JP2009158766A - Wiring board and connection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection method of excellently connecting wiring boards to each other. <P>SOLUTION: There is provided the connection method for wiring boards in which the wiring boards each having a belt-like connection terminal for connection with the other board are connected to each other, wherein the connection method includes the stages of positioning the wiring boards so that connection terminals face each other with a conductive junction structure interposed therebetween; and heating and then cooling the conductive bonding body to mutually fix the connection terminals. The conductive junction structure is a material which produces air bubbles when heated, a plurality of connection terminals are provided together to the respective wiring boards, and a projection is formed on a space surface of at least one adjacent connection terminal of at least one wiring board. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wiring board connecting method for electrically connecting a wiring board and a wiring board.

  In flip chip mounting in which electronic components are mounted on a substrate, bumps are formed on wiring terminals. In recent years, as a technology for forming bumps on wiring terminals, conductive particles (for example, solder powder) are self-assembled on wiring terminals instead of conventional techniques such as solder paste method and super solder method. Thus, a method of forming a bump, or a method of mounting a flip chip by forming a connection body between electrodes by self-assembling conductive particles between electrodes of a wiring board and a semiconductor chip has been proposed. (For example, see Patent Document 1 and Patent Document 2).

  9 (a) to 9 (d) and FIGS. 10 (a) to 10 (d) are diagrams for explaining a technique of bump formation for self-assembling conductive particles.

  First, as shown in FIG. 9A, a resin 114 containing solder powder 116 and a bubble generating agent (not shown) is supplied onto a substrate 31 having a plurality of pad electrodes 32. Next, as shown in FIG. 9B, a flat plate 140 is disposed on the surface of the resin 114.

  When the resin 114 is heated in this state, bubbles 30 are generated from the bubble generating agent contained in the resin 114 as shown in FIG. Then, as shown in FIG. 9D, the resin 114 is pushed out of the bubbles as the generated bubbles 30 grow.

  As shown in FIG. 10A, the extruded resin 114 self-assembles in a columnar shape at the interface between the substrate 31 and the pad electrode 32 and the interface with the flat plate 140. A part of the resin 114 present at the edge of the substrate 31 is pushed out from the outer edge of the substrate 31 (not shown).

  Next, when the resin 114 is further heated, as shown in FIG. 10B, the solder powder 116 contained in the resin 114 is melted, and the solder powders 116 contained in the resin 114 self-assembled on the pad electrode 32. Melt-bond.

  Since the pad electrode 32 has high wettability with respect to the melt-bonded solder powder 116, the bump 19 made of the molten solder powder is formed on the pad electrode 32 as shown in FIG.

  Finally, as shown in FIG. 10D, by removing the resin 114 and the flat plate 140, the substrate 31 having the bumps 19 formed on the pad electrodes 32 is obtained. In the above process, the amount of the resin 114 to be supplied is exaggerated. Actually, the amount of the resin 114 which is suitable for self-assembly on the pad electrode 32 and the error 114 is taken into consideration. Supplied.

  The feature of this method is that the resin 114 supplied to the gap between the substrate 31 and the flat plate 140 is heated to generate bubbles 30 from the bubble generating agent, and the bubbles 30 grow to push the resin 114 out of the bubbles. Thus, the resin 114 is self-assembled between the pad electrode 32 of the substrate 31 and the flat plate 140 while containing the solder powder 116.

  The phenomenon that the resin 114 self-assembles on the pad electrode 32 is considered to occur by the mechanism shown in FIGS. 11 (a) and 11 (b).

  FIG. 11A is a view showing a state in which the resin 114 is pushed onto the pad electrode 32 of the substrate 31 by the grown bubbles (not shown). The resin 114 in contact with the pad electrode 32 has an interfacial tension at the interface (so-called force caused by spreading of the resin) Fs larger than the stress Fη generated from the viscosity η of the resin, and therefore spreads over the entire surface of the pad electrode 32. Finally, a columnar resin with the end of the pad electrode 32 as a boundary is formed between the pad electrode 32 and the flat plate 140.

  Note that the columnar resin 114 formed by self-assembly on the pad electrode 32 is subjected to stress Fb due to the growth (or movement) of the bubbles 30 as shown in FIG. The shape of the resin 114 can be maintained by the action of the stress Fη due to η, and the self-assembled resin 114 does not disappear once.

  Here, whether or not the self-assembled resin 114 can maintain a certain shape depends on the area S of the pad electrode 32 and the distance L of the gap between the pad electrode 32 and the flat plate 140 in addition to the interfacial tension Fs, It also depends on the viscosity η. Assuming that T is a standard for maintaining the resin 114 in a certain shape, it is considered that the following relationship holds for the stability.

As described above, this method uses self-assembly due to the interfacial tension of the resin 114,
The resin 114 is formed on the pad electrode 32 in a self-aligned manner. The self-assembly due to the interfacial tension is caused by the pad electrode 32 formed on the surface of the substrate 31 being formed in a convex shape. It can be said that the phenomenon that occurs between the flat plate 140 and the pad electrode 32 that is narrower than the gap between the substrate 31 and the flat plate 140 in the gap formed between the flat plate 140 and the flat plate 140 is used.

  When the above method is used, the solder powder dispersed in the resin 114 can be efficiently self-assembled on the pad electrode, and bump formation with excellent uniformity and high productivity can be realized.

In addition, since the solder powder dispersed in the resin can be self-assembled on the plurality of electrodes on the substrate supplied with the resin without being separated, the above method can be applied to all the wiring substrates supplied with the resin. This is particularly useful when bumps are collectively formed on the electrodes.
Japanese Patent No. 3964911 Japanese Patent No. 3955302

  A technique for self-assembling solder powder on the electrode by self-assembling the resin as described above may be used not only for bump formation but also for other purposes.

  As such an application, the present inventor has found that the technology is used for connection between substrates.

In particular, thin and foldable flexible printed boards (hereinafter referred to as FPC) are often used for internal wiring of electronic devices such as mobile phones and digital cameras. recent years,
With the miniaturization of portable devices and the increase in movable parts, the usage ratio of FPC is increasing. When an FPC is connected to a hard board used for the main board, connector connection is common, and it is a great advantage that the FPC can be repeatedly attached and detached. Even when there is no need for desorption, there is an advantage that connection between substrates can be easily performed. However, the three-dimensional space occupied by the connector is an obstacle to downsizing and thinning of the device. In addition, the current connector has a minimum pitch of 0.3 mm, which makes it difficult to connect electrode terminals with a narrower pitch.

  On the other hand, there is a rigid flex substrate in which a hard substrate and an FPC are completely integrated. The rigid flex substrate has an advantage that the FPC is sandwiched between the inner layers of the hard substrate and does not require a connection portion on the outer periphery. However, the manufacturing process is long, and the process becomes complicated particularly in the combination of hard substrates having different numbers of layers.

  Under these circumstances, recently, when FPCs are connected between separate hard substrates, a wiring substrate having a structure equivalent to a rigid flex substrate can be manufactured. Compared with a rigid flex board, the process can be simplified, and the outer shape and structure of the wiring board are less restricted.

  Therefore, it is considered effective to use the above technique for connecting the wiring boards having such narrow pitch electrode terminals.

  On the other hand, the present inventor has also found the following phenomenon when studying a method of connecting a wiring board and a wiring board by applying the above method. The phenomenon will be described below.

  FIG. 12 shows a wiring board used when considering connection. A plurality of strip-like wirings 33a are provided on the wiring board 31a to form connection terminals 34a in the region indicated by the arrows in the figure.

  The width of the wiring 33a is 0.05 mm, the space 35a between adjacent wirings is 0.05 mm, and the wiring rule is a pitch of 0.1 mm. An appropriate amount of resin 114 containing solder powder and a bubble generating agent (not shown) is applied to the central portion of the connection terminal 34a of the wiring board 31a shown in FIG.

  Next, FIG. 13A shows a state in which one wiring board 31b is overlapped. FIG.13 (b) is sectional drawing of AA of Fig.13 (a). On the wiring board 31b, wirings 33b having the same dimensions as the wiring board 31a are arranged, and the connection terminals 34a and the connection terminals 34b face each other and overlap each other. When the applied resin 114 is heated in this state, the solder powder self-assembles in a region where the connection terminal 34a and the connection terminal 34b overlap and then melts and solidifies to connect the wiring board 31a and the wiring board 31b. It is expected.

  However, when heating was actually performed, as shown in FIG. 14A, the resin 114 and the solder powder moved greatly to a region other than the region where the connection terminal 34a and the connection terminal 34b overlapped. In particular, the movement of the resin 114 and the solder powder to the spaces 35a and 35b adjacent to the spaces 35a and 35b was remarkable.

  FIG. 15 shows a state where the moved and assembled solder powder is melted and solidified. When the overlapping part of the wiring board 31a and the wiring board 31b is observed with an X-ray fluoroscope, the part 16a where the solder gathers outside the connection region, the part 16b where the solder is insufficient in the connection terminal, or the unconnected part 16c. Was observed, and all the solder powder did not collect in the region where the connection terminal 34a and the connection terminal 34b overlapped.

  Thus, in order to connect the wiring boards formed with the fine band-shaped connection terminals together by self-assembling conductive particles such as solder powder on the electrodes, the above-mentioned problems can be solved. I found it necessary.

  The present invention has been made in view of the above, and an object of the present invention is to provide a method for connecting a wiring board, in which connection terminals can be satisfactorily connected to each other.

In order to achieve the above object, a first substrate having a plurality of wirings and a protrusion positioned between the plurality of wirings;
A second substrate having a plurality of wirings;
A connection structure is used in which the wiring of the first substrate and the wiring of the second substrate are joined via a resin.

  The connection structure according to claim 1, wherein a plurality of the protrusions are located in a bonding region between the first substrate and the second substrate.

  The connection structure according to claim 1, wherein the protrusion is a columnar protrusion and the wiring is strip-shaped.

  The connection structure according to any one of claims 1 to 3, wherein there is a protrusion between the wirings of the second substrate.

  The connection structure according to claim 3 or 4, wherein the position of the protrusion on the first substrate and the position of the protrusion on the second substrate are shifted with respect to the direction of the strip-shaped wiring.

In addition, a wiring board connecting method for connecting wiring boards having strip-shaped connection terminals for connection to other boards,
The step of aligning the wiring boards so that the connection terminals face each other with the conductive bonded body sandwiched therebetween, the conductive bonded body is heated, and then cooled, and the connection terminal And a step of fixing each other,
The conductive joint is a material that generates bubbles by heating, and a plurality of the connection terminals are provided on each of the wiring boards,
A wiring board connection method is used in which protrusions are formed on the space surface of at least one adjacent connection terminal of at least one wiring board.

  The wiring board connection method according to claim 6, wherein the protrusions are intermittently formed on a space surface of the connection terminal.

Further, the protrusion is provided in the longitudinal direction on the space surface of the connection terminal,
In the alignment state, the protrusion on the space surface of one of the connection terminals facing each other faces a portion where the protrusion is not formed on the space surface of the other connection terminal. 7 is used.

  Further, the protrusions are respectively formed on the space surfaces of both the connection terminals facing each other, and the protrusions are provided at equal intervals on the space surface of the wiring terminals, and the alignment state , The center line of the protrusion on the space surface of one of the opposing connection terminals is coincident with the center line of the portion sandwiched between at least two of the protrusions on the space surface of the other opposing connection terminal. The method for connecting wiring boards according to claim 8 is used.

Further, the protrusion is provided in the longitudinal direction on the space surface of the connection terminal,
From the alignment state, the projection on the space surface of one of the connection terminals facing each other and the portion where the projection is formed on the space surface of the other connection terminal are opposed to each other. The wiring board bonding method according to any one of 9 is used.

  The wiring board connection method according to claim 6, wherein the protrusion is formed of an insulating resin.

The conductive joined body is a fluid containing conductive particles and a bubble generating agent,
The wiring body connection method according to claim 6, wherein the fluid includes a material that generates a gas by boiling or thermal decomposition by heating.

  The wiring board connection method according to claim 6, wherein the conductive bonded body is an anisotropic conductive material.

  According to the present invention as described above, it is possible to provide a method for connecting a wiring board, in which connection terminals can be satisfactorily connected.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
A wiring board according to the first embodiment of the present invention will be described with reference to FIGS. 1 (a) and 1 (b). FIG. 1A is a plan view of a wiring board, and FIG. 1B is a cross-sectional view taken along line AA.

  A plurality of wirings 33a are provided on the wiring board 31a. A region indicated by an arrow in the figure is a connection terminal 34a formed from an end of the wiring 33a, and the line length of the connection terminal 34a is 1.0 mm. The width of the wiring is 0.05 mm, and the width of the space 35a with the adjacent wiring 33a is 0.05 mm. Accordingly, the wiring 33a is formed with a wiring rule having a pitch of 0.1 mm. In each space 35a, a plurality of protrusions 20a are selectively formed intermittently in the longitudinal direction. The height of the protrusion 20a is lower than that of the connection terminal 34a and is approximately the diameter of the space 35a.

  The protrusions 20a were formed by forming a pattern of the protrusions 20a by photolithography using a photosensitive solder resist, which is an insulating resin, by photolithography, followed by curing by heating. As the shape of the protrusion 20a, a circular columnar body having an outer diameter of about 40 μm was formed. The arrangement of the projections 20a formed in the space 35a in the region of the connection terminal 34a is such that two odd-numbered rows are formed at intervals of 0.2 mm and 0.6 mm from the end portions with a spacing of 0.4 mm, and the even-numbered rows are Two formed at intervals of 0.4 mm at positions of 0.4 mm and 0.8 mm from the end were alternately provided. The height of the protrusion 20a was set to about 10 μm with respect to the thickness of the wiring 33a of about 15 μm (Ni / Au plating thickness of 3 μm formed on a copper foil thickness of 12 μm). However, this example is merely an example, and the shape, arrangement, quantity, and height of the protrusions 20a can be specifically determined each time according to the wiring rules and connection conditions of the connection board. For example, there may be a columnar shape such as a triangular prism or a quadrangular prism.

  In addition, the insulating resin of the protrusion 20a may be any of a thermosetting resin, a thermoplastic resin, and a photo-curing resin that has heat resistance and can be patterned by a method such as photolithography or printing.

  In the above configuration, the wiring board 31a or the wiring board 31b corresponds to the wiring board of the present invention, and the connection terminal 34a or the connection terminal 34b corresponds to the connection terminal of the present invention and corresponds to the protrusion 20a or 20b. The space 35a or 35b corresponds to the space of the present invention.

  Next, as shown in FIG. 2 (a) and FIG. 2 (b), which is a cross-sectional view taken along the line AA, the connection terminal 34a including the space 35a provided with the protrusion 20a and the wiring 33a in the wiring board 31a. A fluid 14 containing conductive particles 16 and a bubble generating agent (not shown) is supplied thereon. Resin was used as the fluid 14 in the first embodiment. Specific examples of the conductive particles 16 and the bubble generating agent will be described later.

  Next, as shown in FIG. 3 (a) and FIG. 3 (b), which is a cross-sectional view taken along the line AA, the second wiring to be connected via the fluid 14 on the wiring substrate 31a. A substrate 31b is disposed.

  The second wiring board 31b has the same shape as the first wiring board 31a, and has a connection terminal 34b having the same shape and the same dimensions as the connection terminal 34a.

  Specifically, the connection terminal 34b of the wiring board 31b is opposed to the connection terminal 34b of the wiring board 31a, and the center line of the protrusion 20a formed in the space 35a of the wiring board 31a and the other wiring board 31b facing each other. The alignment is arranged so that the center line sandwiched between the two protrusions 20b formed in the space 35b coincides.

  By aligning as described above, the protrusions 20a and the protrusions 20b are arranged in a lattice shape with the fluid 14 interposed therebetween.

  When concentrated and heated in the region including the connection terminal 34a and the connection terminal 34b in the state shown in FIG. 3 (b), the fluid 14 contains the fluid 14 as shown in FIG. 3 (c). Bubbles 30 are generated from the bubble generating agent. In addition, a fixed gap w is provided between the wiring 33a of the wiring board 31a and the wiring board 31b of the wiring board 31b. The dimension of the fixed gap w is larger than the particle size of the conductive particles 16. large. Here, the wiring board 31a and the wiring board 31b are fixed or held so as to maintain the fixed gap, and the fluid 14 is heated in this fixed or holding state.

  As shown in FIGS. 3B and 3C, the fluid 14 supplied to the connection terminal 34a is connected to the connection terminal 34a by the surface tension between the ends of the wiring board 31a and the wiring board 31b. In this state, the fluid 14 does not greatly extend beyond the region.

  Next, with reference to FIG. 3D and FIG. 3E, the description of the process after the bubble 30 is generated will be continued.

  As shown in FIG. 3D, the fluid 14 generates bubbles 30 inside by heating. Bubbles 30 grow in response to heating. Further, it moves around in the fluid 14. Thereby, the fluid 14 also moves.

  More specifically, when the internal pressure increases due to expansion, the bubble 30 being heated grows or starts to move to the atmosphere side where the pressure is lower.

  As described above, the connection terminal 34b of the wiring board 31b is opposed to the connection terminal 34b of the wiring board 31a, and the center line of the protrusion 20a formed in the space 35a of the wiring board 31a is opposed to the other wiring board. Since the center line sandwiched between the two protrusions 20b formed in the space 35b of 31b overlaps the protrusions 20a and 20b, the protrusions 20a and 20b are generated from the fluid 14 in a configuration arranged in a lattice pattern. The bubbles 30 grow or move vertically and horizontally and are discharged to the atmosphere.

  As shown in FIG. 3E, the fluid 14 that moves due to the growth and movement of the bubbles 30 gathers at the interface between the connection terminal 34a and the wiring 33a and at the interface between the connection terminal 34b and the wiring 33b. At the same time, the conductive particles 16 in the fluid 14 gather on the wirings 33a and 33b.

  Next, when the fluid 14 is further heated, the conductive particles 16 contained in the fluid 14 are melted as shown in FIG. 3F, and as a result, self-assembly of the conductive particles 16 is completed. That is, the wiring 33a and the wiring 34b are connected by molten conductive particles.

  Next, the molten conductive particles are solidified by stopping the heating and cooling. Thereby, the connection terminal 34a and the connection terminal 34b are completely connected. Finally, the fluid 14 excluding the solidified conductive particles may be left, but after connection, minute conductive particles may remain as a residue on the fluid 14, so that the reliability is improved. In view of this, it is also preferable to remove the fluid 14 together with the residue.

  In the above operation, the protrusions 20a and 20b are formed on the surfaces of the spaces 35a and 35b in the connection regions of the wiring board 31a and the wiring board 31b, respectively, so that the bubbles 30 move greatly in the longitudinal direction within the spaces 35a and 35b. As a result, the fluid 14 and the conductive particles 16 can be prevented from being pushed out of the connection region, and the conductive particles 16 are placed in the gaps w between the wirings 33a and 33b of the connection terminals 34a and 34b facing each other. The fluid 14 that is contained can be efficiently self-assembled to achieve a good connection.

  This principle will be described below while explaining the reason why the present inventors have found abnormal formation of solder powder as conductive particles in the conventional wiring board.

  The phenomenon shown in FIGS. 14A and 15 where the moved solder powder melts and the solder powder collects outside the connection region is considered to occur for the following reason. That is, when the applied resin as the fluid 14 is heated, bubbles are generated from the bubble generating agent contained in the resin, and this moves the resin. The resin also collects the connection terminal 34a and the connection terminal 34b, but when gathered to some extent, as shown in FIG. 14B, which is a cross-sectional view taken along line AA in FIG. Form pillars between them. The pillar is formed as a wall surface along the wirings 33a and 33b, and the bubbles are difficult to grow or move beyond the wall surface.

  Therefore, the direction of bubble growth or the direction of movement after the wall surfaces formed of the resin on the wirings 33a and 33b are limited to the longitudinal direction of the spaces 35a and 35b. Further, since the region where the bubbles are generated is a thin rectangular space, the pressure of the bubbles also increases.

  Due to these causes, the resin that should be gathered between the connection terminals 34a and 34b that are opposed to each other is pushed out of the connection area along with the growth or movement of the bubbles, resulting in a resin flow as shown in FIG. It is thought to occur. Solder powder contained in the leaked resin collects and melts and solidifies outside the connection region.

  On the other hand, the solder powder to be gathered between the connection terminal 34a and the connection terminal 34b is pushed out, and the amount of solder to be formed between the connection terminal 34a and the connection terminal 34b is insufficient. It is thought that a part where solder was insufficient or an unconnected part was generated between them. This is thought to be due to the fact that the regions on the wiring 33a and the wiring 33b that contact the interface between the bubbles that collect the resin and the connection terminals 34a and 34b are limited in the longitudinal direction.

  With respect to the above problems, in the present embodiment, the amount of the fluid 14 leaking to the outside is reduced by adopting the above-described configuration. The portion is self-assembled between the wiring 33a and the wiring 33b. Accordingly, problems such as solder gathering outside the connection region, solder shortage of the joining terminals, solder unconnected, etc. can be solved, and electrical connection between wiring boards having excellent uniformity and high productivity can be performed.

  Here, the protrusion 20b, the fluid 14, the conductive particles 16, and the bubble generating agent used in the first embodiment correspond to the conductive joined body, the conductive particles, and the bubble generating agent of the present invention, respectively. The specific composition is not particularly limited. However, each of the following materials can be used.

  The fluid 14 may be any fluid that has a viscosity that can flow within the range of room temperature to the melting temperature of the conductive particles 16, and also includes a fluid that decreases to a fluid viscosity by heating. . Typical examples include thermosetting resins such as epoxy resins, phenol resins, silicone resins, diallyl phthalate resins, furan resins, and melamine resins, polyester elastomers, fluororesins, polyimide resins, polyamide resins, and aramid resins. A plastic resin, a light (ultraviolet ray) curable resin, or the like, or a combination thereof can be used. In addition to the resin, high boiling point solvents, oils, and the like can also be used.

  In addition, the conductive particles 16 and the bubble generating agent can be used in appropriate combinations from the materials shown in FIGS. If a material having a melting point of the conductive particles 16 higher than the boiling point of the bubble generating agent is used, the fluid 14 is heated to generate bubbles from the bubble generating agent, and the fluid 14 is self-assembled. Furthermore, the fluid 14 can be heated to melt the conductive particles in the self-assembled fluid, and the conductive particles can be metal-bonded.

  The bubble generating agent may be made of two or more materials having different boiling points. If the boiling points are different, there is a difference in the timing of bubble generation and growth. As a result, the movement of the fluid 14 due to the growth of the bubbles is performed in stages, so that the self-assembly process of the fluid 14 is made uniform. Wiring board connection can be performed stably.

  As the bubble generating agent, in addition to the materials shown in FIG. 5, a material that generates bubbles by thermally decomposing the bubble generating agent when the fluid 14 is heated can be used. As such a bubble generating agent, the materials shown in FIG. 6 can be used. For example, when a compound containing crystallization water (aluminum hydroxide) is used, the fluid 14 is thermally decomposed when heated, and water vapor is generated as bubbles.

  In each of the drawings showing the above steps, the amount of fluid 14 to be supplied is exaggerated, and is actually suitable for self-assembly between the connection terminals 34a and 34b. Quantity and quantity taking into account errors are supplied.

Also, if all of the conductive particles 16 contained in the volume (VB) of the fluid 14 (for example, resin) supplied onto the connection terminal 34a contribute to the connection between the wiring 33a and the wiring 33b,
It is considered that the following relational expression (1) holds between the total volume (VA) of the connecting portion and the volume (VB) of the fluid 14.

VA: VB≈SA: SB (1)
In Formula (1), SA represents the total area of the wiring 33a, and SB represents the area of the connection terminal 34a.

  Thereby, content of the electroconductive particle 16 contained in the fluid 14 is represented by the following formula | equation (2).

(Content of conductive particles, volume%) = VA / VB = SA / SB × 100 (2)
Therefore, the optimal content of the conductive particles 16 contained in the fluid 14 can be set generally based on the following formula (3).

(Content of conductive particles 16, volume%) = (SA / SB × 100) ± α (3)
The parameter (± α) is for adjusting the excess and deficiency when the conductive particles 16 self-assemble between the wiring 33a and the wiring 33b, and can be determined according to various conditions. According to formula (3), it is sufficient that the conductive particles 16 dispersed in the fluid 14 are contained in the fluid 14 at a ratio of 0.5 to 30% by volume. In general, the weight ratio of the conductive particles 16 to the fluid 14 is about 7, so that the ratio of 0.5 to 30% by volume generally corresponds to the ratio of 4 to 75% by weight.

  In the first embodiment described above, the connection terminal 34b is disposed after the fluid 14 is supplied onto the connection terminal 34a. However, the present invention is not limited to this, and the positions of the connection terminal 34a and the connection terminal 34b are first aligned. The fluid 14 containing the conductive particles 16 and the bubble generating agent may be supplied to the gap w in advance so as to face the gap w. In short, the present invention is not limited by the order of the steps for aligning the connection substrates.

  In the first embodiment, the number of the protrusions 20a is four per one space 35a and 35b. However, if there are two ends, there is an effect.

(Embodiment 2)
Next, the wiring board in the second embodiment will be described. The second embodiment is shown in FIG. The wiring board 31a has a configuration in which a protrusion 20a is formed in the region of the connection terminal 34a, as in the first embodiment shown in FIGS. 1A and 1B, and detailed description thereof is omitted. Unlike the configuration example shown in FIGS. 1A and 1B, the other wiring board 31b has no projection in the region of the connection terminal 34b.

  Even when the wiring board 31a and the wiring board 31b are opposed to each other and aligned, the protrusion 20a in the area of the connection terminal 34a of the wiring board 31a is formed, so that the resin flow to the outside of the connection area due to the movement of the bubbles can be prevented. Accordingly, it is possible to efficiently suppress the resin including the conductive particles 16 in the region between the connection terminal 34a and the connection terminal 34b and to obtain a good connection.

  Further, when the height of the protrusion 20a is made higher than that of the wiring 33a, the effect is further improved.

(Embodiment 3)
Next, the wiring board in Embodiment 3 of this invention is demonstrated.

  The third embodiment is shown in FIGS. 8A to 8C. FIG. 8A is a plan view of the wiring board, FIG. 8B is a cross-sectional view taken along line AA, and FIG. 8C is a cross-sectional view for explaining a method of connecting the wiring boards.

  In FIG. 8A, the wiring board 31a has a structure in which a protrusion 20a is formed in the region of the connection terminal 34a, as in the first embodiment shown in FIGS. 1A and 1B. The arrangement and height are the same except for the detailed description. A region indicated by an arrow is a connection terminal 34a formed from the end of the wiring 33a, and the line length of the connection terminal 34a is 1.0 mm. The width of the wiring is 0.05 mm, and the width of the space 35a with the adjacent wiring 33a is 0.05 mm. Accordingly, the wiring 33a is formed with a wiring rule having a pitch of 0.1 mm. In each space 35a, a plurality of protrusions 20a are selectively formed intermittently in the longitudinal direction.

  As the shape of the protrusion 20a, a circular columnar body having an outer diameter of about 40 μm was formed. Four protrusions 20a formed in the space 35a in the region of the connection terminal 34a were formed at intervals of 0.2 mm, 0.2 mm, 0.4 mm, 0.6 mm, and 0.8 mm from the end portion.

  In FIG. 8B, the height T1 of the protrusion 20a is formed to be about 25 μm with respect to the thickness T2 of the wiring 33a being about 15 μm (Ni / Au plating thickness 3 μm is formed on the copper foil thickness 12 μm). . The height of the protrusion 20a is set so that 10 μm, which is ½ (half) of the height of the joint, protrudes from the thickness T2 of the wiring 33a when the height of the joint is about 20 μm. This example is merely an example, and the shape, arrangement, quantity, and height of the protrusion 20a can be specifically determined each time according to the wiring rules and connection conditions of the connection board.

  In the above configuration, the wiring board 31a or the wiring board 31b corresponds to the wiring board of the present invention, the connection terminal 34a or the connection terminal 34b corresponds to the connection terminal of the present invention, and corresponds to the protrusion 20a or 20b. The space 35a or 35b corresponds to the space of the present invention.

  As shown in FIG. 8C, the second wiring board 31b to be connected is arranged on the wiring board 31a so that the protrusion 20a of the wiring board 31a and the protrusion 20b of the wiring board 31b come into contact with each other. The configuration. With such a configuration, it becomes easy to secure the necessary thickness T3 of the joint portion, and it is not necessary to adjust the gap between the joint portions in joining the wiring substrate 31a and the wiring substrate 31b.

  Even when the wiring board 31a and the wiring board 31b are opposed to each other and aligned, the protrusion 20a in the joining region of the connection terminal 34a and the connection terminal 34b is formed, so that the resin flow to the outside of the connection region due to the movement of bubbles. This makes it possible to efficiently suppress the resin containing the conductive particles 16 in the region between the connection terminals 34a and 34b, and to obtain a good connection.

  The wiring board connection method according to the present invention has an effect that the connection wiring terminals can be satisfactorily connected, and the wiring board connection method for electrically connecting the wiring board and the wiring board and the wiring board used therefor Useful as.

(A) The block diagram of the wiring board used for the connection method of the wiring board of Embodiment 1 of this invention, (b) AA linear sectional drawing of Fig.1 (a) (A) Top view for demonstrating the connection method of the wiring board of Embodiment 1 of this invention, (b) AA sectional drawing of Fig.2 (a). (A) Top view for demonstrating the connection method of the wiring board of Embodiment 1 of this invention, (b) AA linear sectional drawing of Fig.3 (a), (c) A of FIG.3 (a). The figure for demonstrating the process of the connection method of the wiring board of Embodiment 1 to Embodiment 1 of this invention by -A linear sectional drawing, (d) Embodiment of this invention by AA linear sectional drawing of Fig.3 (a) FIG. 3 is a diagram for explaining the steps of the wiring board connecting method of FIG. 1, and (e) the steps of the wiring board connecting method of the first embodiment of the present invention will be described with reference to the AA linear sectional view of FIG. FIG. 3F is a diagram for explaining the steps of the wiring board connecting method according to the first embodiment of the present invention, based on the AA linear sectional view of FIG. The figure which shows an example of the material of the electroconductive particle concerning each embodiment of this invention The figure which shows an example of the material of the bubble generating agent concerning each embodiment of this invention The figure which shows an example of the material of the bubble generating agent powder concerning each embodiment of this invention Sectional drawing for demonstrating the connection method of the wiring board of Embodiment 2 of this invention. (A) Top view for demonstrating the connection method of the wiring board of Embodiment 3 of this invention, (b) AA linear sectional drawing of Fig.8 (a), (c) Embodiment 3 of this invention. Sectional drawing for demonstrating the connection method of the wiring board of (A) Process sectional view showing basic steps of bump forming method using resin self-assembly, which is a conventional method, (b) Basic steps of bump forming method using resin self-assembly, which is a conventional method Process sectional view shown, (c) Process sectional view showing basic process of bump forming method using resin self-assembly which is a conventional method, (d) Bump using resin self-assembly which is a conventional method Process cross section showing basic process of forming method (A) Process sectional view showing basic steps of bump forming method using resin self-assembly, which is a conventional method, (b) Basic steps of bump forming method using resin self-assembly, which is a conventional method Process sectional view shown, (c) Process sectional view showing basic process of bump forming method using resin self-assembly which is a conventional method, (d) Bump using resin self-assembly which is a conventional method Process cross section showing basic process of forming method (A) The figure for demonstrating the mechanism of the self-assembly of the resin which is the conventional method, (b) The figure for demonstrating the mechanism of the self-assembly of the resin which is the conventional method A diagram for explaining a conventional method of connecting wiring boards using resin self-assembly. (A) A plan view for explaining a conventional method for connecting wiring boards using resin self-assembly, (b) AA cross-sectional view of FIG. 13 (a) (A) The figure which shows the state by which resin and solder powder in the case of the conventional method were extruded from the connection area | region, (b) For demonstrating the principle by which resin and solder powder in the case of the conventional method are extruded from a connection area | region Figure The figure for demonstrating the state which melted and solidified after solder powder gathered in the conventional method.

Explanation of symbols

14 Fluid 16 Conductive particle 20a, 20b Protrusion 30 Bubble 31a, 31b Wiring board 33a, 33b Wiring 34a, 34b Connection terminal 35a, 35b Space

Claims (13)

A first substrate having a plurality of wirings and a protrusion positioned between the plurality of wirings;
A second substrate having a plurality of wirings;
A connection structure in which the wiring of the first substrate and the wiring of the second substrate are joined via a resin. The connection structure according to claim 1, wherein a plurality of the protrusions are located in a bonding region between the first substrate and the second substrate. The connection structure according to claim 1, wherein the protrusions are columnar protrusions and the wiring is strip-shaped. 4. The connection structure according to claim 1, wherein there is a protrusion between the wirings of the second substrate. The connection structure according to claim 3 or 4, wherein the position of the protrusion on the first substrate and the position of the protrusion on the second substrate are provided so as to be shifted with respect to the direction of the strip-shaped wiring. A wiring board connecting method for connecting wiring boards having strip-shaped connection terminals for connection to other boards,
The step of aligning the wiring boards so that the connection terminals face each other with the conductive bonded body sandwiched therebetween, the conductive bonded body is heated, and then cooled, and the connection terminal And a step of fixing each other,
The conductive joint is a material that generates bubbles by heating, and a plurality of the connection terminals are provided on each of the wiring boards,
A method for connecting a wiring board, wherein a protrusion is formed on a space surface of at least one adjacent connection terminal of at least one wiring board. The wiring board connection method according to claim 6, wherein the protrusions are intermittently formed on a space surface of the connection terminal. The protrusion is provided in the longitudinal direction on the space surface of the connection terminal,
In the alignment state, the protrusion on the space surface of one of the connection terminals facing each other faces a portion where the protrusion is not formed on the space surface of the other connection terminal. 8. A method of bonding wiring boards according to 7. The protrusions are formed on the space surfaces of both the connection terminals facing each other, and the protrusions are provided at equal intervals on the space surface of the wiring terminals, and in the alignment state, The center line of the protrusion on the space surface of one of the connection terminals facing each other coincides with the center line of the portion sandwiched between at least two of the protrusions on the space surface of the other connection terminal facing each other. Item 9. A wiring board connection method according to Item 8. The protrusion is provided in the longitudinal direction on the space surface of the connection terminal,
From the alignment state, the projection on the space surface of one of the connection terminals facing each other and the portion where the projection is formed on the space surface of the other connection terminal are opposed to each other. 10. A method for bonding wiring boards according to any one of 9 above. The wiring board connecting method according to claim 6, wherein the protrusion is formed of an insulating resin. The conductive joined body is a fluid containing conductive particles and a bubble generating agent,
The wiring substrate connection method according to claim 6, wherein the fluid includes a material that generates a gas by boiling or thermal decomposition by heating. The wiring board connection method according to claim 6, wherein the conductive joint is an anisotropic conductive material.

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