Abstract:
A method of adhesion inhibiting generation of bubbles is provided. Heating, evacuation and centrifugal degassing are performed on an adhesive  37  disposed in an adhesive container  30  to semi-harden the adhesive  37 , then a semi-hardened adhesive is discharged as disposed in the adhesive container  30  to mount a chip. Removal of bubbles is efficiently performed since semi-hardening and degassing are simultaneously performed. Further, no defective product is produced even if a working process is stopped since no process for semi-hardening a discharged adhesive exists.

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to a technology for mounting a chip on a resin film, more particularly to a technology for fixing a chip to a resin film by discharging a certain amount of adhesive. 
     2. Background Art 
     In recent years, a technology that involves a bare chip made of a semiconductor mounted on a wiring board has been developed, and the technology has been frequently used to manufacture miniature electronic devices such as mobile phones since a packaging area can be made smaller than that of a case where a chip molded into a resin is mounted. 
       FIGS. 7  ( a ) to ( e ) describe a conventional process for mounting a bare chip. First, referring to  FIG. 7  ( a ), numeral  113  shows a base film composed of a flexible resin and a wiring film  122  composed of a patterned copper foil formed on the surface of the base film  113 . 
     To the surface of the base film  113  on which the wiring film  122  is formed, an anisotropic conductive film  115  is affixed as shown in  FIG. 7  ( b ). The base film  113  is placed on a preheating table  151  while orienting the back side thereof downward as shown in  FIG. 7  ( c ). 
     The anisotropic conductive film  115  is composed of a thermosetting resin as a main agent and conductive particles are dispersed in the main agent. 
     The preheating table  151  is preheated at a temperature higher than the curing temperature of the main agent contained in the anisotropic conductive film  115 . Thus, the anisotropic conductive film  115  is heated by heat transmitted through the base film  113 . 
     The main agent of the anisotropic conductive film  115  is semi-hardened by placing both the base film  113  and the anisotropic conductive film  115  on the surface of the base film  113  on the preheating table  151  for a predetermined time. 
     Next, as shown in  FIG. 7  ( d ), the base film  113  and the semi-hardened anisotropic conductive film  115  are moved from the preheating table  151  to a working table  152 ; a semiconductor chip  111  is retained by a pressing jig  129 ; the semiconductor chip  111  is moved to a position above the anisotropic conductive film  115 ; a bump  121  of the semiconductor chip  111  and a connecting part of a wiring film  122  are so positioned as to face each other; and then, as shown in  FIG. 7  ( e ) when the semiconductor chip  111  is pressed against the anisotropic conductive film  115  by the pressing jig  129 , the bump  121  digs into the anisotropic conductive film  115 ; thereby the bump  121  is connected electrically to the wiring film  122  through conductive particles dispersed in the anisotropic conductive film  115 . 
     Since the pressing jig  129  and the working table  152  are heated at a temperature higher than that of the preheating table  151 , by keeping the jig  129  to be pressed against the back side of the semiconductor chip  111  for a predetermined time, the main agent in the anisotropic conductive film  115  hardens and, thus, the semiconductor chip  111  is fixed to the base film  113 . 
     In the case where the anisotropic conductive film  115  is hardened as above, the anisotropic conductive film  115  is first heated on the preheating table  151 , the film is moved to the surface of the working table  152  after the film is semi-hardened, and then mounting and heating of the semiconductor chip  111  is performed; thereby heating time on the working table can be shortened by the extent corresponding to the previous semi-hardening. 
     However, if the semiconductor chip  111  is mounted on the anisotropic conductive film  115  on the working table  152  and the progress of the process is suspended, under the process of preheating before the mounting since the anisotropic conductive film  115  is also kept on the preheating table  151  for a long time, both of the anisotropic conductive films  115  become defective. 
     An alternative processing technique involves using a liquid adhesive material applied onto the base film  113  in place of the anisotropic conductive film  115 . However, this processing has the problems that the material is likely to immix bubbles as compared with the anisotropic conductive film  115 . As a result, a defect in aging caused by voids frequently occurs. 
     SUMMARY OF INVENTION 
     In one aspect, the present invention provides a method for adhesion wherein bubbles are not immixed and a defect does not frequently occur. 
     In one embodiment, the present invention relates to a method for adhesion comprising semi-hardening an adhesive capable of being hardened by proceeding with a reaction through heating; discharging a desired amount of the semi-hardened adhesive from a pore to dispose on an object to be discharged; and mounting an object to be affixed to the object to be discharged by contacting the object to be affixed to the adhesive disposed on the object to be discharged, pressing the object to be affixed against the object to be discharged, and then heating the adhesive existing between the object to be discharged and the object to be affixed to harden the adhesive. 
     Thus, in one embodiment, the present invention comprises a method for adhesion, wherein the object to be affixed is heated in the mounting step. 
     In one embodiment, the present invention comprises a method for adhesion, wherein, before performing the semi-hardening, the adhesive is disposed in an adhesive container, and the semi-hardening step and the discharging step are performed while placing the adhesive in the same adhesive container. 
     In one embodiment, the present invention comprises a method for adhesion, wherein the adhesive container is heated to semi-harden the adhesive in the semi-hardening step. 
     In one embodiment, the present invention comprises a method for adhesion, wherein the adhesive container is heated in the semi-hardening step while applying a centrifugal force to the adhesive container. 
     In one embodiment, the present invention comprises a method for adhesion, wherein the adhesive is heated in the semi-hardening step while placing the adhesive container in a vacuum atmosphere to vacuum-degas the adhesive. 
     In one embodiment, the present invention comprises a method for adhesion, wherein the adhesive is hardened at a reaction rate ranging from 2% or more to 20% or less in the semi-hardening step. 
     In one embodiment, the present invention comprises a method for adhesion, wherein a flexible resin film is used as the object to be discharged and a semiconductor chip is used as the object to be affixed. 
     In one embodiment, the present invention comprises a method for adhesion, wherein a connecting part composed of a wiring film on the resin film and a connecting part provided on the chip are brought into contact with each other, and the chip is fixed to the resin film in a state of electrical connection thereof. 
     In another aspect, the present invention relates to an adhesion apparatus that comprises an adhesive container connected to a pore and an adhesive disposed in the adhesive container and that is constituted so as to discharge a desired amount of the adhesive through the pore, wherein the adhesive is disposed in the adhesive container, and a centrifugal force has been applied to the adhesive in a state of being placed in vacuum atmosphere with heating to be vacuum-degassed. 
     In one embodiment, the present invention comprises an adhesion apparatus, wherein the adhesive is semi-hardened at a reaction rate ranging from 2% or more to 20% or less. 
     In one embodiment, the present invention uses an adhesive whose reaction proceeds by heating. The adhesive may contain either a thermosetting resin as a main component or a mixed resin of a thermosetting resin and a thermoplastic resin as a main component. Generally, it contains an additive such as a coupling agent or a curing agent, or a filler. 
     In embodiments of the invention, an adhesive is semi-hardened in an adhesive container and placed in the adhesive container as it stands can be used for a discharging process. In this case, it is no need to move the adhesive to another container, thereby saving labor. 
     When the adhesive is heated to progress semi-hardening, bubbles are generated in the adhesive. In embodiments of the invention, however, a centrifugal force is applied to the adhesive. Accordingly, bubbles in the adhesive quickly move to the surface of the adhesive and disappear. 
     Further, since the adhesive may be placed in a vacuum atmosphere during semi-hardening, bubbles are likely to be generated by an extent that the atmospheric pressure is not existent. When the adhesive is returned under the atmospheric pressure after bubbles have been removed in the state, no bubbles are generated under the atmospheric pressure. In addition, the adhesive is heated during semi-hardening and is degassed in the state. 
     An object for adhesion, having been semi-hardened and being placed in the discharging process, is kept at a lower temperature than that in the semi-hardening process. In addition, since the temperature of the adhesive discharged on the object to be discharged is lower than that of the semi-hardening process, bubbles are never generated in the adhesive that have been degassed in the semi-hardening process. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1  ( a ) to ( c ) show an adhesive container, a plug thereof, and a mouthpiece member thereof, respectively; 
         FIG. 2  ( a ) shows a plugged adhesive container, and  FIG. 2  ( b ) is a view to explain the adhesive inside the container; 
         FIG. 3  ( a ) shows an adhesive container with the mouthpiece member mounted, and  FIG. 3  ( b ) is a view to explain the adhesive inside the container, 
         FIGS. 4  ( a ), ( b ) are views to explain the processes of heating, evacuation and centrifugal degassing; 
         FIGS. 5  ( a ), ( b ) are views to explain the discharging process of a semi-hardened adhesive; 
         FIGS. 6  ( a ) to ( c ) are views to explain the process for mounting chips; and 
         FIGS. 7  ( a ) to ( e ) are views to explain a method for adhesion in a conventional technology. 
     
    
    
     DETAILED DESCRIPTION 
     First, the degassing process by a method according to one embodiment of the invention is described hereunder. 
     Numeral  30  in  FIG. 1  ( a ) shows an adhesive container. 
     The adhesive container  30  has a cylindrical container body  31  with a bottom and a pipe-like protrusion  41 . A hole  34  is formed at a bottom part  32  of the container body  31  and an end of the protrusion  41  is vertically connected to the outer side of the bottom part  32  in the state that an inside  44  of the protrusion  41  is communicated with the hole  34 . 
     Since the protrusion  41  is cylindrical, an aperture  43 , which is located at the other end of the protrusion  41 , is oriented opposite to the aperture  33  of the container body  31 . 
     Numeral  50  in  FIG. 1  ( b ) is a plug comprising a cylindrical plug body  51  with a bottom. 
     Preferably, screw threads are provided on the inner periphery of the plug body  51  and the outer periphery of the protrusion  41 , and it is such constituted that when the plug body  51  is screwed into the protrusion  41  while orienting the aperture  53  of the plug body  51  toward the aperture  43  of the protrusion  41 , the plug  50  is mounted on the adhesive container  30 . 
     In the state that the plug  50  is mounted, as shown in  FIG. 2  ( b ), the bottom part  52  of the plug body  51  in  FIG. 1  ( b ) plugs the aperture  43  in  FIG. 1  ( a ) of the protrusion  41 . 
     In this state, when a liquid adhesive material is poured from the aperture  33  of the adhesive container  30  while orienting the aperture  33  upward and orienting the plug  50  perpendicularly downward, the adhesive material is stored in the lower part of the container body  31 . Numeral  37  in  FIG. 2  ( b ) shows an adhesive material in the container body  41  and in the state, the adhesive material  37  is also filled in the protrusion  41 . The protrusion  41  and the container body  31  are fluid-tightly connected, and since the aperture  43  in  FIG. 1  ( a ) of the protrusion  41  is plugged by the plug  50 , the adhesive  37  does not leak outside. 
     Next, a process for degassing the adhesive material  37  in the adhesive container  30  is described. Numeral  80  in  FIG. 4  ( a ) shows centrifugal degassing apparatus. The centrifugal degassing apparatus  80  is provided with a vacuum chamber  81 , a motor  84 , a rotation axis  83 , an arm  82  and a vacuum pumping system  85 . 
     Symbols  87   a ,  87   b  in  FIG. 4  ( a ) show a plurality of objects to be subjected to a degas operation (objects to be degassed, hereinafter) respectively. Objects to be degassed,  87   a  and  87   b  comprise the adhesive container  30 , the adhesive  37  filled in the adhesive container  30  and the plug  50  to prevent the leakage of the adhesive  37  respectively. In addition, the aperture  33  of the adhesive container  30  of the objects to be degassed,  87   a  and  87   b  may be covered with a lid member to prevent the intrusion of dust. 
     In order to dispose the objects to be degassed,  87   a  and  87   b  in the vacuum chamber  81 , a lid or door of the vacuum chamber  81  is first opened and the objects to be degassed,  87   a  and  87   b  are hung at the arm  82 . As for the objects to be degassed,  87   a  and  87   b  hung at the arm  82 , the plug  50  orients perpendicularly downward and the aperture  33  of the container body  31  orients upward. 
     When the interior of the vacuum chamber  81  is evacuated by the vacuum pumping system  85  after closing the vacuum chamber  81  to prevent the intrusion of the atmosphere, the internal pressure of the vacuum chamber  81  is lowered less than the atmospheric pressure. Namely, the adhesive  37  is placed in a vacuum atmosphere and, therefore, gasses dissolved in the adhesive  37  separate out as bubbles, and micro bubbles inflate. 
     The objects to be degassed,  87   a  and  87   b  are so constituted as to be freely swung in a plane running perpendicular at the rotation center of the arm  82 , and when a motor  84  is started to allow a rotation axis  83  to rotate around the perpendicular rotation axis while performing evacuation, the arm  82  is rotated in a horizontal plane and a centrifugal force is applied to the objects to be degassed,  87   a  and  87   b.    
     When a centrifugal force is applied to the objects to be degassed,  87   a  and  87   b , the objects to be degassed,  87   a  and  87   b  are on the level with the arm  82  by the centrifugal force and are rotated with the plug  50  oriented toward the outer direction of a rotation and the aperture  33  of the container body  31  oriented toward the central direction of the rotation. 
     Thus, a centrifugal force bigger than the gravitational force is applied to the adhesive  37  and, as a result, the adhesive  37  is strongly pressed against the bottom  32  of the container body  31  and the plug  50 ; on the contrary, bubbles in the adhesive  37  are forcibly pushed to the central direction of the rotation. And when the bubbles reach the surface of the adhesive  37 , gasses constituting the bubbles are released in a vacuum atmosphere and are discharged to the outside of the vacuum atmosphere by the vacuum pumping system  85 . 
     In addition, in the centrifugal degassing apparatus  80 , a heater  88  is disposed in the vicinity of objects to be degassed,  87   a  and  87   b  under rotation. 
     It is such constituted that, by preheating the heater  88  when objects to be degassed,  87   a  and  87   b  are rotated, infrared rays are irradiated to objects to be degassed,  87   a  and  87   b  under rotation. 
     Accordingly, the adhesive container  30  constituting the objects to be degassed,  87   a  and  87   b  under rotation is heated, therefore the adhesive  37  in the adhesive container  30  is designed to be heated while a centrifugal force generated by the rotation is applied thereto. 
     Accordingly, since the hardening reaction of the adhesive  37  is proceeded by the heating, gasses dissolved in the adhesive  37  are likely to be generated as bubbles and, further, the generated bubbles are degassed by the centrifugal force and the evacuation. 
     However, if the hardening reaction of the adhesive  37  during evacuation, heating and centrifugal degassing excessively proceeds, the adhesive  37  can not be discharged in a subsequent process. Accordingly, it is preferable to proceed with the hardening reaction at a reaction rate ranging from 2% or more to 20% or less. 
     After heating, evacuation and centrifugal degassing are performed for a predetermined time, the motor  84  is stopped, the evacuation of the vacuum chamber  81  by the vacuum pumping system  85  is finished and the objects to be degassed,  87   a  and  87   b  are taken out of the centrifugal degassing apparatus  80 . 
     Next, the plug  50  is replaced with a mouthpiece member  60  shown in  FIG. 1  ( c ). 
     The mouthpiece member  60  is a tapered tube, wherein the size of an aperture  63  of a bigger diameter at the opposite side to the tapered part is almost the same size as the outer diameter of the protrusion  41 , and preferably, a screw thread is provided on the internal surface of the aperture  63  to mount the mouthpiece member  60  to the top of the protrusion  41 . 
     Numeral  18  in  FIGS. 3  ( a ) and ( b ) shows an adhesion apparatus comprising a semi-hardened adhesive  38 , the adhesive container  30  accommodating the adhesive  38 , the mouthpiece member  60  mounted to the adhesive container  30 , and a lid member  70  covering the aperture  33  of the container body  31 . 
     The adhesive  38  has been subjected to heating, evacuation and centrifugal degassing while being contained in the adhesive container  30  and is semi-hardened. 
     A pipe  71  is connected to the lid member  70  at one end thereof, and to a gas cylinder not shown in the  FIGS. 3  ( a ) and  3  ( b ) at the other end. 
     A clearance  39  is formed between the lid member  70  and the liquid surface of the semi-hardened adhesive  38  and, when a certain amount of gas is sent from the gas cylinder, the gas is designed to be supplied to the clearance  39  through the pipe  71 . 
     A pore  64 , which is the discharging outlet of a small diameter, is disposed at the tip of the tapered part  62  of the mouthpiece member  60 . 
     The gas supplied to the clearance  39  presses the liquid surface of the semi-hardened adhesive  38  and the same volume of the adhesive  38  as that of the gas supplied is discharged from the pore  64 . 
     Numeral  27  in  FIG. 5  ( a ) is a working table for coating, on which a base film  13  composed of a resin is disposed. A wiring film composed of a patterned copper foil is extended on the surface of the base film  13 . Numeral  22  in  FIG. 5  ( a ) is a part of the wiring film, which serves as a connecting part to which a chip is electrically connected as described later. 
     Above the connecting part  22 , the adhesive container  30  in the state shown in  FIGS. 3  ( a ), ( b ) is disposed, whose pore  64  of the mouthpiece member  60  is oriented to the surface of the base film  13 . 
     Next, a certain amount of gas is supplied to the container body  31  and a certain amount of the semi-hardened adhesive  38  is then discharged from the pore  64 . 
     Numerical  12  in  FIG. 5  ( b ) shows a semi-hardened adhesive discharged. The connecting part  22  is extended on the base film  13 , and the surface of the base film  13  and that of the connecting part  22  are partially covered with the adhesive  12  discharged. 
     Numeral  15  in  FIG. 6  ( a ) shows a substrate where a certain amount of the adhesive  12  is coated on the base film  13 . 
     The substrate  15  is moved from the working table for coating  27  to a working table for mounting  28  disposed near the working table for coating  27 . 
     Next (as shown in  FIGS. 6   a–   6   c ), a chip  11  retained by a pressing jig  29  is rested above the connecting part  22  of the substrate  15 , positioning is performed between the connecting part  21  of the chip  11  and the connecting part  22  of the substrate  15 , the pressing jig  29  is moved downward, and the chip  11  is dabbed at the surface of the adhesive  12 . When the chip  11  is pressed by the pressing jig  29 , the chip  11  pushes the adhesive  12  away to allow the connecting parts  21 ,  22  to contact with each other. Although an integrated circuit or individual semiconductor chip constituted of a silicon crystal, GaAs crystal or the like is normally used for the chip  11 , a silicon chip for a conduction test is used here. 
     A heater is disposed inside the pressing jig  29  to preheat the chip  11  at a temperature at which the hardening reaction of the adhesive  12  is progressed and, consequently, the adhesive  12  is heated by the chip  11 . 
     The working table for coating  28  is heated at a predetermined temperature so that it does not cool the adhesive  12 . 
     The reaction of resin components in the adhesive  12  proceeds through heat supplied from the chip  11  and, when connecting parts  21 ,  22  as contacted with each other are hardened up to 100% or near 100%, the chip  11  is mounted on the substrate  15  by the hardened adhesive  12 . 
     In this case, since the hardening reaction has proceeded in the adhesive  12  before temperature up by the chip  11  to make the same be semi-hardened, a time period until the complete hardening of the adhesive  12  can be shortened by an extent corresponding to the hardening reaction beforehand. 
     After the complete hardening of the adhesive  12  to allow the chip  11  to be mounted on the base film  13 , the pressing jig  29  is removed from the chip  11 , the substrate  15  mounted with the chip  11  is moved to a subsequent process and the substrate  15  just after coated with the adhesive  12  is moved from the working table for coating  27  to the working table for mounting  28  and mounting of the chip  11  is continued. 
     As mentioned above, according to the invention the adhesive  12  is not heated on the working table for coating  27 , therefore even if a trouble occurs in the mounting process of the chip  11  or other processes and the substrate  15  is left as it stands on the working table for coating  27 , no defect occurs in the substrate since the hardening reaction of the adhesive  12  does not proceed. 
     EXAMPLES 
     Adhesives  38  of Examples 1 to 8 and Comparative Examples 1 to 8 were prepared by changing kinds of resins and heating conditions during vacuum degassing, the chip  11  was affixed with the adhesive  12  discharged on the base film  13 , and then mounting conditions were evaluated. In the following Table 1, kinds of resins, heating conditions and results of evaluation are indicated. 
                                                                                                                 TABLE 1                           Heating condition   Evaluation results                    A   B   C   D   E   F   G   Remarks                        Resin 1                                       Comparative   Room   600   0   ◯   X   ◯   X   Generation of voids       Example 1   temperature       Example 1   60   180   1.9   ◯   ◯   ◯   ◯       Example 2   60   1800   21.5   ◯   ◯   ◯   ◯       Comparative   60   2100   23.5   X   —   —   —   Dispensing unable       Example 2       Example 3   40   600   1.9   ◯   ◯   ◯   ◯       Example 4   100   120   15   ◯   ◯   ◯   ◯       Comparative   100   50   5.2   ◯   X   ◯   X   Insufficient degassing,       Example 3                               generation of voids       Comparative   110   50   20.2   ◯   X   ◯   X   Insufficient degassing,       Example 4                               generation of voids       Resin 2       Comparative   Room   600   0   ◯   X   ◯   X   Generation of voids       Example 5   temperature       Example 5   60   100   2.2   ◯   ◯   ◯   ◯       Example 6   60   900   20.4   ◯   ◯   ◯   ◯       Comparative   60   1200   24.5   X   —   —   —   Dispensing unable       Example 6       Example 7   40   300   2.1   ◯   ◯   ◯   ◯       Example 8   100   60   16.2   ◯   ◯   ◯   ◯       Comparative   100   50   7.3   ◯   X   ◯   X   Insufficient degassing,       Example 7                               generation of voids       Comparative   110   45   19.6   ◯   X   ◯   X   Insufficient degassing,       Example 8                               generation of voids               (Note)       For Comparative Examples 1 and 5, a vacuum centrifugal degassing was performed at a room temperature (25 ± 2° C.) for 900 seconds.       A: Heating temperature (° C.)       B: Heating time (second)       C: Measurement result of reaction rate (%)       D: Evaluation result of dispensability       E: Evaluation result of appearance       F: Evaluation result of initial conductivity       G: Evaluation result of conductivity after aging            
(1) Resin
         The components of “Resin 1” in Table 1 are HP4032:EP828:HX3748:A187:RY200=40:20:40:3:5.   The components of “Resin 2” are HP4032:EP630:HX3921:A187:RY200=30:30: 40:3:5.   HP4032: Epoxy resin made by Dainippon Ink And Chemicals, Incorporated.   EP828, EP630: Epoxy resins made by Japan Epoxy Resins Co., Ltd.   HX3748, HX3921: Curing agents made by Asahi Kasei Corporation   A187: Coupling agent made by Nihonunica Corporation   PY200: Filler made by Nippon Aerosil Co., Ltd.       
     All of the above are commercially available under the names given from the companies disclosed. 
     (2) Conditions of Evacuation, Heating and Centrifugal Degassing 
     
         
         
           
             Pressure in the vacuum chamber  81 : 5 mTorr or less 
             Distance between rotation center and the adhesive  37  under degassing: about 30 cm 
             Rotational speed: 1,000 to 1,800 rpm 
             Temperature of the adhesive  37  under rotation: Heating condition A in Table 1 
             Heating time: Heating condition B in Table 1
 
(3) Substrate  15 
 
             Base film  13 : Polyimide film of 20 μm thick. 
             Wiring film: Copper foil of 12 μm thick. 
             Connecting part  22 : Ni/Au plated layer is formed on the wiring film.
 
(4) Chip  11 
 
             Dimensions: 6.3×6.3×0.4 mm 
             Connecting part  21 : Copper bump of diameter 60 μm and height 20 μm and Au plated layer is formed on the surface.
 
(5) Mounting Conditions
 
             Temperature of the pressing jig  29  and pressing period: 200° C./10 seconds for Resin 1 and 230° C./5 seconds for Resin 2. 
             Temperature of the working table for mounting  28 : 80° C. 
             Pressing pressure: 60 g/bump
 
(6) Content of Evaluation
 
1) C: Measurement Results of Reaction Rate (%)
 
           
         
       
    
     The reaction rate R is found by the following formula from the calorific value Q 1  of DSC (differential scanning calorimetry) before evacuation, heating and centrifugal degassing are performed and the calorific value Q 2  of DSC after evacuation, heating and centrifugal degassing were performed.
 
 R ={(1− Q   2 )/ Q   1 }×100
 
2) D: Evaluation Results of Dispensability
 
     An adhesive that could be discharged was determined ◯ and an adhesive that could not be discharged was determined X when the adhesive container 30 of 10 cm 3  and the pore 64 of diameter 1 mm were used. 
     3) E: Evaluation Results of Appearance 
     An adhesive without no void (no bubble) was determined ◯ and an adhesive with void (bubble) was determined X when the adhesive  12  discharged on the base film  13  was visually observed before mounting the chip  11 . 
     4) F: Evaluation Results of Initial Conductivity 
     Resistance value was measured between the connecting parts  21  and  22  with the four-terminal method. An adhesive with the maximum resistance value of 100 mΩ or less was determined ◯ and an adhesive with the maximum resistance value exceeding 100 mΩ was determined X. 
     5) G: Evaluation Results of Conductivity After Aging 
     An adhesive mounted with the chip  11  was left in an atmosphere at 85° C. and 85% RH for 1,000 hours, and then the same evaluation as the initial conductivity evaluation was conducted. 
     (7) Conclusion 
     The chip mounting methods according to the present invention (Examples 1 to 8) did not generate voids. 
     The evaluation results of Comparative Examples 1 to 8 show that the dispensability was poor when a reaction rate was too high and voids were generated when the same was too low. 
     The conditions of heating, evacuation and centrifugal degassing are preferable when the heating temperature is 40° C. or more and 100° C. or less and the reaction rate is 2% or more and 20% or less, judging from the differences in the heating conditions and the reaction rates of Examples 1 to 8 and Comparative Examples 1 to 8. It is desirable that the time is 60 seconds or longer. 
     OTHER EXAMPLES 
     As examples other than Examples and Comparative Examples described in Table 1, Resin 1 and Resin 2 filled in the adhesive container  30  respectively were subjected to processing of evacuation and centrifugal degassing at room temperature for 900 seconds, then were left in a vacuum oven controlled at 60° C. for 600 seconds, and were heated and degassed in a vacuum atmosphere. The reaction rates of Resin 1 and Resin 2 were 10.2% and 15.6%, respectively. These adhesives showed preferable results in all of the evaluation items D to G. 
     OTHER COMPARATIVE EXAMPLES 
     As Comparative Examples, each of Resin 1 and Resin 2 was left in a vacuum oven controlled at 60° C. for 600 seconds to be heated and degassed in a vacuum atmosphere. After terminating the heating and degassing, each of them was taken out of the vacuum oven and tried to be filled in the adhesive container  30 . However, both could not be filled in the container because of increased viscosity, resulting from too much proceeding of the reaction. 
     Advantageously, embodiments of the present invention provide adhesion free from bubbles. 
     While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.