JP3645765B2 - Solder connection structure, BGA type semiconductor package mounting structure, and BGA type semiconductor package mounting process - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a solder connection structure, and more specifically, electrically connects a semiconductor package having a concave and convex electrode at the bottom, such as a BGA (Ball Grid Array) type semiconductor package, onto a substrate. The present invention relates to a solder connection part structure of a BGA type semiconductor package. The present invention also relates to a mounting structure for such a BGA type semiconductor package. The present invention further relates to a solder paste used for a mounting structure of a BGA type semiconductor package. The present invention further relates to an electrode forming process of a BGA type semiconductor package. The present invention further relates to a mounting process for a BGA type semiconductor package.
[0002]
[Prior art]
The BGA type semiconductor package is characterized in that the mounting area is reduced by arranging electrodes in an area array at the bottom of the package, but due to its connection structure, the stress relaxation mechanism of the solder connection portion is weak.
[0003]
It is known that the life of the solder connection portion depends on the connection cross-sectional area, the solder height, the volume, and the like, and is improved by increasing the solder height.
[0004]
Therefore, a method has been proposed in which a dam is made of a material that does not wet with solder (solder resist or the like), the solder is made into a cylindrical shape, and the height is increased.
[0005]
[Problems to be solved by the invention]
However, when the solder is formed in a cylindrical shape, the solder tends to be spherical due to the surface tension of the solder itself. For this reason, there has been a problem that a phenomenon occurs in which the solder is divided at the cylindrical portion, and as a result, a connection failure occurs.
[0006]
The present invention has been made to solve the above-described problems, and an object thereof is to provide a solder connection portion structure that does not cause a connection failure.
[0007]
Another object of the present invention is to provide a mounting structure of a BGA type semiconductor package that does not cause connection failure.
[0008]
Another object of the present invention is to provide a solder paste that does not cause poor connection.
[0009]
Still another object of the present invention is to provide an electrode forming process of a BGA type semiconductor package which is improved so as not to cause a connection failure.
[0010]
It is still another object of the present invention to provide a BGA type semiconductor package mounting process improved so as not to cause connection failure.
[0011]
[Means for Solving the Problems]
  The solder connection structure according to claim 1 is provided on one substrate, and has a higher melting point than the solder.At least the surface gets wet with the solderA first solder including a dissimilar material having a composition is provided. A second solder made of solder is provided on the other substrate.A recess is formed on at least one surface of one substrate and the other substrate,The first solder and the second solder are brought into contact with each other to melt them., Dissimilar materials in the vicinity of the electrodes in the recesses in at least one of the one substrate and the other substrateIt becomes.
[0012]
According to a preferred embodiment of the present invention, the specific gravity of the dissimilar material is substantially equal to that of solder. Further, the specific gravity of the different material may be larger than that of the solder. Further, the dissimilar material may be composed of a dissimilar material having a specific gravity greater than that of solder and a dissimilar material having a specific gravity smaller than that of solder.
[0013]
The shape of the different material is preferably spherical.
Further, the dissimilar material may be made of a material that gets wet with the solder, or may have a surface coated with a metal that gets wet with the solder.
[0014]
  In the mounting structure of the BGA type semiconductor package according to claim 2, solder and a melting point higher than that of the solder are formed on one substrate.At least the surface gets wet with the solderA first solder including a dissimilar material having a composition is provided. A second solder made of solder is provided on the other substrate.A recess is formed on at least one surface of one substrate and the other substrate,The first solder and the second solder are brought into contact and melted., Dissimilar materials in the vicinity of the electrodes in the recesses in at least one of the one substrate and the other substrateIt becomes.
[0015]
Also in the invention according to claim 2, as the dissimilar material, those used in the preferred embodiment of claim 1 can be used.
[0016]
The size of the different material preferably satisfies the following formula.
D- {B- (B²−ρ²)^1/2} / 2 <A <2D
D: Concave height: ρ: Concave width: A: Dissimilar material diameter, B: Solder ball diameter
It is preferable to use lead-free solder as the solder.
[0017]
  IsThe paste isIn one aspect,It consists of a solder powder, a fluxing agent, and a powder of a different material having a higher melting point than that of the solder and a surface wetted by the solder.
[0018]
According to the present invention, the specific gravity of the dissimilar material is substantially equal to that of solder.
Further, the specific gravity of the different material may be larger than that of the solder.
[0019]
Further, it may be preferable that the specific gravity of the dissimilar material is smaller than that of the solder.
The dissimilar material may be composed of a dissimilar material having a specific gravity greater than that of solder and a dissimilar material having a specific gravity smaller than that of solder.
[0020]
The shape of the different material is preferably spherical.
In addition, the dissimilar material is preferably coated with a metal that wets the surface of the dissimilar material.
[0025]
  Claim3In the mounting process of the BGA type semiconductor package according to the above, first, a solder paste comprising a solder powder, a flux agent, and a powder of a different material having a melting point higher than that of the solder and at least the surface being wetted by the solder, Print on the mounting board. A BGA type semiconductor package is mounted on the mounting substrate. The solder paste is melted, whereby the BGA type semiconductor package is electrically connected to the mounting board via solder partially mixed with different materials, while the mounting board and the BGA type semiconductor are connected. The dissimilar material is unevenly distributed in the vicinity of the electrode in the recess formed on at least one surface of the package.
[0026]
  Claim4In the mounting process of the BGA type semiconductor package according to the above, first, a stencil having an opening for screen printing is formed on the mounting substrate. In the stencil opening, a dissimilar material having a composition having a melting point higher than that of the solder and at least the surface being wetted by the solder is placed. A solder paste is printed on the mounting board. Remove the stencil. A BGA type semiconductor package having solder balls is placed on the mounting substrate. The solder paste is melted, whereby the solder balls of the BGA type semiconductor package are connected to the mounting board, and the dissimilar material is mixed into the solder balls, while the mounting board and the BGA type semiconductor package are mixed. The dissimilar material is unevenly distributed in the vicinity of the electrode in the recess formed on at least one surface.
[0027]
  Claim5In the mounting process of the BGA type semiconductor package according to the above, first, one substrate and the other substrate to be connected to each other with solder are prepared. A first solder made of solder is formed on the one substrate. A second solder comprising a first dissimilar material having a composition having a higher melting point than that of the solder and having a specific gravity smaller than that of the solder, and a second dissimilar material having a composition having a higher melting point than that of the solder and having a specific gravity greater than that of the solder. Formed on the other substrate. The first solder and the second solder are brought into contact with each other to melt them.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0029]
Embodiment 1
In the solder connection portion structure according to the first embodiment, a dissimilar material made of a metal having a melting point higher than that of the solder is disposed in the connection recess using solder, and the electrode in the recess is electrically connected via the solder containing the dissimilar material. The present invention relates to a solder connection part structure that performs a general connection.
[0030]
Referring to FIG. 1, the connection recess is formed by an opening of insulator 2 and electrode pad 3. The dissimilar material 1 is disposed in the connection recess. Solder balls 6 are electrically connected to the recesses. In the figure, 16 represents a sealing resin.
[0031]
The mounting process of the BGA type semiconductor package, in which different materials are inserted into the solder balls of the mounting structure of the BGA type semiconductor package and electrical connection is made, will be described with reference to FIGS. Referring to FIG. 2, solder paste 7 is printed on mounting board 13 using stencil 12. In the figure, reference numeral 14 denotes a printing squeegee. Thereafter, the stencil 12 is removed.
[0032]
Referring to FIG. 3, metal 1 which is a different material is mixed in solder ball 6 of BGA type semiconductor package 5. The BGA type semiconductor package 5 to be electrically connected is mounted on the mounting substrate 13. The solder balls 6 and the solder paste 7 of the BGA type semiconductor package 5 are melted by passing through a reflow furnace, and both are joined. In FIG. 3, 3 represents an electrode pad, 15 represents an LSI chip, and 16 represents a sealing resin. Since the metal 1 is present in the opening of the insulator 2 in the connection portion where the BGA type semiconductor package 5 and the mounting substrate 13 are electrically connected, the solder 6 is separated when connecting to the mounting substrate 8. The problem is solved and the metal 1 supplements the electrical connection.
[0033]
Embodiment 2
In the second embodiment, brass (Cu—Zn alloy, specific gravity = 8.44 g / cm) as an example of a different material whose melting point is higher than that of solder and specific gravity is equivalent to that of solder.^Three) Was used. At this time, the specific gravity of the solder (Sn—Pb eutectic) is 8.3 to 8.5 g / cm.^ThreeThe specific gravity of the dissimilar material and the solder is almost the same. In another embodiment, zinc (specific gravity = 7.143 g / cm) is used for a combination of different materials and solder.^Three) And solder (Sn-3.5Ag-0.7Cu or Sn-4.7Ag-1.7Cu or Sn-0.7Cu or Sn-9Zn, both specific gravity = 7.27 to 7.4 g / cm^Three) Can be used. In these cases, since the specific gravity is substantially equal to each other, it is a feature that the movement of different materials does not occur when the solder is melted.
[0034]
Embodiment 3
In the present embodiment, Cu (specific gravity = 8.96 g / cm) is an example of a different material having a higher melting point than solder and a higher specific gravity than solder.^Three) Was used. Solder (specific gravity = 8.3-8.5 g / cm^Three), And the different materials have the property of being settled and locally unevenly distributed when the solder is melted. For example, a semiconductor device having this connection structure is placed on top, mounted on a substrate, and solder on the substrate is melted, so that dissimilar materials are unevenly distributed on the substrate side, and bonding is realized.
[0035]
Referring to FIG. 4, when a BGA type semiconductor package using a different material 1 having a specific gravity larger than that of the connection portion of solder 6 is mounted on the surface of the mounting substrate, the different material 1 is in the solder 6 when the solder 6 melts. Referring to FIG. 5, the dissimilar material 1 cannot be placed in the opening of the insulator 2 of the BGA type semiconductor package.
[0036]
However, referring to FIG. 6, dissimilar material 1 can be placed in via portion 4 of mounting substrate 13, and a BGA type semiconductor package mounting structure can be realized.
[0037]
7 and 8, when the BGA type semiconductor package is mounted on the back surface of the mounting substrate 13 using the different material 1 having a specific gravity larger than that of the connection portion of the solder 6, the BGA type semiconductor package is used. When the solder 6 is melted, the dissimilar material 1 falls to the electrode side of the mounting substrate 13, and when it is rotated 180 ° again, the dissimilar material 1 enters the opening of the insulator 2 of the BGS type semiconductor package. A mounting structure of a BGS type semiconductor package on which the material 1 is placed can be realized.
[0038]
Embodiment 4
As an example of a dissimilar material whose melting point is higher than that of solder and whose specific gravity is lower than that of solder, Fe (specific gravity = 7.87 g / cm^Three) Or Al (specific gravity = 2.699 g / cm)^Three) Was used. Such dissimilar materials are solder (specific gravity = 8.3-8.5 g / cm^Three) Has a small specific gravity, so that the dissimilar material floats when the solder is melted and has a local uneven distribution characteristic. For example, by bonding a semiconductor device having the present connection structure on top, mounting it on a substrate, and melting the solder on the substrate, it is possible to realize a junction characterized by uneven distribution of different materials on the semiconductor package side.
[0039]
Referring to FIG. 9A, when the different material 1 having a specific gravity smaller than that of the solder 6 connection portion is used, the different material 1 floats in the solder 6 when the solder is melted. The dissimilar material 1 is not present in the two openings. However, referring to FIG. 9B, when the BGA type semiconductor package is mounted on the surface of the mounting substrate 13, if the BGA type semiconductor package is rotated by 180 °, the dissimilar material 1 is generated when the solder 6 is melted again. Emerges. As a result, referring to FIG. 10, it is possible to realize a mounting structure of a BGA type semiconductor package in which the different material 1 is placed in the opening of the insulator 2 of the BGA type semiconductor package.
[0040]
However, referring to FIG. 11, in the case of mounting on both sides in the case of double-sided mounting, in the case of the mounting structure of the BGA type semiconductor package, it is rotated 180 ° again. Therefore, when the solder is melted, the dissimilar material 1 floats as shown in FIG. With reference to FIG. 12, the mounting structure of the BGA type semiconductor package in which the different material 1 is placed in the via portion 4 of the mounting substrate 13 can be realized.
[0041]
Embodiment 5
As an example of a combination of a dissimilar material having a higher melting point than solder and a specific gravity greater than that of solder and a different material having a specific gravity smaller than that of solder, Cu (specific gravity = 8.96 g / cm)^Three), Fe (specific gravity = 7.87 g / cm)^Three), Solder (specific gravity = 8.3-8.5 g / cm)^Three) Was used. In the present embodiment, since the different material that settles when the solder melts and the different material that floats exist, it is possible to obtain a joint structure in which different materials are placed on the upper and lower surfaces of the joint.
[0042]
Embodiment 6
In order to facilitate the movement of different materials in the molten solder due to the difference in specific gravity with the solder when the solder is melted, the shape of the different materials is made substantially spherical.
[0043]
Embodiment 7
In the present embodiment, a different material made of a material that gets wet with solder is used as an example, but other materials may be used. For example, in order to improve the wettability characteristics with the solder, the surface of a different material may be subjected to, for example, Au—Ni plating.
[0044]
Embodiment 8
In the present embodiment, referring to FIG. 13, the diameter A of the different material 1 is set smaller than the height of the opening of the insulator 2. When the height of the opening of the insulator 2 is D, the opening diameter of the insulator 2 is ρ, the solder ball diameter is B, and the diameter of the dissimilar material 1 is A, the solder ball 8 is disposed in the opening of the insulator 2. The clearance between the solder ball 8 and the electrode pad 3 is
D- {B- (B²−ρ²)^1/2} / 2
Therefore, when the solder ball 8 is melted, wetting between the different material 1 and the solder ball 8 is possible.
[0045]
Referring to FIG. 14, when the diameter A of the different material 1 is larger than the height of the opening of the insulator 2, the opening height of the insulator 2 is larger than at least the radius A / 2 of the different material 1. Therefore, when the solder ball 8 is mounted by the ball adsorption device, the solder ball 8 does not come off from the opening of the insulator 2.
[0046]
Embodiment 9
In the above embodiment, as the material of the solder ball, Sn-Pb eutectic solder, Sn-3.5Ag-0.7Cu, Sn-4.7Ag-1.7Cu, Sn-0.7Cu, Sn-9Zn, etc. Lead-free solder is effective.
[0047]
Embodiment 10
The present embodiment also relates to a process for forming an electrode of a BGA type semiconductor package in which a different material is inserted into a solder ball of the BGA type semiconductor package and electrical connection is made. In the present embodiment, paste-like solder obtained by kneading solder powder, a flux agent, and different materials is used.
[0048]
First, referring to FIG. 15, a solder paste 10 in which a different material 1 is mixed is printed in an opening of an insulator 2 in a BGA type semiconductor package.
[0049]
Referring to FIG. 16, solder ball 8 is adsorbed by ball adsorbing device 9 and arranged in the opening of insulator 2 of the BGA type semiconductor package on which the solder paste is printed. By mixing the different materials 1 in advance, the step of inserting the different materials 1 immediately before printing can be omitted. Heating is performed using a reflow furnace or the like, and the solder balls 8 and the solder paste 7 are melted and joined.
[0050]
Embodiment 11
In the present embodiment, as a specific example of the tenth embodiment, brass (Cu—Zn alloy, specific gravity = 8.44 g / cm) is used as an example of a different material having a melting point higher than that of solder and a specific gravity equivalent to that of solder.^Three) Was used. At this time, the specific gravity of the solder (Sn—Pb eutectic) is 8.3 to 8.5 g / cm.^ThreeThe specific gravity of the dissimilar material and the solder is almost the same. In another embodiment, zinc (specific gravity = 7.143 g / cm) is used for a combination of different materials and solder.^Three) And solder (Sn-3.5Ag-0.7Cu or Sn-4.7Ag-1.7Cu or Sn-0.7Cu or Sn-9Zn, specific gravity = 7.27 to 7.4 g / cm)^Three) Can be used. In these cases, since specific gravity is substantially equal to each other, there is a feature that the movement of different materials does not occur when the solder is melted.
[0051]
Embodiment 12
In this embodiment, as a specific example of the tenth embodiment, Cu (specific gravity = 8.96 g / cm) is used as an example of a different material having a melting point higher than that of solder and a specific gravity higher than that of solder.^Three) Was used. Solder (specific gravity = 8.3-8.5 g / cm^Three), And the different materials have the property of being settled and locally unevenly distributed when the solder is melted.
[0052]
Embodiment 13
In the present embodiment, as a specific example of the tenth embodiment, Fe (specific gravity = 7.87 g / cm) is used as an example of a different material whose melting point is higher than that of solder and whose specific gravity is smaller than that of solder.^Three) Or Al (specific gravity = 2.699 g / cm)^Three) Was used. Solder (specific gravity = 8.3-8.5 g / cm^ThreeSince the specific gravity of the dissimilar material is smaller than that of), the dissimilar material floats up when the solder melts and is locally unevenly distributed.
[0053]
Embodiment 14
In this embodiment, as a specific example of the tenth embodiment, Cu (specific gravity = 8.96 g /) is used as an example of a combination of a dissimilar material having a melting point higher than that of solder and a specific gravity larger than that of solder and a small dissimilar material. cm^Three), Fe (specific gravity = 7.87 g / cm)^Three), Solder (specific gravity 8.3-8.5 g / cm^Three) Was used. In the present embodiment, it is possible to obtain a joint structure in which different materials that precipitate when the solder melts and different materials that float are present, and different materials are present on the upper and lower surfaces of the joint.
[0054]
Embodiment 15
In the present embodiment, as a specific example of the tenth embodiment, the shape of the dissimilar material is substantially spherical in order to make it easier for the dissimilar material to move in the molten solder due to the difference in specific gravity with the solder when the solder is melted.
[0055]
Embodiment 16
In the present embodiment, as a specific example of the tenth embodiment, a material obtained by applying Au—Ni plating or the like to a different material is used in order to improve the wetting characteristics between the different material and the solder.
[0056]
Embodiment 17
The present embodiment relates to an electrode forming process of a BGA type semiconductor package in which a different material is inserted into a solder ball of the BGA type semiconductor package and electrical connection is made.
[0057]
Referring to FIG. 17, dissimilar material 1 is arranged in the opening of insulator 2 in the BGA type semiconductor package with the electrode surface facing up.
[0058]
Thereafter, as shown in FIG. 16, the solder balls 8 are disposed in the openings of the insulator 2 of the BGA type semiconductor package after the solder paste 7 is printed by the ball suction device 9. It heats using a reflow furnace etc., the solder ball 8 and the solder paste 7 are fuse | melted, and these are joined.
[0059]
Embodiment 18
The eighteenth embodiment also relates to an electrode forming process of a BGA type semiconductor package in which a different material is inserted into a solder ball of the BGA type semiconductor package and electrical connection is made.
[0060]
Referring to FIG. 17, dissimilar material 1 is arranged in the opening of insulator 2 in the BGA type semiconductor package with the electrode surface facing up.
[0061]
Referring to FIG. 18, solder paste 7 is printed in the opening of insulator 2 of the BGA type semiconductor package.
[0062]
As shown in FIG. 16, the solder balls 8 are arranged in the openings of the insulator 2 of the BGA type semiconductor package after the solder paste 7 is printed by the ball suction device 9. It heats using a reflow furnace etc., the solder ball 8 and the solder paste 7 are fuse | melted, and these are joined.
[0063]
Embodiment 19
The nineteenth embodiment relates to an electrode forming process of a BGA type semiconductor package in which a different material is inserted into a solder ball of the BGA type semiconductor package and electrical connection is made.
[0064]
Referring to FIG. 19, solder paste 7 is printed in the opening of insulator 2 in the BGA type semiconductor package. Solder balls 11 mixed with different materials 1 are arranged by the ball suction device 9 in the openings of the insulator 2 in the BGA type semiconductor package after the solder paste 7 is printed. It heats using a reflow furnace etc., the solder ball | bowl 11 and the solder paste 7 are fuse | melted, and these are joined.
[0065]
Embodiment 20
The present embodiment relates to a mounting process of a BGA type semiconductor package in which a different material is mixed into a solder ball of the mounting structure of the BGA type semiconductor package to perform electrical connection.
[0066]
Referring to FIG. 20, solder paste 10 kneaded with dissimilar material 1 is printed on substrate 13.
[0067]
Referring to FIG. 21, a BGA type semiconductor package 5 is mounted on a mounting substrate 13 on which a solder paste 10 in which a different material 1 is kneaded is printed.
[0068]
Heating is performed using a reflow furnace or the like, and the solder balls 6 and the solder paste 10 of the BGA type semiconductor package 5 are melted and joined. By mixing the different materials 1 in advance, it is possible to save time for inserting the different materials 1 immediately before printing.
[0069]
Embodiment 21
The present embodiment relates to a mounting process of a BGA type semiconductor package in which different materials are mixed in a solder ball of a mounting structure of a BGA type semiconductor package and electrical connection is made.
[0070]
Referring to FIG. 22, a stencil 12 for printing a solder paste is provided on a substrate 13, and the different material 1 is placed in the opening of the stencil 12.
[0071]
Referring to FIG. 23, the solder paste 7 is supplied by the printing squeegee 14 to the opening of the stencil 12 after the dissimilar material 1 is inserted, and then the stencil 12 is removed. Thereafter, referring to FIG. 21, BGA type semiconductor package 5 is mounted on mounting substrate 13 on which dissimilar material 1 and solder paste 10 are printed. It heats using a reflow furnace etc., the solder ball 8 and the solder paste 7 are fuse | melted, and these are joined.
[0072]
Embodiment 22
In this embodiment, as a specific example of the embodiment 11, as a combination of a different material having a higher melting point than that of the solder and a specific gravity higher than that of the solder and a small different material, Cu (specific gravity = 8.96 g / cm^Three), Fe (specific gravity = 7.87 g / cm)^Three), Solder (specific gravity = 8.3-8.5 g / cm)^Three) Was used. In the present embodiment, it is possible to obtain a joint structure that has different materials that float when the solder melts and different materials that float, and the different materials are contained in the upper and lower surfaces of the joint.
[0073]
Embodiment 23
Referring to FIG. 24, when a BGA type semiconductor package using a different material 1 having a specific gravity smaller than that of the connection portion of solder 6 and a different material 1 having a higher specific gravity is mounted on the mounting substrate 13, the front side of the mounting substrate 13. At the time of melting the solder 6, the dissimilar material 1 having a large specific gravity settles on the electrode via 4 of the mounting substrate 13, and the dissimilar material 1 having a small specific gravity floats to the opening of the insulator 2 of the BGA type semiconductor package, An electrode part can be formed.
[0074]
Similarly, referring to FIG. 25, a BGA type semiconductor package using the seed material 1 having a specific gravity smaller than that of the connection portion of the solder 6 and the different material 15 having a higher specific gravity is mounted on the mounting substrate 13 on both sides. In this case, the dissimilar material 1 can float or descend due to the difference in specific gravity of the solder, and the dissimilar material 1 can be present in the recess. In the figure, 17 is an electrode pad.
[0075]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0076]
【The invention's effect】
As described above, according to the present invention, in the portion (bump) electrically connected to the pad portion in the BGA type semiconductor package, the dissimilar material exists in the opening of the insulator, so that The solder separation phenomenon can be eliminated, the production yield can be improved, and the connection reliability after mounting can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a connection portion structure in which a different material exists in a connection recess using solder according to the present invention.
FIG. 2 is a cross-sectional view showing a state in which a solder paste is printed on a mounting board using a stencil.
FIG. 3 is a cross-sectional view showing a state where a BGA type semiconductor package having a different material in a recess is mounted on a mounting substrate.
FIG. 4 is a cross-sectional view of a BGA type semiconductor package in which a different material having a specific gravity greater than that of solder exists in a recess.
FIG. 5 is a cross-sectional view of a mounting structure of a BGA type semiconductor package at the time of melting a solder when a different material has a specific gravity smaller than that of solder.
FIG. 6 is a cross-sectional view of a mounting structure of a BGA type semiconductor package in which a dissimilar material having a specific gravity greater than that of solder exists in a recess of the mounting substrate.
FIG. 7 is a cross-sectional view of a BGA type semiconductor package in which a different material having a specific gravity equivalent to that of solder exists in a recess.
FIG. 8 is a cross-sectional view when a BGA type semiconductor package is mounted on the back side of the mounting substrate.
FIG. 9A is a cross-sectional view of a BGA type semiconductor package in which a different kind of material having a specific gravity smaller than that of solder exists, and FIG. 9B is a cross-sectional view when the semiconductor package is mounted on a mounting substrate printed with paste.
FIG. 10 is a cross-sectional view of the mounting structure of the BGA type semiconductor package after the dissimilar material floats.
FIG. 11 is a cross-sectional view when a BGA type semiconductor package having a different material having a specific gravity smaller than that of solder is mounted on the back of the mounting substrate.
FIG. 12 is a cross-sectional view of a mounting structure of a BGA type semiconductor package in which a dissimilar material having a specific gravity smaller than that of solder floats in a recess of the mounting substrate, and the dissimilar material exists in the recess.
FIG. 13 is a view for explaining the definition of the connection structure in which different materials exist in the connection recesses using solder according to the present invention, and shows a case where the diameter of the different materials is smaller than the height of the opening of the insulator. It is a figure.
FIG. 14 is a diagram showing a connection structure in which a different material exists in a connection recess using solder according to the present invention, and shows a case where the diameter of the different material is larger than the height of the insulator opening.
FIG. 15 is a cross-sectional view when a solder paste mixed with different materials is printed in a BGA type semiconductor package recess.
FIG. 16 is a cross-sectional view of mounting a solder ball on a concave portion of a BGA type semiconductor package on which paste printing has been performed with a ball suction device.
FIG. 17 is a cross-sectional view when a different material is inserted into a BGA type semiconductor package recess.
FIG. 18 is a cross-sectional view when a solder paste is printed in a BGA type semiconductor package recess.
FIG. 19 is a cross-sectional view of a solder ball mixed with different materials in a paste-printed BGA type semiconductor package recess when mounted by a ball suction device.
FIG. 20 is a cross-sectional view when a solder paste mixed with different materials is printed on a mounting board using a stencil.
FIG. 21 is a cross-sectional view when a solder ball is mounted on a paste printed mounting board by a ball suction device.
FIG. 22 is a cross-sectional view when dissimilar materials are placed on the mounting board using a stencil.
FIG. 23 is a cross-sectional view when a solder paste is printed on a mounting board using a stencil.
FIG. 24 is a cross-sectional view of a mounting structure of a BGA type semiconductor package in which different types of materials having larger and smaller specific gravity than solder are present in the mounting substrate and the BGA type semiconductor package recess.
25 is a cross-sectional view of the mounting structure of the BGA type semiconductor package at the time of melting the solder when the mounting structure of the BGA type semiconductor package shown in FIG. 24 is mounted on both sides.
[Explanation of symbols]
1 Dissimilar material, 2 Insulator in BGA type semiconductor package, 3 electrode pad, 6 solder, 16 sealing resin.

Claims (5)

A first solder provided on one substrate and including a solder and a different material having a higher melting point than the solder and at least a surface wetted by the solder;
A second solder provided on the other substrate and made of solder,
A recess is formed on at least one surface of the one substrate and the other substrate,
The first solder and the second solder are brought into contact with each other to melt them, and the dissimilar material is unevenly distributed in the vicinity of the electrode in the recess in at least one of the one substrate and the other substrate. Solder connection structure. A first solder provided on one substrate and including a solder and a different material having a higher melting point than the solder and at least a surface wetted by the solder;
A second solder provided on the other substrate and made of solder;
A recess is formed on at least one surface of the one substrate and the other substrate,
A BGA formed by bringing the first solder and the second solder into contact with each other, melting them, and causing the dissimilar material to be unevenly distributed in the vicinity of the electrode in the recess in at least one of the one substrate and the other substrate. Type semiconductor package mounting structure. A step of printing a solder paste consisting of a solder powder, a flux agent, and a powder of a dissimilar material made of a composition having a melting point higher than that of the solder and at least the surface being wetted by the solder on the mounting board;
Placing a BGA type semiconductor package on the mounting substrate;
The solder paste is melted, whereby the BGA type semiconductor package is electrically connected to the mounting board through solder partially mixed with the dissimilar material, while the mounting board and the BGA type are connected. And a step of unevenly distributing the dissimilar material in the vicinity of the electrode in the recess formed on at least one surface of the semiconductor package. Forming a stencil having an opening for screen printing on the mounting substrate;
Placing a dissimilar material composed of a composition having a melting point higher than that of the solder and at least the surface being wetted by the solder in the stencil opening; and
Printing a solder paste on the mounting substrate;
Removing the stencil;
Placing a BGA type semiconductor package having solder balls on the mounting substrate;
The solder paste is melted, thereby connecting the solder balls of the BGA type semiconductor package and the mounting board, and mixing the different materials into the solder balls, while the mounting board and the BGA type semiconductor package are And a step of unevenly distributing the dissimilar material in the vicinity of an electrode in a recess formed on at least one surface of the BGA type semiconductor package. Preparing one substrate and the other substrate to be connected to each other with solder;
Forming a first solder made of solder on the one substrate;
A second solder comprising a first dissimilar material having a higher melting point than that of the solder and having a specific gravity lower than that of the solder; and a second dissimilar material having a composition having a higher melting point than that of the solder and having a higher specific gravity than that of the solder. Forming on the other substrate;
Bringing the first solder and the second solder into contact with each other and melting them;
BGA type semiconductor package mounting process comprising:

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