JPH10189815A - Mounting structure for semiconductor element mounting substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure of a high quality and a highly reliable semiconductor element mounted substrate, having high connection reliability and unaffected by thermal affection. SOLUTION: A semiconductor element housing package A, which is provided with an insulated substrate 1, having a semiconductor element 5, and a metallized wiring layer 3, is arranged on an electric circuit substrate B having a wiring conductor 8 and thermal expansion coefficient different from that of the insulated substrate 1, and a semiconductor element mounting substrate, having a notched part 9, which is electrically non-conductive on a part other than a semiconductor element housing cavity, is mounted on the main surface of the insulated substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure of a semiconductor element mounting substrate such as a semiconductor element housing package.

[0002]

2. Description of the Related Art A wiring board has a structure in which a metallized wiring layer is disposed on the surface or inside of an insulating substrate. As a typical example using this wiring board, a semiconductor element, especially
There is a semiconductor element housing package for housing a semiconductor element such as SI.

According to the package for accommodating a semiconductor element, a metallized wiring layer such as W or Mo is provided on the surface and inside of an insulating substrate made of alumina ceramic or the like, and a connection terminal is further provided on the bottom surface. A cavity for accommodating a semiconductor element is formed at the center of the upper surface, and the cavity is hermetically sealed by a lid.

[0004] As the degree of integration of a semiconductor element increases, the number of electrodes formed thereon increases, and the number of terminals of the semiconductor storage package also increases accordingly.

[0005] However, even if the number of terminals is increased, the dimensions of the semiconductor storage package itself are limited. In addition, in order to meet the market needs for recent miniaturization, the connection of the semiconductor storage package is required. It is necessary to increase the formation density of the terminals.

Therefore, in order to increase the number of terminals of the semiconductor storage package, a technique of arranging a pin grid array (PGA) in which metal pins such as Kovar are connected to the lower surface thereof is most commonly performed. Recently, a so-called quad flat package (QFP) in which gull-wing (L-shaped) metal pins are connected to metallized wiring layers led to four side surfaces, and four side surfaces of the package are provided with electrode pads and have no lead pins A leadless chip carrier (LCC), a chip size package (CSP) in which a Si chip is flip-chip mounted, a ball grid array (BGA) in which a number of spherical terminals made of solder are arranged on the lower surface of an insulating substrate, and the like are presented. It is said that among these, the BGA can achieve the highest density.

[0007] This ball grid array (BGA)
A connection terminal in which a spherical terminal made of a brazing material such as solder is brazed to a connection pad, and the spherical terminal is placed on and abuts on a wiring conductor of an electric circuit board. Is heated and melted at a temperature of about 250 to 400 [deg.] C., and the spherical terminals are bonded to a wiring conductor to be mounted on an electric circuit board. And
With such a mounting structure, each electrode of the semiconductor element housed inside the semiconductor element housing package is electrically connected to the electric circuit board via the metallized wiring layer and the connection terminal.

[0008]

The insulating substrate of these semiconductor storage packages is made of ceramics such as alumina, mullite, low-temperature fired material, etc.
It is said that it has the above-mentioned high strength characteristics and that the reliability of the multilayer technology such as a metallized wiring layer is also high.

However, when the semiconductor element is housed in the semiconductor element housing package, or the semiconductor element is mounted on the wiring board, and then mounted on a printed board made of glass-epoxy resin, etc. Occasionally generated heat is repeatedly applied to both the insulating substrate and the printed circuit board, thereby generating a large thermal stress due to the difference in thermal expansion between the two substrates.

[0010] Such thermal stress has a small effect when the number of terminals in the semiconductor storage package is 300 or less, but as the number of terminals exceeds 300 or the size of the semiconductor storage package increases, the thermal stress increases. The thermal stress increases, and the thermal stress acts on the outer peripheral portion of the connection pad on the lower surface of the insulating substrate and the bonding interface between the wiring conductor and the terminal of the external electric / electrical circuit board due to repetition of operation and stop of the semiconductor element, There is a problem that the connection pads are peeled off from the insulating substrate, and the terminals are peeled off from the wiring conductors. As a result, the wiring substrate and the semiconductor storage package cannot be stably and electrically connected to the printed circuit board for a long period of time.

Accordingly, an object of the present invention is to provide a high-quality and high-reliability semiconductor element mounting that is not affected by heat when a wiring board such as a semiconductor element storage package is mounted on an electric circuit board. It is to provide a mounting structure of a substrate.

[0012]

According to the present invention, there is provided a mounting structure of a semiconductor element mounting substrate, wherein a wiring substrate having an insulating substrate provided with a semiconductor element and a metallized wiring layer is electrically connected to the metallized wiring layer. In a mounting structure having an electrically conductive wiring and being disposed on an electric circuit board having a different coefficient of thermal expansion from that of the insulating substrate, a cutout portion that is electrically non-conductive is provided on a main surface of the insulating substrate. Features.

In another aspect of the present invention, the wiring substrate is a package for storing a semiconductor element, and a cutout portion is formed on a main surface of the insulating substrate except for a cavity for storing a semiconductor element. It is characterized by having been provided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 show a mounting structure of a package for accommodating a BGA type semiconductor element according to the present invention, and FIG. 1 is a sectional view thereof. FIG. 2 is a perspective view thereof, and FIG. 3 is an enlarged sectional view of a main part thereof.

In these figures, A is a package for housing a semiconductor element, and B is an electric circuit board. First, in the semiconductor element housing package A, 1 is an insulating substrate, 2 is a lid, 3 is a metallized wiring layer, 4 is a connection terminal, 5 is a semiconductor element, and the semiconductor element 5 is formed by the insulating substrate 1 and the lid 2. A cavity 6 for hermetically receiving the inside is formed. Then, the semiconductor element 5 is bonded and fixed on the insulating substrate 1 via an adhesive such as glass or resin.

A metallized wiring layer 3 is provided on the surface and inside of the insulating substrate 1, and is electrically connected to the semiconductor element 5 and the connection terminal 4. Projecting terminals 4b made of a brazing material such as solder (tin-lead alloy) are attached to each connection terminal 4 via a connection pad 4a. The protruding terminal 4b is formed by connecting a spherical or columnar brazing material to the connection pad 4a.
Or by printing a brazing material on the connection pads 4a by a screen printing method.

As shown in FIGS. 3 and 4, cavities 6 are formed on the front and back surfaces of the insulating substrate 1 as the main surface.
In addition, a notch 9 is provided. The notch 9 may have a circular shape or various shapes such as a square and a triangle, and the size thereof may be appropriately selected. However, it can be said that the greater the total area of the cutouts 9, the greater the effect of the present invention.

The cutout 9 may be formed on the front surface and the back surface, which are the main surfaces of the insulating substrate 1, or only one of them, and may be provided between the connection terminals 4 as shown in FIG. Good.

The other external electric circuit board B is generally called a printed circuit board, 7 is an insulator, 8 is a wiring conductor formed on the insulator 7,
The insulator 7 is made of a material containing an organic resin, specifically, a glass-epoxy composite material. In the case of such a composite material, the coefficient of thermal expansion at 40 to 400 ° C is 12 to 16 ppm / ° C. The wiring conductor 8 is usually made of a metal conductor such as Cu, Au, Al, Ni, or Pb-Sn in view of the matching of the thermal expansion coefficient with the insulator 7 and good electrical conductivity.

In order to mount the semiconductor element housing package A on the electric circuit board B, the protruding terminals 4b of the insulating substrate 1 are placed and contacted on the wiring conductors 8 of the electric circuit board B. By heating at a temperature of ~ 400 ° C,
The protruding terminal 4 b itself made of a brazing material such as solder is melted and joined to the wiring conductor 8 and mounted on the electric circuit board B. It is preferable that a brazing material is formed on the surface of the wiring conductor 8 so as to be easily connected to the protruding terminal 4b.

Thus, according to the mounting structure of the BGA type semiconductor device housing package having the above-described structure, the heat generated when the semiconductor device 5 is operated is repeatedly applied to both the insulating substrate 1 and the insulator 7, and thereby, both the substrates Due to the difference in thermal expansion between them, even if a situation where large thermal stress occurs,
By forming the notch 9 on the main surface (front and back) of the insulating substrate 1, the apparent Young's modulus is reduced,
The stress generated in the connection terminals 4 between the insulating substrate 1 and the insulator 7 was reduced, and the connection reliability was improved.

[0022]

EXAMPLE Next, a heat cycle test was performed on the mounting structure of the present invention as follows. A semiconductor device housing package A (in which a cutout 9 according to the present invention is provided only on the upper surface or lower surface, or only on the lower surface, of the insulating substrate 1 (low-temperature fired substrate having a Young's modulus of 110 Gpa and a thermal expansion coefficient of 7 ppm / ° C.)) However, the semiconductor element 5 was not mounted) on the electric circuit board B (printed board), and each of the sample Nos. 1 to No. 3 was fabricated. Further, as a comparative example, a mounting structure corresponding to a semiconductor element housing package having no cutout 9 was also manufactured.

The package A has a size of 35 mm square and a thickness of 1.2 mm, and the shape of the notch on each surface is a circle having a diameter of 0.1 mm and a depth of 0.25 mm between the wirings in the wiring forming area. Was formed 100 times. The non-wiring formation region has a diameter of 1 mm and a depth of 0.25 mm.
20 notches were formed.

Then, each sample is placed in a thermostat in an air atmosphere and held for 15 minutes in an atmosphere set at -40 ° C., and further held for 15 minutes in an atmosphere set at 125 ° C. for one cycle. A test is performed to repeat the cycle, and the electrical resistance between the wiring conductor 8 of the electric circuit board B and the wiring of the package A for semiconductor element storage is measured for each cycle, and until the electrical resistance changes. When the durability was measured by measuring the number of cycles, the results shown in Table 1 were obtained.

[0025]

[Table 1]

As is clear from the results shown in Table 1, the sample No. of the present invention. 1 to No. The sample No. 3 exhibits high life characteristics, and especially the sample No. In No. 1, the resistance did not change even after 1500 cycles, whereas in Comparative Example 700
An increase in resistance was observed during the cycle.

[0027]

As described above, according to the mounting structure of the semiconductor element mounting board of the present invention, when the wiring board such as the semiconductor element storing package is mounted on the electric circuit board, the semiconductor element is provided. The provision of the electrically non-conductive cutout portion on the main surface of the insulating substrate allows a large thermal stress to occur between the insulating substrate and the electric circuit board having a different coefficient of thermal expansion. In addition, the apparent Young's modulus of the insulating substrate is reduced, and high connection reliability is obtained. As a result, a high-quality and high-reliability semiconductor element mounting substrate mounting structure that is not affected by heat can be provided. Was.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mounting structure of a BGA type semiconductor device housing package according to the present invention.

FIG. 2 is a perspective view of a BGA type semiconductor element storage package according to the present invention.

FIG. 3 is an enlarged sectional view of a main part of a mounting structure of a package for housing a BGA type semiconductor element according to the present invention.

[Explanation of symbols]

 Reference Signs List A Package for storing semiconductor element B Electric circuit board 1 Insulating substrate 2 Lid 3 Metallized wiring layer 4 Connection terminal 5 Semiconductor element 6 Cavity 4a Connection pad 4b Projecting terminal 7 Insulator 8 Wiring conductor 9 Notch

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kenichi Nagae 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute (72) Inventor Masahiko Higashi 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Kyocera Shikisha Research Institute

Claims (2)

[Claims] A wiring board having an insulating substrate on which a semiconductor element is provided and a metallized wiring layer has a thermal expansion different from that of the insulating substrate, the wiring board having wiring electrically connected to the metallized wiring layer. A mounting structure for a semiconductor element mounting substrate, wherein a cutout portion is provided on a main surface of the insulating substrate in a mounting structure disposed on an electric circuit board exhibiting a ratio. 2. The semiconductor device according to claim 1, wherein the wiring substrate is a package for housing a semiconductor element, and a cutout portion is provided on a main surface of the insulating substrate in addition to a cavity for housing the semiconductor element. Mounting structure of mounting board.