JPH098080A - LSI mounting structure and semiconductor device mounting method - Google Patents

Abstract

(57) [Summary] [Purpose] Enables evaluation of LSI package replacement,
An LSI mounting structure and a mounting method for easily and accurately aligning a multi-pin, high-speed operation LSI package with a wiring board. [Constitution] A positioning boss 3 and a concave groove 4 corresponding to a package lead 7 are provided on the bottom surface of a cylindrical structure 2, the width of the concave groove is larger than the sum W + dw of the lead width and its dimensional tolerance, and the depth of the concave groove is Greater than the lead thickness and shorter than the lead length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting a semiconductor device having a package with a built-in high-speed LSI, which is used in the fields of optical / telecommunication and optical / electrical information processing, and an LSI required for the mounting. The present invention relates to a mounting structure.

[0002]

2. Description of the Related Art Conventionally, a semiconductor device having a high-speed LSI built-in package has a leaded package (hereinafter referred to as an LSI package) having a built-in LSI using a wiring board having a glass epoxy or ceramic material as a core substrate.
One or more of the above are mounted on the above substrate, and LS
It is composed of passive elements such as chip resistors and chip capacitors arranged and mounted around the I package. In this case, the LSI package is inspected using an evaluation board (test board) having a package socket before being mounted, and only non-defective LSI packages are selected. After that, the LSI package and each passive element are electrically and mechanically connected to the electrode pads of the wiring board by means such as solder reflow. The package socket is LS
It is used to evaluate a plurality of LSI packages on the same test board by replacing the I package.

[0003]

However, in the package socket of the above test board, the measurable operating speed is several tens due to impedance mismatch at the electrical connection point from the package lead (terminal) to the substrate.
It was limited to about 0 Mb / s.

In order to improve this, there has been considered a method of directly fixing the LSI package to the electrode pad of the wiring board as shown in FIG. 6 without using the package socket. In this case, the LSI package 6 is pressed against the wiring board 11 by the insulating substrate 33. However, the alignment between the package lead 7 and the electrode pad 12 of the wiring board 11 requires the LSI package 6 to be aligned. A ceramic frame 35 is used. That is, the ceramic frame 35 is inserted along the inner wall 32 into the opening 31 provided in the wiring board 11. At that time, the position of the package is determined by the relationship between the size of the opening 31 and the outer size of the ceramic frame 35. After that, the package lead 7 is fixed by the protruding portion 34 of the insulating substrate 33 (fixing screws and the like are omitted). However, since the manufacturing accuracy (tolerance) of the ceramic frame 35 is as large as ± 0.2 mm with respect to one side of the frame, the leads 7 of the LSI package 6 are originally formed on the wiring board as shown in FIG. 5A. What should be arranged within the width of the electrode pad 12 is the state (positional shift amount δ) in which the positional relationship between the lead 7 and the electrode pad 12 is displaced in parallel to the one side direction as shown in FIG. 5B. Alternatively, as shown in FIG. 5C, the positional relationship between the leads 7 and the electrode pads 12 may shift in the rotation direction as the LSI package 6 rotates (rotation angle θ). The number of terminals is as large as 100 or more (in this case, the lead pitch of the LSI package is also reduced to 1 mm or less), and in the case of an LSI package that operates at a high speed of 1 Gb / s or more, it is caused by the poor positioning accuracy. Then, reflection occurs due to the discontinuity of connection between the wiring board electrode pad and the package lead, or in the worst case, the package lead is short-circuited to the adjacent electrode pad with respect to the wiring board electrode pad that should be connected originally. There were various problems such as being caused. That is, in the above conventional method, the greatest drawback is that it is difficult to align the electrode pads of the wiring board and the package leads in a self-aligning manner.

The present invention makes it possible to evaluate the replacement of an LSI package and to easily and accurately align a high-speed LSI package having a large number of pins with a wiring board.
An object is to obtain an SI mounting structure and its mounting method.

[0006]

SUMMARY OF THE INVENTION The above object is to provide a semiconductor device comprising a package with leads and a wiring board which incorporates an LSI therein, and which is used for the alignment of the leads of the package and the wiring board. In the structure for mounting LSI, at least two positioning bosses are provided on the bottom surface of the structure formed in a tubular shape, and a recessed shape is formed in the same number as the number of leads of the package and at the same intervals as the distance between adjacent leads. A groove is provided on the bottom surface of the peripheral edge of the tubular structure, the width of the concave groove is larger than the sum W + dw of the width W of the lead of the package and the dimensional tolerance dw thereof, and the depth of the concave groove is An LSI mounting structure can be obtained by making the thickness of the lead larger than the thickness of the lead and the length of the concave groove shorter than the length of the lead.

As a method of mounting the semiconductor device, a step of inserting the leads of the package into a concave groove provided on the bottom surface of the peripheral edge of the LSI mounting structure together with at least two positioning bosses, and the package L above
The step of fixing and holding the SI mounting structure, the step of inserting the positioning boss into the positioning hole of the wiring board, and the insulating holding plate that surrounds the LSI mounting structure along the outer periphery thereof are A fixing hole provided in the pressing plate and a package fixing hole provided in the wiring board so that the leads of the package are pressed by the pressing plate onto the electrode pads of the wiring board, respectively. And a step of separating the LSI mounting structure from the wiring board.

[0008]

According to the present invention, the leads of the LSI package are arranged in the concave grooves of the LSI mounting structure, and the holding plate fitted along the outer periphery of the LSI mounting structure is the lead of the LSI package. Is pressed against the wiring board,
The LSI package and the electrode pads provided on the wiring board are electrically connected. The positioning boss provided on the LSI mounting structure can be easily aligned by being fitted into the positioning hole provided on the wiring board.
Therefore, the position of the lead of the LSI package is determined in a self-aligned manner by the positioning boss and the concave groove of the LSI mounting structure.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of an LSI mounting structure according to the present invention, FIGS. 2 and 3 are diagrams showing a method of mounting a semiconductor device using the LSI mounting structure, and FIG. It is a figure which shows the semiconductor device mounted by the said mounting method using the structure for use.

In FIG. 1 showing a structure for mounting LSI according to the present invention, (a) is a bottom view and (b) is a side view thereof. This embodiment shows a cylindrical LSI mounting structure 1, which is symmetrical when viewed from the bottom. Above LSI
The mounting structure 1 has four cylindrical positioning bosses 3 each, one at each of the four corners of the cylindrical structure 2.
Between the two positioning bosses 3, 40 concave grooves 4 are formed on the bottom surface of the peripheral edge of the cylindrical structure 2 with a total of four sides arranged at equal intervals and at the same pitch. The structure 2 is formed in a tubular shape by providing an opening 5 having different vertical / horizontal and depth dimensions at approximately the center of the body 2. The width of the concave groove 4 is the sum of the lead width W = 0.2 mm of the LSI package (not shown in the drawing) to which the present LSI mounting structure 1 is applied and its dimensional tolerance dw = 0.05 mm, that is, W + dw.
= 0.25, the depth of the groove 4 is larger than the lead thickness of 0.15 mm, the length of the groove 4 is shorter than the lead length of 5 mm, and the opening 5 is formed in the frame (lead) of the LSI package. The part that determines the external dimensions of the package (excluding parts) is a size that can be inserted.

The LSI mounting structure 1 is made of stainless steel (SU
S) material, etc., and the positioning boss 3 has a cylindrical structure
Alternatively, the positioning boss 3 having a substantially cylindrical shape, which is integrally machined with or is machined from another SUS member, may be integrated by fitting the cylindrical boss 2 which is pre-drilled. The lead width W, the dimensional tolerance dw thereof, the lead thickness and the lead length are not limited to the above-mentioned numerical values.

2A and 2B and 3A to 3C are views showing a mounting method of the semiconductor device, (a), (b) and (a) to (c) show steps in the mounting method, respectively. 2A is a view showing a state in which the LSI package 6 is inserted into the opening 5 of the LSI mounting structure 1 from below. At this time, each lead 7 of the LSI package 6 is a bottom surface of the LSI mounting structure 1. Are roughly arranged in the concave grooves 4 arranged in the. A vacuum suction device 8 having a cavity 9 is applied to the package 6 from above on the side opposite to the surface on which the LSI package 6 is mounted, and by a vacuum pump (not shown) connected to the other end 10 of the cavity 9, The LSI package 6 mounted on the LSI mounting structure 1 is temporarily adsorbed and fixed as shown in (b). At this time, the leads 7 of the LSI package 6 are arranged on the bottom surface of the LSI mounting structure 1. Each of the concave grooves 4 provided is accurately loaded.

Next, the LSI package 6 adsorbed and fixed to the LSI mounting structure 1 is mounted on a wiring board which is a glass-epoxy-based copper-clad laminate.
As shown in (a), the positioning boss 3 provided in the LSI mounting structure 1 is provided with the positioning hole 1 formed in the wiring board 11.
3 is fitted. Through this step, the leads 7 automatically arranged outward from the bottom surface of the LSI package 6 are accurately aligned with the electrode pads 12 provided on the wiring board 11. The electrode pad 12 is plated with gold in order to reduce the connection resistance.

Next, as shown in FIG. 3B, the insulating plate 1
Insulating holding plate 1 composed of 6 and strength reinforcing plate 17
5 is pressed from above the leads 7 of the LSI package 6 which are accurately aligned on the electrode pad 12, and the fixing holes 19 and the wiring board 11 provided at the four corners of the holding plate 15 are pressed.
Using the package fixing hole 14 provided on the
Fix with 0, nut 21, etc. Therefore, LSI
The leads 7 of the package 6 are the electrode pads 1 of the wiring board 11.
2 will be fixed respectively. After that, by removing the LSI mounting structure 1, the mounting of the LSI package 6 on the wiring board 11 is completed as shown in FIG.

FIG. 4 shows an example of a semiconductor device manufactured based on the semiconductor device mounting method according to the present invention. In FIG. 4, in addition to the positioning holes 13 corresponding to the positioning bosses, the wiring board 11 ′ has a copper wiring 22 on the extension of the electrode pad 12 and a through hole 23 connected to a part of the copper wiring 22. It is shown. In the figure, 6 is an LS incorporating a multi-pin signal processing LSI that operates at a high speed of 1 Gb / s or more.
I package (illustrated as 40 pins in the drawing for convenience), 24 is a package incorporating a 1: 2 DEMUX-IC with a small number of terminals, 25 is a connector for connecting a signal to an external device, and 26 and 27 are potentiometers, respectively. And DIP switch, 28 is a power supply terminal, 29
And 30 are a terminating resistor and a capacitor, respectively. These components are previously mounted and fixed to the wiring board 11 'by a conventional method such as reflow. Then L
The SI package 6 is mounted and fixed to the wiring board 11 'according to the procedure described in the method of mounting the semiconductor device.
The positioning hole 13 shown in the figure shows a trace obtained by removing the LSI mounting structure. In such a semiconductor device, a high-speed signal enters from the connector 25 and the copper wiring 2
2. LSI via IC package 24 and copper wiring 22
It is transmitted to the package 6. A part of the signal processed and converted by the LSI package 6 is sent to the terminating resistor 29, and the remaining signal is transmitted to an external device via the copper wiring 22 and the connector 25. Power for driving the IC package 24 and the LSI package 6 is supplied from the power supply terminal 28.

When a high-speed input signal of 1 Gb / s or more was put into this semiconductor device for operation, there was almost no distortion of the output signal waveform, and it was confirmed that there was no practical problem.

[0017]

As described above, the structure for mounting LSI and the method for mounting a semiconductor device according to the present invention are a semiconductor device including a package with leads and a wiring board in which the LSI is built. In an LSI mounting structure for alignment used for connection to a wiring board, at least two positioning bosses are provided on the bottom surface of the cylindrical structure, and they are adjacent to each other in the same number as the number of leads of the package. Concave grooves arranged at the same intervals as the leads are provided on the bottom surface of the peripheral edge of the cylindrical structure, and the width of the concave grooves is the width W of the leads of the package.
Is larger than the sum W + dw of the dimension tolerance dw and
The depth of the concave groove is larger than the thickness of the lead, and the length of the concave groove is shorter than the length of the lead, or the lead of the package is formed in a cylindrical shape for LSI mounting. At least 2 on the bottom of the body
A step of inserting the positioning boss into a concave groove provided together with the positioning boss; a step of fixing and holding the package to the LSI mounting structure; a step of inserting the positioning boss into a positioning hole of a wiring board; Inserting the LSI mounting structure from above and pressing the leads of the package against the electrode pads of the wiring board by the holding plate made of an insulating material that surrounds the LSI mounting structure along the outer periphery,
Particularly, the number of pins is 100 pins or more due to the steps of fixing by means of the fixing holes provided on the holding plate and the package fixing holes provided on the wiring board, and the step of separating the LSI mounting structure from the wiring board. 1 Gb / s with multiple pins
Measurement and evaluation of high-speed LSI packages such as the above-mentioned LSI packages that operate at high speed can be easily and accurately aligned with the wiring board in a self-aligning manner, and the LSI packages can be easily replaced. It has a great effect as a jig. Further, similar effects can be expected in realizing a semiconductor device that operates at high speed.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an LSI mounting structure according to the present invention, in which (a) is a bottom view and (b) is a side view.

FIG. 2 is a diagram showing a method of mounting a semiconductor device using the above LSI mounting structure, and FIGS. 2A and 2B are diagrams showing states in respective steps.

3A to 3C are diagrams showing a method of mounting a semiconductor device using the LSI mounting structure, and FIGS. 3A to 3C are diagrams showing states in respective steps subsequent to FIG.

FIG. 4 is a diagram showing a semiconductor device mounted by the mounting method using the LSI mounting structure.

5A and 5B are diagrams showing a positional relationship between a lead of a package and an electrode pad on a wiring board according to a conventional method, FIG. 5A showing a normal positional relationship, FIG. 5B showing parallel positional deviation, and FIG. [Fig. 3] is a diagram illustrating positional deviation in the rotation direction.

FIG. 6 is a diagram showing a conventional LSI package measurement / evaluation jig.

[Explanation of symbols]

 1 LSI mounting structure 2 Cylindrical structure 3 Positioning boss 4 Recessed groove 6 Package 7 Leads 11 and 11 'Wiring board 12 Electrode pad 13 Positioning hole 14 Package fixing hole 15 Holding plate

Claims (2)

[Claims] 1. A semiconductor device comprising a leaded package containing an LSI and a wiring board, wherein an LSI mounting structure for alignment used to connect the lead of the package and the wiring board is provided. At least two positioning bosses are provided on the bottom surface of the above-mentioned structure formed in a ring shape, and concave grooves provided at the same number as the number of leads of the package and at the same intervals as the leads are provided in the cylindrical structure. Provided on the bottom surface of the peripheral edge of the package, and the width of the concave groove is the sum W of the lead width W of the package and its dimensional tolerance dw.
An LSI mounting structure, wherein the depth of the concave groove is larger than + dw, the depth of the concave groove is larger than the thickness of the lead, and the length of the concave groove is shorter than the length of the lead. 2. A method of mounting a semiconductor device comprising a package with leads and a wiring board having a built-in LSI, wherein at least two leads of the package are provided on a peripheral bottom surface of an LSI mounting structure formed in a cylindrical shape. A step of inserting the positioning boss into a concave groove provided together with the positioning boss; a step of fixing and holding the package to the LSI mounting structure; a step of inserting the positioning boss into a positioning hole of a wiring board; Insert from above the structure for
The holding plate made of an insulating material that surrounds the LSI mounting structure along the outer periphery of the package mounts the fixing holes provided on the holding plate and the wiring board so that the leads of the package are pressed against the electrode pads of the wiring board. A method for mounting a semiconductor device, comprising: a step of fixing the package by a provided package fixing hole; and a step of separating the LSI mounting structure from the wiring board.