JPH08306819A - Semiconductor device, circuit board, and mounting method - Google Patents

Abstract

PURPOSE: To provide a semiconductor device wherein design freedom of wiring or the like is remarkably improved, by enlarging the region capable of wiring and reducing pad pitch. CONSTITUTION: The interval between the substrate 1 back of a semiconductor device and one surface of a printed circuit board 13 which surface faces the substrate 1 is set larger than the sum of the thickness t1 of a wiring on the substrate 1 back and the thickness t2 of a wiring on the one surface of the printed circuit board. A substrate retaining part member 12 is arranged on the back of the substrate 1, the part member 12 sets the interval to be a constant value and retains the substrate. The constant value is smaller than or equal to the sum of the following; the thickness t1 of the wiring of the substrate 1 back, the diameter R of a solder ball to be joined to a pad part of the wiring of the substrate 1 back, and the thickness t2 of a wiring of the one surface of the printed circuit board. By this constitution, the region capable of wiring is enlarged, and pad pitch can be reduced, so that design freedom of wiring or the like is remarkably improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a BGA (Ball Grid Array) package.

[0002]

2. Description of the Related Art Some semiconductor device packages are called BGA (Ball Grid Array) packages in which solder balls are bonded to pads on the back surface of a printed circuit board. FIG. 6 shows (a) BGA, respectively.
FIG. 7 is a bottom view of the package, (b) a cross-sectional view taken along line XY in FIG. 6 (a), and (c) an end view of the BGA package housed in a stick.

A semiconductor chip 3 is bonded onto a printed circuit board 1 by a mount paste 4, and a bonding wire 5 connects the semiconductor chip 3 and a wiring 6 on the printed circuit board 1. Wiring 6 is through hole 8
Through, and is connected to a pad portion to which the solder ball 7 on the back surface of the printed circuit board 1 is joined. Semiconductor chip 3
However, after being sealed with the mold resin 2, the solder balls 7
Is joined to the pad portion.

FIG. 7 is an explanatory view showing a method of joining solder balls of a BGA package. First, the flux 16 is applied to the pad portion 6a on the back surface of the BGA package by the nozzle 15 (FIG. 7A). Next, solder balls (S
(n / Pb = 63/27) 7 is vacuum-adsorbed by a template (a plate having through holes having a diameter smaller than that of the solder ball 7 and provided at the same pitch as the pad portion 6a) 17, and flux is applied to the pad portion 6a on the back surface of the BGA package. The adhesive force is used for attachment (FIG. 7 (b)). After that, the solder ball 7 is bonded to the pad portion 6a on the back surface of the BGA package by heating with a furnace or a laser. The solder balls 7 are reflowed when connecting the BGA package to another printed circuit board.

FIG. 8 is an explanatory view showing a state in which the BGA package is connected to another printed circuit board by reflowing the solder balls. If the connection is successful,
As shown in FIG. 8A, with the solder balls 7 in a substantially cylindrical shape (7p), the pad portions 6a of the wiring on the printed circuit board 1 of the BGA package and the other printed circuit board 13 are formed. The pad portion 9a of the wiring is connected.

[0006]

However, the BGA
When the package is sent to the subsequent manufacturing process or test process, it is housed in a stick and conveyed as shown in FIG. 6C, so that the following inconvenience occurs.
That is, at this time, since the contact surface 11a of the BGA package and the stick rub against each other, the wiring 6 on the printed circuit board 1 needs to avoid the contact surface 11a. Therefore, the wiring cannot be drawn outside the wirable region 14 surrounded by the broken line in FIG.
Restricted in wiring design.

Further, as shown in FIG. 8, when the solder balls are reflowed to connect the BGA package to another printed circuit board, the distance between the printed circuit board 1 of the BGA package and the other printed circuit board 13 is increased. However, when the size becomes smaller than the normal state (FIG. 8A), the shape of the solder ball 7 becomes a substantially barrel shape (FIG. 8B), and the distance between the printed circuit board 1 and another printed circuit board 13 is further increased. Becomes smaller, the solder balls 7 are completely crushed and sticking out occurs. Therefore, the pad pitches of the wiring pad portions 6a on the printed circuit board 1 and the wiring pad portions 9a on the printed circuit board 13 are set so that the protruding solders are not short-circuited even when such solder spillage occurs. It had to be set aside large enough. Therefore, there is a limitation in the wiring design due to the limitation of reducing the pad pitch.

The present invention has been made in view of the above problems, and an object thereof is to design a wiring or the like by enlarging a wirable area and further reducing a pitch of a pad portion for joining a solder ball. It is an object of the present invention to provide a semiconductor device in a BGA package with improved flexibility.

[0009]

According to the semiconductor device of the present invention, the substrate is connected to the substrate, the semiconductor chip mounted on the surface of the substrate and connected to the circuit on the surface of the substrate by the bonding wire. A wiring that connects the pad portion disposed on the back surface of the substrate and the circuit on the front surface of the substrate facing the pad portion of the wiring on one surface of the planned printed circuit board, and is joined to the pad portion of the board, Solder balls that connect the pad part of the board and the pad part of the printed circuit board by reflow are disposed on the back surface of the board, and the distance between the back surface of the board and one surface of the printed circuit board is Is larger than the sum of the thickness of the wiring on the back side of the printed circuit board and the thickness of the wiring on the one side of the printed circuit board, and the thickness of the wiring on the back side of the board and the diameter of the solder ball and the wiring on the one side of the printed circuit board thickness Characterized by comprising a substrate support member for holding set below the predetermined interval sum.

According to the first structure of the circuit board of the present invention, the wiring is provided on the front surface, and the wiring having the pad portion is electrically connected to a part or all of the wiring on the front surface and is provided on the back surface. A semiconductor chip electrically connected to wiring on the surface is placed and bonded on the surface, and a solder ball used for connection to another substrate is bonded to the pad portion;
A second substrate on the surface of which a wiring having a pad portion connected to the pad portion on the back surface of the first substrate is disposed on the surface at a position facing the pad portion on the back surface of the first substrate; The wiring on the rear surface of the substrate and the wiring on the front surface of the second substrate do not contact each other, and the solder balls may simultaneously contact the pad portion of the wiring on the rear surface of the first substrate and the pad portion of the wiring on the second substrate surface. As described above, a substrate supporting member formed on the back surface of the first substrate is provided, which sets and holds the space between the back surface of the first substrate and the front surface of the second substrate at a constant interval.

According to the second structure of the circuit board of the present invention, the thickness of the wiring provided on one surface of the first substrate and having the pad portion is t ₁ , and the first substrate is mounted. The thickness of the wiring, which is disposed on one surface of the second substrate and has a pad portion at a position facing the pad portion on the one surface of the first substrate, is t ₂ , When the radius of the solder ball used for connection by reflow between the pad portion and the pad portion of the second substrate is r, the height h ₁ from one surface of the first substrate is expressed by the following equation t ₁ + t ₂ A substrate supporting member satisfying <h ₁ <t ₁ + t ₂ + 4/3 · r is formed on one surface of the first substrate.

According to the third structure of the circuit board of the present invention, the thickness of the wiring provided on one surface of the first substrate and having the pad portion is t ₁ , and the first substrate is mounted. The thickness of the wiring, which is disposed on one surface of the second substrate and has a pad portion at a position facing the pad portion on the one surface of the first substrate, is t ₂ , When the radius of the solder ball used for connection by reflow between the pad portion and the pad portion of the second substrate is r, the height h ₂ from one surface of the first substrate is expressed by the following equation h ₂ = t _A substrate supporting member satisfying ₁ + t ₂ + 4/3 · r is formed on one surface of the first substrate.

According to the fourth configuration of the circuit board of the present invention, the thickness of the wiring provided on one surface of the first substrate and having the pad portion is t ₁ , and the first substrate is mounted. The thickness of the wiring, which is disposed on one surface of the second substrate and has a pad portion at a position facing the pad portion on the one surface of the first substrate, is t ₂ , Assuming that the radius of the solder ball used for connection by reflow between the pad portion and the pad portion of the second substrate is r, the height h ₃ from one surface of the first substrate is expressed by the following formula t ₁ + t ₂ A substrate supporting member satisfying + 4/3 · r <h ₃ ≦ t ₁ + t ₂ + 2r is formed on one surface of the first substrate.

According to the circuit board mounting method of the present invention,
One side of the first board on one side of the second board on which the first board is to be mounted, on one side of the first board on which the wiring having the pad portion is arranged Is larger than the sum of the thickness of the wiring having the pad portion arranged to face the pad portion of the first surface and the thickness of the wiring on the one surface of the first substrate, and the pad portion and the first substrate Second step of forming a board supporting member having a height equal to or less than a value obtained by adding a diameter and a sum of solder balls used for connection with a pad portion of the board by reflow, and on a surface of the other side of the first board. A step of mounting the semiconductor chip, and wire bonding between the wiring on one surface of the first substrate and the wiring on the other surface of the first substrate, which is partially or entirely electrically continuous, and the semiconductor chip And the solder ball is bonded to the pad part on the one side of the first substrate. And the step of contacting the solder ball with the pad portion on the one surface of the second substrate, and reflowing the solder ball to form the pad portion on the one surface of the first substrate and the second substrate. And a step of connecting to a pad portion on one surface.

In the semiconductor device according to the present invention, the following constitution may be added.

It is preferable that the substrate support member is provided at each corner of the back surface of the substrate.

The substrate supporting member may be arranged along the two opposite sides of the back surface of the substrate.

The substrate supporting member may be arranged along the side edges other than the two side edges.

It is preferable that the substrate supporting member has a columnar or prismatic shape.

The tip of the substrate supporting member is preferably formed in a substantially hemispherical shape or a tapered shape.

It is preferable that the substrate supporting member has a substantially rectangular parallelepiped shape formed from approximately one end to the other end of each end side.

The distance between the back surface of the board and the surface on one side of the printed circuit board is preferably set and held by a board supporting member so that the shape of the solder ball after reflow becomes substantially drum-shaped. .

The space between the back surface of the board and the surface on one side of the printed circuit board may be set and held by the board supporting member so that the shape of the solder ball after reflow becomes substantially columnar. .

The space between the back surface of the board and the surface on one side of the printed circuit board may be set and held by a board supporting member so that the shape of the solder ball after reflow becomes substantially barrel-shaped. .

The height of the substrate supporting member from the back surface of the substrate is
The height of the solder ball after reflowing should be substantially drum-shaped.

The height of the substrate supporting member from the back surface of the substrate is
The solder ball may have a height such that the shape after reflow becomes a substantially cylindrical shape.

The height of the substrate support member from the back surface of the substrate is
The height of the solder ball after reflow may be substantially barrel-shaped.

It is preferable that a film for reducing frictional force is formed on a portion of the substrate supporting member including a contact surface or a contact point with the printed circuit board.

The contact surface or contact point between the board supporting member and the printed circuit board may be adhered.

Further, it is preferable that a resin encapsulating body for encapsulating the semiconductor chip is provided.

The substrate supporting member is preferably made of the same material as the resin sealing body.

The substrate supporting member may be made of ceramic.

[0033]

The distance between the back surface of the substrate and the surface on one side of the printed circuit board is determined by the thickness of the wiring on the back surface of the substrate and the thickness of the wiring on the one side of the printed circuit board. Since the board supporting member is provided, the board supporting member is set to be larger than the sum of the thickness of the wiring on the back surface of the board, the diameter of the solder ball, and the thickness of the wiring on one surface of the printed circuit board, and is set to a predetermined interval or less. When the semiconductor device is stored in the stick, the contact part between the semiconductor device and the stick is only the substrate support member, the back surface of the substrate does not contact the stick, and the wirable area is expanded, and the semiconductor device is printed. When connected to a circuit board, the board support member sets the distance between the board and the printed circuit board appropriately, and the pad pitch of the wiring on the board can be reduced, improving the degree of freedom in designing the wiring. To do.

Of the first substrate and the second substrate, each of which has a pad portion which is arranged facing each other and connected to each other, the first substrate is provided on one surface of the first substrate. The wiring on the rear surface of the substrate and the wiring on the front surface of the second substrate do not contact each other, and the solder balls may simultaneously contact the pad portion of the wiring on the rear surface of the first substrate and the pad portion of the wiring on the second substrate surface. As described above, since the first substrate back surface and the second substrate front surface are provided with a substrate supporting member formed on the first substrate back surface and holding the same at a constant interval, the wirable area is expanded. However, the pad pitch of the wiring on the substrate can be reduced, and the degree of freedom in designing the wiring and the like is improved.

Of the first substrate and the second substrate, each of which has a pad portion which is disposed so as to face each other and is connected to each other, the first substrate is provided on one surface of the first substrate. Since the board supporting member having the height satisfying the predetermined formula is provided, the connection state with the printed circuit board can be ensured.

Of the first substrate and the second substrate, each of which has a pad portion which is arranged so as to face each other and is connected to each other, the second substrate is formed on one surface of the first substrate. Since the board supporting member having the height satisfying the predetermined formula is provided, the pad pitch of the wiring on the board can be reduced and the connection state with the printed circuit board can be optimized.

Of the first substrate and the second substrate, each of which has a pad portion arranged and connected to face each other on one side, the third substrate is provided on one face of the first substrate. Since the board supporting member having a height satisfying the predetermined formula is provided, the pad pitch of the wiring on the board can be reduced, and the degree of freedom in designing the wiring and the like is improved.

In the method of mounting the circuit board, one of the first and second substrates, which has pad portions arranged and connected to face each other so as to face each other, is provided on one side of the first substrate. Since the step of forming the substrate supporting member having a predetermined height on the surface is provided, the wirable region of the first substrate is enlarged, and the pad pitch of the wiring on the substrate can be reduced, The degree of freedom in design is improved.

Since the substrate supporting members are arranged at the respective corners of the back surface of the substrate, the area where wiring can be performed can be maximized and the pad pitch of the wiring on the substrate can be reduced. This will greatly improve the degree of freedom in designing the wiring and the like.

Since the substrate supporting members are arranged along the two opposite sides of the back surface of the substrate, the wirable area can be expanded, and the pad pitch of the wiring on the substrate can be increased. By reducing the size, the degree of freedom in designing the wiring and the like is significantly improved.

Further, since the board supporting member is arranged along the side edges other than the two side edges, the stability is high when the stick is stored and when the stick is connected to the printed circuit board.

Since the substrate supporting member has a columnar or prismatic shape, the area where wiring is possible is expanded, the degree of freedom in design is improved, and when the stick is housed, the board supporting member does not interfere with the printed circuit board. High stability at the time of connection can be easily obtained.

Since the tip of the substrate supporting member is formed in a substantially hemispherical shape or a tapered shape, the frictional force between the stick and the substrate supporting member when the semiconductor device is housed in the stick is reduced. .

Since the board supporting member has a substantially rectangular parallelepiped shape formed from almost one end to the other end of each side, it is stable when the stick is housed and when it is connected to the printed circuit board. The degree increases.

The distance between the back surface of the board and the surface on one side of the printed circuit board is set and held by the board supporting member so that the shape of the solder ball after reflow becomes substantially drum-shaped. The pad pitch of the wiring on the substrate can be reduced, and the degree of freedom in designing the wiring and the like is improved.

The distance between the back surface of the board and the surface on one side of the printed circuit board is set and held by the board supporting member so that the shape of the solder ball after reflow becomes substantially cylindrical. The pad pitch of the wiring on the board can be reduced, and the connection state with the printed circuit board can be optimized.

The distance between the back surface of the board and the surface on one side of the printed circuit board is set and held by the board supporting member so that the shape of the solder ball after reflow becomes substantially barrel-shaped. The connection state with the printed circuit board can be ensured.

The height of the substrate supporting member from the back surface of the substrate is
Since the shape of the solder balls after reflow has a substantially drum shape, the pad pitch of the wiring on the substrate can be reduced, and the degree of freedom in designing the wiring and the like is improved.

The height of the substrate supporting member from the back surface of the substrate is
Since the shape of the solder balls after reflow has a substantially cylindrical shape, the pad pitch of the wiring on the board can be reduced, and the connection state with the printed circuit board can be optimized. be able to.

The height of the substrate support member from the back surface of the substrate is
Since the shape of the solder balls after reflow has a substantially barrel shape, the connection state with the printed circuit board can be ensured.

Since the film for reducing the frictional force is formed on the portion of the substrate support member including the contact surface or the contact point with the printed circuit board, the stick is not used when the semiconductor device is stored in the stick. The frictional force with the substrate supporting member is reduced.

Since the contact surface or contact point between the board supporting member and the printed circuit board is adhered, the connection state between the pad portion on the back surface of the board and the pad portion on one surface of the printed circuit board is determined. Can be held securely.

Further, since the resin sealing body for sealing the semiconductor chip is provided, the reliability of the semiconductor device is improved.

Since the substrate supporting member is made of the same material as the resin sealing body, it can be formed simultaneously with the resin sealing of the semiconductor device.

Since the substrate supporting member is made of ceramic, when the substrate is a ceramic multilayer laminated plate or the like, it can be formed integrally with the substrate.
It can be made lightweight and excellent in durability.

[0056]

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

FIG. 1A is a bottom view of a semiconductor device of a BGA package according to the first embodiment of the present invention, respectively.
(B) A sectional view taken along the line AB in FIG. 1 (a), (c) a BGA according to the first embodiment of the present invention housed in a stick.
It is an end view of the semiconductor device of a package.

A ceramic multilayer laminate, a printed circuit board, or any other suitable substrate is used as the substrate 1, and the mount paste 4 is provided on the surface of the substrate 1.
The semiconductor chip 3 is bonded by the above, and the semiconductor chip 3 and the wiring 6 on the substrate 1 are connected by the bonding wire 5. The wiring 6 passes through the through hole 8 and is connected to a pad portion to which the solder ball 7 on the back surface of the substrate 1 is joined. The pad portion is provided with a pad pitch facing the pad portion of another printed circuit board to which the substrate 1 is joined, and the solder balls 7 are joined to this pad portion. The semiconductor chip 3 is sealed with the mold resin 2.

Further, a cylindrical substrate support member 12 is provided at each corner of the back surface of the substrate 1. Substrate support member 1
2 is made of the same material as the mold resin 2 or an appropriate material such as ceramic. Substrate support member 1
When 2 is formed of the same material as the mold resin 2,
The substrate supporting member 12 may be formed at the same time when the semiconductor chip 3 is sealed with the mold resin 2. Alternatively, when the substrate 1 is a ceramic multilayer laminate, the substrate supporting member 12 may be formed integrally with the substrate 1. The substrate supporting member 12 may be provided at a plurality of positions along the edge of the back surface of the substrate 1, and the shape thereof is not limited to the cylindrical shape and may be a prismatic shape.

The BGA package is stored in a stick and conveyed as shown in FIG. 1C when it is sent to the subsequent manufacturing process or test process. BGA at this time
The package and the stick are rubbed against each other at the contact surface 11 between the substrate support member 12 and the stick,
The back of the stick does not rub against the stick. Therefore, a region where wiring cannot be provided conventionally (see FIG.
Since the wiring can be provided also on the outer side of the wirable region 14 surrounded by the broken line in (a), the degree of freedom in designing the wiring and the like is improved.

FIG. 2 shows the pad portion 6 of the wiring 6 on the back surface of the substrate 1.
The solder ball 7 joined to a and the printed circuit board 13 in which the pad portion 9a of the wiring 9 is arranged at a position facing the pad portion 6a of the wiring 6 on the back surface of the substrate 1 come into contact with each other, and the reflow of the solder ball 7 is caused. It is an explanatory view showing the previous state and defining the size of each part.

The radius of the solder ball 7 is r, the diameter is R, and the thickness of the wiring 6 on the back surface of the substrate 1 or the pad portion 6a of the wiring 6 is t.
₁ , the thickness of the wiring 9 on the printed circuit board 13 or the pad portion 9a of the wiring 9 is t ₂ , and the height of the substrate supporting member 12 from the rear surface of the substrate 1 is h.

FIG. 3 shows the pad portion 6 of the wiring 6 on the back surface of the substrate 1.
solder ball 7a joined to a and wiring 6 on the back surface of substrate 1
Pad portion 9a of the wiring 9 at a position facing the pad portion 6a of
And the printed circuit board 13 on which the solder balls 7 are disposed, the solder balls 7a are in a state before reflow (FIG. 3A) and after reflow (FIGS. 3B, 3C, and 3D).
It is explanatory drawing which shows (e).

FIG. 3A is a view similar to FIG.
A case where the height h of the substrate supporting member 12 from the rear surface of the substrate 1 is h ₁ , h ₂ , and h ₃ described later is shown in one drawing.

FIG. 3B shows the substrate 1 of the substrate supporting member 12.
Height h from the back side, the shape 7b after reflow of the solder balls 7a indicates a case of the height h ₂ of a substantially cylindrical shape.
The value of h ₂ is the radius r, the volume of the height h ₂ cylinder, the radius r
From the volume of the sphere of, it is calculated as follows. πr ² (h ₂ −t ₁ −t ₂ ) = 4/3 · πr ³ (1) h ₂ = t ₁ + t ₂ + 4/3 · r (2) The shape 7 b of the solder ball 7 after reflow is substantially cylindrical. The height h ₂ is the optimum value of the height h that can reduce the pad pitch while ensuring the best connection between the pad portion 6a of the wiring 6 and the pad portion 9a of the wiring 9. is there. The shape 7b of the solder balls 7a after reflow does not necessarily become a perfect cylindrical shape due to the influence of surface tension, but the pad pitch can be reduced within a range in which adjacent solder balls 7b are not short-circuited.

In order to ensure the connection state between the pad portion 6a of the wiring 6 and the pad portion 9a of the wiring 9, the height h is preferably set to h ₁ (<h ₂ ).

FIG. 3C shows the substrate 1 of the substrate supporting member 12.
Height h from the back side, the shape 7c after reflow of the solder balls 7a indicates a case of a height h ₁ which is a Ryakutarugata. h
The value of ₁ is at least the thickness t ₁ of the pad portion 6a of the wiring 6.
And the thickness t ₂ of the pad portion 9a of the wiring 9 are larger than the sum, the wiring 6 and the wiring 9 can be protected and expressed by the following equation. t ₁ + t ₂ <h ₁ <t ₁ + t ₂ + 4/3 · r (3) The height h ₁ at which the shape 7 c of the solder ball 7 a after reflow is substantially barrel-shaped is the pad pitch, and the height h = h _It must be made larger than in the case of ₂ , but the pad portion 6 of the wiring 6
It is possible to secure the connection state between a and the pad portion 9a of the wiring 9 most reliably, and at the same time protect the wiring 6 and the wiring 9.
It is the value of the height h.

In order to reduce the pad pitch to the minimum, the height h is preferably set to h ₃ (> h ₂ ).

FIG. 3D shows the substrate 1 of the substrate supporting member 12.
The height h from the back surface is the height h ₃ at which the shape 7d of the solder ball 7a after the reflow has a substantially hourglass shape. h
The maximum value of ₃ is, before reflowing the solder balls 7a,
The height is such that it can be bonded to the pad portion 6a of the wiring 6 on the back surface of the substrate 1 and the pad portion 9a of the wiring 9 on the printed circuit board 13 (see FIG. 3A). That is, h ₃ is represented by the following equation. t ₁ + t ₂ + 4/3 · r <h ₃ ≦ t ₁ + t ₂ + R = t ₁ + t ₂ + 2r (4) The shape 7d of the solder ball 7a after reflow is h = h
_{Since it is 3} (> h ₂ ), it becomes a substantially drum shape as shown in FIG. The height h ₃ at which the shape 7d of the solder ball 7a after reflow is substantially drum-shaped is to minimize the pad pitch while ensuring the connection between the pad portion 6a of the wiring 6 and the pad portion 9a of the wiring 9. Is the value of the height h.

In each of the above-described cases, the contact surface 2 between the board supporting member and the printed circuit board 13 is formed at the same time as, or before and after the reflow of the solder balls 7a.
By bonding 0b, 20c, and 20d, it is possible to more reliably maintain the connection state between the pad portion 6a of the wiring 6 and the pad portion 9a of the wiring 9.

As shown in FIG. 3 (e), the height h
Even when = h ₁ , the solder ball 7a is reflowed (7a and 7e are in respective states before and after reflow) by appropriately maintaining the distance between the board 1 and the printed circuit board 13. The shape 7e after the reflow can be made into a substantially cylindrical shape. In this case, the substrate support member 1
The effect of providing 2 can be obtained only when the BGA package is stored in the stick, but for the reason described above,
The degree of freedom in designing wiring and the like can be improved. As described above, according to the value of the height h of the substrate supporting member 12 from the rear surface of the substrate 1, it is possible to obtain the effect of reducing the pad pitch and protecting the wiring.

FIG. 4A is a bottom view of a semiconductor device of a BGA package according to the second embodiment of the present invention, respectively.
FIG. 4B is a sectional view taken along the line CD in FIG. Second
In this embodiment, the substrate support members 12f are provided at two or more locations along the opposite sides of the back surface of the substrate 1.

Further, the substrate supporting member 12f in the second embodiment has a cylindrical shape whose tip portion is processed into a substantially hemispherical shape. By forming the substrate support member 12f in such a shape, the frictional force when the BGA package is stored in the stick is minimized, and the substrate support member 12f is reduced.
It is possible to prevent damage to f. In order to further reduce the frictional force, a low friction resin film such as polytetrafluoroethylene (trade name Teflon) may be coated on the tip of the substrate supporting member 12f.

The shape of the substrate supporting member 12f is not limited to a cylindrical shape, but may be a prismatic shape, and the processed shape of the tip portion is not limited to a hemispherical shape and may be a tapered shape.

FIG. 5A is a bottom view of a semiconductor device of a BGA package according to the third embodiment of the present invention, respectively.
FIG. 6B is a sectional view taken along the line EF of FIG. Third
In this embodiment, the substrate support member 12g is provided along the opposite sides of the back surface of the substrate 1 from approximately one end to the other end of each edge.

By forming the substrate support member 12g in such a shape, the BGA package can be supported more reliably when the BGA package is stored in the stick and after the solder balls 7 are reflowed.

In each of the above embodiments, the substrate supporting member can obtain the above-mentioned predetermined effects as long as it can support the substrate 1 at at least three points.

[0078]

As described above, according to the semiconductor device of the present invention, the substrate supporting member for setting and holding the gap between the back surface of the substrate and the surface on one side of the printed circuit board at a predetermined distance is provided. Therefore, the area where wiring can be performed is expanded, the distance between the board and the printed circuit board is set appropriately by the board supporting member, the pad pitch of the wiring on the board can be reduced, and the degree of freedom in designing the wiring and the like is increased. improves.

According to the first structure of the circuit board of the present invention, the circuit board is formed on the back surface of the first substrate for setting and holding the space between the back surface of the first substrate and the front surface of the second substrate at a constant interval. Since it has a substrate support member, the area where wiring is possible is expanded,
It is possible to reduce the pad pitch of the wiring on the board,
The degree of freedom in designing wiring etc. is improved.

According to the second structure of the circuit board of the present invention, since the board supporting member having a height satisfying the first predetermined expression is provided on one surface of the first board, the printed circuit board is provided. The connection state with the substrate can be ensured.

According to the third structure of the circuit board of the present invention, the board supporting member having a height satisfying the second predetermined formula is provided on one surface of the first board. The pad pitch of the wiring can be reduced, and the connection state with the printed circuit board can be optimized.

According to the fourth structure of the circuit board of the present invention, the board supporting member having a height satisfying the third predetermined expression is provided on one surface of the first board. The pad pitch of the wiring can be reduced, and the degree of freedom in designing the wiring and the like is improved.

According to the circuit board mounting method of the present invention,
Since the step of forming the substrate supporting member having a predetermined height on the surface of the one side of the first substrate is provided, the wirable area of the first substrate is expanded and the pad pitch of the wiring on the substrate is increased. Even if the size is reduced, it is possible to prevent a short circuit between pads during mounting.

Since the substrate supporting members are arranged at the respective corners on the back surface of the substrate, the area where wiring can be performed can be maximized and the pad pitch of the wiring on the substrate can be reduced. This will greatly improve the degree of freedom in designing the wiring and the like.

Since the substrate supporting members are arranged along the two opposite sides of the back surface of the substrate, the wirable area can be expanded, and the pad pitch of the wiring on the substrate can be increased. By reducing the size, the degree of freedom in designing the wiring and the like is significantly improved.

Further, since the board supporting member is arranged along the side edges other than the two side edges, the stability is high when the stick is stored and when the stick is connected to the printed circuit board.

Since the substrate supporting member has a columnar shape or a prismatic shape, the area where wiring is possible is expanded, the degree of freedom in design is improved, and when the stick is housed, the board supporting member does not interfere with the printed circuit board. High stability at the time of connection can be easily obtained.

Since the tip of the substrate supporting member is formed in a substantially hemispherical shape or a tapered shape, the frictional force between the stick and the substrate supporting member when the semiconductor device is housed in the stick is reduced. .

Since the board supporting member has a substantially rectangular parallelepiped shape formed from almost one end to the other end of each end side, it is stable when the stick is stored and connected to the printed circuit board. The degree increases.

The distance between the back surface of the board and the surface on one side of the printed circuit board is set and held by the board supporting member so that the shape of the solder ball after reflow becomes substantially drum-shaped. The pad pitch of the wiring on the substrate can be reduced, and the degree of freedom in designing the wiring and the like is improved.

The space between the back surface of the board and the surface on one side of the printed circuit board is set and held by the board supporting member so that the shape of the solder ball after reflow becomes substantially cylindrical. The pad pitch of the wiring on the board can be reduced, and the connection state with the printed circuit board can be optimized.

The distance between the back surface of the board and the surface on one side of the printed circuit board is set and held by the board supporting member so that the shape of the solder ball after reflow becomes substantially barrel-shaped. The connection state with the printed circuit board can be ensured.

The height of the substrate support member from the back surface of the substrate is
Since the shape of the solder balls after reflow has a substantially drum shape, the pad pitch of the wiring on the substrate can be reduced, and the degree of freedom in designing the wiring and the like is improved.

The height of the substrate support member from the back surface of the substrate is
Since the shape of the solder balls after reflow has a substantially cylindrical shape, the pad pitch of the wiring on the board can be reduced, and the connection state with the printed circuit board can be optimized. be able to.

The height of the substrate support member from the back surface of the substrate is
Since the shape of the solder balls after reflow has a substantially barrel shape, the connection state with the printed circuit board can be ensured.

Since the film for reducing the frictional force is formed on the portion of the substrate supporting member including the contact surface or the contact point with the printed circuit board, the stick is not used when the semiconductor device is stored in the stick. The frictional force with the substrate supporting member is reduced.

Since the contact surface or contact point between the substrate supporting member and the printed circuit board is adhered, the connection state between the pad portion on the back surface of the substrate and the pad portion on one surface of the printed circuit board is determined. Can be held securely.

Further, since the resin sealing body for sealing the semiconductor chip is provided, the reliability of the semiconductor device is improved.

Since the substrate supporting member is made of the same material as the resin encapsulant, it can be formed simultaneously with the resin encapsulation of the semiconductor device.

Since the substrate supporting member is made of ceramic, it can be formed integrally with the substrate when the substrate is a ceramic multilayer laminated plate or the like.
It can be made lightweight and excellent in durability.

[Brief description of drawings]

FIG. 1 is an explanatory view of a semiconductor device of a BGA package according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram that defines the dimensions of each part of the solder ball 7 before reflow.

FIG. 3 is an explanatory view showing states before and after reflow of the solder balls 7a.

FIG. 4 is an explanatory diagram of a BGA package semiconductor device according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a BGA package semiconductor device according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram of a semiconductor device of a conventional BGA package.

FIG. 7 is an explanatory view showing a method of joining solder balls of a BGA package.

FIG. 8 is an explanatory view showing a connection state after solder ball reflow.

[Explanation of symbols]

1 Board 2 Mold Resin 3 Semiconductor Chip 4 Mount Paste 5 Bonding Wire 6 Board Wiring 6a Board Wiring Pad 7 Solder Ball 8 Through Hole 9 Printed Circuit Board Wiring 9a Printed Circuit Board Wiring Pad 10 Stick 11, 11a Contact surface between BGA package and stick 12 Board supporting member 13 Printed circuit board 15 Nozzle 16 Flux 17 Template 20 Contact surface between board supporting member and second printed circuit board

Claims (23)

[Claims] 1. A substrate, a semiconductor chip mounted on the surface of the substrate and connected to a circuit on the surface of the substrate by a bonding wire, and a surface of one side of a printed circuit board to which the substrate is to be connected. Wiring for connecting the pad portion arranged on the back surface of the substrate facing the pad portion of the wiring and the circuit on the front surface of the substrate, and being joined to the pad portion of the substrate and being reflowed, Solder balls that connect the pad section and the pad section of the printed circuit board, and the gap between the back surface of the board and the one side surface of the printed circuit board, which is disposed on the back surface of the board, It is larger than the sum of the thickness of the wiring on the back surface and the thickness of the wiring on the one surface of the printed circuit board, and the thickness of the wiring on the back surface of the substrate, the diameter of the solder ball, and the printed circuit board. A semiconductor device, comprising: a substrate support member that is set and held at a constant interval equal to or less than the sum of the thickness of the wiring on the one surface of the plate. 2. A wiring is provided on the front surface, and a wiring having a pad portion that is electrically continuous with a part or all of the wiring on the front surface is provided on the back surface and electrically connected to the wiring on the front surface. A semiconductor chip is placed and bonded on the front surface, and a first substrate having solder pads used for connection to another substrate bonded to the pad portion is opposed to the pad portion on the back surface of the first substrate. A second substrate on the surface of which a wiring having a pad portion connected to the pad portion on the back surface of the first substrate by the reflow of the solder ball is arranged; a wiring on the back surface of the first substrate; The wiring on the surface of the second substrate is not in contact with each other, and the solder balls can simultaneously contact the pad portion of the wiring on the back surface of the first substrate and the pad portion of the wiring on the surface of the second substrate. The first substrate backside and the second substrate frontside Holds set the interval to a predetermined interval, the circuit board characterized by comprising a substrate supporting member formed on the first substrate on the backside. 3. A surface of one side of a second board on which the first board is mounted is provided with a thickness t ₁ of a wiring provided on one side of the first board and having a pad portion. The thickness of the wiring that is disposed and has a pad portion at a position facing the pad portion on one surface of the first substrate is t ₂ , the pad portion of the first substrate and the pad of the second substrate When the radius of the solder ball used for the connection by reflow with the part is r,
Of the substrate supporting member whose height h ₁ from the surface on one side of the substrate satisfies the following expression t ₁ + t ₂ <h ₁ <t ₁ + t ₂ + 4/3 · r on the surface of the one side of the first substrate. A circuit board characterized by being formed on. 4. The thickness of the wiring provided on one surface of the first substrate and having a pad portion is t ₁ , and the thickness of the wiring on the one surface of the second substrate on which the first substrate is mounted. The thickness of the wiring that is disposed and has a pad portion at a position facing the pad portion on one surface of the first substrate is t ₂ , the pad portion of the first substrate and the pad of the second substrate When the radius of the solder ball used for the connection by reflow with the part is r,
A substrate supporting member whose height h ₂ from one surface of the _first substrate satisfies the following expression h ₂ = t ₁ + t ₂ + 4/3 · r is formed on the one surface of the first substrate. A circuit board characterized by that. 5. The thickness of the wiring provided on one surface of the first substrate and having a pad portion is t ₁ , and the thickness of the wiring on the one surface of the second substrate on which the first substrate is mounted. The thickness of the wiring that is disposed and has a pad portion at a position facing the pad portion on one surface of the first substrate is t ₂ , the pad portion of the first substrate and the pad of the second substrate When the radius of the solder ball used for the connection by reflow with the part is r,
Of the substrate supporting member whose height h ₃ from one surface of the _first substrate satisfies the following formula t ₁ + t ₂ + 4/3 · r <h ₃ ≦ t ₁ + t ₂ + 2r A circuit board characterized by being formed on it. 6. The above-mentioned one-sided surface of a second substrate on which the above-mentioned first substrate is to be mounted, on the one-sided surface of a first substrate on which wiring having a pad portion is arranged. The thickness is greater than the sum of the thickness of the wiring having the pad portion arranged facing the pad portion on the one side of the first substrate and the thickness of the wiring on the one side of the first substrate, and Forming a substrate supporting member having a height equal to or less than a value obtained by adding the sum of the diameter of a solder ball used for connection by reflow between the pad portion of the first substrate and the pad portion of the second substrate; A step of mounting a semiconductor chip on the other surface of the first substrate; and a part of or all of the wiring on the one surface of the first substrate electrically continuous with the first substrate A step of connecting the wiring on the other surface to the semiconductor chip by wire bonding; A step of joining the solder ball to a pad portion on one surface of the first substrate; and a step of contacting the solder ball with a pad portion on one surface of the second substrate, Reflowing to connect the pad portion on the one surface of the first substrate and the pad portion on the one surface of the second substrate to each other. How to implement. 7. The semiconductor device according to claim 1, wherein the substrate supporting member is provided at each corner of the back surface of the substrate. 8. The semiconductor device according to claim 1, wherein the substrate supporting member is provided along each of two opposite edges of the back surface of the substrate. 9. The semiconductor device according to claim 8, wherein the substrate supporting member is further provided along an edge other than the two edges. 10. The semiconductor device according to claim 1, wherein the substrate supporting member has a columnar shape or a prismatic shape. 11. The semiconductor device according to claim 10, wherein the tip end portion of the substrate supporting member is formed in a substantially hemispherical shape or a tapered shape. 12. The semiconductor device according to claim 8, wherein the substrate support member has a substantially rectangular parallelepiped shape formed from substantially one end to the other end of each edge. Characteristic semiconductor device. 13. The semiconductor device according to claim 1, wherein the distance between the back surface of the board and the one surface of the printed circuit board is the shape of the solder ball after reflow. The semiconductor device is set and held by the substrate supporting member so as to have a substantially drum shape. 14. The semiconductor device according to claim 1, wherein the distance between the back surface of the substrate and the one surface of the printed circuit board is the shape of the solder ball after reflow. The semiconductor device is characterized in that it is set and held by the substrate supporting member so that is substantially cylindrical. 15. The semiconductor device according to claim 1, wherein the distance between the back surface of the substrate and the one surface of the printed circuit board is the shape of the solder ball after reflow. Is set and held by the substrate supporting member such that the semiconductor device has a substantially barrel shape. 16. The semiconductor device according to claim 1, wherein a height of the substrate supporting member from the back surface of the substrate is substantially a drum shape after the reflow of the solder balls. The semiconductor device is characterized in that 17. The semiconductor device according to claim 1, wherein the height of the substrate support member from the back surface of the substrate is substantially cylindrical after the reflow of the solder balls. The semiconductor device is characterized in that 18. The semiconductor device according to claim 1, wherein the height of the substrate supporting member from the back surface of the substrate is substantially a barrel shape after the reflow of the solder balls. The semiconductor device is characterized in that 19. The semiconductor device according to claim 1, wherein a portion of the substrate supporting member including a contact surface or a contact point with the printed circuit board reduces frictional force. A semiconductor device comprising: 20. The semiconductor device according to claim 1, wherein a contact surface or a contact point between the substrate supporting member and the printed circuit board is bonded. Semiconductor device. 21. The semiconductor device according to claim 1, further comprising a resin encapsulant encapsulating the semiconductor chip. 22. The semiconductor device according to claim 21, wherein the substrate supporting member is made of the same material as the resin sealing body. 23. The semiconductor device according to claim 1, wherein the substrate supporting member is made of ceramic.