JP5696852B2 - Solder connection sheet and electronic component mounting method using the same - Google Patents

Description

  The present invention relates to a solder connection sheet and an electronic component mounting method using the same.

  In the case where electronic components such as semiconductor elements are mounted on a circuit board, in recent years, there is a tendency that the element size is reduced, the distance between the electrodes is reduced, and the number of electrodes is increased. In such a case, it becomes difficult to individually supply the conductive material to the joint position between the electronic component and the circuit board.

  For this reason, there is a technique in which a conductive material is embedded in a through hole of a connection sheet in advance and the connection sheet is sandwiched between a circuit board and a semiconductor element to perform bonding (Patent Document 1). However, conventionally, since a resin connection sheet is used, if a solder material is used as the conductive material, the connection sheet melts due to reflow heating of the solder, making it difficult to connect with solder. ing. In addition, since the resin sheet is not easily crushed by pressing during mounting, it is necessary to fill the through hole with a conductive material in order to reliably perform bonding, and there is a problem that adjacent electrodes are easily bridged.

JP 2003-31617 A

  The present invention has been made in view of such a situation, and the object thereof is easy and reliable without short-circuiting between adjacent electrode terminals even when the distance between electrode terminals formed in an electronic component is narrow. Another object is to provide a solder connection sheet capable of connecting each electrode terminal of an electronic component to a connection terminal of a circuit board, and a mounting method of an electronic component using the same.

In order to achieve the above object, the solder connection sheet according to the first aspect of the present invention is:
A sheet base material that is composed of a woven fabric or a non-woven fabric, and in which a plurality of through-holes penetrating the front and back surfaces are formed in a predetermined pattern;
A solder member that is held inside the through hole and is previously molded into a ball shape.

  In the first aspect of the present invention, since the sheet base material is composed of a woven fabric or a non-woven fabric, the heat resistance is improved, and the solder member embedded in the through hole is melted to be easily formed into a ball shape. can do. By holding the solder member formed in a ball shape in advance in the through hole, it is possible to control the amount of solder stably, and the connection reliability is improved.

  Further, by holding the solder member formed in a ball shape in the inside of the through hole, the surface of the solder member is moved away from the outer peripheral edge of the through hole, and bridges between adjacent solder members can be prevented. Moreover, at the center position of the through hole, the solder member has a shape that protrudes most toward the space outside the front and back surfaces of the sheet base material (in the direction in which the electronic component and the circuit board are connected). Thus, each electrode terminal of the electronic component can be reliably connected to the connection terminal of the circuit board.

  That is, according to the first aspect of the present invention, even when the distance between the electrode terminals formed on the electronic component is narrow, the substrate on which the solder connection sheet is interposed and the electronic component are pressed against each other. Moreover, each electrode terminal of the electronic component can be easily and reliably connected to the connection terminal of the circuit board without short-circuiting between the adjacent electrode terminals only by heating.

  Moreover, since the sheet | seat base material is comprised with the woven fabric or the nonwoven fabric, it is excellent in a pressure deformation property. Therefore, when pressing and heating the board and electronic component with the solder connection sheet interposed between them, it is possible to uniformly compress and deform with a certain level of pressure, regardless of the pressure. In addition, the thickness after pressurization is constant. For this reason, the sheet base material adheres to both the substrate and the electronic component with a constant thickness after pressing. Therefore, the positional accuracy after the connection between the substrate and the electronic component is improved, the thermal shock resistance is also improved, and the connection reliability is improved. Moreover, it is easy to cope with solder bump shapes of various sizes only by changing the hole diameter and pattern of the through holes formed in the sheet base material.

The solder connection sheet according to the second aspect of the present invention is:
A sheet base material that is composed of a woven fabric or a non-woven fabric, and in which a plurality of through-holes penetrating the front and back surfaces are formed in a predetermined pattern;
A solder member held inside the through hole and having a volume smaller than the internal volume of the through hole.

  In the 2nd viewpoint of this invention, since the sheet | seat base material is comprised with the woven fabric or the nonwoven fabric similarly to the 1st viewpoint, it is excellent in heat resistance and pressure deformation property. Therefore, when the substrate and the electronic component with the solder connection sheet interposed therebetween are pressed and heated, the sheet base material is uniformly compressed and deformed in the thickness direction, and the sheet base material is formed between the substrate and the electronic component. Good adhesion to both sides. Therefore, the thermal shock resistance after the connection between the substrate and the electronic component is improved, and the connection reliability is improved.

  In the second aspect of the present invention, a solder member having a volume smaller than the internal volume of the through hole is held inside the through hole. Therefore, stable solder amount control is possible, and connection reliability is improved. Further, when the substrate and the electronic component between which the solder connection sheet is interposed are pressed and heated, after the thickness of the solder connection sheet made of woven fabric or nonwoven fabric is reduced, the solder member is The connection terminal of the circuit board and each electrode terminal of the electronic component are brought into contact with each other to be melted and alloyed so that they are securely connected, and the adjacent electrode terminals are not short-circuited.

  Therefore, in the second aspect of the present invention, even when the distance between the electrode terminals formed in the electronic component is narrow, the substrate and the electronic component with the solder connection sheet interposed therebetween are pressurized and heated mutually. Thus, it is possible to connect each electrode terminal of the electronic component to the connection terminal of the circuit board easily and reliably without short-circuiting between adjacent electrode terminals. Moreover, it is easy to cope with solder bump shapes of various sizes only by changing the hole diameter and pattern of the through holes formed in the sheet base material.

  The sheet base material may be impregnated with an adhesive. By impregnating the sheet base material with the adhesive, the adhesion between the substrate and the electronic component is improved by the sheet base material. Therefore, the thermal shock resistance after the connection between the substrate and the electronic component is improved, and the connection reliability is further improved. Moreover, it becomes easy to hold | maintain a solder member in the through-hole of a sheet | seat base material by making a sheet | seat base material impregnate an adhesive agent.

  The adhesive may be filled in the through hole, and the adhesive filled in the through hole may hold the solder member inside the through hole. With this configuration, it becomes easy to hold the ball-shaped solder member inside the through hole.

  In the first aspect of the present invention, it is preferable that after the ball-shaped solder member is formed, the sheet base material is impregnated with an adhesive and / or the through hole is filled with the adhesive. This is because if the order is reversed, the adhesive will fly off due to the heat when producing the ball-shaped solder member.

  In the second aspect of the present invention, the sheet base material may be impregnated with an adhesive before the through hole is filled with the solder member. When the adhesive is impregnated before the solder member is filled, it is easy to uniformly impregnate the sheet base material with the adhesive.

  The adhesive may contain a component having a flux function. When the adhesive contains a flux component, it is not necessary to separately prepare a flux required for solder connection.

  The sheet base material may be impregnated with a semi-cured resin. The semi-cured resin is preferably a resin that completes curing depending on the heating temperature (for example, 220 to 260 ° C.) at the time of mounting the substrate, but it may be in a form in which the curing is completed by performing after-curing after mounting the substrate. In the first aspect of the present invention, the semi-cured resin impregnation is preferably performed after the ball-shaped solder member is formed, and in the second aspect of the present invention, before the solder member is filled. It is preferable to carry out in the state.

  The sheet base material may be composed of a nonwoven fabric. By comprising a nonwoven fabric, the difference in thermal expansion coefficient between the length and breadth is small, and the positional deviation of the solder member during heating for melting the solder is small. Moreover, by comprising with a nonwoven fabric, it is excellent in a density freedom degree, crushability, productivity, through-hole processability, etc. compared with a woven fabric. Since the degree of freedom in density is excellent, the density of the fibers can be freely set according to the amount of the adhesive or resin impregnated. In addition, because it is excellent in crushability, even when the distance between the electrode terminals formed in the electronic component is narrow, it is possible to compress the solder connection sheet well without short-circuiting between the adjacent electrode terminals, In addition, each electrode terminal of the electronic component can be connected to the connection terminal of the circuit board easily and reliably.

  A release sheet that can be peeled off during use may be laminated on the front surface and / or back surface of the sheet base material. The release sheet can securely hold the solder member inside the through hole by suppressing the fall of the solder member held in the through hole.

  An adhesive layer may be formed on the release surface of the release sheet from the sheet base material. By forming the adhesive layer, the solder member held in the through hole can be prevented from dropping and the solder member can be reliably held inside the through hole.

The electronic component mounting method according to the present invention includes:
Placing the solder connection sheet according to any of the above between a surface of a circuit board on which a connection terminal of a predetermined pattern is formed and a terminal formation surface of an electronic component;
And pressurizing and heating the substrate and the electronic component with the solder connection sheet interposed therebetween.

FIG. 1 is a cross-sectional view of a main part of a solder connection sheet according to an embodiment of the present invention. 2 (A) to 2 (E) are schematic cross-sectional views showing an example of a method for manufacturing the solder connection sheet shown in FIG. 3 (A) to 3 (C) are schematic cross-sectional views illustrating an example of a method for using the solder connection sheet shown in FIG. FIG. 4 is an enlarged cross-sectional view of a main part of FIG. FIGS. 5A and 5B are cross-sectional views of the main part of a solder connection sheet according to another embodiment of the present invention. 6 (A) to 6 (D) are schematic cross-sectional views showing an example of a method for manufacturing the solder connection sheet shown in FIGS. 5 (A) and 5 (B). FIG. 7A to FIG. 7C are schematic cross-sectional views showing a step subsequent to FIG. FIG. 8 is a cross-sectional view of a main part of a solder connection sheet according to still another embodiment of the present invention. 9A to 9D are schematic cross-sectional views illustrating an example of a method for manufacturing the solder connection sheet illustrated in FIG.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
First embodiment

  As shown in FIG. 1, a solder connection sheet 2 according to an embodiment of the present invention has a sheet substrate 4 made of a woven fabric or a non-woven fabric. A plurality of through holes 6 penetrating from the front surface 4a toward the back surface 4b are formed in the sheet base material 4 in a predetermined pattern.

  In the present embodiment, each through hole 6 is a tapered through hole having an inner diameter that decreases from the front surface 4 a to the back surface 4 b of the sheet base material 4. Inside each through-hole 6, a solder member 8 previously formed in a ball shape is held. The shape of the solder member 8 is not particularly limited as long as it is a ball shape, and is not limited to a spherical shape, and may be a ball shape having an elliptical cross section, a truncated cone shape, a shell shape, a cylindrical shape, a spheroid shape, or the like. The ball-shaped solder member 8 is formed by reflow heat treatment as will be described later.

  The outer diameter d0 of the ball-shaped solder member (minimum outer diameter in the case of other than a spherical shape) is larger than the minimum inner diameter d2 of the through hole 6 in the sheet base material 4, and smaller than the maximum outer diameter d1 of the through hole 6. To be determined. If the outer diameter d0 is too small, the solder member 8 may fall from the through-hole 6, and if it is too large, it bridges with an adjacent solder member, which is likely to cause a short circuit. The volume of the solder member 8 held in each through hole 6 may be smaller than the volume of each through hole 6, but may be larger in this embodiment.

When the through hole 6 is tapered, the relationship among the minimum inner diameter d2 of the through hole 6, the maximum outer diameter d1 of the through hole 6, the thickness t1 of the sheet base material 4, and the taper angle θ1 is as follows. It can be expressed as (1).
tan θ1 = (d1−d2) / (2 × t1) (1)

  The thickness t1 of the sheet substrate 4 is not particularly limited, but is preferably 10 to 60 μm, the maximum outer diameter d1 of the through hole 6 is preferably 25 to 300 μm, and the taper angle θ1 is preferably 60 to 85 degrees. is there. The large-diameter side hole diameter d1, the taper angle θ1, the formation pattern of the through-hole 6, the thickness t1 of the sheet substrate 4 and the like are freely set according to the application.

  In this embodiment, it is preferable that the sheet | seat base material 4 is comprised with the woven fabric or the nonwoven fabric, and is excellent in heat resistance, hole-forming property, and work deformation property. The fiber constituting the woven fabric or the nonwoven fabric is not particularly limited, but is preferably a fiber excellent in heat resistance and insulation, low dielectric constant and low dielectric loss tangent, and excellent in high frequency characteristics, such as glass fiber, BT (bismaleimide triazine). Abbreviation) Resin, aramid fiber, liquid crystal polymer, carbon fiber, PPS (polyphenylene sulfide) fiber, polyimide fiber, fluorine fiber, PEEK (polyether ether ketone) fiber and the like are preferable.

  The heat resistance required for the sheet base material 4 is heat resistance with respect to the temperature at the time of solder melting. For example, at a temperature of 220 to 260 ° C., the heat resistance is required to maintain the shape without melting. Moreover, the drilling workability required for the sheet base material is excellent workability by laser processing or the like. Furthermore, the work deformability of the sheet base material is a characteristic that requires uniform compressive deformation against the compressive load acting in the front and back direction of the sheet base material, and the final thickness is constant regardless of the compressive load. The material of the fiber and the braiding means are selected so as to obtain a thickness. In this embodiment, the sheet | seat base material 4 is comprised with the nonwoven fabric.

  It is preferable that the sheet base material 4 contains an adhesive. Furthermore, the adhesive may contain a component having a flux function during solder bonding. When the adhesive contains a flux component, it is not necessary to separately prepare a flux required for solder connection.

  The sheet base 4 may be impregnated with a semi-cured resin (B stage state). The semi-cured resin is preferably a resin that completes curing depending on the heating temperature (for example, 220 to 260 ° C.) at the time of mounting the substrate, but it may be in a form in which the curing is completed by performing after-curing after mounting the substrate. Specifically, an epoxy resin, a silicone resin, a polyimide resin, a BT resin resin, or the like is used as the semi-cured resin. By impregnating the sheet base material 4 with an adhesive and / or a semi-cured resin, the solder member 8 can be easily held inside each through hole 6.

  As the solder member 8, solder having a melting point of 183 to 240 ° C. is preferable. By heating near the melting point, the solder member 8 has a ball shape inside the through hole 6.

  Next, a method for manufacturing the solder connection sheet 2 shown in FIG. 1 will be described with reference to FIG.

  As shown in FIG. 2A, first, a sheet substrate 4A that is not impregnated with an adhesive, a semi-cured resin, or the like is prepared. Thereafter, as shown in FIG. 2B, tapered through-holes 6 are formed in a predetermined pattern on the sheet base 4A by laser processing, punching processing, drill processing, or the like.

  After that, as shown in FIG. 2C, each through-hole 6 is filled with solder 8A in a fluid state. The solder 8A in a fluid state is filled by a method such as printing or application with a dispenser. When filling, the solder 8A may be filled so as to protrude from the through hole 6.

  When the through hole 6 is formed by laser processing from the front surface 4a of the sheet base 4A, the tapered through hole 6 is easily formed, and the filled solder 8A may flow out from the back surface 4b due to the surface tension. Absent.

  Before filling the solder 8A, the through hole 6 may be filled with a flux in advance. Moreover, you may apply | coat the solder creep-up prevention agent beforehand to the front and back of the sheet | seat base material 4A. Further, the sheet base material 4A may be reinforced by preliminarily impregnating a material that sublimes when heated in a reflow process described later.

  Thereafter, as shown in FIG. 2D, if the solder 8A together with the sheet base material 4A is heated to a temperature higher than the melting temperature of the solder 8A (reflow heat treatment) and cooled, a ball-like shape is formed inside the through hole 6. A solder member 8 is obtained and held in the through hole 6. Thereafter, as shown in FIG. 2E, if the sheet base 4A is impregnated with an adhesive and / or a semi-cured resin, the solder connecting sheet 2 shown in FIG. 1 is obtained.

  Next, an example of a method of using the solder connection sheet 2 shown in FIG. 1 will be described based on FIGS. 3 (A) to 3 (C).

  First, as shown in FIG. 3A, the solder connection sheet 2 is disposed between the IC chip 10 as an electronic component and the interposer substrate 14. Further, the solder connection sheet 2 is also disposed between the interposer substrate 14 and the circuit board 20 such as a PC board.

  The solder connection sheet 2 used between the IC chip 10 and the interposer substrate 14 and the solder connection sheet 2 used between the interposer substrate 14 and the circuit board 20 such as a PC board include the formation pattern of the through holes 6. Basically, they have the same configuration. The interposer substrate 14 is used to connect the electrode terminals 12 formed on the IC chip 10 at a narrow pitch to the connection terminals 22 arranged on the surface of the circuit board 20 at a relatively wide pitch. It is a substrate.

  On the front surface of the interposer substrate 14, connection terminals 16 arranged at a narrow pitch corresponding to the electrode terminals 12 arranged at a narrow pitch formed on the IC chip 10 are formed. The connection terminals 18 corresponding to the connection terminals 22 arranged on the surface of the circuit board 20 at a relatively wide pitch are formed. The connection terminals 16 and the connection terminals 18 formed on the front and back surfaces are electrically connected to each other by a wiring circuit inside the substrate 14.

  First, as shown in FIG. 3B, in a state where the solder connection sheet 2 is disposed between the IC chip 10 and the interposer substrate 14, the IC chip 10 and the substrate 14 are heated under pressure. The applied pressure is not particularly limited, and the applied pressure is such that the thickness t1 of the sheet base material 4 in the solder connecting sheet 2 shown in FIG. 1 is compressed and deformed until the thickness t1 becomes the constant thickness t2 shown in FIG. preferable. The thickness t2 / t1 is preferably 2/3 to 1/3.

  The heating temperature is a temperature at which the solder member 8 is melted and the electrode terminal 12 and the connection terminal 16 are connected with sufficient bonding strength by the solder member B deformed by heating and pressing, as shown in FIG. It is preferable that the temperature is + 10% to + 30% with respect to the melting temperature of the solder.

  Next, as shown in FIG. 3C, with the solder connection sheet 2 disposed between the interposer substrate 14 and the circuit substrate 20, these substrates 14 and 20 are heated and pressurized in the same manner as described above. . Thereby, the connecting terminal 18 and the connecting terminal 22 shown in FIG. 3 are connected with sufficient bonding strength by the solder member 8B (see FIG. 4) which is deformed by heating and pressurizing the solder member 8. It should be noted that other electronic components 24 may be mounted on the circuit board 20.

  In this embodiment, since the sheet base material 4 is composed of a woven fabric or a non-woven fabric, the heat resistance is improved, and the solder member 8A embedded in the through hole 6 is melted to form a ball-shaped solder member 8. It can be easily molded. By holding the solder member 8 formed in a ball shape in advance in the through hole 6, it is possible to control the amount of solder stably, and the connection reliability is improved.

  Further, by holding the solder member 8 formed in a ball shape in advance in the through hole 6, the surface of the solder member 8 moves away from the outer peripheral edge of the through hole 6, thereby preventing bridging between adjacent solder members. be able to. And in the center position of the through-hole 6, since the surface of the solder member 8 becomes the shape which protrudes most toward the space outside the front and back surfaces of the sheet base material (in the direction connecting the electronic component and the circuit board), Each electrode terminal 12 of the IC chip 10 can be reliably connected to the connection terminal 16 of the substrate 14 via the solder member 8.

  That is, according to the present embodiment, even when the distance between the electrode terminals 12 formed on the IC chip 10 is narrow, the substrate 14 and the IC chip 10 with the solder connection sheet 2 interposed therebetween are mutually connected. Each electrode terminal 12 of the IC chip 10 can be connected to the connection terminal 16 of the substrate 14 easily and reliably without short-circuiting between the adjacent electrode terminals 12 only by pressurizing and heating. .

  Moreover, since the sheet | seat base material 4 is comprised with the woven fabric or the nonwoven fabric, it is excellent in the pressure deformation property. For this reason, when the substrate 14 and the IC chip 10 (and the same applies to the substrate 14 and the substrate 20) with the solder connection sheet 2 interposed therebetween are mutually pressurized and heated, a certain amount or more is applied. The pressure can be uniformly compressed and deformed without depending on the applied pressure, and the thickness after pressurization becomes constant.

  For this reason, the sheet base 2 is in close contact with both the substrate 14 and the IC chip 10 with a constant thickness after pressing. Therefore, the positional accuracy after the connection between the substrate 14 and the IC chip 10 is improved, the thermal shock resistance is also improved, and the connection reliability is improved. Moreover, it is easy to cope with solder bump shapes of various sizes by simply changing the hole diameter and pattern of the through holes 6 formed in the sheet base material 4.

  In particular, in the present embodiment, the sheet base material 4 is composed of a nonwoven fabric, so that there is little difference in thermal expansion coefficient in the vertical and horizontal directions, and when the IC chip 10 and the substrate 14 are heated and pressurized with the solder connection sheet 2 interposed therebetween. There is little misalignment of the solder member 8. Moreover, by comprising with a nonwoven fabric, it is excellent in a density freedom degree, crushability, productivity, through-hole processability, etc. compared with a woven fabric.

  In the present embodiment, the sheet base material 4 is impregnated with an adhesive. By impregnating the sheet base material 4 with an adhesive, the solder connection sheet 4 having the sheet base material 4 improves the adhesion between the substrate 14 and the IC chip 10. Therefore, the thermal shock resistance after the connection between the substrate 14 and the IC chip 10 is improved, and the connection reliability is further improved. Further, by impregnating the sheet base material 4 with the adhesive, the solder member 8 can be easily held in the through hole 6 of the sheet base material 4.

  In the manufacturing method of the present embodiment, as shown in FIG. 2D, after the ball-shaped solder member 8 is formed, the sheet base material 4 is impregnated with an adhesive as shown in FIG. . This is because if the order is reversed, the adhesive will fly due to the heat generated when the ball-shaped solder member 8 is produced. Further, the impregnation with the semi-cured resin is preferably performed after the ball-shaped solder member 8 is formed, like the adhesive. If the order is reversed, the semi-cured resin is cured by heat when the ball-shaped solder member 8 is produced, and the pressure-compression characteristics of the solder connection sheet during use may be deteriorated.

  In this embodiment, even if the peeling sheet 30 (refer FIG. 5A) which can be peeled in use is laminated | stacked on the surface 4a and / or the back surface 4b of the sheet | seat base material 4 shown in FIG. 1, Preferably the back surface 4b. Good. The release sheet 30 can suppress the fall of the solder member 8 held in the through hole 6 and reliably hold the solder member 8 inside the through hole 6.

  An adhesive layer 32 (see FIG. 5) may be formed on the release surface of the release sheet 30 from the sheet substrate 4. By forming the adhesive layer 32, the solder member 8 held in the through hole 6 can be prevented from dropping and the solder member 8 can be reliably held inside the through hole 6.

The solder connection sheet 2 is formed between the IC chip 10 and the substrate 14 shown in FIGS. 3A to 3C or between the substrate 14 and the substrate 20 after the release sheet 30 is peeled from the sheet base material 4. It is placed between and heated and pressurized.
Second embodiment

  As shown in FIG. 5 (A) or FIG. 5 (B), a solder connection sheet 2a or 2b according to another embodiment of the present invention is a common modification of the solder connection sheet 2 according to the first embodiment. Common members are denoted by common reference numerals, common descriptions are partially omitted, and differences will be particularly described.

  In the solder connection sheet 2a shown in FIG. 5A, a ball-shaped solder member 8 is disposed inside the through hole 6 formed in the support sheet 4, and the adhesive 7 is filled. . Furthermore, the release sheet 30 is adhered to the back surface of the support sheet 4 through the adhesive layer 32 so as to be peeled off.

  In the solder connection sheet 2b shown in FIG. 5 (B), a ball-shaped solder member 8 is disposed inside the through hole 6 formed in the support sheet 4, and the adhesive 7 is filled. . In this solder connection sheet 2b, unlike the solder connection sheet 2a shown in FIG. 5A, the release sheet 30 is not mounted.

  An example of a method for manufacturing the solder connection sheet 2a shown in FIG. 5A and the solder connection sheet 2b shown in FIG. 5B will be described with reference to FIGS.

  As shown in FIG. 6A, first, a sheet substrate 4A that is not impregnated with an adhesive, a semi-cured resin, or the like is prepared. Thereafter, as shown in FIG. 6 (B), a tapered through hole 6 having a predetermined pattern on the sheet base material 4A and having a smaller inner diameter from the front surface 4a to the back surface 4b of the sheet base material 4A is formed by laser processing or the like. Form.

  Thereafter, as shown in FIG. 6C, the release sheet 30 is detachably attached to the back surface 4b of the sheet substrate 4a via the adhesive layer 32. Next, as shown in FIG. 6D, each through-hole 6 is filled with solder 8A in a fluid state. The solder 8A in a fluid state is filled by a method such as printing. When filling, the solder 8A may be filled so as not to protrude from the through hole 6.

  In the state where the release sheet 30 is mounted on the back surface 4b of the sheet base 4A, when the solder 8A is filled in the through-hole 6, the filled solder 8A has the adhesive layer 32 and the release sheet 30. There is no fear of flowing out of 4b. The release sheet 30 also has a function of reinforcing the sheet base 4A.

  Thereafter, as shown in FIG. 7 (A), if the solder 8A together with the sheet base 4A and the release sheet 30 is heated and cooled to a temperature equal to or higher than the melting temperature of the solder 8A, a ball-like shape is formed inside the through hole 6. A solder member 8 is obtained and held in the through hole 6. Thereafter, as shown in FIG. 7B, if the sheet base material 4A is impregnated with an adhesive and / or a semi-cured resin, and the adhesive is filled in the through holes 6, the solder shown in FIG. A connection sheet 2a is obtained.

  Moreover, if the peeling sheet 30 is removed from the sheet | seat base material 4 as shown in FIG.7 (C) after that, the soldering connection sheet | seat 2b shown in FIG.5 (B) will be obtained. As illustrated in FIG. 7C, the adhesive layer 32 may remain on the back surface 4 b of the sheet base material 4 after the release sheet 30 is removed from the sheet base material 4.

  In the present embodiment, the adhesive 7 is also filled in the through hole 6. With this configuration, the ball-shaped solder member 8 can be easily held inside the through hole 6. Further, by providing the adhesive 7 with a flux function, the bonding between the terminals by the solder member 8 becomes good. In the present embodiment, the outer diameter d0 (see FIG. 1) of the ball-shaped solder member 8 may be smaller than the minimum inner diameter d2 of the through hole 6. This is because the solder member 8 is held inside the through hole 6 by the adhesive 7.

In the manufacturing method of the present embodiment, after forming the ball-shaped solder member 8 as shown in FIG. 7 (A), an adhesive and / or a semi-cured resin is applied to the sheet as shown in FIG. The substrate 4 is impregnated and the adhesive 7 is filled in the through holes 6. The reason is the same as that of the first embodiment described above, in order to prevent the adhesive from being removed and to prevent the semi-cured resin from being cured when the ball-shaped solder member 8 is formed. It is.
Third embodiment

  As shown in FIG. 8, a solder connection sheet 2c according to another embodiment of the present invention shows a modification of the solder connection sheet 2 according to the first embodiment, and common members are denoted by common reference numerals, Some of the common explanations are omitted, and the differences will be particularly explained.

  In the solder connection sheet 2c shown in FIG. 8, the solder member 8C held in each through-hole 6 is a solder member before being formed into a ball shape by being melted and cooled, and may be in a paste form or a solidified state. The inner volume of each through hole 6 is filled to be smaller. For example, when the internal volume of each through hole 6 is V1, and the volume of each solder member 8C is V2, V2 / V1 is preferably 0.95 to 0.5, and more preferably 0.9 to 0.00. 6.

  If the ratio of V2 / V1 is too large, the solder connection sheet 2c is moved between the IC chip 10 and the substrate 14 or between the substrate 14 and the substrate 20 shown in FIGS. 3 (A) to 3 (C). When intervening and using, the solder member 8C protrudes from the through hole 6 together with the compression deformation of the sheet base material 4 and may bridge with the solder member 8C of the adjacent through hole 6. If the ratio of V2 / V1 is too small, the connection between the terminal 12 and the terminal 16 or between the terminal 18 and the terminal 22 shown in FIGS. 3 (A) to 3 (C) becomes insufficient. There is a fear that it is not preferable.

  Next, an example of the manufacturing method of the solder connection sheet 2c shown in FIG. 8 is demonstrated based on FIG. 9 (A)-FIG. 9 (D).

  As shown in FIG. 9A, first, a sheet substrate 4A that is not impregnated with an adhesive, a semi-cured resin, or the like is prepared. Thereafter, as shown in FIG. 9B, the sheet base material 4A is impregnated with an adhesive and / or a semi-cured resin. Thereafter, as shown in FIG. 9C, the sheet base material 4 impregnated with an adhesive and / or semi-cured resin by laser processing or the like is formed in a predetermined pattern from the front surface 4a to the rear surface 4b. A tapered through-hole 6 with a smaller inner diameter is formed.

  Thereafter, as shown in FIG. 9D, the solder connection sheet 2C shown in FIG. 8 is obtained by filling each through-hole 6 with a solder member 8C in a fluid state. The filling of the solder member 8C in a fluid state is performed by a method such as printing or application with a dispenser. At the time of filling, a filling method such as screen printing is preferable so that the volume of the solder member 8C is smaller than the internal volume of the through hole 6.

  In the solder connection sheet 2 c of the present embodiment, a solder member 8 </ b> C having a volume smaller than the internal volume of the through hole 6 is held inside the through hole 6. Therefore, stable solder amount control is possible, and connection reliability is improved. Further, when the substrate 14 and the IC chip 10 or the substrate 20 with the solder connection sheet 2c interposed therebetween are pressed and heated, the solder member 8C is connected to the terminal after the thickness of the solder connection sheet 2c is reduced. 12 and the terminal 16 (or the terminal 18 and the terminal 22) are brought into contact with each other to be melted and alloyed so that they are securely connected, and the adjacent electrode terminals are not short-circuited.

  Therefore, in the present embodiment, even when the distance between the electrode terminals is narrow, only the substrate 14 and the IC chip 10 or the substrate 20 with the solder connection sheet 2c interposed therebetween are pressed and heated to each other. Each electrode terminal 12 of the IC chip 12 can be connected to the connection terminals 16, 18, 22 of the circuit boards 14, 20 easily and reliably without short-circuiting between adjacent electrode terminals. Moreover, it is easy to cope with solder bump shapes of various sizes by simply changing the hole diameter and pattern of the through holes 6 formed in the sheet base material 4.

  In this embodiment, the sheet base material 4 is impregnated with an adhesive and / or a semi-cured resin before the solder member 8C is filled in the through-hole 6, so that the sheet base material 4 is uniformly and / or semi-cured. It is easy to impregnate the resin. Further, since the sheet base 4 made of nonwoven fabric is impregnated with the adhesive and / or the semi-cured resin, the sheet base 4 is reinforced, and then the through holes 6 are formed with high accuracy by laser processing or the like. Easy to do.

  In this embodiment, before filling the through hole 6 with the solder member 8C, the back surface 4b of the sheet base material 4 shown in FIG. 9C is provided with the adhesive layer 32 shown in FIG. The release sheet 30 may be adhered to be peelable.

  When the through-hole 6 is filled with the solder 8A with the release sheet 30 mounted on the back surface 4b of the sheet base material 4, the filled solder 8A has the adhesive layer 32 and the release sheet 30. There is no fear of flowing out of 4b. The release sheet 30 also has a function of reinforcing the sheet base 4A. In the present embodiment, the solder member 8C preferably contains a component having a flux function.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, the resin impregnated in the sheet base material 4A is not limited to the semi-cured resin, but may be impregnated with other resins. In the third embodiment described above, the through holes 6 are formed in the sheet base material 4 impregnated with the adhesive or the resin. However, the through holes 6 are formed in the sheet base material 4A before the impregnation. May be. By forming the through holes 6 by laser processing on the sheet base material 4A before impregnating them, there is no possibility that the heat by the laser processing adversely affects the resin and the adhesive.

2, 2a, 2b, 2c ... Solder connection sheet 4, 4A ... Sheet substrate 4a ... Front surface 4b ... Back surface 6 ... Through-hole 7 ... Adhesive 8, 8A, 8B, 8C ... Solder member 10 ... IC chip 12 ... Electrode terminal 14 ... Interposer board 16, 18, 22 ... Connection terminal 20 ... Circuit board

Claims (10)

A sheet base material that is composed of a woven fabric or a non-woven fabric, and in which a plurality of through-holes penetrating the front and back surfaces are formed in a predetermined pattern;
A solder connection sheet that is held inside the through-hole and has a solder member molded in advance in a ball shape,
A solder connection sheet, wherein V2 / V1 is 0.95 to 0.5, where V1 is an internal volume of the through-hole and V2 is a volume of the solder member before becoming a ball shape .   The solder connection sheet according to claim 1, wherein the sheet base material is impregnated with an adhesive.   3. The adhesive according to claim 1, wherein the adhesive is also filled in the through hole, and the adhesive filled in the through hole holds the solder member in the through hole. Solder connection sheet.   The solder connection sheet according to claim 2, wherein the adhesive contains a component having a flux function.   The solder connection sheet according to claim 1, wherein the sheet base material is impregnated with a semi-cured resin.   The solder connection sheet according to any one of claims 1 to 5, wherein the sheet base material is composed of a nonwoven fabric.   The solder connection sheet according to any one of claims 1 to 6, wherein a release sheet that can be peeled off in use is laminated on the front surface and / or the back surface of the sheet base material.   The solder connection sheet according to claim 7, wherein an adhesive layer is formed on a release surface of the release sheet from the sheet base material. Arranging the solder connection sheet according to any one of claims 1 to 6 between the surface of the circuit board on which the connection terminals of a predetermined pattern are formed and the terminal formation surface of the electronic component;
A method for mounting an electronic component, comprising the step of mutually pressing and heating the substrate and the electronic component with the solder connection sheet interposed therebetween.   9. The solder member formed into a ball shape is obtained by filling the through hole with solder in a fluid state and then heating and cooling to a temperature higher than the melting temperature of the solder. The solder connection sheet according to any one of the above.

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