JP4973122B2 - Circuit board member and circuit board manufacturing method - Google Patents

Description

  The present invention relates to a circuit board member and a circuit board manufacturing method using a flexible film having a highly accurate circuit pattern and excellent productivity.

  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 can obtain a fine pattern of the highest level as a resin substrate by processing a relatively narrow wide polyimide film substrate. However, the progress of miniaturization is approaching the limit. 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.

  In view of the above positional accuracy, it is becoming difficult to improve the processing of the flexible film substrate in particular. 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. Deformation due to expansion and contraction of the 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. Further, the positional shift is caused by an external force such as pulling or twisting, and special attention is required when a thin substrate is used to increase flexibility.

  On the other hand, after bonding a reinforcing plate to a flexible film to form a circuit pattern via an ultraviolet curable organic material layer, the overall strength is increased to suppress deformation due to external force and UV curing. There is a proposal to form a circuit pattern in a state where the peeling force is reduced by irradiating the mold organic layer with ultraviolet rays, and to peel the flexible film with the circuit pattern from the reinforcing plate (see Patent Document 1).

However, when the circuit pattern is formed by irradiating the entire surface of the ultraviolet curable organic layer with ultraviolet rays that sufficiently cure, and the peeling force between the flexible film and the reinforcing plate is low on the entire surface. When a force is applied to the end of the flexible film to peel off the flexible film and the organic layer in a specific process such as attachment to an aqua knife, air knife or jig, the end of the flexible film The part may peel from the organic material layer and cause pattern formation failure or conveyance failure.
JP 2003-298194 A (page 3)

  In view of the above-described problems, an object of the present invention is to provide a method capable of stably manufacturing a highly accurate flexible film circuit board.

That is, this invention consists of the following structures.
( 1 ) A circuit board member in which at least a reinforcing plate, a peelable organic layer, a flexible film, and a circuit pattern are laminated in this order, and a range of less than 30 mm at the maximum from the end of the flexible film to the periphery Then, the flexible film at the four corners, which is a portion that is less than a maximum of 50 mm inward from each of the four apexes of the flexible film, excluding a portion that overlaps with the inner portion of the peripheral portion. The peeling force between the reinforcing plate and the reinforcing plate exceeds 49 N / m and is 490 N / m or less, and the peeling force between the flexible film other than the four corners and the reinforcing plate is 0.098 N / m or more and 49 N / m or less. Board member.

( 2 ) A reinforcing plate is bonded to one side of the flexible film via an ultraviolet curable organic layer, and the ultraviolet curable organic layer is irradiated with ultraviolet rays, and then the flexible film with a circuit pattern is peeled from the reinforcing plate. A method for manufacturing a circuit board, wherein a range of less than 30 mm maximum from the end of the flexible film to the inside is a peripheral portion, and a portion of less than 50 mm maximum from each of the four apexes of the flexible film, The peeling force of the flexible film and the reinforcing plate at the four corners excluding the part overlapping with the part inside the peripheral part is more than 49 N / m and not more than 490 N / m during the circuit pattern formation. A method of manufacturing a circuit board having a circuit pattern of 0.098 N / m or more and 49 N / m or less before the flexible film is peeled off after the circuit pattern is formed.

  According to the present invention, it is possible to eliminate the occurrence of pattern formation failure and conveyance failure due to peeling of the end portion of the flexible film from the organic layer during processing of the circuit pattern. Furthermore, the peeling force between the flexible film and the organic material layer is sufficiently small at the peripheral part of the flexible film, and the circuit pattern formed inside the peripheral part of the flexible film is peeled in a state where high positional accuracy is ensured. can do. It is possible to peel the flexible film from the reinforcing plate after forming the circuit pattern by irradiating the entire surface of the ultraviolet curable organic layer or the periphery of the flexible film with ultraviolet rays, or by separating the periphery of the flexible film. .

  In the present invention, the flexible film is a plastic film, and it is important that the film has a heat resistance sufficient to withstand a thermal process in a circuit pattern manufacturing process and electronic component mounting, such as polycarbonate, polyether sulfide, Films such as polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyimide, polyamide, and liquid crystal polymer can be used. 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, and polyimide.

  The thickness of the flexible film is preferably thin in order to reduce the weight and size of electronic devices, or to form fine via holes. On the other hand, to ensure mechanical strength and maintain flatness. From the viewpoint that a thicker one is preferable, a range of 4 μm to 125 μm is preferable.

  In the present invention, the method for forming the circuit pattern is not particularly limited. For example, the circuit pattern can be formed by attaching a metal foil such as a copper foil with an adhesive layer, or by sputtering, plating, or a combination thereof. be able to. 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.

  The substrate used as the reinforcing plate in the present invention includes inorganic glasses such as soda lime glass, borosilicate glass, and quartz glass, metals such as invar alloy, stainless steel, and titanium, ceramics and glass such as alumina, zirconia, and silicon nitride. A fiber-reinforced resin plate 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. A substrate made of inorganic glass is preferable in that it is difficult to be plastically deformed. Among them, soda lime glass is preferable because it has a large thermal expansion coefficient in the glass and is close to the linear expansion coefficient of the resin film.

  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 method for manufacturing a circuit board of the present invention should be a single wafer type because it is easy to ensure positional accuracy. Is preferred. A sheet means a state where it is handled as an individual sheet, not a long continuous body.

  The peelable organic material layer used in the present invention is composed of an adhesive or a pressure-sensitive adhesive, and the flexible film is attached to the reinforcing plate through the peelable organic material layer and processed, and then the flexible film is applied. It can be peeled off. Examples of such an adhesive or pressure-sensitive adhesive include a pressure-sensitive adhesive called an acrylic or urethane-based re-peeling pressure-sensitive adhesive. Moreover, since the molecular design can be easily performed and the solvent resistance is excellent, what is called a cross-linked type in which a main agent of an adhesive or a pressure-sensitive adhesive and a curing agent are mixed is preferable. In the area inside the peripheral edge of the flexible film, there is sufficient peeling force during the flexible film processing, it can be easily peeled off at the time of peeling, and it does not cause distortion in the flexible film. Those having a peeling force in the region called are preferred. On the other hand, in the peripheral part of the flexible film, there is a sufficient peeling force even in a specific process such as attachment to an aqua knife, an air knife or a jig. Peeling strength is preferred. The silicone resin film is sometimes 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 a tacky epoxy resin film as a peelable organic layer. Forming different types of adhesives or adhesives on the reinforcing plate on the periphery of the flexible film and the two areas inside the periphery makes the process complicated. By forming an organic layer and limiting the range of irradiation with ultraviolet rays, it is preferable because a difference in peeling force can be easily expressed.

  In the present invention, the peeling force is 180 ° peel strength when peeling a 1 cm wide flexible film bonded to a reinforcing plate via an organic layer. Moreover, the peeling rate when measuring peeling force was 300 mm / min. The peeling force measuring device is not particularly limited, and Tensilon generally used for measuring strength and elongation can be suitably employed. Here, the weak adhesion region means a range where the peel force measured under the above conditions is 0.098 N / m to 49 N / m, and the medium adhesion region means a peel force exceeding 49 N / m and 490 N. / M or less.

  In order to control the peeling force of the adhesive or pressure-sensitive adhesive in a region called weak pressure-sensitive adhesive, the flowability after crosslinking is reduced by increasing the molecular weight of one or both of the main agent and curing agent of the adhesive or pressure-sensitive adhesive. In addition, it is possible to control the anchoring property of the adhesive or the pressure-sensitive adhesive to the flexible film. On the other hand, 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 addition, in order to control the peeling force of the adhesive or pressure-sensitive adhesive in a region called weak pressure-sensitive adhesive, the number of functional groups introduced into the molecular chain of the main agent of the adhesive or pressure-sensitive adhesive is increased to increase the number of crosslinking sites with the curing agent. This is also effective, and it is preferable that the peeling force can be adjusted by changing the mixing ratio of the main agent and the curing agent. In addition, in order to control the peeling force of the adhesive or pressure-sensitive adhesive in a region called weak pressure-sensitive adhesive, the thickness of the adhesive or pressure-sensitive adhesive is controlled as a method for controlling the anchoring property of the adhesive or pressure-sensitive adhesive to the flexible film. It is relatively easy to adapt and is effective.

  If the thickness of the peelable organic layer is too small, the uniformity tends to decrease. Therefore, the thickness is preferably 0.1 μm or more, and more preferably 0.3 μm or more. On the other hand, if the thickness of the peelable organic material layer is too large, the anchoring property to the flexible film is improved and the peeling force tends to be too large. Therefore, the thickness is preferably 20 μm or less, and preferably 10 μm or less. More preferably.

  In addition, those in which the peeling force decreases in a low temperature region, those in which the peeling force decreases by ultraviolet irradiation, and those in which the peeling force decreases by heat treatment are also preferably used. Among these, an ultraviolet curable organic material layer is preferable because it has a large change in peeling force and can easily control the peeling force by changing the irradiation amount of ultraviolet rays.

  The ultraviolet curable organic material layer is cured by irradiating with ultraviolet rays, and the peeling force decreases. As an example of such an ultraviolet curable organic material, an adhesive called an acrylic or urethane ultraviolet curable re-peeling adhesive can be mentioned. Moreover, what is called a bridge | crosslinking type which mixes the main ingredient of an adhesive agent or an adhesive, and a hardening | curing agent is excellent in productivity, and is preferable from a rapid expression of peeling force.

  In the present invention, the peeling force between the reinforcing plate bonded through the peelable organic material layer and the flexible film is in the range of more than 49 N / m and less than 490 N / m at the peripheral edge of the flexible film. In the range inside the peripheral edge of the flexible film, it is important that the range is 0.098 N / m or more and 49 N / m or less. If the peeling force when peeling the flexible film from the reinforcing plate is too low, the flexible film may peel from the ultraviolet curable organic layer during circuit pattern formation. On the other hand, if the peeling force is too high, the flexible film may be deformed or broken when it is peeled from the reinforcing plate after the circuit pattern is formed.

  In the present invention, the step of irradiating ultraviolet rays to the inner side of the peripheral portion of the flexible film is preferably before the step of forming the circuit pattern after the reinforcing plate and the flexible film are bonded together. UV curable organic layers often have insufficient water resistance and heat resistance before UV irradiation, and often cause problems such as swelling and foaming when there is a wet or heating process in the circuit pattern formation process. This is because the positional accuracy cannot be ensured or the flatness is impaired.

  Here, the wet process is a resist development process, a plating process, an etching process, a cleaning process, or the like. By irradiating with ultraviolet rays before the wet process, swelling due to the absorption of water by the ultraviolet curable organic layer in a wet process, and a reduction in peeling force and dimensional change due to swelling can be suppressed.

  The heating process is a photoresist baking, a solder resist baking or the like. The step of irradiating with ultraviolet rays is preferably before the heating step. By irradiating ultraviolet rays before the heating process, the ultraviolet reaction site of the ultraviolet curable organic layer is destroyed in the heating process, and the ultraviolet curable organic layer is foamed or deteriorated and the flatness is lost. Can be prevented from becoming difficult to peel off.

  If the thickness of the peelable organic layer is too small, the uniformity tends to decrease. Therefore, the thickness is preferably 0.1 μm or more, and more preferably 0.3 μm or more. On the other hand, if the thickness of the peelable organic material layer is too large, the anchoring property to the flexible film is improved, so that the peel force tends to be too large. More preferably.

In the present invention, the peripheral edge of the flexible film is preferably in the range of less than 30 mm inward from the end of the flexible film. In order to eliminate the occurrence of pattern formation failure or conveyance failure due to peeling of the edge of the flexible film from the peelable organic material layer during the processing of the circuit pattern, The peel force is greater than the range inside the peripheral edge. If the peeling force at the peripheral edge is large, even if a highly accurate circuit pattern is formed on the peripheral edge of the flexible film, the accuracy of the circuit pattern is impaired in the process of peeling the flexible film from the reinforcing plate. Preferably, the ultraviolet curable organic layer formed on the peripheral edge of the flexible film is irradiated with ultraviolet rays of 500 mJ / cm ² or more between the formation of the circuit pattern and the peeling of the flexible film. . According to this method, the peeling force can be reduced even at the peripheral portion, and distortion of the circuit pattern in the process of peeling the flexible film from the reinforcing plate can be suppressed, and a highly accurate circuit pattern can be obtained. When UV light is not irradiated before peeling, the number of circuit patterns that can be produced from one flexible film is reduced when the peripheral edge of the flexible film is in the range of 30 mm or more from the end of the flexible film to the inside. Unit price rises. In order to produce more circuit patterns from the flexible film, it is more preferable that the peripheral edge of the flexible film is in the range of less than 15 mm inward from the end of the flexible film. On the other hand, when the peripheral edge of the flexible film is less than 5 mm inward from the end of the flexible film, it is applied to the end of the flexible film by a specific process such as attachment to an aqua knife, air knife or jig. When a force to peel off the flexible film and the organic layer is applied, a sufficient peeling force cannot be obtained to prevent peeling, and the end of the flexible film is peeled off from the organic layer to form a pattern. This may cause defects and poor conveyance. The peeling interface may be either the interface between the reinforcing plate and the peelable organic layer or the peelable organic layer and the flexible film, but the step of removing the peelable organic layer from the flexible film Therefore, it is preferable to peel off at the interface between the peelable organic layer and the flexible film.

  In order to improve the peeling force between the reinforcing plate and the peelable 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.

In the present invention, it is important that the amount of ultraviolet rays applied to the ultraviolet curable organic layer formed on the peripheral edge of the flexible film during circuit pattern formation is less than 500 mJ / cm ² . Pattern formation by irradiating the UV curable organic layer formed on the peripheral edge of the flexible film during circuit pattern formation by peeling the end of the flexible film from the organic layer during processing of the circuit pattern Since defects and conveyance failures occur, it is more preferable that the amount of ultraviolet rays irradiated to the ultraviolet curable organic layer formed on the peripheral portion of the flexible film during circuit pattern formation is less than 100 mJ / cm ² .

  In the present invention, when the ultraviolet ray curable organic layer formed on the peripheral portion of the flexible film is irradiated with ultraviolet rays after the circuit pattern is formed until the flexible film is peeled off, the peripheral portion of the flexible film Therefore, the amount of deformation of the flexible film after peeling can be suppressed, which is preferable.

  The four corners of the flexible film according to claim 4, which is one aspect of the present invention, will be described with reference to FIG. Reference numeral 301 denotes a flexible film. If a range of less than 30 mm inward from the ends of the four sides of the flexible film is defined as the peripheral edge portion 302, a portion less than 50 mm from each of the four vertices of the flexible film has a radius of 50 mm when each vertex is the center. A portion that is a quarter of the circle less than the portion that overlaps with a portion inside the peripheral portion is a portion denoted by reference numeral 304. That is, the four corners, which are portions less than 50 mm from each of the four apexes of the flexible film, excluding the portion overlapping with the portion inside the peripheral portion, are portions indicated by reference numeral 305. . Further, the peeling force between the flexible film and the reinforcing plate at the four corners indicated by reference numeral 305 is more than 49 N / m and not more than 490 N / m. If the peeling force when peeling the flexible film from the reinforcing plate is too low, the flexible film may peel from the reinforcing plate during circuit pattern formation. On the other hand, if the peeling force is too high, the flexible film may be deformed or broken when it is peeled from the reinforcing plate after the circuit pattern is formed.

  The four corners of the flexible film denoted by reference numeral 305 are particularly likely to be the starting point of occurrence of peeling among the flexible films bonded to the reinforcing plate, and increasing the peeling force of this part is flexible during circuit pattern formation. Since the defect that the adhesive film peels off from the reinforcing plate can be reduced, the effect of improving the product yield is great. By limiting the portions having a large peeling force to the four corners, the strain generation range of the flexible film when peeling the flexible film from the reinforcing plate can be reduced. Further, when the peeling force is changed depending on the difference in the amount of ultraviolet irradiation, the apparatus can be simplified by shielding only the four corners of the flexible film as compared with shielding the entire peripheral edge of the flexible film.

  In order to produce many circuit patterns from a flexible film, it is more preferable that the peripheral edge is within a range of less than 15 mm inward from the ends of the four sides of the flexible film. In addition, in order to suppress the deformation amount of the flexible film after peeling, the peripheral part is a part that is less than 15 mm inward from the end of the four sides of the flexible film, and the part constituting the quarter circle is acceptable. It is more preferable to use a portion of the flexible film that is less than 20 mm from each of the four vertices except for a portion that overlaps a portion on the inner side of the peripheral edge. The portion of the flexible film that is less than 5 mm inward from each of the four apexes is subjected to a force to peel off the flexible film and the organic layer in a specific process such as attachment to an aqua knife, air knife, or jig. In some cases, the four corners of the flexible film may peel off from the organic layer, resulting in pattern formation failure or conveyance failure.

  In the present invention, the peel force between the flexible film other than the four corners and the reinforcing plate is 0.098 N / m or more and 49 N / m or less. Reference numeral 303 in FIG. 2 corresponds to a flexible film other than the four corners. Since the peeling force of the flexible film other than the four corners is sufficiently low, the accuracy of the circuit pattern is not impaired in the process of peeling the flexible film from the reinforcing plate, and a highly accurate circuit pattern can be formed. When the peeling force between the flexible film and the reinforcing plate is less than 0.098 N / m, the peeling force is low, and bubbles are likely to be generated in the process, which causes poor appearance and poor accuracy. On the other hand, when the peeling force between the flexible film and the reinforcing plate exceeds 49 N / m, the flexible film may be deformed or broken when it is peeled from the reinforcing plate after the circuit pattern is formed.

In the present invention, the amount of ultraviolet rays irradiated to the ultraviolet curable organic layer formed at the four corners of the flexible film during circuit pattern formation is less than 500 mJ / cm ² . Pattern formation by radiating ultraviolet rays to the UV curable organic layer formed at the four corners of the flexible film during circuit pattern formation, so that the edge of the flexible film peels off from the organic layer during processing of the circuit pattern Since defects and conveyance failures occur, it is more preferable that the amount of ultraviolet rays irradiated to the ultraviolet curable organic layer formed at the four corners of the flexible film during circuit pattern formation is less than 100 mJ / cm ² .

  The UV curable organic layer used in the present invention has a sufficient peeling force during the flexible film processing, can be easily peeled off at the time of peeling, and does not cause distortion in the flexible film substrate. It is preferable that the peeling force is a weakly adhesive region.

  In order to control the peeling force of the UV curable organic material layer in the weakly adhesive region, by increasing the molecular weight of one or both of the main agent and the curing agent of the adhesive or pressure sensitive adhesive used as the UV curable organic material, It is effective to reduce the fluidity and control the anchoring property of the adhesive or the pressure-sensitive adhesive to the flexible film. In order to improve heat resistance, 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. It is also effective to increase the number of crosslinking sites with the curing agent by increasing the number of functional groups introduced into the molecular chain of the main agent. Furthermore, the peeling force can be adjusted by changing the mixing ratio of the main agent and the curing agent. In addition, in order to control the peeling force of the ultraviolet curable organic material layer to a weakly adhesive region, as a method for controlling the anchoring property to the flexible film, a method for optimizing the thickness of the adhesive or the adhesive can be easily performed. It is an effective method.

  In the flexible film used in the present invention, a circuit pattern may be formed on one surface which is a 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 simultaneously with the pattern formation. 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.

  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 is not deformed by the reinforcing plate and the metal layer during processing. In particular, a highly accurate pattern can be formed.

  According to the present invention, it is possible to easily provide a circuit board with double-sided wiring in which a particularly fine pattern is formed on one side. 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 important as the LSI speeds up and the number of pins is increased due to the increased functionality.

  Furthermore, in the present invention, it is possible to use a reinforcing plate when 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 material layer or an ultraviolet curable organic material layer, and the circuit pattern is applied to the first surface of the flexible film. After forming, the first surface and the second reinforcing plate are bonded together through an organic layer or a UV curable organic layer that can be peeled off, and then the flexible film is peeled from the first reinforcing plate, Next, there is a method in which a circuit pattern is formed on the second surface of the flexible film, and then the flexible film is peeled off from the second reinforcing plate. it can.

  An example of the method for producing a circuit board of the present invention will be described below, but the present invention is not limited to this.

  A silane coupling agent is applied to soda lime glass having a thickness of 1.1 mm using a spin coater, blade coater, roll coater, bar coater, die coater, screen printer or the like. In order to uniformly apply a thin film of a silane coupling agent having a relatively low viscosity to a single substrate that is intermittently sent, it is preferable to use a spin coater. After application of the silane coupling agent, drying is performed by heat drying or vacuum drying to obtain a silane coupling agent layer having a thickness of 20 nm.

  Next, an ultraviolet curable re-peeling adhesive is applied on the silane coupling agent layer with a spin coater, blade coater, roll coater, bar coater, die coater, screen printer or the like. The use of a die coater is preferable in order to uniformly apply a relatively high-viscosity adhesive to the intermittently fed single wafer substrate. After applying the UV curable re-peeling adhesive, it is dried by heat drying or vacuum drying to obtain an UV curable organic layer having a thickness of 3 μm. An air blocking film in which a silicone resin layer is provided on a polyester film is affixed to this ultraviolet curable organic material layer and aged for one week. Instead of laminating an air blocking film, it can be stored in a nitrogen atmosphere or in a vacuum. It is also possible to apply an ultraviolet curable organic layer to a long film substrate, dry it, and then transfer it to a single wafer substrate.

  In the present invention, the ultraviolet curable 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 to be a flexible film and an ultraviolet curable organic material layer, it is preferably formed on the reinforcing plate side.

  Next, the manufacturing method of the film circuit board member by a single wafer system is demonstrated. The single-wafer method is not a reel-to-reel method using slit reel conveyance, which is common in the manufacture of TAB and COF, but a method of producing a film circuit board with a sheet-like substrate. First, a plastic film having a thickness of 25 μm, which is a flexible film substrate, is prepared. The air blocking film on the glass substrate is peeled off, and the plastic film is bonded to the glass substrate. As described above, a metal layer (which may be a circuit pattern on the bonding surface) may be formed in advance on one side or both sides of the plastic film. The plastic film may be pasted in a cut sheet having a predetermined size, or may be pasted and cut while being unwound from a long roll. For such a pasting operation, there is a method of laminating the plastic film on the glass substrate side with low stress and high accuracy by holding the plastic film on the surface of the flexible planar body and then pressing it on the glass substrate. It can be suitably employed. A laminating apparatus used in the above method will be described with reference to FIG.

  Reference numeral 200 is a schematic front view of the laminating apparatus. The flexible sheet 202 is charged by the electrostatic charging device 201 to adsorb the plastic film 203. A flexible fabric or thin film can be used for the flexible planar body 202 and is fixed to the frame body 204. Further, the electrostatic charging device 201 is supported by a support 206 on the base 205, and the support 206 is electrostatically charged with the frame body 204 and the mounting table 207 that move to the left and right in FIG. The device 201 moves so as not to interfere. Next, the glass substrate 209 coated with the peelable organic layer 208 is held on the mounting table 207 by vacuum suction or the like. The plastic film 203 is pressed against the peelable organic material layer 208 together with the flexible planar body 202 with the squeegee 210, and the plastic film 203 is transferred to the glass substrate 209 side. The squeegee 210 is held by a squeegee holder 211 and can be moved and moved up and down. The mounting table 207 can be moved to the left and right in the figure by a rail 212, a guide 213, a nut 214, a bracket 215, a ball screw 217, and a motor 218.

  After the polyimide film is attached to the glass substrate, the ultraviolet curable organic layer inside the peripheral portion of the polyimide film is irradiated with ultraviolet rays while the ultraviolet curable organic layer formed on the peripheral portion of the polyimide film is shielded from light. Cross-linking proceeds.

  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.

  The full additive method is, for example, 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, a blade coater, a roll coater, a bar coater, a die coater, a screen printer 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.

  The semi-additive method is, for example, 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. It is preferable to stack a copper sputtered film on the underlayer from 50 nm to 3000 nm in order to ensure sufficient conduction for subsequent electrolytic plating, improve the adhesion of the metal layer, and prevent pinhole defects. Prior to the formation of the underlayer, plasma treatment, reverse sputtering treatment, primer layer coating, and adhesive layer coating are suitably used to improve the adhesive strength on the polyimide film surface. Among them, the application of an adhesive layer 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 pasting the glass substrate because productivity can be improved. A photoresist is applied onto the underlayer thus formed by a spin coater, blade coater, roll coater, die coater, screen printer, 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 underlying 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 with a thickness of 2 μm to 20 μm, the photoresist is peeled off, and then the underlying layer is removed by a light etching, and further, plating with gold, nickel, tin, etc. is performed as necessary. Get.

  After the air blocking film on the glass substrate is peeled off, the surface on which the circuit pattern is formed is used as a bonding surface, and after the polyimide film is attached to the glass substrate, the above-described semi-additive method, full-additive method, or subtractive method is used. By using this method, a high-definition circuit pattern is formed on the surface opposite to the bonding surface.

  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 the manufacturing process is short and the cost is low.

  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.

  Furthermore, a connection hole can be provided in the polyimide film. That is, it is possible to provide a via hole for electrical connection with the metal layer provided on the bonding surface side 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 drilling such as a carbon dioxide laser, YAG laser, or 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.

  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 metal layer pattern is formed. 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.

  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.

  If necessary, a solder resist film is 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 printing machine, etc., dried, and then exposed to ultraviolet rays through a predetermined photomask and developed. Thus, a solder resist pattern is obtained. Next, curing is performed at 100 ° C. to 200 ° C.

  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. Furthermore, in order to maintain the positional accuracy of the connection with the electronic component, it is more preferable to peel off 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. Also, when the entire surface of the polyimide film is peeled off from the glass substrate, peeling off after irradiating the ultraviolet curable organic layer again with ultraviolet rays after forming the circuit pattern will reduce the peeling force at the periphery of the polyimide film. It becomes easy.

  In the above example, a metal layer is provided on the side of the polyimide film to be bonded, a circuit pattern is first formed on one surface of the flexible film that is not fixed, and then the flexible film is bonded to the glass substrate. To the other side of the circuit pattern. 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.

  On the circuit board obtained by the production method of the present invention, and on the reinforcing plate, a peelable organic layer or an ultraviolet curable organic layer, at least opposite to the surface bonded to the peelable organic layer or the ultraviolet curable organic layer A circuit board member in which a flexible film having a wiring circuit formed on its surface is laminated in this order is subjected to an electronic component connection and a flexible film peeling process, to a wiring board for an electronic device, an interposer for an IC package, a wafer. It is preferably used for a level prober, a wafer level burn-in socket substrate, and the like. It is preferable to use a resistor element or a capacitor element in the circuit pattern as appropriate.

  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.

<Peeling force measurement method>
The peeling force of the polyimide film was measured by the following method. After bonding a polyimide film on the re-release agent 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.

Example 1
A polyimide film (trade name “Kapton” 150EN manufactured by Toray Du Pont Co., Ltd.) having a thickness of 38 μm and a width of 300 mm was prepared as a flexible film. A long polyimide film is mounted on a reel-to-reel type sputtering apparatus, and a 10 nm thick chromium: nickel = 20: 80 (weight ratio) alloy film and a 100 nm thick copper film are in this order. Laminated on top. To a soda-lime glass with a thickness of 1.1 mm and 300 × 350 mm, a UV curable adhesive, trade name “SK Dyne” SW-22 (manufactured by Soken Chemical Co., Ltd.) and a curing agent L45 (Soken Chemical ( Co., Ltd.) was mixed at 100: 3 (weight ratio) and dried at 80 ° C. for 2 minutes to provide an ultraviolet curable pressure-sensitive adhesive layer. The thickness of the ultraviolet curable pressure-sensitive adhesive layer after drying was 3 μm. Next, an air-blocking film made of a film in which a silicone resin layer that can be easily released was provided on a polyester film was bonded to the ultraviolet curable pressure-sensitive adhesive layer, and left for one week.

  A polyimide film provided with a metal layer was cut out to 300 × 350 mm. After the air blocking film was peeled off, a polyimide film provided with a metal layer on an organic material layer that can be peeled off by a laminator apparatus shown in FIG. The flexible sheet 202 made of polyester mesh was charged by the electrostatic charging device 201, and the polyimide film 203 was adsorbed. Next, the glass substrate 209 coated with the peelable organic layer 208 was held on the mounting table 207 by vacuum suction. The polyimide film 203 was pressed against the peelable organic layer 208 together with the flexible planar body 202 with the squeegee 210, and the polyimide film 203 was transferred to the glass substrate 209 side.

Thereafter, the ultraviolet curable pressure-sensitive adhesive layer formed in a range of 20 mm from the end of the polyimide film to the inner side is shielded from light, and the ultraviolet curable pressure-sensitive adhesive layer inside 20 mm from the end of the polyimide film is irradiated with ultraviolet rays from the soda lime glass side. Was irradiated with 1000 mJ / cm ² to photocur the ultraviolet curable pressure-sensitive adhesive layer. The peeling force in the range of 20 mm from the end of the polyimide film at this time was 98 N / m. A positive photoresist was applied onto the copper layer with a spin coater and dried at 80 ° C. for 10 minutes. The photoresist was exposed and developed through a photomask to form a photoresist layer having a thickness of 12 μm in a portion where the plating layer was unnecessary.

  The test photomask pattern had the following shape. First, a circuit pattern was produced in 42 mm in the direction of the glass substrate 300 mm and 23 mm in the direction of the length of the glass substrate 350 mm, and this was made one unit. The units were arranged in such a manner that the glass substrate was equally distributed from the center in the direction of a length of 300 mm, and adjacent to 5 rows at a pitch of 48 mm. Fourteen glass substrates were arranged at a pitch of 23.75 mm, equally spaced from the center in the 350 mm length direction. When the glass substrate is 350 mm long, the distance between the units is 0.75 mm.

Next, a copper layer having a thickness of 8 μm was formed by electrolytic plating in a copper sulfate plating solution using the copper layer as an electrode. The photoresist was stripped with a photoresist stripping solution, and then the copper layer and the chromium-nickel alloy layer that were under the resist layer were removed by soft etching with a hydrogen peroxide-sulfuric acid aqueous solution. Subsequently, a tin layer having a thickness of 0.4 μm was formed on the copper plating layer by electroless plating to obtain a circuit pattern. Thereafter, a protective layer for protecting the circuit pattern was formed on the circuit pattern with a screen printer. Solder resist SN-9000 (manufactured by Hitachi Chemical Co., Ltd.) was used for the protective layer. Curing was carried out in an oven at 120 ° C. for 90 minutes to obtain a protective layer having a thickness of 10 μm. The end of the polyimide film did not peel from the end of the glass substrate during the circuit pattern forming process. Subsequently, the ultraviolet curable pressure-sensitive adhesive layer was irradiated with 1000 mJ / cm ^{2 of} ultraviolet rays from the soda lime glass side, and then the polyimide film substrate of 300 × 350 mm was gradually peeled from the glass substrate by grasping the end of the polyimide film. The peeling force at this time was 4.7 N / m. The polyimide film after peeling did not warp or bend due to peeling. Moreover, when the circuit pattern on the peeled polyimide film was measured with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.), it was within ± 0.01% and was very good.

Example 2
A 300 × 350 mm polyimide film substrate was peeled from the glass substrate in the same manner as in Example 1 except that ultraviolet rays were not irradiated before peeling the polyimide film. Although the peripheral edge of the polyimide film after peeling was slightly curled, no warp or breakage due to peeling occurred in the circuit pattern forming portion of the polyimide film. Moreover, when the circuit pattern on the peeled polyimide film was measured with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.), it was within ± 0.01% and was very good.

Comparative Example 1
Formation of a circuit pattern was started in the same manner as in Example 1 except that the entire surface of the ultraviolet curable adhesive layer was irradiated with 1000 mJ / cm ^{2 of} ultraviolet light from the soda lime glass side and the entire surface of the ultraviolet curable adhesive layer was photocured. . The end portion of the polyimide film was peeled off from the glass substrate by the bubble of the plating solution stirring bubbling in the electroless tin plating process, and the plating apparatus was stopped due to poor conveyance.

Comparative Example 2
Irradiate ultraviolet rays from the side of the polyimide film to the inner side of the polyimide film with the ultraviolet rays from the side of the soda lime glass in a state where the ultraviolet ray curable adhesive layer formed within a range of 40 mm is shielded from light. A 300 × 350 mm polyimide film substrate was produced in the same manner as in Example 1 except that. In the heat treatment step, an ultraviolet curable organic layer formed in a range of 40 mm from the end of the polyimide film to the inside foamed. Subsequently, the ultraviolet curable pressure-sensitive adhesive layer was irradiated with 1000 mJ / cm ^{2 of} ultraviolet rays from the soda lime glass side, and then the polyimide film substrate of 300 × 350 mm was gradually peeled from the glass substrate by grasping the end of the polyimide film. The polyimide film after peeling did not warp or bend due to peeling, but the circuit pattern formed in the range of 40 mm inward from the end of the polyimide film was deformed.

Example 3
With an area of 20 mm from the end of 300 x 350 mm soda lime glass masked with masking tape, an acrylic weak adhesive re-peeling agent “Olivein” EXK01-257 (manufactured by Toyo Ink Co., Ltd.) and a curing agent BXX5134 A mixture of 100: 9 (manufactured by Toyo Ink Co., Ltd.) was applied and dried at 100 ° C. for 30 seconds. The thickness of the re-release agent after drying was 3 μm. Next, after peeling off the masking tape formed on the peripheral edge of soda lime glass, an air blocking film made of a film having a silicone resin layer that is easy to release on a polyester film is applied to the weak adhesive re-release agent layer. Combined. Next, an acrylic medium-tacky re-peeling agent “Siavine” SH-101 (manufactured by Toyo Ink Co., Ltd.) and a curing agent T-501B (Toyo Ink, Inc.) are placed within 20 mm from the edge of a 300 × 350 mm soda lime glass. Co.) was mixed at 100: 3 and dried at 100 ° C. for 2 minutes. The thickness of the re-release agent after drying was 3 μm. Next, an air-blocking film made of a film in which a silicone resin layer that can be easily released was provided on a polyester film was bonded to the medium-adhesive re-release agent layer, and left for one week. Thereafter, a 300 × 350 mm polyimide film substrate was peeled from the glass substrate in the same manner as in Example 1 except that no ultraviolet ray was irradiated. At this time, the peel force in the range of 20 mm from the end of the polyimide film was 3.5 N / m. On the other hand, the peel force in the range of 20 mm from the end of the polyimide film was 88 N / m. Although the peripheral edge of the polyimide film after peeling was slightly curled, no warp or breakage due to peeling occurred in the circuit pattern forming portion of the polyimide film. Moreover, when the circuit pattern on the peeled polyimide film was measured with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.), it was within ± 0.01% and was very good.

Comparative Example 3
Acrylic weak adhesive re-peeling agent “Olivein” EXK01-257 (manufactured by Toyo Ink Co., Ltd.) and curing agent BXX5134 (manufactured by Toyo Ink Co., Ltd.) at 100: 9 on the entire surface of 300 × 350 mm soda lime glass Formation of a circuit pattern was started in the same manner as in Example 3 except that the mixture was applied and dried at 100 ° C. for 30 seconds. Because the edge of the polyimide film was peeled off from the glass substrate due to the bubbling bubbles for stirring the plating solution in the electroless tin plating process, the screen printing device stopped without being able to recognize the alignment marks on the periphery of the polyimide film in the solder resist printing process did. The peeling force at this time was 3.5 N / m.

Example 4
A portion less than 30 mm from each of the four apexes of the flexible film, with a range of less than 15 mm inward from the edges of the four sides of the flexible film being overlapped with a portion located on the inner side of the periphery. The UV-curing pressure-sensitive adhesive layer is irradiated with 3000 mJ / cm ^{2 of} UV light from the soda lime glass side in a state where the four corners, which are portions other than the light-shielding portion, are shielded from light, and the UV-curing pressure-sensitive adhesive layers other than the four corners are photocured. Except for this, a 300 × 350 mm polyimide film substrate was peeled from the glass substrate in the same manner as in Example 2. The peeling force at the four corners at this time was 98 N / m. Moreover, the peeling force except for the four corners was 4.7 N / m. The polyimide film after peeling did not curl, warp or break due to peeling. Further, when the circuit pattern on the peeled polyimide film was measured with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.), it was within ± 0.01%.

Example 5
In the four corners having the same size as the four corners of Example 4, an acrylic-based medium-adhesive re-peeling agent “Siavine” SH-101 (manufactured by Toyo Ink Co., Ltd.) and a curing agent T-501B (Toyo Ink Co., Ltd.) Made of 100: 3), and other than the four corners, an acrylic weak adhesive re-peeling agent “Olivein” EXK01-257 (manufactured by Toyo Ink Co., Ltd.) and a curing agent BXX5134 (Toyo Ink) A 300 × 350 mm polyimide film substrate was peeled from the glass substrate in the same manner as in Example 3 except that a mixture of 100: 9 was manufactured. The peeling force at the four corners at this time was 88 N / m. Moreover, the peeling force except for the four corners was 3.5 N / m. The polyimide film after peeling did not curl, warp or break due to peeling. Further, when the circuit pattern on the peeled polyimide film was measured with a length measuring machine SMIC-800 (manufactured by Sokkia Co., Ltd.), it was within ± 0.01%.

Front view of laminating equipment The top view of the member for circuit boards which showed one of the aspects of this invention

Explanation of symbols

200 Laminating Device 201 Electrostatic Charging Device 203 Flexible Film Substrate (Plastic Film)
207 Mounting table 208 Separable organic layer 209 Reinforcing plate (glass substrate)
210 Squeegee 212 Rail 217 Ball screw 301 Flexible film 302 Peripheral portion 303 Flexible film 304 other than the four corner portions Overlapping portion 305 of the peripheral portion and a quarter circle 305 Four corner portions

Claims (2)

A circuit board member in which at least a reinforcing plate, a peelable organic layer, a flexible film, and a circuit pattern are laminated in this order, and a range of less than 30 mm at the maximum from the end of the flexible film to the inside, Four corners of the flexible film and a reinforcing plate, which are portions less than a maximum of 50 mm inward from each of the four apexes of the flexible film, excluding a portion overlapping with a portion inside the peripheral portion Circuit board member having a peel force between 49 N / m and 490 N / m, and a peel force between the flexible film other than the four corners and the reinforcing plate is 0.098 N / m to 49 N / m . A circuit board that peels off a flexible film with a circuit pattern from a reinforcing plate after a reinforcing plate is bonded to one side of the flexible film through an ultraviolet curable organic layer, and the ultraviolet curable organic layer is irradiated with ultraviolet rays. In the manufacturing method, when a range of a maximum of less than 30 mm inward from the end of the flexible film is defined as a peripheral portion, the peripheral portion is a portion of a maximum of less than 50 mm inward from each of the four apexes of the flexible film. The peeling force between the flexible film and the reinforcing plate at the four corners excluding the part overlapping with the inner part is more than 49 N / m and less than 490 N / m during the circuit pattern formation. A method of manufacturing a circuit board having a thickness of 0.098 N / m or more and 49 N / m or less before forming the flexible film and before peeling the flexible film.

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