JP2005011921A - Electronic device, printed circuit board, printing mask, and method of manufacturing electronic device - Google Patents

Abstract

The present invention provides an electronic device, a printed circuit board, a print mask, and a method for manufacturing the electronic device that prevent a connection failure due to a warp of a semiconductor device during reflow.
A plurality of pads (22) are provided in a grid pattern on a printed circuit board (21) at positions facing solder balls (33) of a semiconductor device (30). A first cream solder 23a is printed on the plurality of pads 22 formed in the center. A thin second cream solder 23b having a diameter smaller than that of the first cream solder 23a is printed on the pad 22 formed on the outer peripheral portion. Therefore, even when the semiconductor device is warped during reflow heating and the outer peripheral portion of the semiconductor device 30 approaches the printed circuit board, the solder supply amount is reduced, so that connection between adjacent solders does not occur.
[Selection] Figure 2

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic device on which an area array type semiconductor component is mounted, further relates to a printed circuit board and a printing mask used for mounting, and further relates to a method of manufacturing an electronic device using the same.
[0002]
[Prior art]
In recent years, as the functionality of semiconductor devices has increased, the pitch between electrodes of a semiconductor device has become narrower, while it has become difficult to ensure manufacturing quality. Therefore, for example, an area array package in which electrodes are arranged in a grid pattern on the back surface of the package, such as BGA (Ball Grid Array) and CSP (Chip Scale Package), has attracted attention. On the other hand, warpage of the substrate of the package at the time of reflow heating has become a problem, and an apparatus for preventing connection failure due to this has been developed (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-10-135276 (FIG. 1)
[0004]
[Problems to be solved by the invention]
However, in the conventional apparatus, cream solder is printed to a thickness corresponding to the amount of warpage in response to a valley warp of the package substrate (a case where the corner portion of the package substrate is warped away from the printed circuit board). There is no consideration for measures against a ridge warp of the package substrate (a case where the corner portion of the package substrate is warped in a direction approaching the printed circuit board).
[0005]
That is, in the case of the package substrate manufactured by the conventional apparatus shown in FIG. 7A, when the package substrate is warped by reflow heating to the state shown in FIG. As shown in 7 (c), a state occurs in which adjacent solders are in contact with each other. Then, even if the reflow heating is finished and the package substrate is warped as shown in FIG. 7D, the contact of the solder generated at the end of the package substrate is not eliminated, and a solder short occurs, resulting in poor connection. There is a problem of causing.
[0006]
The present invention has been made in view of the above points, and an object thereof is to provide an electronic device, a printed circuit board, a printing mask, and a method for manufacturing the electronic device that prevent a connection failure due to a ridge warp of a semiconductor device during reflow. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an electronic device according to the present invention includes an area array type semiconductor component having a plurality of ball-shaped adhesive members on one surface and a plurality of electrode pads, and mounting the area array component. A ball-shaped adhesive member at the center of the surface and the electrode pad are connected by a first adhesive member having a first width, and the ball-shaped adhesive member at the end of the mounting surface of the area array component and the electrode pad And a printed circuit board on which the semiconductor component is mounted. The printed circuit board is connected with a second connection member having a second width smaller than the first width.
[0008]
In order to achieve the above object, a printed circuit board of the present invention has a plurality of electrode pads, has a first width in a printed circuit board on which an area array type semiconductor component is mounted, and a mounting surface of the semiconductor component. A first adhesive member printed on the electrode pad corresponding to the central portion of the semiconductor component, and a second width smaller than the first width, and corresponding to an end portion on the mounting surface of the semiconductor component. And a second adhesive member printed on the electrode pad.
[0009]
In order to achieve the above object, the printing mask of the present invention is a printing mask used for printing an adhesive member on a printed circuit board when the area array type semiconductor component is mounted on the printed circuit board. A first opening for embedding an adhesive member having a first opening diameter, and a portion corresponding to an end of the mounting surface of the semiconductor component. And a second opening for embedding an adhesive member having a second opening smaller than the first opening.
[0010]
In order to achieve the above object, a method of manufacturing an electronic device according to the present invention is a method of manufacturing an electronic device in which an area array type semiconductor component is mounted on a printed circuit board having a plurality of electrode pads. Provided through the portion corresponding to the central portion on the mounting surface, provided through the first opening having the first opening diameter and the portion corresponding to the end portion on the mounting surface of the semiconductor component, A printing mask having a second opening having a second opening smaller than the first opening, and the first and second openings correspond to the electrode pads on the surface of the printed circuit board. Placing the adhesive member in the first and second openings of the printing mask placed on the printed board by the placing step, and placing the printing mask on the pre- Printed on the electrode pad having a first width corresponding to the first opening diameter and corresponding to a central portion of the mounting surface of the semiconductor component. A first adhesive member and a second adhesive member having a second width corresponding to the second opening diameter and printed on the electrode pad corresponding to an end of the mounting surface of the semiconductor component And a step of forming.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a process configuration of a manufacturing apparatus 100 that manufactures an electronic device by mounting a semiconductor device on a printed circuit board.
[0012]
A manufacturing apparatus 100 shown in FIG. 1 includes a first process 11 including a solder printing apparatus 1 on a line, a second process 12 including a component mounting apparatus 2, and a third process including a solder curing furnace 3. Step 13 is included. A PC 8 as a processing apparatus is connected to the first to third steps 11 to 13.
[0013]
In this embodiment, the processing of all processes is executed by a single personal computer (hereinafter referred to as PC). However, the present invention is not limited to this, and a PC is arranged independently for each process, and each PC is integrated. It is also possible to adopt a configuration in which the above-described PC is further arranged.
[0014]
The solder printing apparatus 1 in the first step 11 is a printing mask in which a lead-free cream solder 23 as a conductive adhesive member of a wiring board is described later on each connection electrode of the wiring board supplied from a board supply device (not shown). 40 is used for printing and coating by a printing method. Note that the connection material is not limited to solder, and other connection materials can also be targeted.
[0015]
The component mounting apparatus 2 in the second step 12 is provided at the subsequent stage of the solder printing apparatus 1, and the semiconductor device 30 is mounted at a mounting position on the surface of the wiring board on which the solder is applied. The connecting electrode is disposed so as to face the connecting electrode of the wiring board, placed on the applied solder, and the semiconductor device 30 is mounted on the wiring board.
[0016]
The solder curing furnace 3 of the third step 13 is provided in the subsequent stage of the component mounting apparatus 2, cures the solder with the semiconductor device 30 mounted on the wiring board, and connects the connection electrodes of the semiconductor device 30 with the solder. The semiconductor device 30 is mounted on the wiring board while being fixed to the electrode, and is further transported to the subsequent substrate storage device.
[0017]
Next, the configuration of the printed circuit board 21 according to an embodiment of the present invention and the semiconductor device 30 mounted thereon will be described with reference to FIGS.
[0018]
In the present embodiment, as a semiconductor device, a P-BGA (Plastic Ball Grid Ally), which is likely to be bent at the time of reflow heating, will be described as an example of a semiconductor device. This is an area array component in which an IC chip is mounted on a substrate, wire bonded, and sealed with a mold resin.
[0019]
FIG. 2 is a cross-sectional view of the semiconductor device 30 and the printed circuit board on which the semiconductor device 30 is mounted before the solder is cured (before reflow, that is, after the second step 12). FIG. 3 is a plan view showing the back surface of the semiconductor device 30. FIG. 4 is a cross-sectional view of the semiconductor device 30 and the printed circuit board on which the semiconductor device 30 is mounted (mounted) at the stage of solder curing (reflow, that is, the third step 13).
[0020]
As shown in FIG. 2, the semiconductor device 30 includes a semiconductor chip (not shown), a substrate 31 on which the semiconductor chip is mounted, a mold resin 32 that protects the substrate 31, and solder balls 33. . The solder balls 33 are semicircular solders formed on electrodes (not shown) formed on the back surface of the substrate 31, and a plurality of solder balls 33 are arranged in a grid pattern as shown in FIG.
[0021]
On the printed circuit board 21, a plurality of pads 22 are provided in a lattice shape at positions facing the solder balls 33 of the semiconductor device 30. On the plurality of pads 22, cream solder 23 is printed (applied) using a print mask described later. The electrodes of the semiconductor device 30 and the electrodes of the printed circuit board 21 can be electrically connected via the solder balls 33, the cream solder 23, and the pads 22.
[0022]
The cream solder 23 printed on the pad 22 of the printed circuit board 21 includes a first cream solder 23a and a second cream solder 23b. The 1st cream solder 23a is printed so that it may oppose the solder ball 33 provided in parts other than the area A shown in FIG. 3, ie, a center part.
[0023]
The second cream solder 23b is printed so as to face the solder balls 33 provided in the area A shown in FIG. 3 (that is, the outer peripheral portion of the semiconductor device 30, particularly the corner portion). The second cream solder 23b is printed to have the same height as the first cream solder 23a, a smaller diameter (width) than the first cream solder 23a, and a narrow shape.
[0024]
When the semiconductor device 30 and the printed circuit board 21 in such a state are conveyed to the solder curing furnace 3 and the third step 13 (reflow heating) is performed, the solder balls 33 and the cream solder 23 (3a, 3b) are melted. The electrodes of the semiconductor device 30 and the pads 22 of the printed circuit board 21 are electrically connected. Then, after the solder ball 33 and the cream solder 23 (3a, 3b) are connected by melting and cooling, the solder is solidified and the semiconductor device 30 is fixed to the printed circuit board 21.
[0025]
Further, at the time of reflow heating, the warpage of the semiconductor device 30 occurs because the substrate 31 and the mold resin 32 are made of materials having different thermal expansion coefficients. 4 is a case that occurs particularly during reflow heating at a temperature exceeding the melting point of the mold resin 32.
[0026]
As shown in FIG. 4, when the semiconductor device 30 is warped, the area A shown in FIG. 3 is particularly warped toward the printed circuit board 21, and the central portion of the semiconductor device 30 is warped away from the printed circuit board 21. . That is, as the semiconductor device 30 is warped, the distance between the solder balls 33 in the area A of the semiconductor device 30 and the printed circuit board 21 is narrowed, and the cream solder 23 applied oppositely is pressed.
[0027]
Therefore, in this embodiment, the second cream solder 23b is applied to the portion of the semiconductor device 30 that faces the solder balls 33 in the area A. Therefore, even if the semiconductor device 30 is warped, the distance between the solder ball 33 in the area A and the printed circuit board 21 is reduced, and the second claim solder 23b is pressed, the second claim solder 23b is Since it is applied in a shape thinner than the cream solder 23a, the possibility that adjacent solders come into contact with each other (connection failure) can be kept low.
[0028]
Next, a printing method of the claim solder 33 printed in the first step 11 by the solder printing apparatus 1 will be described with reference to FIGS. 5 and 6. FIG. 5 is a plan view of a printing mask 40 used in the solder printing apparatus 1. FIG. 6 is a diagram showing a method of printing cream solder 23 (23a, 23b) on the printed circuit board 21 using the print mask 40. FIG.
[0029]
The printing mask 40 is used when cream solder is printed. As shown in FIG. 5, an opening 41 penetrating each position corresponding to the pad 22 is formed. The opening 41 includes a first opening 41a for forming the first cream solder 23a and a second opening 41b for forming the second cream solder 23b.
[0030]
The second opening 41b is formed in the area B of the four corners corresponding to the periphery of the corner of the semiconductor device 30, and has a smaller (narrower) opening diameter than the first opening 41a. On the other hand, the first opening 41 b is formed in a portion corresponding to a portion other than the periphery of the corner portion including the central portion of the semiconductor device 30.
[0031]
As a result, the supply amount of cream solder supplied by the second opening 41b is smaller than the supply amount by the first opening 41a, and around the corner of the semiconductor device 30 corresponding to the second opening 41b. A small amount of cream solder is supplied.
[0032]
The printing mask 40 formed in this way is arranged on the printed circuit board 21 so as to overlap the pad 22 as shown in FIG. Then, the cream solder 43 is filled in all the openings 41 (41a, 41b) using the spatula 42. Then, by peeling the print mask 40 from the printed board 21, the first and second cream solders 23a and 23b are printed on the printed board 21 as shown in FIG.
[0033]
As described above, in this embodiment, the (second) cream solder applied on the printed circuit board facing the periphery of the corner of the semiconductor device is less than the (first) cream solder applied to the central portion. By setting the amount to be (thin), even if the substrate of the semiconductor device is warped during reflow heating, it is possible to prevent poor connection due to contact between adjacent solders formed at the corners of the semiconductor device. There is an effect.
[0034]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent a connection failure due to a hill warp of a semiconductor device during reflow.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a manufacturing process of a printed circuit board in an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a semiconductor device 30 and a printed board on which the semiconductor device 30 is mounted at a stage before solder curing (before reflow, that is, after the second step 12).
3 is a plan view showing the back surface of the semiconductor device 30. FIG.
FIG. 4 is a cross-sectional view of the semiconductor device 30 and a printed board on which the semiconductor device 30 is mounted (mounted) at a stage of solder hardening (reflow, that is, a third step 13).
FIG. 5 is a plan view of a printing mask 40 used in the solder printing apparatus 1;
6 is a view showing a method for printing cream solder 23 (23a, 23b) on a printed circuit board 21 using a printing mask 40. FIG.
FIG. 7 is a cross-sectional view of the semiconductor device 30 before and after reflow heating in the prior art and a printed circuit board on which the semiconductor device 30 is mounted.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Solder printing apparatus 2 Component mounting apparatus 3 Solder hardening furnace 21 Printed circuit board 22 Pad 23 Cream solder 23a 1st cream solder 23b 2nd cream solder 30 Semiconductor device (area array component)
31 Substrate 32 Mold resin 33 Solder ball 40 Print mask 41a First opening 41b Second opening

Claims (4)

An area array type semiconductor component having a plurality of ball-shaped adhesive members on one surface;
A plurality of electrode pads, a ball-shaped adhesive member at the center of the mounting surface of the area array component and the electrode pad are connected by a first adhesive member having a first width, and the area array component is mounted. A printed circuit board on which the ball-shaped adhesive member at the end of the surface and the electrode pad are connected by a second connection member having a second width smaller than the first width and the semiconductor component is mounted;
An electronic device comprising: In a printed circuit board having a plurality of electrode pads and mounting an area array type semiconductor component,
A first adhesive member having a first width and printed on the electrode pad corresponding to a central portion on a mounting surface of the semiconductor component;
A second adhesive member having a second width smaller than the first width and printed on the electrode pad corresponding to an end of the mounting surface of the semiconductor component;
A printed circuit board characterized by comprising: When mounting an area array type semiconductor component on a printed circuit board, in a printing mask used for printing an adhesive member on the printed circuit board,
A first opening for embedding an adhesive member provided through the portion corresponding to the central portion of the mounting surface of the semiconductor component and having a first opening diameter;
A second opening for embedding an adhesive member provided penetrating through a portion corresponding to an end of the mounting surface of the semiconductor component and having a second opening smaller than the first opening;
A printing mask characterized by comprising: In a manufacturing method of an electronic device in which an area array type semiconductor component is mounted on a printed board having a plurality of electrode pads,
A first opening having a first opening diameter and penetrating through a portion corresponding to an end portion of the mounting surface of the semiconductor component and penetrating through a portion corresponding to the central portion of the mounting surface of the semiconductor component. A printing mask having a second opening having a second opening smaller than the first opening, the first and second openings being the electrodes on the surface of the printed circuit board. Placing to correspond to the pad;
Embedding an adhesive member in the first and second openings of the printing mask placed on the printed circuit board by the placing step described above;
The printed mask is removed from the printed circuit board, and the electrode has a first width corresponding to the first opening diameter on the printed circuit board and corresponds to a central portion on the mounting surface of the semiconductor component. A first adhesive member printed on the pad and a second width corresponding to the second opening diameter, and printed on the electrode pad corresponding to an end of the mounting surface of the semiconductor component Forming a second adhesive member;
A method for manufacturing an electronic device, comprising:

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