JP6452189B2 - Method for manufacturing flexible electronic device - Google Patents

Description

  In the present invention, a flexible polymer film is temporarily fixed to a hard support to form a polymer film laminate, and then various electronic devices are formed on the polymer film using a printing technique. The present invention relates to a technique for manufacturing a flexible electronic device, in which a flexible electronic device is obtained by peeling the entire device portion from a support.

  Functional elements (devices) such as semiconductor elements, MEMS elements, and display elements are used as electronic components in information communication equipment (broadcast equipment, mobile radio, portable communication equipment, etc.), radar, high-speed information processing devices, etc. Conventionally, it is generally formed or mounted on an inorganic substrate such as glass, a silicon wafer, or a ceramic substrate. However, in recent years, attempts have been made to form various functional elements on a polymer film, as electronic components are required to be lighter, smaller, thinner, and flexible.

  In order to produce a conductor pattern having a width of about 10 μm used for an electronic device by printing, a metal ink finely divided to nano-order and a high-precision printing machine are required. That is, if the metal particles contained in the ink are large relative to the pattern, not only a fine conductor pattern cannot be produced, but it can also cause printing defects and short circuits. In addition, in order to make a flexible device element fabricated on a polymer film compact, high-definition, and high-functional, it is necessary to reduce the thickness of the conductor pattern. Ink is required.

  Various printing methods can be cited as high-definition printing methods. Reverse offset printing can draw even fine wiring, the cross-section of the resulting pattern is rectangular, and the printed pattern is transferred because the ink is completely transferred. It is suitable for drawing a conductor pattern of an electronic device because the surface becomes flat.

  During reverse offset printing, it is necessary to press the plate cylinder against the printing surface. At this time, if the pressing force is too strong, it causes deformation of the printing pattern, deformation of the printing surface, generation of scratches on the printing surface, and the like. For this reason, printing with a so-called kiss touch that hardly applies printing pressure is considered ideal. In order to print by kiss touch, the printing surface must be flat, and if the printing surface is not flat, printing omission or rubbing occurs.

  By the way, when various functional elements are formed on the surface of the polymer film, it is ideal to process by a so-called roll-to-roll process using flexibility which is a characteristic of the polymer film. However, in the industries such as the semiconductor industry, the MEMS industry, and the display industry, a process technology for a rigid flat substrate such as a wafer base or a glass substrate base has been mainstream. Therefore, in order to form various functional elements on the surface of the polymer film using the existing infrastructure, the polymer film is bonded to a rigid support made of an inorganic material (glass plate, ceramic plate, silicon wafer, metal plate, etc.). A process has been proposed in which a desired element is mounted and then peeled off from the support. Such technology is also utilized in printed electronics technology that forms electronic devices based on printing technology, which has recently been accelerated in research and development.

  Various adhesives are used as means for attaching the polymer film to a hard support. Since the polymer film needs to be peeled off from the support after the electronic device is formed, this point must be taken into consideration when selecting the pressure-sensitive adhesive. If an adhesive having an unnecessarily strong adhesive strength is used, the electronic device may be broken or the polymer film may be broken during peeling. On the other hand, if the adhesive force is too low, it may cause troubles such as peeling of the polymer film during the processing process of the electronic device. Therefore, in the case of using a pressure-sensitive adhesive, it is necessary to accurately grasp the adhesive force allowed in the processing process and the peeling process and manage it so that the adhesive force falls within that range. Furthermore, since the adhesive strength of the pressure-sensitive adhesive changes due to heating, humidification, etc., it is necessary to collect appropriate basic data and strictly control the temperature and humidity during the process.

  So far, a pressure-sensitive adhesive whose adhesive force is changed by an external stimulus is known as a peelable pressure-sensitive adhesive. For example, Patent Document 1, Patent Document 2 and Patent Document 3 disclose pressure-sensitive adhesives whose adhesive strength is reduced by heating. Patent Document 4, Patent Document 5 and Patent Document 6 disclose pressure-sensitive adhesives whose adhesive strength is reduced by ultraviolet irradiation. If such an adhesive is used, it is expected that the polymer film will not be peeled off during processing of the electronic device, and the polymer film can be peeled off from the support with a relatively small external force after completion of the electronic device. However, for example, when there is a process involving ultraviolet irradiation in the electronic device manufacturing process, use of an adhesive whose adhesive force changes due to ultraviolet irradiation is limited. In many cases, since the manufacturing process of an electronic device includes a heating process, it is practically difficult to use a pressure-sensitive adhesive whose adhesive strength is reduced by heating.

  As a peelable pressure-sensitive adhesive suitable for temporary fixing of a polymer film to a support, a pressure-sensitive adhesive whose adhesive strength varies greatly depending on temperature is disclosed in Patent Document 7, and according to this, cooling is performed. Adhesive strength can be reduced. Since such a pressure-sensitive adhesive rarely includes a cooling step during the device manufacturing process, it can be said that the pressure-sensitive adhesive has a relatively high degree of freedom and is easy to use.

JP-A-11-166164 Japanese Patent Laid-Open No. 2004-18604 JP 2000-71170 A JP-A-1-272130 Japanese Patent Laid-Open No. 62-153376 Japanese Patent Laid-Open No. 2-187478 JP 2000-351951 A

  However, we tackled the manufacture of flexible electronic devices using nano metal ink and reverse offset printing method by bonding the polymer film and the support using the adhesive that can reduce the adhesive force by cooling as described above. However, for example, when it is necessary to draw a high-definition conductor pattern such as a thin film transistor (hereinafter abbreviated as “TFT”), there is a problem that the obtained TFT does not operate well.

  The present invention has been made paying attention to the above-described circumstances, and its purpose is to manufacture a flexible electronic device without causing malfunction in the mounted electronic device even when a high-definition conductor pattern is required. It is to establish technology.

  As a result of intensive research to solve the above problems, the present inventors have firstly reversed the cause of malfunction when printing a high-definition conductor pattern such as when manufacturing a TFT. When printing with a very weak printing pressure as in the offset printing method, the conductor pattern printed on the polymer film temporarily fixed to the support is likely to be chipped or blurred, resulting in a short circuit. Second, when peeling the polymer film from the support, condensation occurs due to cooling, the moisture in the condensation causes deformation of the film, conductors oxidize and conductivity decreases, and semiconductor performance decreases. And found that there is a short circuit when the entire device is operated. And by controlling the method of laminating the film so as to fit the undulation that appears on the surface of the polymer film when temporarily fixing the polymer film to the support, the first cause is avoided, The cooling at the time of peeling the polymer film from the support is performed by bringing a refrigerant into contact with the surface on the support side of the polymer film composite obtained by temporarily fixing the support and the polymer film. Assuming that the cause is avoided, the present inventors have found that a flexible electronic device can be manufactured without causing a malfunction in an electronic device to be mounted even when a high-definition conductor pattern is required, and the present invention has been completed.

  That is, in the method for producing a flexible electronic device according to the present invention, a polymer film is temporarily fixed to a hard support through an adhesive layer to form a polymer film composite, and a contact type using metal nanoparticle ink. In a method for manufacturing a flexible electronic device, a conductor pattern is printed on a surface of a polymer film side of the polymer film composite using at least a printing method, and finally a polymer film is peeled from a support through a heating step. The polymer in a state where the pressure-sensitive adhesive layer has any of a melting point, a glass transition temperature, or an inflection point temperature of a storage elastic modulus in a range of −20 ° C. to 20 ° C. and temporarily fixed to a support. The difference in height of the undulation on the surface of the film is 3 μm or less, and the warp of the four corners of the polymer film composite before printing is 3 mm or less. Upon peeling the molecular film, and wherein contacting the coolant on the surface of the support side of the polymeric film composite.

  In the present invention, the temperature of the refrigerant may be controlled to be equal to or lower than the temperature within the range of −20 ° C. to 20 ° C. among the melting point, glass transition temperature, or inflection point temperature of the storage elastic modulus of the pressure-sensitive adhesive layer. preferable.

In the present invention, the ratio of the heat capacity of the refrigerant to the heat capacity of the support (refrigerant / support) is preferably 1.1 or more.
In this invention, it is preferable that the said polymer film consists of 1 or more types selected from the group which consists of a polyethylene terephthalate, a polyethylene naphthalate, a polyimide, and a polycarbonate.

In the present invention, when the polymer film is temporarily fixed to the support, the tension applied to the polymer film is preferably 0.3 MPa or less.
In the present invention, it is preferable that the peeling surface when peeling the polymer film from the support is the interface between the polymer film and the pressure-sensitive adhesive layer, and the 180-degree peeling strength at that time is 1 N / cm or less.
In the present invention, it is preferable to employ a reverse offset printing method as the contact printing method.

  According to the present invention, when the polymer film is temporarily fixed to the support, the undulation that appears on the surface of the polymer film is contained within a predetermined range, and the cooling when the polymer film is peeled from the support is supported with the support. Since the coolant is brought into contact with the support-side surface of the polymer film composite that is temporarily fixed to the polymer film, malfunctions may occur in the mounted electronic device even when a high-definition conductor pattern is required. Flexible electronic devices can be manufactured.

  The method for producing a flexible electronic device of the present invention includes a step of temporarily fixing a polymer film to a hard support through an adhesive layer to form a polymer film composite (temporary fixing step), and the polymer film composite. Including a step of printing a conductor pattern on the surface of the polymer film (printing step), a heating step, and a step of peeling the polymer film from the support (peeling step).

(Temporary fixing process)
In the temporary fixing step, the polymer film composite is prepared by temporarily fixing the polymer film to a hard support through an adhesive layer. Here, it is important to temporarily fix so that the height difference of the undulations on the surface of the polymer film in the state temporarily fixed to the support is 3 μm or less. In the present invention, the term “uneri” means that when an arbitrary straight line is selected on the surface of the polymer film composite on the polymer film side and the change in the height is observed at a measurement length of 10 mm, the adjacent concave and convex portions It means the unevenness with the largest difference in height. If the height difference of the ridge exceeds 3 μm, the printed conductor pattern is chipped or rubbed when printed by the contact-type printing method described later, thereby causing a short circuit. The level difference of the undulation on the surface of the polymer film is preferably 2.5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less. In order to control the level difference of the undulation within the above range, for example, the unevenness of the surface (temporary fixing surface) of the support is reduced, the uneven thickness of the adhesive layer or the film itself is suppressed, or the flat surface of the roller part at the time of lamination To prevent damage to the film during lamination (for example, laminating a polymer film with a protective sheet attached), between the support and the adhesive layer during lamination, or the adhesive layer What is necessary is just to devise, such as preventing the foreign material between the film and the polymer film.

  The hard support that can be used in the present invention may be a plate made of an inorganic material that can be used as a substrate, such as a glass plate, a ceramic plate, a silicon wafer, a metal, and the like. And composites such as those in which these are laminated, those in which they are dispersed, and those containing these fibers. Among these, a glass plate is preferable in terms of cost and lightness.

  The thickness of the support is not particularly limited, but is preferably from 0.1 mm to 3.0 mm, more preferably from 0.3 mm to 2.0 mm, and still more preferably from 0.5 mm to 1.5 mm. If the support is too thin, it may be difficult to handle the polymer film composite or the polymer film composite may be easily warped. On the other hand, if the support is too thick, the mass increases. Doing so may make handling difficult.

  The surface roughness of the support is preferably such that the maximum height (Ry) is 5 μm or less and the arithmetic average roughness (Ra) is 2.5 μm or less. Ry is preferably 3 μm or less, more preferably 1 μm or less, further preferably 0.5 μm or less, particularly preferably 0.01 μm or less, and Ra is more preferably 0.5 μm or less, further preferably 0.25 μm or less, particularly Preferably it is 0.01 micrometer or less. When the maximum height (Ry) and arithmetic average roughness (Ra) of the support are in the above ranges, it is easy to suppress undulation on the surface of the polymer film in the polymer film composite. In the present invention, “maximum height (Ry)” and “arithmetic average roughness (Ra)” mean “maximum height (Ry)” and “arithmetic average” defined in Japanese Industrial Standards (JISB 0601-1994). It means “roughness (Ra)” and can be measured using, for example, a surface roughness meter.

  The polymer film that can be used in the present invention is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate, polyimide, and polycarbonate. Among these, at least one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyimide, and polycarbonate is preferable.

  The thickness of the polymer film is not particularly limited, but is preferably 10 μm or more and 200 μm or less, more preferably 20 μm or more and 190 μm or less, and further preferably 30 μm or more and 150 μm or less. If the polymer film is too thin, the fine irregularities generated from the hard support and the pressure-sensitive adhesive tend to appear remarkably, and it becomes difficult to maintain the minimum mechanical strength as the base material of the electronic device. The film may be difficult to peel off. On the other hand, if it is too thick, the film may be bent when it is peeled off from the support.

In the present invention, the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer for temporarily fixing the support and the polymer film has an adhesive force (peeling strength) that varies depending on the temperature. It has the property that power is reduced.
In the present invention, the pressure-sensitive adhesive layer has a melting point, a glass transition temperature, or an inflection point temperature of storage elastic modulus within a range of −20 ° C. to + 20 ° C. (hereinafter referred to as “displacement point” in the present invention). There is also. Here, the inflection point temperature of the storage elastic modulus is a curve obtained by measuring the storage elastic modulus by scanning the temperature from the low temperature side to the high temperature side, and plotting the temperature on the horizontal axis and the storage elastic modulus on the vertical axis. It is the temperature which becomes an inflection point. When the displacement point of the pressure-sensitive adhesive layer exceeds 20 ° C., the adhesive strength becomes too weak and the film will be peeled off naturally during the process after temporary fixing. On the other hand, if it is less than −20 ° C., the peel strength is high. It becomes too much and peeling becomes difficult even if it cools. The displacement point of the pressure-sensitive adhesive layer is more preferably −15 ° C. to + 10 ° C., and further preferably −5 ° C. to + 5 ° C.

  As an adhesive which forms the said adhesive layer, resin which has the said displacement point in the range of -20 degreeC-20 degreeC can be used. Specifically, what has the said physical property should just be selected suitably from well-known resin used for adhesives, such as a silicone resin, an epoxy resin, an acrylic resin, a polyester resin, for example. Moreover, the adhesive using the side chain crystalline polymer which has the property to which adhesive force reduces by cooling can also be used preferably.

  The pressure-sensitive adhesive layer may be formed by applying a liquid or wax-like composition containing the above-mentioned pressure-sensitive adhesive to a support or a polymer film (coating method), or using a double-sided pressure-sensitive adhesive sheet. The double-sided pressure-sensitive adhesive sheet may be formed by bonding one surface to a support and the other surface to a polymer film (double-sided pressure-sensitive adhesive sheet method). From the viewpoint of simplicity, the latter double-sided PSA method is preferred. The pressure-sensitive adhesive layer may be formed first on either the support or the polymer film, but is preferably formed on the support first. In addition, when forming an adhesive layer in a support body, it is preferable to wash | clean the surface previously using UV cleaning apparatus etc.

  When forming an adhesive layer by the said coating method, it is preferable to apply | coat so that the thickness of the coating film after drying may be 5 micrometers or more and 30 micrometers or less. As the coating method, for example, conventionally known methods such as spin coating, doctor blade, applicator, comma coater, screen printing method, casting from a nozzle with a slit, extrusion by an extruder, slit coating, reverse coating, dip coating, etc. The coating means may be used.

  The surface roughness of the pressure-sensitive adhesive layer formed by the coating method is preferably such that the maximum height (Ry) is 3 μm or less and the arithmetic average roughness (Ra) is 2.5 μm or less. Ry is more preferably 1 μm or less, further preferably 0.5 μm or less, and Ra is more preferably 0.5 μm or less, and even more preferably 0.25 μm or less. When the maximum height (Ry) and arithmetic average roughness (Ra) on the surface of the pressure-sensitive adhesive layer are in the above ranges, it is easy to suppress undulation on the surface of the polymer film in the polymer film composite. In order to make the roughness of the surface of the pressure-sensitive adhesive layer within the above range, for example, by reducing the unevenness of the surface of the support (temporary fixing surface) or increasing the wettability of the surface of the support (temporary fixing surface) What is necessary is just to make uniform coating inside and to suppress coating nonuniformity by using a high precision coating machine.

  The double-sided pressure-sensitive adhesive sheet may have a pressure-sensitive adhesive layer on both sides of a base material (plastic sheet, nonwoven fabric sheet, etc.), or may have only a pressure-sensitive adhesive layer without having a base material. Good. Preferably, the structure having a base material is composed only of the pressure-sensitive adhesive layer because a difference in shrinkage from the pressure-sensitive adhesive layer is caused in the process of heating such as bonding and firing of the conductor nano ink, which causes unevenness. It is desirable that

  When the pressure-sensitive adhesive layer is formed by the double-sided pressure-sensitive adhesive sheet method, the lower limit of the thickness (total thickness) of the double-sided pressure-sensitive adhesive sheet is 5 μm or more for improving the handling property of the pressure-sensitive adhesive and alleviating the unevenness of the hard support. Is preferably 10 μm or more, more preferably 20 μm or more. On the other hand, the upper limit of the thickness (total thickness) of the double-sided pressure-sensitive adhesive sheet is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less in order to reduce unevenness caused by unevenness in the thickness of the sheet-like pressure-sensitive adhesive itself. .

  When the pressure-sensitive adhesive layer is formed by the double-sided pressure-sensitive adhesive sheet method, a known laminating method can be appropriately employed as a method for laminating the double-sided pressure-sensitive adhesive sheet and the support or the polymer film. Specifically, a roll laminating method, a press method, or a method by pressurization with two rolls is generally used. In addition, it can also heat to about 30 to 100 degreeC at the time of bonding, for example using the roll provided with the heating function. In that case, there is no restriction | limiting in the material of a roll.

  When the pressure-sensitive adhesive layer is formed by the double-sided pressure-sensitive adhesive sheet method, when the double-sided pressure-sensitive adhesive sheet is bonded to the support or the polymer film, the contact surface with the pressure-sensitive adhesive layer in the pasting machine (for example, a roll part of a roll laminator) ) Is preferably 3 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less. If the contact surface of the applicator is uneven, the surface of the polymer film may be wavy.

  The surface roughness of the pressure-sensitive adhesive layer formed by the double-sided pressure-sensitive adhesive sheet method preferably has a maximum height (Ry) of 3 μm or less. More preferably, it is 1 micrometer or less, More preferably, it is 0.5 micrometer or less. When the maximum height (Ry) of the pressure-sensitive adhesive layer surface is in the above range, it becomes easy to suppress undulation on the surface of the polymer film in the polymer film composite. In order to make the surface roughness of the pressure-sensitive adhesive layer within the above range, for example, the unevenness of the surface (temporary fixing surface) of the support is reduced, the uneven thickness of the pressure-sensitive adhesive layer itself is suppressed, What is necessary is just to improve the flatness.

  As a method for adhering the polymer film to the support on which the pressure-sensitive adhesive layer is formed, a known laminating method can be appropriately employed. Specifically, a roll laminating method, a press method, or a method by pressurization with two rolls is generally used. In addition, it can also heat to about 30 to 100 degreeC at the time of bonding, for example using the roll provided with the heating function. In that case, there is no restriction | limiting in the material of a roll.

  When the polymer film is bonded to the support on which the pressure-sensitive adhesive layer is formed, the tension applied to the polymer film is preferably 1.0 MPa or less. If the tension applied to the polymer film is too high, the resulting polymer film composite may be warped at the four corners of the film. The tension applied to the polymer film is more preferably 0.5 MPa or less, and still more preferably 0.3 MPa or less.

  When a polymer film is pasted on a hard support coated with an adhesive, the difference in level of unevenness on the contact surface with the adhesive layer in the pasting machine (for example, the roll part of a roll laminator) must be 3 μm or less. Is more preferably 1 μm or less, still more preferably 0.5 μm or less. If the contact surface of the applicator is uneven, the surface of the polymer film may be wavy.

  In the present invention, it is important that the warpage of the four corners of the polymer film composite before printing is 3 mm or less. If the curvature of the four corners of the polymer film composite exceeds the above range, problems such as missing prints at the center and difficulty in fixing during printing will cause problems in printing by the contact printing method. Moreover, even if printing can be performed, it may be difficult to uniformly contact the refrigerant, resulting in cooling spots, and finally distortion may occur in the flexible electronic device (TFT or the like) after peeling from the support. The warp of the four corners of the polymer film composite is preferably 2 mm or less, more preferably 1 mm or less.

(Printing process)
In the printing step, the conductor pattern is printed on the polymer film side surface of the polymer film composite using at least a contact-type printing method using metal nanoparticle ink. In other words, a plurality of printing methods can be used in combination in the printing process, but in the present invention, at least one of them must be a contact type printing method using metal nanoparticle ink. I must.
The contact-type printing method is an image transfer method in which an intermediate medium such as a printing plate or a blanket is directly brought into contact with a polymer film as a final medium, for example, letterpress printing, intaglio printing, planographic printing, stencil printing. And reverse offset printing. Contact printing is much shorter in printing time than non-contact printing and is suitable for high-speed production. The printing resolution in contact printing is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less.

The letterpress printing is a method in which ink is adhered to a convex part of a plate having a concave part and a convex part formed on the surface, and the ink is transferred to a printed matter.
The intaglio printing means that a resin resin having a high fluidity is supplied onto the intaglio, the excess ink supplied to the intaglio printing plate is scraped with a doctor, and at the same time, the ink corresponding to the pixel portion corresponding to the indentation pattern is filled with the ink. This is a method of transferring directly to a printing material such as paper or plastic through a young or rubber blanket.

In the lithographic (offset) printing, an area having adhesion to the printing ink and a non-adhesion area are formed on the surface of the printing plate, and the printing ink is repelled in the non-adhesion area. In this method, a printing plate is formed by attaching printing ink only to a certain area.
The stencil printing is a method in which printing ink is supplied from the support side which is a master, is leached through a perforated portion of the polymer film, and is printed on a printing paper in contact with the polymer film surface of the master.

The reverse offset printing is a printing method in which the ink coated on the entire surface of the blanket cylinder is transferred to a patterned relief plate, and the remaining ink is transferred to a workpiece.
In the present invention, it is preferable to employ the reverse offset printing method among the contact printing methods described above. According to the reverse offset printing, high-precision pattern printing with a printing accuracy of about ± 10 μm or less and a resolution of about 10 μm or less is possible, and the semi-dried ink is transferred to the film, so that the cross-sectional shape is A rectangular printed body can be formed.

  The metal nanoparticle ink used in the contact-type printing method may be appropriately set according to the required characteristics of the flexible electronic device to be produced. For example, platinum, gold, silver, copper, nickel, palladium, zinc, Examples include tin and iron. The metal nanoparticle ink may be only one type or two or more types.

  Although the particle diameter of the metal nanoparticle ink is not particularly limited, for example, the median diameter (d50) is preferably 1 nm to 500 nm, more preferably 200 nm or less, and still more preferably 100 nm or less.

  In the present invention, warping of the four corners of the polymer film composite after printing is preferably 3 mm or less, more preferably 2 mm or less, and further preferably 1 mm or less. If the four corners of the polymer film composite are warped after printing, the flexible electronic device (TFT or the like) after peeling from the support may be distorted.

(Heating process)
In this invention, a heating process is included. The heating step may be, for example, heating performed to increase the adhesive force of the pressure-sensitive adhesive layer when forming a polymer film composite in which a polymer film and a support are temporarily fixed. It may be performed for firing metal nanoparticles, may be performed for polymerizing organic polymers used for insulators, etc., and is included in metal nanoparticles and organic polymers You may perform in order to remove a solvent.

  The temperature in the heating step may be appropriately set according to the purpose, but is preferably 200 ° C. or lower, more preferably 180 ° C. or lower, and further preferably 150 ° C. or lower.

(Peeling process)
In the peeling step, the polymer film on which the conductor pattern is printed is peeled from the support of the polymer film composite. In the present invention, in peeling the polymer film from the support, it is important to bring the refrigerant into contact with the support-side surface of the polymer film composite. If the pressure-sensitive adhesive layer is cooled only from one side by bringing the refrigerant into contact with the surface on the support side instead of cooling the entire polymer film composite, the occurrence of condensation can be suppressed, and the deformation of the film It is possible to avoid problems caused by moisture, such as conductor oxidation, semiconductor performance degradation, and short circuit during device operation.

  In the present invention, as the coolant, it is preferable to use a material having a predetermined shape having a surface that can be brought into contact with the support-side surface of the polymer film composite, after cooling to a predetermined temperature. The material of the refrigerant is not particularly limited, but, for example, a glass plate, a ceramic plate, a silicon wafer, a metal other than these, a material in which these are laminated, a material in which these are laminated, and these are dispersed And composites such as those containing fibers made of these.

  The refrigerant is preferably made of a material whose heat capacity is larger than the heat capacity of the support, and in particular, the heat capacity ratio (refrigerant / support) between the heat capacity of the refrigerant (refrigerant material) and the heat capacity of the support is 1.1. It is preferable that it is above, and it is more preferable that it is 1.3 or more. If this heat capacity ratio is smaller than the above range, the support may be insufficiently cooled, and the peeling strength of the pressure-sensitive adhesive layer cannot be lowered, and peeling tends to be difficult.

  The temperature of the refrigerant (that is, the temperature of the refrigerant material when used as a refrigerant) is equal to or less than the temperature of the displacement point of the pressure-sensitive adhesive layer (one of melting point, glass transition temperature, or inflection point temperature of storage elastic modulus). It is preferable to control. For example, if the glass transition temperature of the pressure-sensitive adhesive layer is 0 ° C., the temperature of the refrigerant is preferably 0 ° C. or less.

  The contact area when the support side of the polymer film composite is brought into contact with the cooling medium is preferably 80% or more, more preferably 90% or more of the total area of the polymer film composite (support). It is preferably 95% or more, and most preferably 100% (that is, contact with the entire surface of the support). If the contact area is too small, cooling may be insufficient and peeling may be difficult. Needless to say, the contact area may be larger than the total area of the polymer film composite (support).

  The contact time when the surface on the support side of the polymer film composite is brought into contact with the cooling medium should be shorter than the time when condensation starts to occur, and may be set as appropriate according to the type of refrigerant, heat capacity, contact area, etc. However, it is usually 1 second to 60 seconds, preferably 2 seconds to 50 seconds, more preferably 5 seconds to 40 seconds, and further preferably 10 seconds to 30 seconds.

  The polymer film can be peeled off from the support only if the pressure-sensitive adhesive layer is cooled by a predetermined cooling method (that is, bringing the refrigerant into contact with the support-side surface of the polymer film composite). There is no particular limitation, and for example, the end portion of the polymer film may be scratched or a slight cut may be made to create a wrinkled portion that triggers peeling, and the polymer film may be pulled from that portion.

  The peeling surface when peeling the polymer film from the support is preferably the interface between the polymer film and the pressure-sensitive adhesive layer. If it peels in the interface of a polymer film and an adhesive layer, since an adhesive layer does not remain in a polymer film, it can be used conveniently as an electronic device.

  The 180 degree peel strength when the polymer film is cooled and peeled from the support is preferably 1 N / cm or less. The 180 degree peel strength is more preferably 0.5 N / cm or less, and still more preferably 0.1 N / cm or less. When the 180-degree peel strength at the time of cooling peeling is within the above range, it is possible to prevent the conductor pattern and the mounted device from being damaged at the time of peeling.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.
The physical properties in the following examples were measured and evaluated by the following methods.

<Displacement point of adhesive layer (glass transition temperature)>
About the pressure-sensitive adhesive (pressure-sensitive adhesive layer of the double-sided cooling release sheet) used for temporary fixing of the polymer film and the support, using a DSC differential thermal analyzer, it absorbs and releases heat due to structural changes in the range from room temperature to 200 ° C The glass transition temperature was determined from the presence or absence of.

<Unery on the surface of the polymer film in the polymer film composite>
After a polymer film is bonded to a support to form a polymer film composite, before printing, the following is performed using a palpation type surface roughness meter ("Surfcoder ET4000L-J" manufactured by Kosaka Laboratory Ltd.) The surface of the polymer film was analyzed under the following conditions. And the difference in height between the highest point and the lowest point in the total measurement length (10 mm) was defined as undulation.
Measurement temperature: Room temperature Measurement speed: 200 μm / sec Atmosphere: Atmospheric measurement length: 10 mm

<180 degree peel strength>
The 180 degree peel strength between the support and the polymer film at the time of cooling peeling was measured according to the following conditions in accordance with the 180 degree peeling method specified in JIS C 6471. This measurement was performed before printing, after a polymer film was bonded to the support to form a polymer film composite.
Device name: “Autograph AG-IS” manufactured by Shimadzu Corporation
Measurement temperature: 5 ° C
Peeling speed: 50 mm / min Measurement atmosphere: Air measurement Sample width: 1 cm

<Confirmation of peeling surface>
About the polymer film after cooling peeling, it was confirmed by visual observation whether the adhesive layer remained on the surface. If there is no residual adhesive layer, it can be said that the film is peeled off at the interface between the polymer film and the adhesive layer.

<War of the four corners of the polymer film composite>
Before and after printing, a polymer film composite (both A4 size) was used as a measurement sample, and each sample was placed on a flat plate (such as a glass plate) so that the support side would be down. With respect to the four corners of the film composite, the distance from the lower surface (surface on the support side) of the composite to the upper surface of the flat plate was measured with a ruler, and the average value of the four values obtained was defined as the warp of the four corners.

Example 1
1. Formation of pressure-sensitive adhesive layer on support Glass (Corning “Eagle XG”: size A4, thickness 1.1 mm, maximum height (Ry) 7 nm, arithmetic average roughness (Ra) 1 nm, heat capacity 116 J / K The substrate was cleaned by irradiating it with UV light for 180 seconds using a UV cleaning device, and then a commercially available double-sided cooling release pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on both sides (sheet 1: glass of the pressure-sensitive adhesive layer) A transition temperature of 18 ° C) is cut into A4 size, the protective film on one side is peeled off, and support is performed using a single-wafer laminator device at a pasting temperature (the temperature of the support at the time of pasting) of 50 ° C. In this laminator device, the support (glass plate) is adsorbed to the device under reduced pressure via a stainless steel hot plate with a hole (set temperature: 50 ° C.). Then, the double-sided cooling release pressure-sensitive adhesive sheet is adsorbed to the apparatus under a reduced pressure through a 300-mesh screen.
Tension applied to the double-sided cooling / peeling adhesive sheet at the time of pasting: 0.3 MPa
Gap between support and double-sided cooling / peeling adhesive sheet: 0.9 mm
Roller rubber hardness: 70 degrees Roller supply pressure: 0.5 MPa
Roller moving speed: 5mm / sec. Pushing amount when pasting: 0.3mm

2. Formation of Polymer Film Composite Next, a polyimide film (“XENOMAX (registered trademark) model number F38LR” manufactured by Toyobo Co., Ltd.) as a polymer film is bonded to the support provided with the pressure-sensitive adhesive layer, and the polymer composite is bonded. Got. Specifically, the remaining protective film of the double-sided cooling release pressure-sensitive adhesive sheet bonded to the support is peeled off, and the same laminator device as that used in “1. Formation of pressure-sensitive adhesive layer on the support” is used on the peeled surface. The polyimide film was bonded by setting the bonding temperature (temperature of the adhesive layer at the time of bonding) to 50 ° C. Laminating conditions are the same as “1. Formation of pressure-sensitive adhesive layer on support” except that “Double-sided cooling release pressure-sensitive adhesive sheet” in “1. Formation of pressure-sensitive adhesive layer on support” is read as “polyimide film”. It was.

3. Printing and heating of conductor pattern On the surface of the obtained polymer film composite on the polymer film side, using a reverse offset printing machine, a silver nano ink for reverse printing was used to form a rectangle with a length of 3 mm and a width of 200 μm in 10 rows × A conductor pattern arranged in 12 rows (120 in total) was printed. Next, in order to sinter the printed silver nano ink, the polymer film composite after printing is subjected to a heat treatment at 180 ° C. for 30 minutes in a clean oven, and after heating, it is quickly removed from the oven and allowed to cool at room temperature. Thus, a polymer film composite (referred to as “post-printing composite”) on which a conductor pattern was formed was obtained. At the time of heating, nitrogen gas was passed through the oven so that the clean oven had an atmosphere with an oxygen concentration of 0.1 vol% or less.

4). Separation of polymer film A glass plate (size 300 mm × 300 mm, thickness 1.1 mm: heat capacity 165 J / K) cooled to −20 ° C. in a freezer set to −20 ° C. was used as a refrigerant, and the glass plate as this refrigerant The entire surface was brought into contact with the surface on the support side of the composite after printing for about 10 seconds in an atmosphere at a temperature of 23 ° C. ± 1 ° C. and a humidity of 40% ± 10%. A polymer having a conductor pattern is formed by scratching the end portion to create a bent portion that triggers peeling, and gently pulling the bent portion as it is at a peeling angle of about 45 degrees to peel the polymer film from the support. A film (referred to as “conductor film”) was obtained.

5. Conductivity evaluation Eight random measurement points were selected from the obtained conductor film, the specific resistance value was measured using a semiconductor parameter analyzer (“B1500A” manufactured by Agilent Technologies, Inc.), and the average value was measured. The resistance value of the film was used. The results are shown in Table 1.

(Examples 2 to 5 and Comparative Examples 1 and 2)
A conductor film was obtained in the same manner as in Example 1 except that the polymer film or the double-sided cooling release adhesive sheet was changed to that shown in Table 1, and the resistance value was obtained in the same manner as in Example 1 with respect to the obtained conductor film. Was measured. The results are shown in Table 1.

In Table 1, the following abbreviations were used.
・ Polymer film PI: Polyimide (“XENOMAX (registered trademark) F38LR” manufactured by Toyobo Co., Ltd .: thickness 38 μm)
PEN: Polyethylene naphthalate (“Teonex (registered trademark) model number Q65FA” manufactured by Teijin DuPont Films Ltd .: thickness 125 μm)
PC: Polycarbonate (“Pure Ace (registered trademark) model number SS120 manufactured by Teijin Limited”: thickness 120 μm)
PET: Polyethylene terephthalate (“Cosmo Shine (registered trademark) model number A1555” manufactured by Toyobo Co., Ltd .: thickness 188 μm)

Double-sided cooling release pressure-sensitive adhesive sheet Sheet 1: Double-sided pressure-sensitive adhesive sheet having a glass transition temperature of 18 ° C. and a thickness of 25 μm Sheet 2: Double-sided pressure-sensitive adhesive sheet having a glass transition temperature of −18 ° C. and a thickness of 30 μm Sheet 3: Pressure-sensitive adhesive Double-sided pressure-sensitive adhesive sheet having a glass transition temperature of 20 ° C. and a thickness of 47 μm Sheet 4: Double-sided pressure-sensitive adhesive sheet having a glass transition temperature of the pressure-sensitive adhesive layer of −60 ° C. and a thickness of 40 μm

(Example 6, Example 7)
Instead of the refrigerant material (glass plate with a heat capacity of 165 J / K) used in “4. peeling of polymer film” in Example 1, in Example 6, an aluminum plate (A5052: size 300 mm × 300 mm, thickness 1.1 mm) : Heat capacity 235 J / K), and in Example 7, a conductive film was obtained in the same manner as in Example 1 except that a glass plate (size 400 mm × 400 mm, thickness 1.1 mm: heat capacity 298 J / K) was used. The resistance value of the obtained conductor film was measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
A conductor film was obtained in the same manner as in Example 1 except that “4. Release of polymer film” in Example 1 was changed as follows. The value was measured. The results are shown in Table 1.
4). Peeling of polymer film After storing the composite for 1 minute in a freezer set to -20 ° C, immediately after printing, scratch the end of the polymer film of the composite to create a crease that triggers peeling. Then, the polymer film was peeled from the support by gently pulling from the bent portion as it was at a peeling angle of about 45 degrees to obtain a polymer film (conductor film) having a conductor pattern.

(Comparative Example 4)
In Example 1, “Gap between support and double-sided cooling release pressure-sensitive adhesive sheet” and “Pressure-sensitive adhesive layer” in “1. Formation of pressure-sensitive adhesive layer on support” and “2. Formation of polymer film composite” A conductor film was obtained in the same manner as in Example 1 except that the “gap between the provided support and the polymer film” was changed to 2 mm, and the resistance value of the obtained conductor film was changed in the same manner as in Example 1. It was measured. The results are shown in Table 1.

(Comparative Example 5)
In “1. Formation of pressure-sensitive adhesive layer on support” and “2. Formation of polymer film composite” in Example 1, bonding of the support and the double-sided cooling release pressure-sensitive adhesive sheet, A polymer film composite was obtained in the same manner as in Example 1 except that the laminator apparatus used for bonding the provided support and the polymer film was changed to a roll laminator apparatus.
Specifically, in “1. Formation of pressure-sensitive adhesive layer on support”, the cleaning surface of the support (glass plate) and the surface of the pressure-sensitive adhesive layer of the double-sided cooling release pressure-sensitive adhesive sheet are opposed to “2. In `` Formation of polymer film composite '', a double-sided cooling release adhesive sheet or polymer film is placed on the roll part of the roll laminator device so that the surface of the adhesive layer of the support with the adhesive layer faces the polymer film. Lamination was performed in a state where the support or the support with the pressure-sensitive adhesive layer was heated to 80 ° C. At the time of bonding, the tension applied to the double-sided cooling release pressure-sensitive adhesive sheet or polymer film was 1.5 MPa.
Using the obtained polymer film composite, printing was performed in the same manner as in “3. Printing and heating of conductor pattern” in Example 1. However, the warp of the polymer film composite is large, and printing is performed. I couldn't.

  From Table 1, a flexible film having a conductor pattern with a low resistance value can be obtained by peeling the polymer film by a method in which the swell of the polymer film composite is within a predetermined range and a refrigerant is brought into contact with the support. I understand that.

(Application examples)
Using the polymer film composite obtained in “2. Formation of polymer film composite” in Example 1, Comparative Example 1 and Comparative Example 3, a bottom-gate / bottom-contact TFT was fabricated and its performance Evaluated.

  That is, first, a gate electrode pattern was printed on a polymer film of a polymer film composite using a silver nano ink with a reverse offset printer, and then heated at 180 ° C. for 30 minutes. After sufficiently cooling at room temperature, the gate insulating film ink was applied using a die coater and heated at 180 ° C. for 30 minutes. After sufficiently allowing to cool at room temperature, the source / drain electrode pattern was printed on a reverse offset printing machine using silver nanoink, and then heated at 180 ° C. for 30 minutes. After sufficiently cooling at room temperature, the semiconductor ink was then printed with an inkjet printer and heated at 120 ° C. for 30 minutes. Thereafter, the support and the polymer film were peeled off in the same manner as in “4. Stripping of the polymer film” in each of the examples and comparative examples, thereby producing a flexible TFT. The number of printed patterns was about 300,000 in total of 640 in the horizontal direction and 480 in the vertical direction.

When the mobility of the obtained flexible TFT was measured with a semiconductor parameter analyzer (“B1500A” manufactured by Agilent Technologies), a mobility of 0.163 cm ² / Vs was obtained according to Example 1. However, in Comparative Example 1 and Comparative Example 3, the mobility was as low as 10 ⁻⁴ cm ² / Vs or less. In Comparative Example 1, it is considered that defects occurred in the gate electrode and the source / drain electrode at the time of printing, and in Comparative Example 3, dew condensation occurred at the time of peeling, so that the performance of the semiconductor deteriorated.

  From the above results, a TFT having good characteristics (mobility) can be obtained by peeling the polymer film by a method in which the swell of the polymer film composite is within a predetermined range and a coolant is brought into contact with the support. I understand that.

  According to the method for manufacturing a flexible electronic device of the present invention, even when a high-definition conductor pattern is printed on a polymer film temporarily fixed to a support, it is possible to avoid occurrence of malfunction in the mounted electronic device. . Such a manufacturing method greatly contributes to a technology / industry field in which a flexible electronic device is manufactured mainly using printing technology.

Claims (8)

A polymer film is temporarily fixed to a hard support through an adhesive layer to form a polymer film composite, and at least the contact type printing method using metal nanoparticle ink is used to increase the height of the polymer film composite. In the method for producing a flexible electronic device, a conductor pattern is printed on the surface on the molecular film side, subjected to a heating step, and finally the polymer film is peeled from the support.
The pressure-sensitive adhesive layer has a melting point, a glass transition temperature, or an inflection point temperature of a storage elastic modulus in a range of −20 ° C. to 20 ° C.,
The height difference of the undulation on the surface of the polymer film in the state temporarily fixed to the support is 3 μm or less, and the warp of the four corners of the polymer film composite before printing is 3 mm or less,
When peeling the polymer film from the support, use is made of dew generation suppression means for bringing a refrigerant into contact with the surface of the polymer film composite on the support side, and in the dew condensation generation suppression means, the support side of the polymer film complex is used. A method for manufacturing a flexible electronic device, wherein a contact time when the surface of the liquid crystal is brought into contact with the refrigerant is shorter than a time when condensation starts to occur . The polymer film surface of the support side of the complex with the refrigerant and the contact time for contacting the method of manufacturing a flexible electronic device according to claim 1 or less 60 seconds 1 second.   The temperature of the said refrigerant | coolant is controlled below to the temperature of what is in the range of -20 degreeC-20 degreeC among melting | fusing point of the said adhesive layer, glass transition temperature, or the inflection point temperature of a storage elastic modulus. Manufacturing method for flexible electronic devices.   The method for manufacturing a flexible electronic device according to any one of claims 1 to 3, wherein a ratio (refrigerant / support) between a heat capacity of the refrigerant and a heat capacity of the support is 1.1 or more.   The method for producing a flexible electronic device according to any one of claims 1 to 4, wherein the polymer film is composed of one or more selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyimide, and polycarbonate.   The method for producing a flexible electronic device according to any one of claims 1 to 5, wherein a tension applied to the polymer film is 0.3 MPa or less when the polymer film is temporarily fixed to the support.   The peeling surface when peeling the polymer film from the support is an interface between the polymer film and the pressure-sensitive adhesive layer, and the 180-degree peeling strength at that time is 1 N / cm or less. The manufacturing method of the flexible electronic device as described in a term.   The manufacturing method of the flexible electronic device as described in any one of Claims 1-7 which employ | adopts the reverse offset printing method as said contact type printing method.