JP2003152003A - Structure and method for mounting by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which supports a multi-pin of a BGA package and ensures soldering property in the area mounting with high density. SOLUTION: A structure 5 has a base material 1 and a through hole 2 in which holes penetrating into the base material 1 are arranged in a grid array. As a mounting process of soldering a solder bump 8 formed in a BGA package 6 to a land 10 wired in a printed circuit substrate 11, a mask is mounted on the printed circuit substrate 11, and a solder paste is coated from on the mask, whereby the solder paste is printed on the land wired on the printed circuit substrate 11 from an opening part of a hole opened in the mask plate. The structure is adhered to the printed wiring substrate in a state that a position of the land 10 that the solder paste is printed is aligned with a position of the through hole 2. The BGA package is loaded in a state that the position of the through hole 2 is aligned with a position of each solder bump formed on the BGA package 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor packaging, which is required to have a high density and a small size, a high performance and a high function, and a mobile phone, which is rapidly being miniaturized, and a video camera. More specifically, the present invention relates to a structure which can meet a wide range of needs such as a high density, light, thin, short, and small area mounting technology and an area mounting apparatus, and a mounting method using the structure, in response to demands from these.

[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, on the printed circuit board 101, a BGA package 106 (Ball.
The land 102 is formed so as to correspond to the solder bump 105 of the grid / array. In the area mounting in which the solder bumps 105 of the BGA package and the lands 102 on the printed circuit board are soldered, first, the solder paste 103 is printed on the lands 102 from the openings of the mask by screen printing using a mask. .

At this time, the printing amount of the solder paste 103 is the shape of the opening of the mask, the mask thickness, and the solder paste 1.
Although it is controlled by controlling the squeegee speed for printing No. 03, etc., it has not reached the point where the printing amount of the solder paste 103 is stably and quantitatively maintained. Since the occurrence of solder joint failure in the next step is caused by the printed state of the solder paste 103, it is necessary to visually inspect the printed state after printing the solder paste 103. For such a visual inspection, the BGA package 106 is mounted on the printed circuit board 101.
When mounted on, the solder joint part is BGA package 10
This is especially necessary in the case where it is hidden behind the back side of No. 1, that is, when it is difficult to visually detect a defective solder joint after mounting.

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 at the same time the opening size of the mask is made small, so that the printed shape becomes a conical shape.
Even if the printed area is similar to that of the non-defective product, the printed amount of the solder paste 103 becomes insufficient, resulting in poor conduction between the solder bump 105 and the land 102.

The above-mentioned conduction failure is difficult to detect because it occurs only in a certain part of the lands 102 in the printing state of all the lands 102.

Further, 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 failure.

FIG. 7 (b) is a state diagram showing a solder joint failure caused by a variation in the printing amount of the solder paste 103. Solder paste 103 with respect to the area of land 102
Since the solder paste 103 is printed in a large amount, the solder paste 103 protrudes from the land 102, and the adjacent land 10
Short-circuiting between the two causes 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, the reason why the printing amount of the solder paste 103 is not stable is that when the printing process of the solder paste 103 is repeatedly performed, the solder paste 103 adheres to and remains in the mask opening portion, and is eventually fixed. 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 occur as the solder paste 103 is printed on the fine lands 102. Therefore,
For printing the solder paste 103 on the fine land 102, the squeegee speed is controlled and the solder paste 1 from the mask opening is used.
It is necessary to secure the missing property of 03.

FIG. 7C is a state diagram showing a solder joint failure when the print 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, or smaller, in order to secure the printing amount of the solder paste 103, the solder particles also change to a small diameter. I have no choice. This secures the detachability of the solder paste 103 with respect to the fine mask opening, and enables stable solder paste 103.
This is because the quantity is printed.

The dropout property of the solder paste 103 is set so that at least 5 solder particles are aligned 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 soldering is performed in a state where the oxidized solder particles and the oxidizable solder particles are mixed, the melting temperature of each solder particle varies, and the solder particles that cannot form the fillet are generated as the solder balls 108. To do.
When the solder balls 108 that are not fixed are generated around the lands 102 of the printed circuit board 101, short-circuiting occurs 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 aligned and placed. 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 usually 1: 1.

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 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.

Since the surface temperature of the BGA package 106 and the temperature of the solder bump 105 differ depending on the size of the BGA package 106, the BGA package 10
In the case of mixed mounting of 6 different sizes, it is necessary to set the solder joint conditions such that sufficient solder joint properties can be obtained within the heat resistant temperature range of each BGA package 106. 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-free solder has a joining condition in a high temperature region where the conventional soldering temperature cannot be used for fusion joining, heat resistance of the terminals of the BGA package 106 and other electronic components 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, a thermosetting resin is generally used for the underfill material 107 that is poured in, and the resin is cured by processing under heating conditions suitable for the thermosetting. The BGA package 106 in the future is in the direction of increasing the number of input / output terminals and satisfying the requirements for finer pitches in order to satisfy the required specifications with a small area. In response to the above request of the BGA package 106, a reflow device dedicated to area mounting becomes necessary.

[0017]

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 intends to solve these problems and realize 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.

[0019]

In order to solve the above problems, a structure of the present invention is a structure provided between a solder bump of an element and a circuit board, and has a role of an underfill function by heating. And a through hole is provided in the base material so as to correspond to the arrangement of the solder bumps provided on the element. Further, the mounting method according to the present invention includes a step of providing a solder paste on a land provided on a circuit board, a solder bump provided on an element, and a spacer having a through hole provided at a position corresponding to the solder bump. , And a step of bonding the lands so that they are aligned with each other, and a step of heating the solder bumps to melt the solder bumps and melt-integrate with the solder paste on the lands. In addition, a step of providing a solder paste on the land provided on the circuit board, a solder bump provided on the element, a through hole is provided at a position corresponding to the solder bump, and a metal is provided on at least a part of the through hole. A step of bonding the provided spacer and the circuit board in such a manner that the metal of the through hole and the solder bump are brought into contact with each other, and the solder bump is melted by heating the solder bump, thereby forming a metal and solder paste. And a step of melt-integrating. Further, it is decided to seal the solder joints of the solder bumps and the lands by including a step of melting the spacers by heating the spacers to flow out to the solder joints and a step of thermally curing the spacers.

As a first structure of the structure of the present invention, a spacer composed of a base material and a through hole having a hole formed in the base material and a solder bump of a BGA package which is a package of a semiconductor device is arranged on the base material. The spacer functions as a mask for the solder bumps by being sandwiched between the solder bumps and the printed circuit board, and a structure that functions as an underfill function by being heated.

As a second structure of the structure of the present invention, a structure is such that a metal is applied to at least a part of the through hole of the structure of the first structure.

As a third structure of the structure of the present invention, a structure having a metal organic compound as the metal of the structure of the second structure is used.

The present invention uses a screen printing method on the land as a mounting method for connecting the solder bump of the BGA package and the land wired on the printed circuit board using the structure of the first structure. A step of printing a solder paste with a solder paste, a step of aligning the land and the solder bump wired on the through hole and the printed circuit board, and a step of further supplying a heat source to the solder bump, The mounting method includes a step of melting the solder bump and melting and integrating with the solder paste on the land.

The present invention is a mounting means using the structure of the first structure, further comprising a step of supplying a heat source to the spacer as a mounting method for sealing the solder joint portion of the solder bump and the land, The mounting method includes a step of melting the spacer by heating and flowing out to the solder joint portion, and a step of thermally curing the spacer.

According to the present invention, as a first means of a mounting method for connecting a solder bump of a BGA package and a land wired on a printed circuit board using the structure having the second to third structures, the structure is provided on the land. And a step of printing a solder paste using a screen printing method, and then a step of aligning and bonding the land applied to the printed circuit board with the land on the printed circuit board in a state where the metal application point in the through hole and the solder bump are in contact with each other. The mounting method further includes a step of supplying a heat source to the solder bumps, and a step of melting the solder bumps by heating to melt and integrate the metal and the solder paste on the land.

The present invention is a mounting means using the structures of the second to third structures, and further a step of supplying a heat source to the spacer as a mounting method for sealing the solder joint portion of the solder bump and the land. The mounting method includes a step of melting the spacer by heating and flowing out to the solder joint portion, and a step of thermally curing the spacer.

The present invention is a mounting means using the structures of the first to third structures, and further, as a mounting method for sealing the solder joint portion of the solder bump and the land, a BGA package and a printed circuit board are used. The mounting method has a step of applying an underfill material to the gap and a step of thermally curing the underfill material.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the present invention is a spacer composed of a base material and a through hole having a hole formed in the base material and a solder bump of a BGA package which is a semiconductor device package. . 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 this 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. Next, the spacer of the present invention is bonded 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. Furthermore, the position of the through hole,
The BGA package is mounted on the spacer in a state where the positions of the solder bumps formed on the BGA package are aligned. By applying pressure from the upper portion of the BGA package, the solder bumps are inserted into the inner holes of the through holes of the spacers, as shown in FIG. 2B.

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 land is individually isolated, and the solder bump of the BGA package terminal is present on the spacer to establish a closed space for solder bonding.

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. The temperature of the reflow device is set to a temperature at which the solder bump melts. 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 the solder bonding is performed within the through hole of the spacer according to the present invention, the solder can be separated from the adjacent land, and reliable solder bonding can be performed.

Next, the reflow device is heated to a temperature at which the spacer melts. The spacer heated at the solder 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 means that when a product mounted with a printed circuit board receives an impact stress due to being dropped, this stress is concentrated on the BGA package and its solder joint. Since the solder joint portion of the BGA package does not have a lead frame as in the QFP package, stress concentrates on the weakest portion and breakage occurs around the joint portion. 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. The grid array arrangement of the through holes of the spacer is determined by the arrangement of the solder bumps of the BGA package. The number of terminals in the solder bump array of the BGA package varies depending on the input / output specifications and size, and many terminals are arrayed within a limited area. Therefore, the through hole of the spacer of the present invention is
By arranging according to the specifications of the A package,
It can be used for a wide variety of BGA packages.

Further, 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 having the second structure as described above, the spacer has a structure in which metal is applied to at least a part of the inner ring portion of the through hole. By using this spacer, the solder bump formed on the BGA package and the land wired on the printed circuit board are solder-bonded.

As a mounting process, a mask is mounted on a printed circuit board, and a solder paste is applied on the mask, so that a land wired on the printed circuit board through an opening of a hole formed in the mask plate. The solder paste is printed on top.

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 aligned, Attach the spacer to the printed wiring board. Further, the BGA package is mounted on the spacer with the position of the metal of the through hole and the position of the solder bump formed on the BGA package being matched.

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 land is individually isolated, and the solder bump of the BGA package terminal is present on the spacer to establish a closed space for solder bonding.

Further, by pressing from above the BGA package, the solder bump is brought into contact with the metal portion formed in 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, it flows into the reflow apparatus in the state of being stuck together, and the BGA package and the printed circuit board are heated by preheating. At this time, the solder bumps are also heated via the terminals formed on the BGA 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, and the solder bump and the metal are melt-bonded to each other. Further, the solder bump and the metal melt-bonded are brought into contact with the solder paste on the land inside the through hole of the spacer to be melted and integrated. Since the solder bonding is performed within the through hole of the spacer according to the present invention, the solder can be separated from the adjacent land, and reliable solder bonding can be performed. this is,
It is convenient to carry out solder joining in a limited range of the through holes to prevent excess solder paste from flowing into adjacent lands.

Further, the flux in the solder paste is
Since the lands and the solder balls are individually separated by a pair by the spacer, they can be reliably attached to the solder balls when the environmental temperature rises.

Therefore, as 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 raised to a temperature at which the spacer melts. The spacer heated at the solder 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. Furthermore, since the spacer itself of the present invention also serves as an underfill material, the burden on the manufacturing process can be reduced.

By forming the metal formed on the spacer of the present invention into a thin film, the contact range 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 solder amount with respect to the land area. By controlling the solder paste side to the extent of preliminary soldering, reliable soldering can be performed.

Further, FIG. 4 shows a spacer having a structure in which the inner ring of the through hole is coated with metal and solder flux on the metal. By applying flux to the inner ring of metal,
It plays a role in preventing metal oxidation 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. Furthermore, in the mounting process of the present invention, the variation of the surface state on the land is very important, and by applying the pre-flux, it is possible to prevent the solder ball and to secure the solder bondability on the land. It becomes an auxiliary means. Furthermore, the metal is BGA
It is necessary to use a material that melts below the heat resistant temperature of the package. In short, in the mounting process, the environment in which the resin of the BGA package is heated in the reflow device is generated, so that the temperature at which the metal part is melted needs to be set 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 of the third structure described above is a spacer having a structure in which a metal compound formed by firing a metal organic compound and a metal simple substance 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. Further, in the above structure, it is necessary to form an alignment mark having directional meaning on the base material. 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.

[0044]

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

Spacers 5 of the first to third configurations according to the present invention
The cross-sectional structure of is shown in FIG. The spacer 5 has a structure in which a through hole 2 is provided in the base material 1. The through holes 2 are provided in the base material 1 so as to correspond to the arrangement of the solder bumps 8 of the BGA package which is a semiconductor element package. The base material 1 is a thermosetting resin, and has a property that it has low expandability and shrinkage due to heat and humidity and low hygroscopicity. Further, the base material 1 has a feature that its adhesive strength is increased by being heated. FIG. 1A is a sectional configuration diagram of the configuration of the base material 1.

FIG. 1B shows a case where the base material 1 has a constitution 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 through holes 2 are arranged in a grid 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 arrangement of the grid array of the through holes, the spacers 5 can be utilized for various kinds of BGA packages 6 by providing the through holes 2 in the base material 1 based on the coordinates of the arrangement of the solder bumps 8. The aperture ratio of the through hole 2 varies depending on the spherical diameter of the solder bump 8. The solder bumps 8 formed on the BGA package 6 have multi-pin input / output signals wired in a limited package area.

By determining the aperture ratio of the through hole 2 in accordance with the ball diameter of the solder bump 8, the spacer 5 can be used in a wide variety of BGA packages 6. As the spacer of the second structure of the present invention, a metal is applied to at least a part of 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. At this time, the organic component is dried by baking the metal and applied in a thin film shape to the inner ring portion of the through hole 2. Further, there is a configuration in which the metal 4 is applied to the through hole 2 and then the flux material 14 is applied.

As shown in FIG. 4A, by applying the flux 14 to the inner ring of the metal 4 formed on the spacer 5, the metal 4 plays a role of preventing oxidation of the metal 4 and maintaining solder wettability.

As shown in FIG. 4B, the printed circuit board 1
By applying the pre-flux 15 to the surface of the land 10 of No. 1, 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, and by applying the pre-flux 15, the solder ball is prevented and the land 10 is prevented.
It serves as an auxiliary means for ensuring the solder bondability above. As the temperature at which the metal 4 is melted, by selecting a material 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, a wide variety of BGA packages 6 can be obtained. The spacer 5 can be utilized.

As the spacer of the third structure of the present invention, a metal compound formed by firing a metal 4 from a metal organic compound and a metal simple substance 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. Further, as shown in FIG. 1, by providing a notch at one corner of the spacer 5, the mounting directions of the BGA package 6 and the printed circuit board 11 can be matched. A first example of the mounting process using the spacer 5 having the first structure 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 spacer 5
The alignment mark 3 provided on the substrate 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 land 10 on which the solder paste 9 is printed and the position of the through hole 2 provided on 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 constitution of the present invention. In the above process, the BGA package 6, the spacer 5 and the printed circuit board 11 are bonded together. At this time, the spacer 5 serves as a framework for dividing the fine through-hole 2 into individual lands 10.

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 bump 8 is inserted into the inner ring of the through hole 2 of the spacer 5.

FIG. 2B is a state diagram of the spacer 5 of the first constitution of the present invention. In the above process, the solder paste 9 on the land 10 is individually isolated, and the solder bump 8 of the BGA package terminal 7 is present on the spacer 5 to establish the form of the closed space for solder joining. it can.

Next, as shown in FIG. 5 (d), the BGA package 6, the spacer 5 and the printed circuit board 11 are attached to each other, and are conveyed to the heating means 22 by the conveying means 25. 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 warm air.

FIG. 2C is a state diagram of the spacer 5 having the first structure according to the present invention. In the above process, the solder bumps 8 are also heated via the BGA package terminals 7, and the solder paste 9 is also heated via the lands 10 of the printed circuit board 11. Next, the heating temperature control means 23 raises the temperature to a temperature at which the solder bumps 8 melt.

FIG. 2D is a state diagram of the spacer 5 of the first constitution of the present invention. In the above process, the solder bumps 8 heated at the melting temperature are melted, and the solder paste 9 on the lands 10 inside the through holes 2 of the spacer 5 is melted.
It comes into contact with and is melted and integrated. Through hole 2 of spacer 5
Since the solder bonding is performed within the range, the adjacent lands 10 can be separated from each other, and reliable solder bonding can be performed.

Next, as shown in FIG. 5 (e), 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 constitution of the present invention. In the above process, the spacer 5 heated to the melting temperature reacts to the heat capacity and collapses the mask shape, and the BGA package 6 and the printed circuit board 1
It flows into the space of No. 1 and is 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. 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 second and third configurations of the present invention will be described below. As shown in FIG. 5A, the printed circuit board 11 and the mask 16 are attached to each other, and the solder paste 9 on the mask 16 is attached.
By moving the squeegee 17 in the direction of the arrow 18, the solder paste 9 is extruded from the opening of the mask 16 and the land 1 wired on the printed circuit board 11 is ejected.
Printed on top of zero. 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 is read.
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 lands 10 on which the solder paste 9 is printed and the positions of the through holes 2 provided in the spacer 5 are attached 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. 3A is a state diagram of the spacer 5 having the second to third constructions 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 solder bumps 8 are inserted into the inner holes of the through holes 2 of the spacer 5 by applying pressure in the direction of arrow 21 by the pressurizing means 20.

FIG. 3B is a state diagram of the spacer 5 of the second to third constructions of the present invention. In the above process, land 1
0 solder paste 9 is individually isolated, spacer 5
The presence of the solder bump 8 of the BGA package terminal 7 on the top of the BGA package terminal 7 can establish a closed space for soldering. Further, by applying pressure from above the BGA package 6, the solder bumps 8 become the spacers 5.
The metal 4 portion formed on the inner ring of the through hole 2 is in a contact state. By bringing the metal 4 in the spacer 5 into contact with the solder bump 8, 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, the BGA package 6, the spacer 5 and the printed circuit board 11 are attached to each other, and then the carrier means 25 causes the heating means 22 to flow.
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 of the second to third 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 raises the temperature 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 bumps and the solder bumps 8 and the metal 4 which are fusion-bonded to each other are land 10 inside the through hole 2 of the spacer 5.
It contacts the upper solder paste 9 and is melted and integrated. Since solder bonding is performed within the range of the through hole 2 of the spacer 5,
The adjacent lands 10 can be separated from each other, and reliable soldering can be performed. Since the solder bonding is performed in the limited area of the through hole 2, the environment temperature is confined and the land 10 on the printed circuit board 11 is sealed.
The heat is conducted to the solder paste 9 and the activation of the solder paste 9 is improved, so that reliable solder joining can be performed. Next, FIG. 5 (e)
As described above, the heating temperature control means 23 raises the temperature to the temperature at which the spacer 5 melts.

FIG. 3D is a state diagram of the spacer 5 of the second to third constructions 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, heat-treat it again, and cure it.

[0068]

As described above, according to the present invention, the first structure of the spacer is formed in the base material and the through hole in which the base material and the solder bump of the BGA package which is a package of the semiconductor device are arranged on the base material. By sandwiching the spacer configured as described above between the solder bump and the printed circuit board, the spacer functions as a mask for the solder bump, and by heating, the structure has a role of an underfill function.

As the second structure of the structure of the present invention, the structure of the first structure is such that at least a part of the through hole is coated with a metal.

As a third structure of the structure of the present invention, a structure having a metal organic compound as the metal of the structure of the second structure is used.

As a result, the following effects can be 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 for various types of BGA packages.

Furthermore, by determining the aperture ratio of the through hole according to the ball diameter of the solder bump, various types of BGA can be obtained.
The spacer of the present invention can be utilized in a package.

Furthermore, the solder paste on the lands is individually isolated, and the solder bumps of the BGA package terminals are present on the spacers of the present invention to establish the form of the closed space for solder joining. it can.

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 according to the present invention, it is possible to separate from the adjacent land, and it is possible to carry out the reliable solder bonding.

The solder joint portion of the BGA package is QFP.
Since the package does not have a lead frame, stress concentrates on the weakest points and damage occurs around the joint.By fixing and protecting the periphery of the solder joint with the spacer of the present invention, the strength is improved. It is up.

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 cross-sectional view showing a structure of a spacer according to the present invention.

FIG. 2 is a state diagram schematically showing a process in the present invention for mounting a package and a circuit board using the spacer according to the present invention.

FIG. 3 is a state diagram schematically showing a process in the present invention for mounting a package and a circuit board using the spacer according to the present invention.

FIG. 4 is a state diagram schematically showing a case where the inner ring of the through hole is mounted using a spacer provided with metal and flux.

FIG. 5 is a process chart schematically showing a mounting process of the present invention.

FIG. 6 is a process chart schematically showing a conventional mounting process.

FIG. 7 is a state diagram for explaining a solder joint failure when the amount of printed solder paste varies in the related art.

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

[Explanation of symbols]

1 base material 2 through holes 4 metal 5 spacers 6 BGA package 8 Solder bump 10 lands 11 circuit board

Continued front page    (72) Inventor Takahito Endo             1-8 Nakase, Nakase, Mihama-ku, Chiba City, Chiba Prefecture             Ico Instruments Co., Ltd. (72) Inventor Shuhei Yamamoto             1-8 Nakase, Nakase, Mihama-ku, Chiba City, Chiba Prefecture             Ico Instruments Co., Ltd. F term (reference) 5E319 AA03 AC01 BB05 CC02 CC22                       GG01 GG05                 5E336 AA04 CC32 DD22 DD32 EE02                       EE05 GG06 GG10 GG16                 5F044 LL13 LL17 RR18 RR19                 5F061 AA01 BA04 CA26

Claims (7)

[Claims] 1. A structure provided between a solder bump of an element and a circuit board, comprising a base material that plays a role of an underfill function by heating, and the base material has a solder bump provided on the element. A structure provided with through holes corresponding to the arrangement of. 2. The structure according to claim 1, wherein a metal is applied to at least a part of the through hole. 3. The structure according to claim 2, wherein the metal has a metal organic compound. 4. A step of providing a solder paste on a land provided on a circuit board, a solder bump provided on an element, and a spacer provided with a through hole at a position corresponding to the solder bump,
By including a step of attaching the lands so that they are aligned with each other, and a step of heating the solder bumps to melt the solder bumps and melt-integrate with the solder paste on the lands. A mounting method characterized in that lands are solder-bonded. 5. A step of providing a solder paste on a land provided on a circuit board, a solder bump provided on an element, a through hole provided at a position corresponding to the solder bump, and at least the through hole. A step in which the spacer provided with a metal partly and the circuit board are bonded together by aligning the positions of the metal of the through hole and the solder bump so that the solder bump is in contact, And a step of melting the solder bumps to melt and integrate the metal and the solder paste, whereby the solder bumps and the lands are solder-joined. 6. The step of melting the spacer by heating the spacer to flow out to the solder joint portion, and the step of thermally curing the spacer, thereby sealing the solder joint portion of the solder bump and the land. 6. The mounting method according to claim 4 or 5, wherein: 7. The method according to claim 4, further comprising: a step of applying an underfill material in a gap between the BGA package and the printed circuit board; and a step of thermally curing the underfill material. Implementation method described in section.