel at the interface between the organic layer and the flexible film.
[0022]
In order to improve the adhesive force between the reinforcing plate and the organic layer, the reinforcing plate may be subjected to a primer treatment such as application of a silane coupling agent. In addition to the primer treatment, cleaning by ultraviolet treatment, ultraviolet ozone treatment, etc., surface roughening treatment such as chemical etching treatment, sand blast treatment or fine particle dispersion layer formation is also preferably used.
[0023]
In the present invention, the peel strength of the peelable organic layer can be measured by the 180 ° peel strength when peeling a 10 mm wide flexible film bonded to the reinforcing plate via the organic layer. As a sample for measuring the peel force, the same material as the circuit board member to be actually produced was used, and a 10 mm width sample was produced with a three-layer structure of reinforcing plate / organic material layer / flexible film. Here, the peeling speed when measuring the peeling force was 300 mm / min. Moreover, the temperature of the sample for measuring the peeling force when measuring the peeling force was the same as the temperature of the member for circuit board when peeling the flexible film from the reinforcing plate in the actual process. The peeling force measuring device is not particularly limited, and Tensilon generally used for measuring strength and elongation can be employed.
[0024]
If the island-shaped anti-adhesion region is fine and the peel force cannot be measured by the above method, the peel width may be narrowed and measured.
[0025]
In the present invention, the peelable organic layer may not be a continuous layer. For example, a form in which an organic substance is lacking in an island shape is also a preferable aspect of the present invention.
[0026]
In the present invention, the anti-adhesion region refers to a region having a relatively low peel strength present in a peelable organic layer. When electronic components are mounted on a circuit pattern formed on a flexible film fixed on a reinforcing plate, it can be mounted with very high dimensional accuracy. However, when the flexible film is peeled off from the reinforcing plate, A large stress is applied, which may cause bending or disconnection of the circuit pattern formed on the flexible film. If there is a part having a lower peeling force than those parts surrounded by a part exhibiting a relatively high peeling force, it is possible to suppress these problems by mounting an electronic component on this part. That is, it is preferable that an anti-adhesion region is provided in a substantially lower portion where the electronic component is mounted. Further, when a plurality of types of electronic components are mounted, the electronic components may be mounted on an organic material layer having a large peeling force from the flexible film as long as the electronic components have a width of 3 mm or less.
[0027]
The shape of the anti-adhesion region may be an island shape, and the number and shape of the islands are not particularly limited, but are preferably multiple islands and uniform. For example, in a mode in which the shape of the peelable organic layer excluding the anti-adhesion region is a substantially lattice shape, that is, a relatively high peel force portion is formed in a substantially lattice shape, and a relatively low peel force portion remains. If it forms in this part, the holding | maintenance force of a flexible film can fully be ensured, and the operation | work which cuts out the flexible film after electronic component mounting to a small piece becomes easy, and is preferable.
[0028]
The peel force in the region showing a relatively high peel force is preferably in the range of 2 g / cm to 100 g / cm in terms of peel force, and the peel force in the tack-proof region having a relatively small peel force is 0.0 g. / Cm or more and less than 2 g / cm. When the portion where the peeling force between the organic layer and the flexible film is large and the portion where the peeling force between the organic layer and the flexible film are both less than 2 g / cm, the flexible film is formed during circuit pattern formation. May peel off from the organic layer. Also, if the peeling force of the portion where the peeling force between the organic layer and the flexible film exceeds 100 g / cm, the flexible film may be deformed by the stress at the time of peeling or the circuit pattern may be disconnected. It can be a cause. In addition, when the peel force between the anti-adhesion region and the flexible film is 2 g / cm or more, after connecting the electronic component on the circuit pattern of the portion where the peel force between the organic layer and the flexible film is small When the flexible film is peeled off, a large force is applied to the connection part of the electronic component, which may cause the circuit pattern to be bent or disconnected.
[0029]
The island-shaped adhesion prevention region is not particularly limited as long as the peel strength is relatively small. For example, the island-like adhesion prevention region is formed by not providing a peelable organic material in the adhesion prevention region. Further, it can be formed by, for example, coating two or more organic layers having different peeling forces separately in an island shape.
[0030]
As a method of forming a portion on which the organic material that can be peeled is not provided on the reinforcing plate, the portion on the reinforcing plate that does not form the organic material is masked in advance, and an organic material layer is formed on top of the mask to form the organic material. The method of removing and the method of utilizing screen printing etc. are mentioned, It uses preferably.
[0031]
In addition, when two or more organic layers having different peeling forces are applied separately, it is necessary to control in a direction to reduce the peeling force of the adhesive or pressure-sensitive adhesive. By increasing the molecular weight of both, the flowability after crosslinking can be reduced, and the anchoring property of the adhesive or pressure-sensitive adhesive to the flexible film can be controlled. In order to improve the heat resistance of the adhesive or pressure-sensitive adhesive, it is preferable to increase the molecular weight of one or both of the main agent and the curing agent of the adhesive or pressure-sensitive adhesive. In order to reduce the peeling force of the adhesive or pressure-sensitive adhesive, it is also effective to increase the number of cross-linking sites with the curing agent by increasing the number of functional groups introduced into the molecular chain of the main agent of the adhesive or pressure-sensitive adhesive. The peeling force can also be adjusted by changing the mixing ratio of the main agent and the curing agent. In addition, as a method of reducing the peeling force of the adhesive or the pressure-sensitive adhesive and controlling the anchoring property of the adhesive or the pressure-sensitive adhesive to the flexible film, it is relatively difficult to optimize the thickness of the adhesive or the pressure-sensitive adhesive. It is an easy method and is effective.
[0032]
  In the present invention, the island-shaped anti-adhesion region is a film.OrSilicone treeFor fatI can. As the film, a plastic film or a metal foil is preferably used. As the plastic film, films such as polycarbonate, polyether sulfide, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyimide, polyamide, and liquid crystal polymer are preferably used. If the thickness of the plastic film is thin, handling becomes difficult, and if it is thick, irregularities that occur on the flexible film cause problems in photolithography, and bubbles are generated at the end of the plastic film when bonded. Therefore, the range of 0.1 μm to 5 μm is preferable.
[0033]
In the present invention, a silicon compound represented by the following general formula or the like is suitably employed as the silicone resin used in the island-shaped adhesion prevention region.
Si (OR¹)_Four, R²Si (OR¹)_Three, R² ₂Si (OR¹)₂Such. Where R¹, R²Represents a hydrocarbon group.
[0034]
More specifically, tetraoxime silane, vinyl trioxime silane and the like are preferably used. If the thickness of the silicone resin is too thin, the adhesive strength will not decrease sufficiently, and if it is thick, the unevenness that occurs on the bonded flexible film will cause problems in photolithography, or plastic film will be stuck when bonding the flexible film. Since air bubbles may be generated at the end, the range of 0.1 μm to 5 μm is preferable.
[0035]
The surface shape of the organic layer on the side bonded to the flexible film forming the circuit pattern is preferably a flat surface. That is, when the cross-sectional shape of the organic material layer has a steep taper due to the unevenness of the organic material layer, bubbles may remain at the end of the organic material layer when the flexible film is bonded to the reinforcing plate via the organic material layer. In addition, when the reinforcing plate and the flexible film are bonded to each other through the organic material layer, the flexible film may be stretched at the end surface of the organic material layer to fix the deformation. The taper angle at the end of the organic layer is preferably 60 ° or less, and more preferably 45 ° or less. Also, when the part where the peel force between the organic layer and the flexible film is large rides on the part where the peel force between the organic layer and the flexible film is small, or between the organic layer and the flexible film When the portion where the peel strength is small rides on the portion where the peel strength between the organic layer and the flexible film is large, the taper angle of the end portion of the organic layer on the side where the strip is on may be 60 ° or less. Preferably, it is 45 degrees or less.
[0036]
The method for forming the island-shaped anti-adhesion region using a plastic film is not particularly limited. For example, after a polyester film coated with a silicone resin is bonded to a peelable organic layer and the anti-adhesive part is cut out A method such as peeling the polyester film from the peelable organic layer can be used.
[0037]
Moreover, screen printing etc. are preferably used for the method of forming an island-shaped adhesion prevention area | region using a silicone resin, for example.
[0038]
In the flexible film used in the present invention, circuit patterns may be formed on both sides of the flexible film. For example, a circuit pattern may be formed on the pasting surface prior to pasting with the reinforcing plate. In this case, it is preferable to form an alignment mark with the circuit pattern formed on the other surface when the circuit pattern is formed. In order to make use of the high definition of the high definition pattern formed on the surface opposite to the bonding surface, it is very effective for the production of the high definition pattern to provide the alignment mark. The alignment mark reading method is not particularly limited, and for example, an optical method, an electrical method, or the like can be used. The alignment mark can also be used for alignment when the flexible film is bonded to the reinforcing plate. The shape of the alignment mark is not particularly limited, and a shape generally used in an exposure machine or the like can be suitably used.
[0039]
After the flexible film is attached to the reinforcing plate, the circuit pattern formed on the surface opposite to the attaching surface of the flexible film can prevent deformation of the flexible film caused by processing by the reinforcing plate. Particularly, a highly accurate pattern can be formed.
[0040]
Advantages of using double-sided wiring include crossover through through-holes, increasing the degree of freedom in wiring design, and LSI that operates at high speed by propagating the ground potential to the vicinity of the required location with thick wiring In addition, the power supply potential can be propagated to the vicinity of the necessary location with thick wiring as well, so that the potential drop can be prevented even at high-speed switching, the operation of the LSI can be stabilized, and external noise can be blocked as an electromagnetic wave shield. This is very effective as the LSI speeds up and the number of pins is increased by increasing the number of functions.
[0041]
Furthermore, in the present invention, it is possible to use a reinforcing plate for processing both sides of the flexible film, and to form a pattern with particularly high precision on both sides. For example, the first reinforcing plate and the second surface of the flexible film are bonded together via a peelable organic layer, and a circuit pattern is formed on the first surface of the flexible film. After the first surface and the second reinforcing plate are bonded to each other through the organic layer, the flexible film is peeled off from the first reinforcing plate, and then a circuit pattern is formed on the second surface of the flexible film. Then, the method of peeling a flexible film from the 2nd reinforcement board is mentioned, High-precision circuit pattern processing can be implement | achieved on both surfaces.
[0042]
It is important that the step of connecting the circuit board of the present invention to an electronic component such as an IC is before the step of peeling the flexible film having the circuit pattern from the reinforcing plate. Compared to connecting a circuit board and an electronic component such as an IC after peeling the flexible film from the reinforcing plate, it is not affected by the dimensional change of the flexible film due to temperature and humidity conditions at the time of connection. This is because good connection accuracy can be obtained.
[0043]
The present invention provides a circuit board member in which a peelable organic layer and a flexible film having a circuit pattern are laminated in this order on a reinforcing plate, and the peelable organic layer is an island-like adhesive. Although the circuit board including the prevention region is included, it does not prevent the presence of other laminated components. For example, a protective film or the like may be laminated. Further, in the island-shaped anti-tack region, there may be a lake-like region having different peel strength.
[0044]
Next, although the preferable one aspect | mode which manufactures the circuit board of this invention is demonstrated below, this invention is not limited to this.
[0045]
A peelable organic substance is applied to an aluminoborosilicate glass having a thickness of 0.7 mm by a spin coater, a blade coater, a roll coater, a bar coater, a die coater, screen printing or the like. Use of a die coater is preferable in order to uniformly apply to a single-wafer substrate sent intermittently. As a method of applying an anti-adhesion area and applying a single peeling force to the portion in contact with the peripheral edge of the flexible film, a portion on which a peelable organic substance on the glass substrate is not applied in advance is used. It is possible to remove the organic material that can be removed together with masking by applying masking and organic material that can be peeled off from the entire surface. Masking may be removed by applying an organic material having a relatively low adhesive strength on the entire surface from the mask.
[0046]
After the peelable organic material is applied, it is dried by heat drying or vacuum drying to obtain a peelable organic material layer having a thickness of 5 μm. An air blocking film having a silicone resin layer provided on a polyester film is affixed to the peelable organic layer and aged for one week. Instead of attaching an air blocking film, it can be stored in a nitrogen atmosphere or in a vacuum. It is also possible to apply a peelable organic material layer to a long film substrate, transfer it to a single wafer substrate after drying.
[0047]
In the present invention, the peelable organic layer may be initially formed on the flexible film side, may be formed on the reinforcing plate side, or may be formed on both. In order to control the ease of formation and the peeling interface between the flexible film and the organic layer, it is preferably formed on the reinforcing plate side.
[0048]
Next, the air blocking film is peeled off, and a polyimide film is attached. The thickness of the polyimide film is preferably in the range of 7.5 μm to 125 μm. A metal layer may be formed in advance on one or both sides of the polyimide film. It is preferable to provide a metal layer on the side of the polyimide film on which the reinforcing plate is attached because it can be used as a ground layer for shielding electromagnetic waves. The polyimide film may be pasted in a cut sheet of a predetermined size, or may be pasted and cut while being unwound from a long roll. A roll-type laminator or a vacuum laminator can be used for such a pasting operation.
[0049]
When the metal layer is not provided in advance on the surface opposite to the bonding surface of the polyimide film, the metal layer can be formed by a full additive method or a semi-additive method.
[0050]
The full additive process is the following process. The surface on which the metal layer is to be formed is treated with a catalyst such as palladium, nickel or chromium and dried. The catalyst referred to here does not act as a nucleus for plating growth as it is, but it becomes a nucleus for plating growth by activation treatment. Next, the photoresist is applied by a spin coater, blade coater, roll coater, bar coater, die coater, screen printing or the like and dried. The photoresist is exposed and developed through a photomask having a predetermined pattern to form a resist layer in a portion where a plating film is unnecessary. Thereafter, after activating the catalyst, the polyimide film is immersed in an electroless plating solution composed of a combination of copper sulfate and formaldehyde to form a copper plating film having a thickness of 2 μm to 20 μm. Get.
[0051]
The semi-additive process is the following process. On the surface on which the metal layer is to be formed, chromium, nickel, copper, or an alloy thereof is sputtered to form an underlayer. The thickness of the underlayer is usually in the range of 1 nm to 1000 nm. Laminating a copper sputtered film on the underlayer further from 50 nm to 3000 nm is effective for ensuring sufficient conduction for subsequent electrolytic plating, improving the adhesion of the metal layer, and preventing pinhole defects. Prior to the formation of the underlayer, plasma treatment, reverse sputtering treatment, primer layer application, and adhesive layer application are suitably performed on the polyimide film surface in order to improve adhesion. Among them, application of an adhesive such as epoxy resin, acrylic resin, polyamide resin, polyimide resin, and NBR is preferable because it has a great effect of improving the adhesive force. These treatments and application may be performed before the glass substrate is pasted, or may be performed after the glass substrate is pasted. It is preferable that continuous treatment with a roll-to-roll process is performed on a long polyimide film before attaching the glass substrate in order to improve productivity. A photoresist is applied onto the underlayer thus formed by a spin coater, blade coater, roll coater, die coater, screen printing or the like and dried. The photoresist is exposed and developed through a photomask having a predetermined pattern to form a resist layer in a portion where a plating film is unnecessary. Next, electrolytic plating is performed using the base layer as an electrode. As the electrolytic plating solution, a copper sulfate plating solution, a copper cyanide plating solution, a copper pyrophosphate plating solution, or the like is used. After forming a copper plating film having a thickness of 2 μm to 20 μm, the photoresist is peeled off, and then the underlying layer is removed by a light etching to obtain a circuit pattern. Further, gold, nickel, tin or the like is plated as necessary.
[0052]
After peeling off the air blocking film on the glass substrate and pasting the polyimide film on the glass substrate, a high-definition circuit on the surface opposite to the bonding surface by the semi-additive method, the full additive method, or the subtractive method A pattern can be formed.
[0053]
The subtractive method is a method of forming a circuit pattern using a photoresist and an etching solution when a solid metal layer is formed on a polyimide film, and is a method with a short manufacturing process and low cost. .
[0054]
In particular, in order to obtain a high-definition circuit pattern, it is preferable to employ a semi-additive method or a full additive method.
[0055]
Furthermore, a connection hole can be provided in the polyimide film. That is, it is possible to provide a via hole for making an electrical connection with the metal layer provided on the side of the bonding surface with the glass substrate, or to provide a ball mounting hole for the ball grid array. As a method for providing the connection hole, laser etching such as carbon dioxide laser, YAG laser, excimer laser, or chemical etching can be employed. In the case of employing laser etching, it is preferable that a metal layer is present on the glass film attachment surface side of the polyimide film as an etching stopper layer.
[0056]
As the chemical etching solution for the polyimide film, hydrazine, potassium hydroxide aqueous solution, or the like can be used. Further, a patterned photoresist or a metal layer can be employed as the chemical etching mask. When electrical connection is made, it is preferable that after the connection hole is formed, the inner surface of the hole is made into a conductor by plating at the same time as the formation of the metal layer pattern. The diameter of the connection hole for electrical connection is preferably 15 μm to 200 μm. The hole for installing the ball preferably has a diameter of 80 μm to 800 μm.
[0057]
Although the timing for forming the connection holes is not limited, it is preferable to form the connection holes from the opposite side of the polyimide film bonding surface after the polyimide film is bonded to the glass substrate.
[0058]
If necessary, a solder resist film can be formed on the circuit pattern. For fine circuit patterns, it is preferable to use a photosensitive solder resist. A photosensitive solder resist is applied onto the circuit pattern with a spin coater, blade coater, roll coater, bar coater, die coater, screen printer, etc., dried, and then exposed to UV light and developed through a predetermined photomask. Obtain a solder resist pattern. Next, it is cured at 100 ° C. to 200 ° C.
[0059]
Next, an electronic component is connected to the circuit pattern on the polyimide film. In order to maintain the positional accuracy of the connection with the electronic component, it is preferable to peel the polyimide film from the glass substrate after connecting the electronic component to the circuit pattern on the polyimide film. As a connection method with an electronic component, for example, solder connection, connection by anisotropic conductive film, connection by metal eutectic, connection by non-conductive adhesive, wire bonding connection, etc. can be adopted.
[0060]
Next, the polyimide film on which the circuit pattern is formed is peeled from the glass substrate. It is preferable to use a laser, a high-pressure water jet, a cutter, or the like to cut the polyimide film with a circuit pattern into individual pieces or an assembly of individual pieces before peeling because the handling becomes easy.
[0061]
In the case of forming a high-definition circuit pattern on both surfaces of the flexible film, it is preferable that the surface of the surface on which the circuit pattern is first formed is bonded to the glass substrate. In this case, a flexible film is bonded to a glass substrate, a circuit pattern is formed on the surface opposite to the glass substrate bonding surface by a subtractive method, a semi-additive method or a full additive method, and then another glass After the circuit formation surface side of the flexible film is bonded to the substrate, the first glass substrate is peeled off, and the circuit pattern is formed on the other surface by a subtractive method, a semi-additive method or a full additive method, Thereafter, a method of peeling the glass substrate is preferably used.
[0062]
The circuit board member of the present invention is preferably used for a wiring board of an electronic device, an IC package interposer, a wafer level burn-in socket board, and the like. It is permissible as appropriate to insert a resistance element or a capacitance element into the circuit pattern.
[0063]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In the examples, the Young's modulus was a value determined according to JIS R1602. Moreover, peeling force was measured with the following method.
[0064]
<Peeling force measurement method>
The peeling force of the polyimide film was measured by the following method. After bonding a polyimide film on the peelable organic layer formed on the reinforcing plate, the polyimide film was cut into a width of 10 mm. The force for peeling a 10 mm wide polyimide film in the 180 ° direction at a peeling speed of 300 mm / min using “Tensilon” manufactured by TMI was defined as the peeling force. For the sample for measuring the peel force, the same material as the circuit board member to be actually produced is used, and a 10 mm width is produced with a three-layer structure of reinforcing plate / peelable organic layer / flexible film. did. Moreover, the temperature of the sample for measuring the peeling force when measuring the peeling force was the same as the temperature of the member for circuit board when peeling the flexible film from the reinforcing plate in the actual process.
[0065]
Example 1
The inside of the flask was replaced with a nitrogen atmosphere, 228 parts by weight of N, N-dimethylacetamide was added, and 19.88 parts by weight of 1,1,3,3-tetramethyl-1,3-bis (3-aminopropyl) disiloxane Was dissolved. Next, 25.76 parts by weight of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride was added, and the mixture was stirred at 10 ° C. for 1 hour in a nitrogen atmosphere. Then, it was made to react, stirring at 50 degreeC for 3 hours, and the adhesive agent which consists of a polyimide precursor varnish was obtained.
[0066]
Using a comma coater, Young's modulus is 930 kg / mm²The adhesive was continuously applied to one side of a long polyimide film having a thickness of 25 μm and a width of 300 mm (“UPILEX” manufactured by Ube Industries, Ltd.). Then, it was dried at 80 ° C. for 10 minutes, 130 ° C. for 10 minutes, 150 ° C. for 15 minutes, and cured at 250 ° C. for 5 minutes. The film thickness of the adhesive layer after curing was 1 μm. Five polyimide films with different lots were prepared.
[0067]
A masking tape was prepared as follows. A die coater was prepared by mixing a 4 μm thick polyethylene terephthalate film with re-peeling adhesive “SK Dyne” 1499 (manufactured by Soken Chemical Co., Ltd.) and curing agent D90 (manufactured by Soken Chemical Co., Ltd.) at a ratio of 100: 6. Formed using. The thickness of the re-peeling adhesive layer after drying and aging was 3 μm.
[0068]
The portion corresponding to the lower part of the electronic component mounting portion of the photomask pattern was bonded to the 0.7 mm thick and 300 mm square aluminoborosilicate glass with the masking tape. The masking part was a square with a side of 10 mm and was arranged independently of each other inside the peripheral edge of the glass. In a die coater, UV curable acrylic adhesive “SK Dyne” SW-11A (manufactured by Soken Chemical Co., Ltd.) and curing agent L45 (manufactured by Soken Chemical Co., Ltd.) mixed at a ratio of 50: 1 as an organic layer. Was applied to a glass substrate and dried at 80 ° C. for 2 minutes. The thickness of the ultraviolet curable organic layer after drying was 5 μm. The masking tape is peeled off, and then an air-blocking film made of a film in which a silicone resin layer that is easy to release is provided on a polyester film is attached to the UV-curable organic material layer (aluminoborosilicate glass / UV-curable organic material) Layer / polyester film composition) The mixture was allowed to stand at room temperature for 1 week.
[0069]
Next, while peeling off the air blocking film, the polyimide film was attached to the side of the glass substrate on which the ultraviolet curable organic layer was formed with a roll laminator with the adhesive layer as the front. Then, 1000mJ / cm of ultraviolet rays from the glass substrate side²Irradiation was performed to cure the UV curable organic layer.
[0070]
By sputtering, a chromium-nickel alloy film having a thickness of 5 nm and a copper film having a thickness of 200 nm were laminated in this order on an adhesive layer provided on the surface opposite to the bonding surface. Subsequently, a positive photoresist was applied onto the copper film with a spin coater and dried at 80 ° C. for 10 minutes. Next, after exposing the photoresist through a photomask, the photoresist was developed to form a resist layer having a thickness of 10 μm in a portion where a plating film was unnecessary. In the test photomask pattern, 240 connection pads (width: 25 μm, length: 80 μm) with a pitch of 50 μm are arranged in a square with 60 lines in a portion where the UV curable re-peeling adhesive is not formed. Wirings having a width of 20 μm and a length of 5 mm extending from the center of the connection pad having a width of 25 μm and extending toward the outside of the square were equally arranged in 4 rows and 4 columns within a 300 mm square. Further, four markers (disposed 200 mm apart from each other in the direction parallel to the side), which are arranged about 141 mm diagonally from the center of the substrate for length measurement, were provided on the photomask pattern.
[0071]
After developing the photomask, it was post-baked at 120 ° C. for 10 minutes. Next, a copper layer having a thickness of 5 μm was formed by electrolytic plating using the copper film as an electrode. The electrolytic plating solution was a copper sulfate plating solution. Thereafter, the photoresist was stripped with a photoresist stripping solution, and then the copper film and the chromium-nickel alloy film under the resist layer were removed by soft etching with a hydrogen peroxide-sulfuric acid aqueous solution. Subsequently, a nickel layer having a thickness of 1 μm and a gold layer having a thickness of 0.2 μm were laminated in this order on the copper plating film by electrolytic plating. Nickel electroplating was performed in a Watt bath. The gold electroplating solution was a neutral gold plating solution using potassium cyano gold (I) acid. Thus, a metal film pattern was obtained.
[0072]
Distance between two points (200 mm in the x direction and 200 mm in the y direction) that were originally about 283 mm apart in the diagonal direction provided for length measurement using the length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.) As a result, the five polyimide films of different lots were within ± 5 μm with respect to the photomask pattern, and the position accuracy was kept very good.
[0073]
Next, a 4 mm × 4 mm model IC chip in which 240 gold-plated bumps are arranged in a peripheral structure with a pitch of 50 μm is heated from the chip side to 150 ° C., and an ultrasonic bonder is used to connect the connection pads and metal on the circuit pattern. Joined.
From the peel force chart, the peel force between the UV curable re-peeling adhesive and the polyimide film is 5.0 g / cm, and the peel force between the aluminoborosilicate glass and the polyimide film is 0 g / cm. There was a region with a relatively low peel force. Moreover, the temperature at the time of peeling was 25 degreeC.
[0074]
During the formation of the circuit pattern, the polyimide film did not peel from the UV-curable re-peeling adhesive. Next, a suction pad was applied to the polyimide film, and the film was gradually peeled off from the glass from the end to obtain a circuit board member. Even at the IC chip bonding portion, the polyimide film could be easily peeled off, and the circuit pattern did not bend or deformed.
[0075]
The lattice pattern on the peeled polyimide film was originally about 283 mm away in the diagonal direction described above as the point where the center points of the intersecting metal film lines intersected with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.). When the distance between two points (points separated by 200 mm in the x direction and 200 mm in the y direction) was measured, all five polyimide films from different lots were within ± 5 μm with respect to the photomask pattern and were very good. Moreover, when the flatness of the polyimide film peeled off from the substrate was visually observed, it was very good.
[0076]
  Example 2
Masking tape is not affixed to the glass that is the reinforcing plate, the UV curable re-peeling adhesive is uniformly formed on the entire surface, and only the portion corresponding to the lower part of the model IC chip mounting portion is 1 μm thick before the polyimide film is bonded. A circuit board member was obtained in the same manner as in Example 1 except that the polyester film was attached. From the peel force chart, the peel force between the UV curable re-peeling adhesive and the polyimide film is 5.0 g / cm.esterThe peel force between the film and the polyimide film was 0 g / cm. Further, in the same manner as in Example 1, after the IC chip was bonded to the circuit pattern, a suction pad was applied to the polyimide film, and the film was gradually peeled off from the glass. The polyimide film could be easily peeled even at the IC chip joint, and the circuit pattern was not broken or deformed. When measuring the distance between two points originally separated by about 283 mm in the diagonal direction (200 mm in the x direction and 200 mm in the y direction) with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.), lot The five different polyimide films were within ± 5 μm of the photomask pattern and were very good.
[0077]
  Example 3
  The organic layer was formed on the entire surface without applying masking tape to the reinforcing plate glass, and a silicone-coated polyethylene terephthalate film that can be easily peeled was bonded to the organic layer.TheThe lower part of the Dell IC chip mounting partDie-cut and removed, removed partAn anti-adhesion layer with a thickness of 1 μm made of tetraoxime silane is provided only onThen, remove all the silicone-coated polyethylene terephthalate film.A circuit board member was obtained in the same manner as in Example 1 except that. From the peel force chart, the peel force between the polyimide film and the anti-adhesion layer made of tetraoxime silane was 1.0 g / cm. Further, in the same manner as in Example 1, after the IC chip was bonded to the circuit pattern, a suction pad was applied to the polyimide film, and the film was gradually peeled off from the glass. The polyimide film could be easily peeled even at the IC chip joint, and the circuit pattern was not broken or deformed. When measuring the distance between two points originally separated by about 283 mm in the diagonal direction (200 mm in the x direction and 200 mm in the y direction) with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.), lot The five different polyimide films were within ± 5 μm of the photomask pattern and were very good.
[0078]
Comparative Example 1
A circuit board member was obtained in the same manner as in Example 1 except that the masking tape was not attached to the glass as the reinforcing plate and the organic layer was formed on the entire surface. Further, in the same manner as in Example 1, the IC chip was bonded to the circuit pattern. The position accuracy and the like were measured in the same manner as in Example 1. The position accuracy was within ± 5 μm with respect to the photomask pattern, and the position accuracy was kept very good. The bumps of the model IC chip and the connection pads on the circuit pattern The alignment of was very good. However, in the part where the IC chip is bonded, the peeling force from the polyimide film from the glass increases, and after the peeling from the glass, a part of the circuit pattern on the polyimide film is broken, which increases the reliability. There was a problem.
[0079]
Comparative Example 2
UV curable acrylic adhesive "SK Dyne" SW-22 (manufactured by Soken Chemical Co., Ltd.) as a UV curable re-peeling adhesive with a die coater on 0.7 mm thick, 300 mm square aluminoborosilicate glass ) And a curing agent L45 (manufactured by Soken Chemical Co., Ltd.) at a ratio of 50: 1 is applied to a glass substrate at 5 locations with a 5 mm gap so that the adhesive becomes a strip with a width of 55 mm. And dried at 80 ° C. for 2 minutes. The thickness of the UV curable re-peeling adhesive after drying was 1 μm. Next, an air-blocking film made of a film in which a silicone resin layer that can be easily released is provided on a polyester film is attached to the UV-curable re-peeling adhesive (aluminoborosilicate glass / UV-curable re-peeling adhesive). / Structure having silicone resin layer / polyester film portion and aluminoborosilicate glass / silicone resin layer / polyester film portion) The mixture was allowed to stand at room temperature for 1 week.
[0080]
  Next, the polyimide film was affixed with the roll-type laminator to the side in which the ultraviolet curable re-peeling adhesive was formed on the glass substrate while peeling off the air blocking film. Then, 1000mJ / cm of ultraviolet rays from the glass substrate side ² A metal layer pattern was obtained in the same manner as in Example 1 except that the UV curable re-peeling adhesive was cured by irradiation.The connection pad on the circuit pattern should be placed on the 5mm wide part without adhesive.It was.
[0081]
When measuring the distance between two points originally separated by about 283 mm in the diagonal direction (200 mm in the x direction and 200 mm in the y direction) with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.), lot The five different polyimide films were within ± 5 μm with respect to the photomask pattern, and the positional accuracy was kept very good.
[0082]
    Next, at a 50 μm pitch240Gold plated bumps arranged in a peripheral structure4mm x4The model IC chip of mm was metal bonded to the connection pads on the circuit pattern using an ultrasonic bonder while heating the chip IC chip to 150 ° C. from the chip side.
[0083]
The peeling force between the polyimide film and the UV curable re-peeling adhesive was 5 g / cm. During the formation of the circuit pattern, the polyimide film did not peel from the UV-curable re-peeling adhesive. Next, the polyimide film was gradually peeled from the glass substrate from the end. The polyimide film peeled off at the interface with the UV curable re-peeling adhesive and did not curl. In addition, the polyimide film could be easily peeled even at the IC chip bonding portion, and the circuit pattern did not bend or deformed. However, in the part where only two types of glass substrate and polyimide film exist, chemicals enter between the glass substrate and polyimide film in the wet process, and plating quality defects and heating due to the introduction of impurities into the subsequent process Sometimes swelling occurred.
[0084]
  According to the present invention, expansion and contraction due to a wet process in the processing step, or pulling and twisting, deformation due to external force such as damage at the time of peeling from the reinforcing plate is suppressed, and microfabrication and electronic components closer to the design value are achieved. Can be installed, SpecialIn addition, a high-definition circuit board member can be provided, and its practicality is great.

Claims (3)

A circuit board member in which a peelable organic material layer and a flexible film having a circuit pattern are laminated in this order on a reinforcing plate, and the peelable organic material layer has an island-like anti-stick region. unrealized, member for a circuit board, wherein the silicone resin or film is provided in the antiblocking area. 2. The member for a circuit board according to claim 1, wherein a shape of the peelable organic material layer excluding the adhesion preventing region is substantially a lattice shape. A circuit board member in which a peelable organic material layer and a flexible film having a circuit pattern are laminated in this order on a reinforcing plate, and the peelable organic material layer has an island-like anti-stick region. wherein said circuit electronic components are mounted on the pattern, member for a circuit board, wherein the antiblocking region in a substantially lower portion of the mounting portion.