JP2003046230A - Structure and mounting method using this structure - Google Patents

Abstract

(57) [Problem] To provide a structure that ensures high-density area mounting solder jointability corresponding to multiple pins of a BGA package. SOLUTION: A structure 5 has a base member 1 and a through hole 2 in which holes penetrated through the base member 1 are arranged in a grid array shape. As a mounting process for soldering the solder bumps 8 formed on the BGA package 6 and the lands 10 wired on the printed circuit board 11, a mask is mounted on the printed circuit board 11, and solder paste is applied from above the mask. Is applied, the solder paste is printed on the lands wired to the printed circuit board 11 from the openings of the holes formed in the mask plate. The solder paste is attached to the printed wiring board in a state where the position of the land 10 on which the solder paste is printed and the position of the through hole 2 match. The BGA package is mounted with the position of the through hole 2 and the position of each solder bump formed on the BGA package 6 aligned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile phone, a video camera, etc., which are rapidly becoming higher in performance, higher in function and smaller in size, from the semiconductor packaging industry which requires high density and small size. The present invention relates to a structure capable of meeting a wide range of needs such as a high density, light, thin, short, and small area mounting technology and an area mounting apparatus in accordance with the mobile electronic device industry and the demands of the electronic devices, and a mounting method using the structure.

[0002]

2. Description of the Related Art Reflow mounting, which is a type of conventional area mounting method, will be described with reference to FIG. As shown in FIG. 6A, a BGA package 106 (Ball Grid), which is a kind of semiconductor package, is provided on the printed circuit board 101.
The land 102 corresponding to the solder bump 105 of the array is formed. For area mounting in which the solder bumps 105 of the BGA package 106 and the lands 102 on the printed circuit board 101 are solder-bonded, first, a screen printing method is used above the lands 102.
The solder paste 103 is printed from the opening of the mask.

At this time, the printing amount of the solder paste 103 is the opening shape of the mask, the mask thickness, and the solder paste 10.
Although the squeegee speed for printing No. 3 is managed, the amount of printed solder paste 103 cannot be stably and quantitatively maintained. Therefore, the solder paste 103
Since the printed state is due to the occurrence rate of defective solder joints in the next step, after the solder paste 103 is printed, the printed state of the solder paste 103 is visually inspected using an apparatus or the like. In the above visual inspection, when the BGA package 106 is mounted on the printed circuit board 101, the solder joint portion is hidden behind the BGA package 101.
This is because it becomes difficult to find a defective solder joint.

FIG. 7A is a first state diagram of a solder joint failure when the print amount of the solder paste 103 varies. The shape in which the solder paste 103 is printed on the land 102 is not sufficient in the height direction, and since the printing amount of the solder paste 103 is insufficient, solder joint becomes insufficient and conduction failure occurs. This is because the size of the land 102 on the printed circuit board 101 is made small and the opening size of the mask is made small at the same time, so that the printed shape becomes a conical shape and the printing area on the land 102 is the same as that of a good product. Is insufficient, the conduction between the solder bump 105 and the land 102 becomes poor.

The above-mentioned conduction failure is difficult to detect because it occurs only in a part of the lands 102 in the printing state of all the lands 102. Furthermore, when some external shock is applied to the printed circuit board 101 in a state where the solder joint is insufficient, the solder joint portion is broken to cause a secondary conduction defect.

FIG. 7B is a second state diagram of the solder joint failure when the printing amount of the solder paste 103 varies. Since a large amount of the solder paste 103 is printed on the area of the land 102, the solder paste 103 is in a state of protruding from the land 102, and a short circuit occurs between the adjacent lands 102, resulting in poor conduction. In mass production work, this is due to the phenomenon of wear at the contact portion due to repeated work of the mask and squeegee, which is used as a factor that the printed amount of the solder paste 103 becomes unstable. Therefore, the mask opening shape and the squeegee shape are deformed, and the printing pressure is changed, so that the printing amount of the solder paste 103 becomes unstable.

Further, as a factor that the printed amount of the solder paste 103 becomes unstable, when the printing process of the solder paste 103 is repeatedly performed, the solder paste 10 is applied to the mask opening.
This is because 3 adheres and remains, and eventually adheres. Therefore, the adhesion between the mask opening and the land is impaired, and the printed amount of the solder paste 103 is not stable. The above factors are
This occurs as the solder paste 103 is printed on the fine land 102. Therefore, for printing the solder paste 103 on the fine land 102, it is necessary to control the squeegee speed and ensure the detachability of the solder paste 103 from the mask opening.

FIG. 7C is a third state diagram of the solder joint failure when the printing amount of the solder paste 103 varies. When the pitch of the joining terminals of the BGA package 106 is made finer than the conventional 0.8 mm to 0.5 mm, 0.3 mm, and further finer, in order to secure the printing amount of the solder paste 103, the solder particles are similarly formed. It cannot be traced without changing to a smaller diameter. This is to ensure that the solder paste 103 can be removed from the fine mask openings and stably print the amount of the solder paste 103.

The dropout property of the solder paste 103 is set so that the solder particles are aligned at least 5 particles with respect to the area of the mask opening. When the solder particle size is reduced, the packing density of the solder particles increases and the surface area of the total particles increases, so that the amount of flux per particle decreases. Therefore, the oxidation of the solder particles and the flux becomes faster than before.

When solder bonding is performed in a state where the oxidized solder particles and the solder particles to be oxidized are mixed, the melting temperature of each solder particle varies, and the solder particles that cannot form the fillet are generated. It is generated as a solder ball 108. This non-stick solder ball 108
Occurs around the land 102 of the printed circuit board 101, causing a short circuit between the adjacent lands 102, resulting in poor conduction.

As shown in FIG. 6B, the BGA package 1
The solder bumps 105 are formed on the terminals 104 arranged in a grid array shape of No. 06. The solder bumps 105 and the lands 102 of the printed circuit board 101 on which the solder paste 103 is printed are placed while aligning them. The relationship between the diameter of the terminal 104 of the BGA package and the diameter of the land 102 of the printed circuit board 101 is 1: 1.
It is usual to correspond in.

FIG. 8A shows the first solder joint failure due to variations in mounting of the solder bump 105 and the land 102.
FIG. This shows a case where the solder bump 105, which is the terminal 104 of the BGA package, is displaced from the predetermined land 102 when the BGA package 106 is mounted, and the solder bump 105 is mounted. At this time, solder bump 1
Due to the positional deviation between 05 and the land 102, a short circuit occurs between the adjacent lands 102, resulting in poor conduction.

FIG. 8B shows the second solder joint failure due to variations in mounting of the solder bump 105 and the land 102.
FIG. This is because when the amount of the solder paste 103 on the land 102 is large, the solder paste 103 applied by the impact force when the BGA package 106 is mounted.
Are scattered to generate solder balls 108. Due to this cause, short-circuiting occurs between the adjacent lands 102, resulting in poor conduction.

Next, as shown in FIG. 6 (c), the solder bumps 105 and the lands 102 of the printed circuit board 101 are in contact with each other and flowed to the reflow device. In the reflow apparatus, the solder bump 105 and the solder paste 103 on the land 102 are melted and soldered.
In a normal reflow solder bonding method, first, the reflow device is heated to a constant temperature. Further, the printed circuit board 101 and the BGA package 10 are preheated.
The surface temperature of 6 is made uniform. When the heating time of the preheat is performed more than necessary, the solder balls 108 as shown in FIG. 8B are generated. Also, when the preheat temperature is rapidly increased, the solder ball 1
A mounting defect such as 08 occurs.

After that, the solder is melted by heating it up to the solder melting temperature. At that time, in a state where the solder bump 105 and the solder paste 103 are melted, the surface tension of the solder itself generates a self-alignment effect, and the solder can be bonded to a predetermined land 102. The surface temperature of the BGA package 106 and the temperature of the solder bump 105 are B
Since a temperature difference occurs depending on the size of the GA package 106, when mounting different sizes of the BGA package 106 in a mixed mounting manner, the solder bonding conditions should be such that sufficient solder bondability is obtained within the heat resistant temperature range of each BGA package 106. Must be set. Further, in recent years, lead-free solder has been adopted, and in the solder composition, a single metal occupies 90% of the component, and the solder fluidity is inferior to the conventional Sn-Pb solder, and the self-alignment effect is descend. Furthermore, since the lead-less solder has a joining condition in a high temperature range where the conventional soldering temperature cannot perform the fusion joining, the BGA package 1
The heat resistance of the terminal of No. 06 and other electronic parts becomes a problem. Therefore, it is necessary to secure the solder bondability within the range of the melting temperature of the leadless solder and the heat resistant temperature of the component.

Next, as shown in FIG. 6D, a resin material called an underfill material 107 is poured into the gap between the BGA package 106 and the printed circuit board 101. By applying the above-mentioned underfill material 107, the purpose is to alleviate stress and protect the solder joint portion from causing defects when external stress or the like is applied to the solder joint portion. After that, the poured underfill material 107 is
A thermosetting resin is generally used, and the resin is cured by treating it under heating conditions suitable for the thermosetting.

The BGA package 106 in the future is in the direction of increasing the number of pins of input / output terminals to meet the required specifications with a small area and finer pitch of terminals corresponding thereto. In response to the above request of the BGA package 106, a reflow device dedicated to area mounting becomes necessary.

[0018]

The area mounting by the conventional BGA package has the following problems. (1) Variations in the printing accuracy of the solder paste affect the solder bondability, resulting in mounting failure. (2) When the solder paste printing process is mass-produced, the solder paste adheres to the mask opening, so that the adhesion between the land and the mask opening is impaired. (3) By reducing the size of the solder particles, the speed of oxidation increases. Solder balls are generated under the influence of this oxidation. (4) It is necessary to secure solder bondability within a limited temperature range by adopting leadless solder.

Therefore, the present invention aims at the following. (1) To secure solder bondability of high-density area mounting corresponding to multiple pins of BGA package. (2) The solder bondability is ensured without affecting the printing accuracy of the solder paste. (3) Solder bondability is ensured in a process in which oxidation of solder particles is less likely to occur. (4) By sealing the solder joint portion, solder defects due to external stress or the like are alleviated and protected.

[0020]

In order to solve the above problems, as a first structure of the structure of the present invention, a through hole having a base material and holes penetrating the base material arranged in a grit array shape. The spacer is configured to have.

As a second structure of the structure of the present invention, the through-hole of the structure of the first structure is a ball grid array (hereinafter referred to as B
(GA package) is arranged in a grid array shape corresponding to the arrangement of the solder bumps.

As a third structure of the structure of the present invention, the through hole of the structure of the first (b) structure changes the aperture ratio of the hole in accordance with the spherical diameter of the solder bump of the BGA package. It was configured. As a fourth structure of the structure of the present invention, a metal is applied to at least a part of the inner hole portion of the through hole of the structure having the above structure. As a fifth structure of the structure of the present invention, a metal is applied in a thin film shape to the inner ring portion of the through hole of the structure having the above structure.

As a sixth structure of the structure of the present invention, at least a part of a metal is applied to the hole inner ring portion of the through hole of the structure of the above structure, and a solder flux is applied on the metal. It has a structure. As a seventh structure of the structure of the present invention, a metal is applied in a thin film shape to the inner ring portion of the through hole of the structure having the structure,
Further, a solder flux is applied on the metal. As an eighth structure of the structure of the present invention, the metal of the structure having the structure is melted below the heat resistant temperature of the BGA package. As a ninth structure of the structure of the present invention, the metal of the structure of the structure is
It was constructed using a metal organic compound. As a tenth structure of the structure of the present invention, the base material of the structure having the above structure forms an alignment mark having directional meaning.

According to the present invention, as the first step of the mounting method using the structure having the above-mentioned structure, at least the solder bumps of the BGA package and the lands wired on the printed circuit board are solder-bonded to each other. Then, a step of implementing a means for printing the solder paste by using the screen printing method was adopted.

According to the present invention, as the second step of the mounting method using the structure having the above-mentioned structure, the through hole formed in the spacer and the land wired on the printed circuit board are further aligned from the first step. This is a step of performing a means for bonding while performing. As a third step of a mounting method using the structure having the above-described structure, the present invention further implements a means for bonding the solder bumps of the BGA package to the positions of the through holes formed in the spacer, from the second step. It was a process to do.

According to the present invention, as the fourth step of the mounting method using the structure having the above-mentioned structure, a step of inserting the solder bump portion into the inner ring of the through hole is further carried out from the third step. The present invention further comprises, from the fourth step, a fifth step of the mounting method using the structure having the above-described structure.
This is a step of implementing a means for supplying a heat source that melts the solder bumps. The present invention further comprises, from the fifth step, a sixth step of the mounting method using the structure having the above-mentioned structure.
This is a step of implementing a means for melting and integrating the solder bumps and the solder paste and performing solder joining. According to the present invention, as the seventh step of the mounting method using the structure having the above-described structure, a step of further supplying a heat source for melting the spacer from the sixth step is adopted.

According to the present invention, as an eighth step of the mounting method using the structure having the above-mentioned structure, a step of further thermally hardening the spacer after the melting is carried out from the seventh step.

According to the present invention, as a ninth step of the mounting method using the structure having the above structure, the BG is further added from the sixth step.
This is a step of performing a means for applying an underfill material in the gap between the A package and the printed circuit board. According to the present invention, as a tenth step of the mounting method using the structure having the above-described structure, a step of thermally curing the underfill material is further carried out from the ninth step.

According to the present invention, as the first step of the mounting method using the structure having the above structure, at least the solder bumps of the BGA package and the lands wired on the printed circuit board are solder-bonded to each other. Then, a step of implementing a means for printing the solder paste by using the screen printing method was adopted. The present invention further comprises, from the first step, a second step of a mounting method using the structure having the above-mentioned structure,
The step is to carry out a means for bonding the metal formed on the inner ring of the through hole formed in the spacer and the land wired on the printed circuit board while aligning them. As a third step of the mounting method using the structure having the above structure, the present invention further aligns the metal parts formed in the inner ring of the through holes of the spacer with the solder bumps of the BGA package as the second step. The step of carrying out the means for contacting is made. The present invention further comprises, as a fourth step of a mounting method using the structure having the above-mentioned structure, from the third step,
This is a step of implementing a means for supplying a heat source that melts the solder bumps.

According to the present invention, as a fifth step of the mounting method using the structure having the above-mentioned structure, a step of carrying out a means for melting and integrating the solder bump and the metal and solder-joining is further implemented from the fourth step. .

According to the present invention, as the sixth step of the mounting method using the structure having the above-mentioned constitutions 4 to 7, the metal melt-integrated with the solder bump and the solder paste on the land are soldered from the fifth step. This is a step of implementing the means to be joined. According to the present invention, as the seventh step of the mounting method using the structure having the above-described structure, a step of further supplying a heat source for melting the spacer from the sixth step is adopted.
The present invention provides an eighth mounting method using the structure having the above structure.
As a step, the step of performing heat curing after the spacer is melted is further performed from the seventh step. According to the present invention, as a ninth step of the mounting method using the structure having the above-described structure, a step of applying an underfill material to a gap between the BGA package and the printed circuit board is further carried out from the sixth step. . According to the present invention, as a tenth step of the mounting method using the structure having the above-described structure, a step of thermally curing the underfill material is further carried out from the ninth step.

Further, the structure of the present invention has a through hole, and at least one of the surfaces having the opening of the through hole is brought into contact with an electronic component. The electronic component can be stably fixed by bringing the surface of the opening of the through hole into contact with the electronic component. Also, it is possible to facilitate the soldering of the electronic device through the through hole.

[0033]

In the structure having the first structure as described above, the spacer is composed of the base material and the through holes arranged in the grit array shape in the holes penetrating the base material. As a mounting process for solder-bonding the solder bumps formed on the BGA package to the lands wired on the printed circuit board using the spacer, a mask is mounted on the printed circuit board, and the mask is mounted on the mask. By applying the solder paste, the solder paste is printed on the lands wired on the printed circuit board through the openings of the holes formed in the mask plate.

Next, the spacer of the present invention is attached to the printed wiring board in a state where the position of the land printed with the solder paste and the position of the through hole provided in the spacer of the present invention are aligned. . Further, the BGA package is mounted on the spacer in a state where the positions of the through holes and the positions of the solder bumps formed on the BGA package are aligned. By applying pressure from above the BGA package, the solder bumps are inserted into the through-hole inner ring of the spacer, as shown in FIG. 2B.

The spacer of the present invention serves as a framework for dividing the fine-shaped through hole into individual lands. In short, the solder paste on the lands is individually isolated and the solder bumps of the BGA package terminals are present on the spacers, so that a closed space for solder bonding can be established.

Next, the BGA package and the printed circuit board are heated by preheating by flowing in the reflow apparatus in the above-mentioned bonded state. At this time, BGA
The solder bumps are also heated via the terminals formed on the package, and the solder paste is also heated via the lands of the printed circuit board. Raise the temperature setting of the reflow equipment to the temperature at which the solder bumps melt. The solder bumps heated at the melting temperature are melted and contact with the solder paste on the lands inside the through holes of the spacers to be melted and integrated. Since soldering is performed within the range of the through holes of the spacer of the present invention, it is possible to separate from the adjacent land, and reliable soldering can be performed.

Next, the reflow device is heated to a temperature at which the spacer melts. The spacer heated at the melting temperature is melted and then thermoset. The spacer of the present invention is intended for stress relaxation and protection so as not to cause a defect in the solder joint when external stress or the like is applied to the solder joint. This is because when a product equipped with a printed circuit board receives impact stress due to falling,
This stress is concentrated on the BGA package and the solder joint. The solder joint part of the BGA package is QF
Since it does not have a lead frame like the P package,
The stress concentrates on the weakest point and fracture occurs around the joint.

In short, the strength can be increased by fixing and protecting the periphery of the solder joint with the spacer of the present invention. Furthermore, since the spacer itself of the present invention also serves as an underfill material, the burden on the manufacturing process can be reduced.

In the structure of the second structure as described above, the through holes in the spacer are arranged in a grid array shape corresponding to the arrangement of the solder bumps formed in the BGA package.

The quantity of the solder bumps of the BGA package varies depending on the required specifications. Further, the surface area of the BGA package is shortened, and many terminals are arranged within the limited surface area. Therefore, by arranging the through holes of the spacer of the present invention in accordance with the specifications of the BGA package, the spacer can be used in a wide variety of BGA packages.

In the structure having the third structure as described above, the aperture ratio of the through hole in the spacer is changed according to the spherical diameter of the solder bump formed in the BGA package. In the solder joining process using the spacer of the present invention, the relationship between the aperture ratio of the through hole and the solder bump is very important. In short, it is a mounting process of solder-bonding the solder bumps within the range framed by the aperture ratio of the through holes.

In the structure of the fourth structure as described above, the base material and the holes penetrating the base material are provided in the through holes arranged in the grit array shape and at least a part of the inner ring portion of the through holes. It is a spacer having a structure coated with metal. As a mounting process for solder-bonding the solder bumps formed on the BGA package to the lands wired on the printed circuit board using the spacer, a mask is mounted on the printed circuit board, and the mask is mounted on the mask. By applying the solder paste, the solder paste is printed on the lands wired on the printed circuit board through the openings of the holes formed in the mask plate.

Next, in a state where the position of the land printed with the solder paste and the position of the metal formed on the inner ring of the through hole provided in the spacer of the present invention are combined, Attach the spacer to the printed wiring board. Further, the BGA package is mounted on the spacer in a state where the position of the metal in the through hole and the position of the solder bump formed on the BGA package are matched.

The spacer of the present invention functions as a framework for dividing the fine through holes into individual lands. In short, the solder paste on the lands is individually isolated and the solder bumps of the BGA package terminals are present on the spacers, so that a closed space for solder bonding can be established.

Further, by applying pressure from above the BGA package, the solder bumps are brought into contact with the metal portion formed on the inner ring of the through hole of the spacer. By bringing the metal in the spacer of the present invention into contact with the solder bump, the oxide film formed on each surface is destroyed. Therefore, the contact portion between the metal and the solder bump has good conductivity and thermal conductivity, and reliable solder bonding can be performed.

Next, the BGA package and the printed circuit board are heated by preheating by flowing in the reflow apparatus in the above-mentioned bonded state. At this time, BGA
The solder bumps are also heated via the terminals formed on the package, and the solder paste is also heated via the lands of the printed circuit board. Raise the temperature setting of the reflow equipment to the temperature at which the solder bumps melt. The solder bump heated at the melting temperature is melted and causes an alloying reaction with the metal in the inner ring of the through hole of the spacer, whereby the solder bump and the metal are melt-bonded to each other.

Further, the solder bump and the metal, which are fusion-bonded to the metal, come into contact with the solder paste on the land inside the through hole of the spacer and are fused and integrated. Since soldering is performed within the range of the through holes of the spacer of the present invention, it is possible to separate from the adjacent land, and reliable soldering can be performed. This performs the solder joint in the limited range of the through hole, and thus serves to contain the ambient temperature.

The effect of confining the ambient temperature is to raise the ambient temperature between the printed circuit board and the BGA package. When the environmental temperature rises, heat is transferred to the lands on the printed circuit board, the activation of the solder paste is improved, and reliable solder joining can be performed.
As a means for raising the environmental temperature, there is a method of heating from the printed circuit board side, but the same effect can be obtained by using the spacer of the present invention.

Next, the reflow device is heated to a temperature at which the spacer melts. The spacer heated at the melting temperature is melted and then thermoset.

The spacer of the present invention is intended for stress relaxation and protection so as not to cause defects in the solder joint when external stress or the like is applied to the solder joint. Furthermore, since the spacer itself of the present invention also serves as an underfill material, the burden on the manufacturing process can be reduced.

In the structure of the fifth structure as described above, the base material and the holes penetrating the base material are formed into the through holes arranged in the grit array shape and the inner ring of the through holes is formed into a thin film shape. It is a spacer having a structure coated with metal. By forming the metal forming the spacer of the present invention into a thin film,
The contact area between the solder bump and the metal portion is stabilized. As a result, the electrical conductivity and thermal conductivity of the contact portion are stably improved, and reliable solder bonding can be performed.

Further, in order to improve the variation in the printing amount of the solder paste, which was the cause of the solder joint failure in the prior art, the thickness of the metal to be melted is used as a substitute for the amount of the solder with respect to the land area. By controlling the solder paste side to the extent of preliminary soldering, reliable soldering can be performed.

The structure having the sixth and seventh structures as shown in FIG. 4 is a spacer having a structure in which a metal is applied to the inner ring of the through hole and a solder flux is applied to the metal. By applying the flux to the inner ring of the metal formed on the spacer of the present invention, it plays a role of preventing oxidation of the metal and maintaining solder wettability. By applying pre-flux to the land surface of the printed circuit board, it plays a role of preventing oxidation of the land and maintaining solder wettability. In the mounting process of the present invention, the variation of the surface condition on the land is very important, and applying the pre-flux serves as an auxiliary means for preventing the solder ball and ensuring the solder bondability on the land.

In the structure having the eighth structure as described above, the metal is a spacer having a structure in which the metal melts at a temperature lower than the heat resistant temperature of the BGA package. In the mounting process of the present invention, an environment occurs in which the resin of the BGA package is heated in the reflow device. Therefore, it is necessary to set the temperature at which the metal portion is melted to be lower than the heat resistant temperature of the BGA package. Therefore, the maximum heating temperature of the mounting process of the present invention is set to be equal to or lower than the heat resistant temperature of the BGA package.

The structure having the ninth structure as described above is a spacer having a structure in which a metal compound formed by firing a metal organic compound and a simple metal are used as the metal. A feature of the metal required in the mounting process of the present invention is that it has good meltability with the solder paste and the solder bump and contains the same component as the solder. The metal of the present invention is a metal compound containing tin, silver, zinc, copper, bismuth or the like as a main component, or a simple metal.

In the structure of the tenth structure as described above, the base material is a spacer having a structure for forming an alignment mark having a directional meaning. In the mounting process of the present invention, the orientation of the BGA package, the spacer, and the printed circuit board must be taken into consideration. Therefore, it is possible to prevent misalignment or the like by attaching the alignment mark having the directionality of the spacer to the base material.

[0057]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a plan view of the spacer 5 of the first structure according to the present invention. 1 (b) and 1 (d) are partially enlarged views of FIG. 1 (a), and FIG. 1 (c) and FIG.
(E) is sectional drawing of FIG.1 (b) and FIG.1 (d).
1 (b) and 1 (c), the spacer 5 is
It is composed of a base material 1 and through holes 2 arranged on the base material 1 in a grid array shape. The base material 1 is a thermosetting resin, and has a property that it has little expandability and shrinkage due to heat and humidity and has low hygroscopicity. Further, the base material 1 has a feature that its adhesive strength is increased by being heated.

FIGS. 1D and 1E are views showing the second structure of the base material 1. The base material 1 has a structure in which the thermosetting resin having the above-mentioned characteristics is back-treated on the basis of polyimide or the like. The through hole 2 is formed by forming a conical hole in the base material 1. The array of the through holes 2 is configured in a grit array shape. As a processing means for the through-hole 2, there are a means for mechanically penetrating, a means for melting with a solvent, and a laser processing means.

As the spacer 5 of the second structure of the present invention,
The through holes 2 have a grit array shape corresponding to the arrangement of the solder bumps 8 formed on the BGA package 6 of the semiconductor chip. The solder bumps 8 formed on the BGA package 6 have different arrangements and quantities depending on the required specifications. By providing the through holes 2 in the base material 1 based on the coordinates of the solder bump 8 array, the spacers 5 can be utilized in a wide variety of BGA packages 6.

As the spacer 5 of the third structure of the present invention,
The through hole 2 has a structure in which the aperture ratio of the hole is changed according to the spherical diameter of the solder bump 8 formed on the BGA package 6. The solder bumps 8 formed on the BGA package 6 have multi-pin input / output signals wired in a limited package area. Therefore, the ball diameter of the solder bump 8 also differs depending on the required specifications. By determining the aperture ratio of the through hole 2 based on the spherical diameter of the solder bump 8, the spacer 5 can be used for the BGA packages 6 of various types.

As the spacer 5 of the fourth structure of the present invention,
The base material 1 and the holes penetrating the base material 1 are configured such that the metal 4 is applied to at least a part of the through hole 2 arranged in a grit array shape and the inner ring portion of the through hole 2. As a means for applying the metal 4 to the through holes 2, the metal 4 is applied to each through hole 2 by a dispenser. After that, the entire spacer 5 is baked to apply the metal 4 to at least a part of the through hole 2.

As the spacer 5 of the fifth constitution of the present invention,
The base material 1 and the holes penetrating the base material 1 are arranged in a grit array shape, and the inner ring of the through hole 2 is coated with metal 4 in a thin film shape. As a means for applying the metal 4 to the through holes 2, the metal 4 is applied to each through hole 2 by a dispenser. After that, the entire spacer 5 is baked, so that the metal 4 is applied to the inner ring of the through hole 2 by forming a thin film.

As the spacer 5 of the sixth and seventh structures of the present invention, the metal 4 is applied to the inner ring of the through hole 2, and the flux material 14 is applied on the metal 4. Figure 4 (a)
As described above, by applying the flux 14 to the inner ring of the metal 4 formed on the spacer 5, the metal 4 serves to prevent oxidation of the metal 4 and maintain solder wettability. As shown in FIG. 4B, by applying the pre-flux 15 to the surface of the land 10 of the printed circuit board 11, it plays a role of preventing oxidation of the land 10 and maintaining solder wettability. The variation of the surface condition on the land 10 is very important,
Applying the pre-flux 15 serves as an auxiliary means for preventing solder balls and ensuring solder bondability on the lands 10.

As the spacer 5 of the eighth structure of the present invention,
The metal 4 is melted below the heat resistant temperature of the BGA package 6. By selecting the metal 4 that melts at a melting temperature lower than the heat resistant temperature at which the surface of the BGA package 6 is heated and the shape change of the surface resin occurs, the spacer 5 can be used for various types of BGA packages 6.

As the spacer 5 of the ninth structure of the present invention,
As the metal 4, a metal compound formed by firing a metal organic compound and a simple metal are used. The metal 4 is a metal compound containing tin, silver, zinc, copper, bismuth or the like as a main component, or a simple metal. It is preferable that the main component of the metal 4 has a melting temperature characteristic equivalent to that of the solder paste material 9.

As the spacer 5 of the tenth constitution of the present invention, the substrate 1 forms the alignment mark 3 having the meaning of directionality. As shown in FIG. 1, by providing a notch at one corner of the spacer 5, it becomes possible to match the mounting directions of the BGA package 6 and the printed circuit board 11.

A first example of the mounting process using the spacer 5 of the first to third configurations of the present invention will be described below.

As shown in FIG. 5A, the printed circuit board 1
1 and the mask 16 are bonded to each other, and the solder paste 9 on the mask 16 is moved in the direction of the arrow 18 by the squeegee 17, so that the solder paste 9 is extruded from the opening of the mask 16 and wired to the printed circuit board 11. Printed on 10. Next, as shown in FIG. 5B, the alignment mark 3 provided on the spacer 5 is read by the alignment mark recognition means 19 to bond the spacer 5 and the printed circuit board 11 together.

At this time, the lands 10 on which the solder paste 9 is printed and the positions of the through holes 2 provided in the spacer 5 are bonded together. Furthermore, the alignment mark 3 provided on the spacer 5 is read by the alignment mark recognition means 19 and the spacer 5 and the BGA package 6 are bonded together.

FIG. 2A is a state diagram of the spacer 5 of the first to third configurations of the present invention. In the above process, the BGA package 6, the spacer 5 and the printed circuit board 11 are bonded together. The spacer 5 at this time is
The fine-shaped through hole 2 serves as a framework for dividing the land 10 into individual lands.

Next, as shown in FIG. 5C, the pressure is applied in the direction of the arrow 21 by the pressure applying means 20 so that the solder bumps 8 are inserted into the inner holes of the through holes 2 of the spacer 5.

FIG. 2B is a state diagram of the spacer 5 of the first to third configurations of the present invention. In the above process, land 1
0 solder paste 9 is individually isolated, spacer 5
By forming the solder bumps 8 of the BGA package terminal 7 on the above, the form of the closed space for soldering can be established.

Next, as shown in FIG. 5D, with the BGA package 6, the spacer 5 and the printed circuit board 11 bonded together, the carrier means 25 causes them to flow to the heating means 22. Further, the heating temperature control means 23 raises the temperature to preheat to heat the BGA package 6 and the printed circuit board 11.

As the heating means 22, there are a method of flowing in a reflow furnace to raise the environmental temperature, an air reflow method of flowing in the reflow furnace and blowing air spotwise, and a hot air supply method of directly blowing hot air.

FIG. 2C is a state diagram of the spacer 5 of the first to third configurations of the present invention. In the above process, the solder bumps 8 are also heated via the BGA package terminals 7,
Furthermore, the solder paste 9 is also heated via the land 10 of the printed circuit board 11. Next, the heating temperature control means 23
Is raised to a temperature at which the solder bumps 8 melt.

FIG. 2D is a state diagram of the spacer 5 of the first to third configurations of the present invention. In the above steps, the solder bumps 8 heated at the melting temperature are melted and come into contact with the solder paste 9 on the lands 10 inside the through holes 2 of the spacer 5 to be melted and integrated. Since the solder bonding is performed within the range of the through hole 2 of the spacer 5, the adjacent land 10 can be isolated and reliable solder bonding can be performed. Next, as shown in FIG. 5E, the heating temperature control means 23 raises the temperature to a temperature at which the spacer 5 melts.

FIG. 2 (e) is a state diagram of the spacer 5 of the first to third configurations of the present invention. In the above process, the spacer 5 heated to the melting temperature flows into the space between the BGA package 6 and the printed circuit board 11 while destroying the mask shape in response to the heat capacity, and then thermoset. The spacer 5 is for the purpose of stress relaxation and protection so as not to cause defects in the solder joint portion when external stress or the like is applied to the solder joint portion.

Furthermore, since the spacer 5 itself also serves as an underfill material, the load on the manufacturing process can be reduced. In addition, a method of applying an underfill material around the BGA package 6 from the state of FIG. 2D and performing heat treatment again to cure the underfill material is also preferable.

A second embodiment of the mounting process using the spacers 5 of the fourth to seventh structures of the present invention will be described below.
As shown in FIG. 5A, the printed circuit board 11 and the mask 1
6 are pasted together and the solder paste 9 on the mask 16 is moved in the direction of the arrow 18 by the squeegee 17,
The solder paste 9 is extruded from the opening of the mask 16,
It is printed on the land 10 wired on the printed circuit board 11.

Next, as shown in FIG. 5B, the alignment mark 3 provided on the spacer 5 is read by the alignment mark recognition means 19 and the spacer 5 and the printed circuit board 11 are bonded together. At this time, the bonding is performed in a state where the position of the land 10 on which the solder paste 9 is printed and the position of the metal 4 formed on the inner ring of the through hole 2 provided in the spacer 5 are combined. At this time, the position of the land 10 on which the solder paste 9 is printed and the spacer 5
The bonding is performed in a state where the positions of the through holes 2 provided in the above are matched. Furthermore, the alignment mark 3 provided on the spacer 5 is read by the alignment mark recognition means 19 and the spacer 5 and the BGA package 6 are bonded together.

FIG. 3A is a state diagram of the spacer 5 having the fourth to seventh structures of the present invention. In the above process, the BGA package 6, the spacer 5 and the printed circuit board 11 are bonded together. The spacer 5 at this time is
The fine-shaped through hole 2 serves as a framework for dividing the land 10 into individual lands. Next, as shown in FIG. 5 (c), the solder bump 8 is inserted into the through hole 2 inner ring of the spacer 5 by applying pressure in the direction of the arrow 21 by the pressing means 20.

FIG. 3B is a state diagram of the spacer 5 having the fourth to seventh structures of the present invention. In the above process, land 1
0 solder paste 9 is individually isolated, spacer 5
By forming the solder bumps 8 of the BGA package terminal 7 on the above, the form of the closed space for soldering can be established. Further, by applying pressure from the upper portion of the BGA package 6, the solder bump 8 is brought into contact with the metal 4 portion formed on the inner ring of the through hole 2 of the spacer 5. Metal 4 and solder bump 8 in spacer 5
By contacting with, the oxide film formed on each surface is destroyed. Therefore, the contact portion between the metal 4 and the solder bump 8 has good conductivity and thermal conductivity, and reliable solder bonding can be performed.

Next, as shown in FIG. 5D, with the BGA package 6, the spacer 5 and the printed circuit board 11 bonded together, the carrier means 25 causes them to flow to the heating means 22. Further, the heating temperature control means 23 raises the temperature to preheat to heat the BGA package 6 and the printed circuit board 11.

FIG. 3C is a state diagram of the spacer 5 having the fourth to seventh structures of the present invention. In the above process, the solder bumps 8 are also heated via the BGA package terminals 7,
Furthermore, the solder paste 9 is also heated via the land 10 of the printed circuit board 11. Next, the heating temperature control means 23
Is raised to a temperature at which the solder bumps 8 melt. The solder bumps 8 heated at the melting temperature are melted and cause an alloying reaction with the metal 4 in the inner ring of the through hole 2 of the spacer 5, and the solder bumps 8 and the metal 4 are metal-melt bonded.

Further, the metal-melt-bonded solder bumps 8 and the metal 4 come into contact with the solder paste 9 on the lands 10 inside the through holes 2 of the spacer 5 and are fused and integrated.

Since solder bonding is performed within the range of the through hole 2 of the spacer 5, it is possible to separate from the adjacent land 10, and reliable solder bonding can be performed. this is,
In order to carry out solder joining in the limited range of the through hole 2,
It plays a role of confining the environmental temperature, heat is transferred to the land 10 on the printed circuit board 11, the activation of the solder paste 9 is improved, and reliable solder bonding can be performed. Next, as shown in FIG. 5E, the heating temperature control means 23 raises the temperature to a temperature at which the spacer 5 melts.

FIG. 3D is a state diagram of the spacer 5 of the fourth to seventh structures of the present invention. In the above process, the spacer 5 heated to the melting temperature flows into the space between the BGA package 6 and the printed circuit board 11 while destroying the mask shape in response to the heat capacity, and then thermoset. The spacer 5 is for the purpose of stress relaxation and protection so as not to cause defects in the solder joint portion when external stress or the like is applied to the solder joint portion. Further, since the spacer 5 itself also serves as an underfill material, the load on the manufacturing process can be reduced. It is also preferable to apply an underfill material around the BGA package 6 from the state of FIG. 3C and perform heat treatment again to cure the underfill material.

[0089]

As described above, according to the present invention, the first structure of the spacer is composed of the base material and the through holes formed in the base material and the holes penetrating the base material.

As the second structure of the spacer, the through holes of the structure of the first structure are arranged in a BGA package grid array shape. As a third structure of the spacer, the through holes of the structures shown in FIGS. 1D and 1E have a structure in which the aperture ratio of the holes is changed in accordance with the spherical diameter of the solder bump of the BGA package. . As a fourth structure of the spacer, the first to
At least a part of the inner ring portion of the through hole of the structure having the structure 3 is coated with metal. As a fifth structure of the spacer, a metal is applied in a thin film shape to the inner ring portion of the through hole of the structure having the first to third structures. Further, as a sixth structure of the spacer, at least a part of metal is applied to the inner ring portion of the through hole of the structure of the first to third structures, and solder flux is further applied onto the metal.

As a seventh structure of the spacer, in the inner ring portion of the through hole of the structure having the first to third structures,
The metal is applied in the form of a thin film, and the solder flux is applied on the metal. Further, as an eighth structure of the spacer, the metal of the structure having the fourth to seventh structures is melted at a temperature lower than the heat resistant temperature of the BGA package. Also, as the ninth configuration of the spacer,
The metal of the structure having the fourth to seventh structures is formed by using a metal organic compound. As the tenth structure of the spacer, the base material of the structure having the first to ninth structures forms an alignment mark having a meaning of directionality. As a result, the following effects are obtained.

By adjusting the arrangement of the through holes to the specifications of the BGA package, the spacer of the present invention can be used in a wide variety of BGA packages. Further, the spacer of the present invention can be used for various kinds of BGA packages by determining the aperture ratio of the through hole according to the ball diameter of the solder bump. Furthermore, the solder paste on the land is individually isolated, and the solder bump of the BGA package terminal is present on the spacer of the present invention, so that a closed space for solder bonding can be established.

Further, by bringing the metal in the spacer of the present invention into contact with the solder bump, the oxide film formed on each surface is destroyed, and the contact portion has good conductivity and thermal conductivity. As a result, reliable soldering can be performed. Furthermore, in order to improve the variation in the printing amount of the solder paste, the thickness of the metal that melts the solder is used as a substitute for the amount of solder for the land area, and the solder paste side is suppressed to the extent of preliminary soldering to ensure reliable solder joining. Can be implemented.

Since the solder bonding is performed within the range of the through hole of the spacer of the present invention, it is possible to separate from the adjacent land, and it is possible to carry out the reliable solder bonding. Since the solder joint of the BGA package does not have a lead frame like the QFP package, stress concentrates at the weakest point and destruction occurs around the joint. Therefore, the solder joint is surrounded by the spacer of the present invention. The strength can be increased by fixing and protecting by fixing. Furthermore, since the spacer itself of the present invention also serves as an underfill material, the burden on the manufacturing process can be reduced.

[Brief description of drawings]

FIG. 1 is a view showing a spacer having first to tenth configurations of the present invention.

FIG. 2 is a state diagram showing a state of the spacer having the first to third configurations of the present invention.

FIG. 3 is a state diagram showing states of spacers having fourth to seventh configurations of the present invention.

FIG. 4 is a diagram showing a state where fluxes and the like of the spacers having fourth to seventh configurations of the present invention are applied.

FIG. 5 is a process chart showing a mounting process of the spacer having the first to tenth configurations of the present invention.

FIG. 6 is a process diagram of a conventional mounting process.

FIG. 7 is a state diagram showing a solder joint failure when a variation in the solder paste printing amount occurs in the conventional technique.

FIG. 8 is a state diagram of a solder joint failure due to variations in mounting of solder bumps and lands in the related art.

[Explanation of symbols]

1 base material 2 through holes 3 alignment marks 4 metal 5 spacers 6 BGA package 7 BGA package terminal 8 Solder bump 9 Solder paste 10 lands 11 printed circuit boards 12 Solder joint state 15 Preflux 16 masks 17 Squeegee 18, 21, 24 arrows 19 Alignment mark recognition means 20 Pressurizing means 22 Heating means 23 Heating temperature control means 25 transportation means 101 printed circuit board 102 lands 103 Solder paste 104 BGA package terminal 105 solder bump 106 BGA package 107 Underfill material 108 Solder Ball 113 Solder joint state 214 Flux material

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takahito Endo             1-8 Nakase, Nakase, Mihama-ku, Chiba City, Chiba Prefecture             Ico Instruments Co., Ltd. F term (reference) 5E319 AA03 AB05 AC11 BB04 BB05                       CD21 CD29                 5F044 LL13

Claims (31)

[Claims] 1. A structure comprising a base material and through-holes penetrating the base material, the through-holes arranged in a grit array shape. 2. The grit array-shaped array corresponding to the array of solder bumps of a ball grid array (hereinafter referred to as “BGA package”) which is a package of a semiconductor chip, wherein the through holes are arranged. Structure. 3. The structure according to claim 1, wherein the through hole changes the aperture ratio of the hole in accordance with the spherical diameter of the solder bump of the BGA package. 4. The structure according to claim 1, wherein a metal is applied to at least a part of an inner ring of the through hole. 5. The structure according to claim 1, wherein the inner ring of the through hole is coated with a metal in a thin film shape. 6. The structure according to claim 1, wherein a metal is applied to at least a part of an inner ring of the through hole, and a solder flux is applied to the metal. 7. The structure according to claim 1, wherein a metal is applied in a thin film shape to the inner ring of the through hole, and a solder flux is applied on the metal. 8. The structure according to claim 4, wherein the metal melts at a temperature lower than a heat resistant temperature of the BGA package. 9. The structure according to claim 4, wherein a metal organic compound is included as the metal. 10. The structure according to claim 1, wherein an alignment mark having a directional meaning is formed on the base material. 11. A screen on the pattern as a mounting method comprising the structure according to claim 1 and connecting a solder bump of a BGA package and a land wired on a printed circuit board. A mounting method comprising at least a step of printing a solder paste using a printing method. 12. The mounting method according to claim 11, wherein the mounting method further comprises positioning the through hole in the structure according to any one of claims 1 to 3 and a land wired on the printed circuit board. A mounting method comprising a step of adhering while performing the adhering. 13. The mounting method according to claim 12, further comprising a step of bonding a solder bump of a BGA package and the through hole together. 14. The mounting method according to claim 13, further comprising the step of inserting the solder bump inside the through hole. 15. The mounting method according to claim 14, further comprising a step of supplying a heat source to the solder bumps to melt the solder bumps. 16. The mounting method according to claim 15, wherein the mounting method further includes a step of melting and integrating the solder bump and the solder paste on the land to perform solder joining. Method. 17. The mounting method according to claim 16, wherein the mounting method further includes a step of supplying a heat source to the spacer to melt the spacer. 18. The mounting method according to claim 17, further comprising a step of thermally curing the spacer after the spacer is melted. 19. The mounting method according to claim 16, further comprising the step of applying an underfill material in a gap between the BGA package and the printed circuit board. . 20. The mounting method according to claim 19, further comprising the step of thermally curing the underfill material. 21. A screen having a structure according to any one of claims 4 to 7 as a mounting method for connecting a solder bump of a BGA package and a land wired on a printed circuit board as a mounting method. A mounting method comprising at least a step of printing a solder paste using a printing method. 22. The mounting method according to claim 21, wherein the mounting method further includes a metal formed on an inner ring of the through hole in the structure and a printed circuit board. A mounting method, which comprises a step of bonding the land wired to the land while aligning the land. 23. The mounting method according to claim 22, further comprising the step of bringing the solder bump of the BGA package into contact with a metal formed on the inner ring of the through hole. How to implement. 24. The mounting method according to claim 23, further comprising the step of supplying a heat source to the solder bumps to melt the solder bumps. 25. The mounting method according to claim 24, further comprising the step of melting and integrating the solder bumps and the metal and soldering them together. 26. The mounting method according to claim 25, further comprising a step of solder-bonding a metal melt-integrated with the solder bump and a solder paste on the land. How to implement. 27. The mounting method according to claim 26, further comprising the step of supplying a heat source to the spacer to melt the spacer. 28. The mounting method according to claim 27, further comprising a step of thermally curing the spacer after the spacer is melted. 29. The mounting method according to claim 26, further comprising the step of applying an underfill material in a gap between the BGA package and the printed circuit board. . 30. The mounting method according to claim 29, further comprising the step of thermally curing the underfill material. 31. A structure having a through hole, wherein at least one surface having an opening of the through hole is brought into contact with an electronic component.