JP2010199098A - Board laminate and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a board laminate that properly makes soldering between lands formed on a facing surface of each substrate, even if displacement occurs between the lands, and to provide a method of manufacturing the same. <P>SOLUTION: Protrusions 7 are formed on a part of the outer circumferential end of a land center 6 of a second land 5 provided on a second substrate so as to be radial in a plane direction from the outer circumferential direction. With this configuration, even if a first land 4 provided on a first substrate and the second land 5 are displaced, the protrusions 7 compensate an area of soldering with the first land 4, the soldering can properly be made between the first land 4 and the second land 5 compared to a conventional method. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In particular, the present invention relates to a substrate laminate and a method for manufacturing the same, which can appropriately solder the lands to each other even when the lands formed on the opposing surfaces of the substrates are displaced from each other.

Patent Document 1 below discloses a method for joining ceramic wiring boards. In this document, conductor portions (land portions) of the same type of substrate are joined together by cream solder.
JP-A-8-204330

  The above-mentioned patent document does not describe a technique for appropriately soldering the land portions when the substrates are displaced and the land portions are displaced.

  For example, when stacking different substrates by soldering, such as a multi-layer substrate that is a stack of functional circuit boards with individual functions, different physical properties of each substrate, especially different stretchability, manufacturing process Due to deformation based on (firing, bonding, etc.), the land portions are likely to be misaligned, and in such a case, a configuration is required in which the land portions are securely soldered together.

  However, if the land portions are enlarged so that the land portions overlap each other even if misalignment occurs, wirings cannot be formed at high density on the substrate, and the cream solder melts and the volume decreases. In other words, problems such as adhesion to only one land and loss of continuity occurred.

  Accordingly, the present invention is to solve the above-described conventional problems, and in particular, even when the land portions formed on the opposing surfaces of the respective substrates are misaligned, the land portions are appropriately soldered. It aims at providing the board | substrate laminated body which can be joined, and its manufacturing method.

The present invention includes a plurality of opposing substrates each having a wiring formed thereon,
A substrate laminate in which one or more land portions are formed on opposite surfaces of one of the substrates and the other of the substrates, and the land portions are joined by a solder layer to be electrically connected. Because
A protruding portion is formed in a part of the outer peripheral end of at least one of the land portions so as to extend in a plane direction from the outer peripheral end.

  Thereby, even if it solder-joins in the state from which the land part shifted, it can solder-join between each land part appropriately compared with the past. In addition, since the protrusions are provided to compensate for the positional deviations without increasing the land part as a whole, the land area is relatively small, and the rise when the solder melts is large. The part can be reliably conducted. Therefore, in the present invention, since a slight positional shift between the land portions can be allowed as compared with the prior art, a highly reliable substrate laminate is obtained with respect to the electrical connectivity between the land portions.

In the present invention, at least one set of the land portions bonded between the substrates is displaced in the center position,
It is preferable that the protrusion formed on at least one of the pair of land portions includes a first protrusion extending in a direction substantially parallel to a relative displacement direction of the land portions. As a result, the land portions can be accurately soldered.

  In the present invention, it is preferable that a plurality of the projecting portions extend in a planar direction from an outer peripheral end of the land portion. In particular, it is preferable that the protruding portions extend radially from the outer peripheral end of the land portion. As a result, the allowable range of positional deviation between the land portions can be widened, and the substrate laminate is excellent in electrical connectivity between the land portions.

  In the present invention, one of the substrates may be a resin film, and the protruding portion may have a portion that extends substantially parallel to a direction in which the resin film has a large thermal shrinkage. Since the resin film has a large thermal shrinkage in a specific direction in manufacturing and an error in the position is likely to occur in that direction, the land portions can be appropriately connected with the solder layer by extending the protruding portion in this direction in advance.

  In the present invention, it is preferable that the land center portions excluding the projecting portions of the opposing land portions are formed with substantially the same area. Thereby, the rise when the solder melts can be increased, the bonding strength between each land portion and the solder layer can be increased, and a highly reliable substrate laminate can be provided.

  In the present invention, each substrate is formed of a different material. For example, each substrate is formed of a material having a different thermal expansion coefficient. In such a case, the land portions are likely to be misaligned due to variations in deformation due to the heating process in the manufacturing process of each substrate and the heating process (reflow process) when forming the solder layer. Thus, it is possible to appropriately solder the lands and provide a highly reliable substrate laminate.

  In the present invention, each substrate may be formed by a manufacturing process having a different thermal history. In such a case, the land portions are likely to be misaligned due to variations in the deformation of each substrate, but even in this case, according to the present invention, the land portions can be appropriately soldered together, and a highly reliable substrate laminate is provided. it can.

  In the present invention, for example, each board is a functional circuit board having an individual function. Even in such a case, the land portions are likely to be misaligned due to variations in the deformation of each functional circuit board. Even in this case, according to the present invention, the land portions can be appropriately solder-bonded, and the substrate lamination with excellent reliability can be achieved. Can provide the body.

  In the present invention, it is preferable that at least a part between the opposing surfaces excluding the formation region of the solder layer is bonded by an adhesive layer. Thereby, the joint strength between the opposing surfaces of the substrate can be further increased.

  Further, in the present invention, the adhesive layer is formed over the entire area between the opposing surfaces excluding a space region that extends from the periphery of the solder layer to the outside, and the solder layer is formed of cream solder, It is preferable that the flux is deposited in the space region. Accordingly, the bonding strength between the opposing surfaces of the substrate can be effectively increased, and the land portions can be appropriately connected with the solder layer.

The method for producing a substrate laminate in the present invention is as follows.
Forming one or more land portions on the opposing surfaces of each substrate, and at this time, forming a projecting portion extending in a planar direction from the outer peripheral end on a part of the outer peripheral end of at least one land portion; ,
A step of joining each land portion with a solder layer in a state where the facing surfaces of each substrate face each other;
It is characterized by having.

  According to the present invention, by providing the protruding portion, even when a positional deviation occurs between the opposing substrates, the land portions can be appropriately connected and the bonding strength by the solder layer can be maintained. . In addition, to compensate for the positional deviation by providing a protruding part, without increasing the land part as a whole, the area of the land part is relatively small, and the rise when the solder melts can be increased, The land part can be reliably conducted. Therefore, in the present invention, a slight positional deviation between the substrates can be allowed, and even when the positioning accuracy is low or there is a positional deviation due to deformation of each substrate, the land portions can be appropriately connected as compared with the conventional case.

  In this invention, it is preferable to form the 1st protrusion part extended in the relative shift | offset | difference direction of the other party land part with respect to the land part of the side in which the said protrusion part is formed, and a substantially parallel direction. Thus, the land portions can be accurately connected by the solder layer.

  In the present invention, it is preferable that a plurality of projecting portions are formed to extend in a planar direction from the outer peripheral end of the land portion. In particular, it is more preferable that the protruding portions are radially extended from the outer peripheral end of the land portion. As a result, the allowable range of positional deviation between the land portions can be widened, and the land portions can be more effectively connected by the solder layer more appropriately.

  Further, in the present invention, it is possible to more effectively increase the bonding strength between the opposing surfaces of the substrate by including a step of bonding at least a part between the opposing surfaces excluding the solder layer forming region with an adhesive layer. Is preferable.

Further, in the present invention, the adhesive layer is formed on the entire area on the facing surface excluding a space region that extends from the periphery of the land portion to the outside, and cream solder is applied on the land portion,
After the substrates face each other through the adhesive layer and the cream solder, the solder is melted by reflow, the flux is deposited in the space region, and the generated gas from the flux is further discharged from the space region to the outside. It is preferable to escape. Accordingly, the solder layer can be appropriately formed, and the adhesive layer is formed over the entire area between the opposed surfaces excluding the space region, so that the bonding strength between the opposed surfaces can be further strengthened.

In the present invention, when the adhesive layer is formed on the facing surface, a thermosetting resin layer is formed,
It is preferable that the thermosetting resin layer is thermoset by heating by the reflow to form the adhesive layer. Thereby, a manufacturing process can be simplified.

  According to the present invention, even when solder bonding is performed in a state where the lands are displaced, it is possible to appropriately solder the lands between the lands. In addition, since the protrusions are provided to compensate for the positional deviations without increasing the land part as a whole, the land area is relatively small, and the rise when the solder melts is large. The part can be reliably conducted. Therefore, in the present invention, since a slight positional shift between the land portions can be allowed as compared with the prior art, a highly reliable substrate laminate is obtained with respect to the electrical connectivity between the land portions.

  FIG. 1A is a cross-sectional view of a substrate laminate showing an embodiment of the present invention (the substrate laminate is shown in a film thickness direction (Z1-Z2 direction shown) along the line AA shown in FIG. 1C. 1) is a cross-sectional view as viewed from the direction of the arrow), FIG. 1 (b) is a back view of the first substrate as viewed from the direction of the arrow B in FIG. 1 (a), and FIG. It is a top view of the 2nd board | substrate provided with the contact bonding layer on the surface seen from the arrow C direction of 1 (a). In FIGS. 1B and 1C, the solder layer 14 shown in FIG. 1A is not shown.

  A substrate laminate 1 shown in FIG. 1A is, for example, a multilayer substrate in which functional circuit substrates having individual functions are laminated. Examples of the functional circuit board include a capacitor inner layer board using a high dielectric constant dielectric layer, a high-speed transmission path board using a low dielectric constant dielectric layer, a coil inner board using a dielectric layer having magnetic properties, and a high heat These are a heat dissipation board, a resistance element inner layer board, and a wiring layer board using a conductive dielectric layer.

  As shown in FIG. 1A, the substrate laminate 1 is obtained by laminating a first substrate 2 and a second substrate 3 via a joint portion 13. Here, for example, the first substrate 2 is the above-described functional circuit substrate or a multilayer substrate, and the second substrate 3 is a (multilayer) substrate on which an input / output filter is formed. A multilayer substrate with an output filter is formed. Reference numeral 12 shown in FIG. 1A is, for example, a substantially spherical protruding electrode, and the multilayer substrate as the substrate laminate 1 is electrically joined to a mother substrate (not shown) or the like via the protruding electrode.

  As shown in FIGS. 1A and 1B, a conductive first land portion 4 is exposed and formed on the lower surface (hereinafter sometimes referred to as an opposing surface) 2a of the first substrate 2. . The planar shape of the first land portion 4 is, for example, a circular shape, but is not limited to a circular shape. In addition to the circular shape, a rectangular shape, an elliptical shape, or the like can be presented. As shown in FIG. 1A, the first land portion 4 has a shape protruding downward from the lower surface 2a (in the Z2 direction in the drawing), but the surface of the first land portion 4 is The same surface as the lower surface 2a may be used.

  As shown in FIGS. 1A and 1C, a second land portion 5 is exposed and formed on the upper surface (hereinafter sometimes referred to as an opposing surface) 3a of the second substrate 3. For example, the second land portions 5 are formed in the same number as the first land portions 4. As shown in FIG. 1A, the second land portion 5 has a shape protruding upward from the upper surface 3a (Z1 direction in the drawing), but the surface of the second land portion 5 is It may be flush with the upper surface 3a.

  As shown in FIG. 1C, each of the second land portions 5 includes a substantially circular land center portion 6 and a part of the outer periphery end of the land center portion 6 in a plane direction (X And a protrusion 7 extending in the (Y-plane direction). Four protrusions 7 are provided in each land portion 5, and the protrusions 7 are formed at intervals of about 90 degrees. The protrusion 7 is provided in order to compensate for a solder joint region with the first land portion 4 with respect to a positional deviation in a predetermined direction between the land portions 4 and 5.

  As shown in FIG. 1A, the first land portion 4 and the second land portion 5 are joined by a solder layer 14.

  The lower surface (opposing surface) 2 a of the first substrate 2 and the upper surface (opposing surface) 3 a of the second substrate 3 except for the formation region of the solder layer 14 are joined by an adhesive layer 8. A hatched portion shown in FIG. 1C indicates a region where the adhesive layer 8 is formed.

  As shown in FIG. 1C, the adhesive layer 8 extends from the peripheral region of the second land portion 5 joined to the first land portion 4 via the solder layer 14 to the outside of the substrate laminate 1 side. It is formed in the whole area between the said opposing surfaces 2a and 3a except the space area | region 9 which leads to.

  FIG. 2 is a partially enlarged cross-sectional view in which a part of the substrate laminate of FIG. 1 is enlarged. The solder layer 14 is formed of cream solder, and a residue 10 such as a flux is deposited in the space region 9 as shown in FIG.

  For example, as shown in FIG. 1A and FIG. 2, the first substrate 2 extends in the X1-X2 direction from the second substrate 3 as a result, and as a result, as shown in FIG. The first land portion 4 and the land center portion 6 of the second land portion 5 are displaced in the X1-X2 direction in the drawing. FIG. 3 is a plan view of the first land portion 4 and the second land portion 5. An overlapping portion of the second land portion 5 with the first land portion 4 is indicated by a dotted line.

  As described above, the first land portion 4 has a substantially circular shape. The land center portion 6 of the second land portion 5 is also substantially circular. As shown in FIG. 3, the center point O1 of the first land portion 4 and the center point O2 of the land center portion 6 of the second land portion 5 are shifted in the X1-X2 direction shown in the drawing.

  For this reason, the opposing area with respect to the height direction of the land center part 6 of the first land part 4 and the second land part 5 is the land center of the first land part 4 and the second land part 5. Although the center points O1 and O2 of the portion 6 are smaller than the case where the center points O1 and O2 coincide with each other in the height direction, in the present embodiment, the projecting portion 7 extending from the outer peripheral end of the land center portion 6 is provided. In the prior art, the protrusion 7 positioned immediately below the misalignment region of the first land portion 4 compensates for the solder joint region with the first land portion 4, and thus the protrusion 7 is not formed. In comparison, the land portions 4 and 5 can be appropriately soldered together. Further, in the present embodiment, the land portions 4 and 5 are relatively small in size because the protrusions 7 are provided to compensate for the positional deviations without increasing the land portions 4 and 5 as a whole. The rise when the solder melts is large, and the land portions 4 and 5 can be reliably conducted. Therefore, in the present embodiment, since a slight positional shift between the land portions 4 and 5 can be allowed as compared with the conventional case, the substrate laminate 1 is highly reliable with respect to the electrical connectivity between the land portions 4 and 5. .

  As shown in FIG. 1C and FIG. 3, a plurality of projecting portions 7 are formed in the planar direction from the outer peripheral end of the land center portion 6 of the second land portion 5. It may be a book.

  However, a plurality of the protrusions 7, in particular, when the protrusions 7 are provided in a radial manner as shown in FIG. 3, the allowable range of misalignment between the land parts 4 and 5 can be widened, and the substrate lamination is excellent in reliability. It becomes the body 1. That is, the center point O1 of the first land part 4 is not only in the X2 direction shown in the figure with respect to the center point O2 of the second land part 5, but also in the X1 direction, the Y1 direction, the Y2 direction shown in the figure, or otherwise. Even when the first land portion 4 is displaced in the plane direction, at least a part of the projecting portion 7 is easily disposed immediately below the position displacement region of the first land portion 4. Can be appropriately soldered together.

  Further, as shown in FIG. 4, at least three protrusions 7 are provided, and if the protrusions 7 are formed to extend at an equal interval of about 120 degrees, the position between the land parts 4 and 5 is shifted. It is easy to arrange at least a part of the projecting portion 7 directly below the position shift region of the first land portion 4 over a wide range, and the first land portion 4 and the second land portion 5 are appropriately soldered. Is possible.

  The configuration in which a plurality of the protruding portions 7 are provided as described above is particularly effective when the relative displacement direction of the first land portion 4 with respect to the second land portion 5 is unknown.

  On the other hand, when the relative displacement direction (X2 direction in FIG. 3) of the first land portion 4 with respect to the second land portion 5 is empirically known or can be predicted, the displacement direction is substantially the same. By extending and forming the protrusions (first protrusions) 7 in parallel directions, the land portions 4 and 5 can be accurately soldered together, and the substrate laminate 1 with higher reliability can be provided. At this time, it is only necessary to provide the protrusion 7 with a first protrusion extending in a direction substantially parallel to the displacement direction. Here, “substantially parallel” means that the first projecting portion is within a range of an inclination angle of ± 20 degrees with respect to the direction of deviation (direction X2 in the drawing) from the center point O2 of the second land portion 5 shown in FIG. If extended, it is defined as “substantially parallel”. For example, one of the substrates 2 and 3 is a resin film, and the protruding portion (first protruding portion) 7 extends in a direction substantially parallel to a direction in which the thermal contraction of the resin film is large. it can. The resin film has a large thermal shrinkage in a specific direction in manufacturing, and a position error tends to occur in that direction. Therefore, by extending the protruding portion 7 in this direction in advance, the land portions 4 and 5 can be appropriately formed as a solder layer. Can be connected.

  In this embodiment, the center position shift does not occur in all the pairs of land portions 4 and 5, and the center position shift occurs when the center position shift occurs only in some of the land portions 4 and 5 pairs. Whether or not the protrusions 7 are formed is arbitrary for the set of land portions 4 and 5 that are not (or is predicted not to be generated), and among the set of land portions 4 and 5 in which the center position shifts. The first protrusions extending in a direction substantially parallel to the relative displacement direction of the land parts 4 and 5 are formed on at least one of the protrusion parts 7 so that all the land parts 4 are formed. 5 can be appropriately connected by the solder layer 14.

  In the embodiment of FIG. 3, the first protrusion corresponds to a protrusion 7 (indicated by a dotted line in FIG. 3) extending from the outer peripheral end of the land center portion 6 in the X2 direction. If the direction is known, only the first projecting portion extending in the X2 direction may be provided on the second land portion 5.

  The extension length L1 of the protrusion 7 is preferably in the range of 50% to 150% of the relative maximum deviation width L2 of the first land portion 4 with respect to the second land portion 5. .

  Here, when specific numerical values of the first land portion 4 and the second land portion 5 are shown, the diameter of the land center portion 6 of the first land portion 4 and the second land portion 5 is 50 μm to 500 μm, A width dimension T1 of the protruding portion 7 is 15 μm to 150 μm, and an extending length L1 of the protruding portion 7 is 20 μm to 200 μm.

  In FIG. 3, the protruding portion 7 has a strip shape having a certain width dimension extending in one direction, but may be, for example, a curved shape or a meandering shape, and the width dimension is not limited to a certain one.

  Next, as shown in FIG. 3, it is preferable that the land center portions 6 of the first land portion 4 and the second land portion 5 are formed with substantially the same area. Here, the same is defined within the range of 80% to 120% of the area of the other land part with respect to the area of one land part. If the second land portion 5 is formed larger than the first land portion 4, for example, the length from the center point O2 of the second land portion 5 shown in FIG. 3 to the tip of the protruding portion 7 extending in the X2 direction shown in FIG. If a large land portion made of a circle having a radius of radius is formed, even if the land portions 4 and 5 are displaced as shown in FIG. 3, the opposing area in the height direction between the land portions 4 and 5 is always constant. Remain big. However, in such a case, since the solder spreads over the entire surface of the land portion 5 that is formed to be large, the height dimension of the solder layer 14 cannot be secured. As a result, the bonding area between the first land portion 4 and the solder layer 14 is reduced, and the first land portion 4 and the second land portion 5 cannot be appropriately soldered (conducting poor conductivity). Problems arise. Therefore, in the present embodiment, the land center portion 6 of the first land portion 4 and the second land portion 5 is formed with substantially the same area, and the rise when the solder melts is more effectively increased. In other words, the bonding strength between the land portions 4 and 5 and the solder layer 14 is increased. The distance between the first land 4 and the second land portion 5 is about 20 μm to 200 μm.

  In the above embodiment, the protruding portion 7 is formed on the second land portion 5, but the protruding portion 7 may be formed on the first land portion 4, and the first land portion 4 The projecting portions 7 may be formed on both the second land portions 5. In the embodiment of FIG. 3, when the protrusion 7 is provided on the first land portion 4, it is preferable to provide the protrusion 7 (first protrusion) extending in the X1 direction shown in the drawing.

  In the present embodiment, the first substrate 2 and the second substrate 3 are separately formed, and then the first land portion 4 of the first substrate 2 and the The second land portion 5 of the second substrate 3 is bonded by soldering. Thus, in order to form the first substrate 2 and the second substrate 3 separately, when the substrates 2 and 3 are functional circuit substrates having individual functions as described above, the substrates 2 and 3 are formed. When the substrates 2 and 3 are joined due to variations in deformation of the substrates 2 and 3 due to differences in stretchability of the substrates 2 and 3 and manufacturing processes (firing, bonding, etc.) of the substrates 2 and 3, Easily misaligned. Even in this case, according to the structure of the joint portion 13 of this embodiment, the land portions 4 and 5 can be appropriately soldered together, and the substrate laminate 1 having excellent reliability can be obtained.

  In the present embodiment, the substrates 2 and 3 may be other than the functional circuit substrate. At this time, the substrates 2 and 3 are formed of different materials. For example, when the substrates 2 and 3 are formed of materials having different thermal expansion coefficients, Due to variations in the deformation of the substrates 2 and 3 due to the heating process (reflow process) when forming the solder layer 14, the land portions 4 and 5 are likely to be misaligned. Even in this case, according to the structure of the joint portion 13 of this embodiment, the land portions 4 and 5 can be appropriately soldered together, and the substrate laminate 1 having excellent reliability can be obtained.

  Alternatively, the first substrate 2 and the second substrate 3 are formed by manufacturing processes having different thermal histories. Even in such a case, the positions of the land portions 4 and 5 of the first substrate 2 and the second substrate 3 are likely to be misaligned, but in this case as well, according to the present embodiment, the land portions 4 and 5 are appropriately soldered. Can be joined.

  The substrate laminate in the present embodiment also includes a laminate structure of the electronic component 20 and the flexible printed board 21 as shown in FIG. Here, a member having a surface facing the flexible printed circuit board 21 of the electronic component 20 is a “board”. Also in the embodiment of FIG. 5, the joint portion 22 between the electronic component 20 and the flexible printed circuit board 21 has the structure of the joint portion 13 described with reference to FIGS. 1 to 3. Even if solder bonding is performed in a state where the positions of the lands on the flexible printed circuit board 21 side are shifted, it is possible to appropriately solder the lands between the lands.

  In the present embodiment, the “substrate” includes not only a rigid substrate but also a flexible substrate such as a flexible printed circuit board.

  The adhesive layer 8 shown in FIG. 1 is not an essential layer. That is, the adhesive layer 8 is formed as necessary.

  Next, a method for manufacturing the substrate laminate 1 shown in FIG. 1 will be described below with reference to FIGS.

  In the step of FIG. 6, as shown in FIGS. 6A and 6B, the first substrate 2 and the second substrate 3 are manufactured, respectively. For example, the first substrate 2 and the second substrate 3 are functional circuit substrates having individual functions, and are manufactured through separate manufacturing processes.

  The first land portion 4 is exposed and formed on the lower surface (opposing surface) 2a of the first substrate 2 shown in FIG. 6A, and the upper surface (opposing surface) 3a of the second substrate 3 shown in FIG. 6B. The second land portion 5 is exposed.

  At this time, as shown in FIG. 6C, the second land portion 5 is formed on a part of the outer peripheral end of the land center portion 6 in a planar direction (XY plane direction in the drawing) from the outer peripheral end. A projecting portion 7 is formed to extend to compensate for a solder joint region with the first land portion 4 with respect to a positional shift between the lands 4 and 5 in a predetermined direction. Specific structures of the first land portion 4 and the second land portion 5 are as described in FIG.

  Subsequently, as shown in FIG. 6C, an adhesive layer 8 is formed on the opposing surface 3a of the second substrate 3 by patterning. A hatched portion shown in FIG. 6C shows a region where the adhesive layer 8 is formed. The adhesive layer 8 is formed by screen printing, for example. The adhesive layer 8 is formed of a paste-like or film-like thermosetting resin layer containing, for example, a thermosetting resin in a solvent. If it is the said paste-like thermosetting resin layer at this time, it will be set as the semi-hardened state which made it dry or not by evaporating the solvent. Moreover, if it is a film-like thermosetting resin layer, it will be set as the semi-hardened state.

  As shown in FIG. 6 (c), the adhesive layer 8 is opposed to the surface of the second land portion 5 except for the space region 9 that extends from the peripheral region to the outside of the side of the second substrate 3. It is formed on the entire surface 3a.

  Subsequently, a cream solder 25 is applied on the second land portion 5 exposed from the space region 9. Since the cream solder 25 is several times (about 2 to 4 times) larger than the solder volume contained in the cream solder 25, the cream solder 25 is not regarded as being on the second land portion 5, and includes a surrounding area. It is preferable to apply to the range. In FIG. 6C, the cream solder 25 is entirely formed on the second land portion 5 and its surrounding area including the insulating facing surface 3 a spreading around the second land portion 5. Specifically, the cream solder 25 is applied.

  Subsequently, as shown in FIG. 7, the opposing surfaces 2 a and 3 a of the first substrate 2 and the second substrate 3 face each other through the cream solder 25 and the adhesive layer 8 to perform alignment.

  Then, the solder is melted by reflow, and the solder is concentrated between the first land portion 4 and the second land portion 5 to form a solder layer 14 (see FIGS. 1A and 2). At this time, residues such as flux can be deposited in the space region 9 provided in the adhesive layer 8 interposed between the first substrate 2 and the second substrate 3 (see FIG. 2). The generated gas can be appropriately released from the space region 9 to the outside. Therefore, the solder layer 14 can be appropriately formed.

  Further, the adhesive layer 8 made of a paste-like thermosetting resin layer is thermoset by heating by the reflow. In this way, the same heating process can form the solder layer 14 and thermally cure the adhesive layer 8, thereby facilitating the manufacturing process.

  By the way, if the first substrate 2 and the second substrate 3 are not deformed by the time of bonding in FIG. 7, the first land portion 4 of the first substrate 2 and the first substrate 2 can be obtained with a high positioning accuracy. Although it is possible to face the second land portion 5 of the second substrate 3 without misalignment, the first substrate 2 and the second substrate 3 are shown in FIG. When the first substrate 2 is deformed by the time of bonding, the first land portion 4 of the first substrate 2 and the second land portion 5 of the second substrate 3 are made to face each other while being displaced.

  For example, when the substrates 2 and 3 are functional circuit boards having individual functions, are made of materials having different thermal expansion coefficients, or are formed by a manufacturing process having different thermal histories, the first The position between the land portions 4 and 5 of the substrate 2 and the second substrate 3 is likely to be displaced.

  In the present embodiment, even if the first land portion 4 and the second land portion 5 face each other in a misaligned state, the projecting portion 7 is provided on the second land portion 5. The projecting part 7 faces at least a part of the displaced first land part 4 in the height direction, and the projecting part 7 compensates for the solder joint region with the first land part 4. Yes.

  Therefore, even if the first land portion 4 and the second land portion 5 are misaligned, it is possible to solder the first land portion 4 and the second land portion 5 appropriately and easily as compared with the conventional case. Bonding is possible, and the bonding strength by the solder layer 14 can also be maintained.

  In the present embodiment, as shown in FIG. 6 (c), a plurality of protruding portions 7 are formed from the outer peripheral end of one second land portion 5. The allowable range can be widened, and the land portions 4 and 5 can be more appropriately connected by the solder layer 14. In particular, it is preferable to form the protrusions 7 radially as shown in FIG.

  Further, from experience, during the process of bringing the substrates 2 and 3 of FIG. 7 to face each other due to differences in the manufacturing process of the substrates 2 and 3 and different physical properties of the substrates 2 and 3, particularly different stretchability, When it is known that the first substrate 2 extends in the X1-X2 direction in the drawing as compared to the second substrate 3, from the two second land portions 5 formed on the X2 side in the drawing, A protruding portion 7 (first protruding portion) is formed in a direction substantially parallel to the illustrated X2 direction, which is a relative displacement direction of the first land portion 4 with respect to the second land portion 5, and is formed on the illustrated X1 side. From the two second land portions 5, the projecting portion 7 (the first portion 7 in the direction substantially parallel to the X1 direction shown in the figure, which is the relative displacement direction of the first land portion 4 with respect to the second land portion 5. By forming the protruding portion, the land portions 4 and 5 can be soldered more accurately.

  For example, when one of the substrates 2 and 3 is a resin film, at least one of the protrusions 7 extends substantially parallel to a direction in which the resin film has a large thermal shrinkage. The resin film has a large thermal shrinkage in a specific direction in manufacturing, and a position error is likely to occur in that direction. Therefore, by extending the protruding portion 7 in this direction in advance, the land portions 4 and 5 can be appropriately formed as a solder layer. Can be connected.

  Further, when it is known in advance (or can be predicted) how much the positional deviation will occur, the extension length of the projecting portion 7 is set to the relative value of the first land portion 4 to the second land portion 5. It is preferable that the length is 50% to 150% of the maximum deviation width, because the land portions 4 and 5 can be soldered more accurately.

(A) is sectional drawing of the board | substrate laminated body which shows embodiment in this invention (The said board | substrate laminated body is a film thickness direction (illustration Z1-Z2 direction) along the AA line shown in FIG.1 (c). Sectional view cut from the direction of the arrow and viewed from the direction of the arrow, (b) is a rear view of the first substrate viewed from the direction of the arrow B in FIG. 1 (a), (c) is the arrow C in FIG. A plan view of a second substrate having an adhesive layer on the surface viewed from the direction; The partial expanded sectional view which expanded a part of board | substrate laminated body of FIG. 1, The top view of the 1st land part shown in FIG. 2, and the 2nd land part, The top view which shows the land part structure of other embodiment, The front view of the said flexible printed circuit board and electronic components for demonstrating that the structure of this embodiment is applicable to joining of a flexible printed circuit board and an electronic component, FIG. 2 is a process diagram illustrating a method of manufacturing the substrate laminate shown in FIG. 1, where (a) is a cross-sectional view showing the same cross-sectional portion as FIG. 1 of the first substrate, and (b) is FIG. Sectional drawing which shows the same sectional part, (c) is a plan view of the second substrate, FIG. 7 is a process diagram performed next to FIG. 6, and is a cross-sectional view showing a state in which the first substrate in FIG. 6A and the second substrate in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate laminated body 2 1st board | substrate 3 2nd board | substrate 4 1st land part 5 2nd land part 6 Land center part 7 Protrusion part 8 Adhesion layer 9 Spatial region 10 Residues 13 and 22 Joining part 14 Solder layer 20 Electronic Component 21 Flexible Printed Circuit Board 25 Cream Solder

Claims (19)

A plurality of opposing substrates each having a wiring formed thereon;
A substrate laminate in which one or more land portions are formed on opposite surfaces of one of the substrates and the other of the substrates, and the land portions are joined by a solder layer to be electrically connected. Because
A substrate laminate, wherein a projecting portion extends in a planar direction from the outer peripheral end to a part of the outer peripheral end of at least one of the land portions. At least one of the land portions bonded between the substrates has a shift in the center position,
2. The projecting portion formed in at least one of the set of land portions includes a first projecting portion extending in a direction substantially parallel to a relative displacement direction of the land portions. Substrate laminate.   The board | substrate laminated body of Claim 1 or 2 with which the said protrusion part is extended in the planar direction from the outer peripheral end of the said land part.   The board | substrate laminated body of Claim 3 with which the said protrusion part is extended radially from the outer peripheral end of the said land part.   5. The substrate according to claim 1, wherein one material of the substrate is a resin film, and the protruding portion has a portion extending substantially parallel to a direction in which the thermal contraction of the resin film is large. Laminated body.   6. The substrate laminate according to claim 1, wherein the land central portions excluding the projecting portions of the opposing land portions are formed with substantially the same area.   The substrate laminate according to any one of claims 1 to 6, wherein each substrate is formed of a different material.   The board | substrate laminated body of Claim 7 currently formed with the material from which a thermal expansion coefficient differs.   The substrate laminate according to any one of claims 1 to 8, wherein each substrate is formed by a manufacturing process having different thermal histories.   The substrate laminate according to claim 1, wherein each substrate is a functional circuit substrate having an individual function.   The board | substrate laminated body in any one of Claim 1 thru | or 10 with which at least one part between the said opposing surfaces except the formation area of the said solder layer is joined by the contact bonding layer.   The adhesive layer is formed over the entire area between the opposing surfaces except for a space region that extends from the periphery to the outside of the solder layer, the solder layer is formed of cream solder, and the flux is in the space region The substrate laminate according to claim 11, which is deposited on the substrate. Forming one or more land portions on the opposing surfaces of each substrate, and at this time, forming a projecting portion extending in a planar direction from the outer peripheral end on a part of the outer peripheral end of at least one land portion; ,
A step of joining each land portion with a solder layer in a state where the facing surfaces of each substrate face each other;
A method for producing a substrate laminate, comprising:   The manufacturing method of the board | substrate laminated body of Claim 13 which forms the 1st protrusion part extended in the relative shift | offset | difference direction of the other party land part with respect to the land part of the side in which the said protrusion part is formed, and a substantially parallel direction. .   The manufacturing method of the board | substrate laminated body of Claim 13 or 14 which extends and forms the several protrusion part in the planar direction from the outer peripheral end of the said land part.   The method for manufacturing a substrate laminate according to claim 15, wherein the protruding portions are formed to extend radially from an outer peripheral end of the land portion.   The method for manufacturing a substrate laminate according to any one of claims 13 to 16, further comprising a step of bonding at least a part between the opposing surfaces excluding the solder layer formation region with an adhesive layer. The adhesive layer is formed over the entire area on the facing surface excluding a space region that extends from the periphery of the land portion to the outside, and cream solder is applied on the land portion,
After the substrates face each other through the adhesive layer and the cream solder, the solder is melted by reflow, the flux is deposited in the space region, and the generated gas from the flux is further discharged from the space region to the outside. The manufacturing method of the board | substrate laminated body of Claim 17 which escapes. When the adhesive layer is formed on the facing surface, a thermosetting resin layer is formed,
The manufacturing method of the board | substrate laminated body of Claim 18 which thermosets the said thermosetting resin layer by the heating by the said reflow, and forms the said contact bonding layer.

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