JPH03248452A - Semiconductor device - Google Patents

Abstract

PURPOSE:To minimize a wiring length from an inner wiring of a package to a circuit substrate by forming an L-shaped outer lead terminal and by alloy- bonding one end thereof pressing a surface of an outer lead terminal attached part on a ceramic substrate. CONSTITUTION:An outer lead terminal 3 is formed to an L-shape whose length of short side part exceeds a height of a ceramic frame body 4. The short side part is made to stand vertical along a side wall of the ceramic frame body 4 and brazed so that an end of the short side part presses a surface of an outer lead terminal attached part 2 arranged on an outer peripheral part of the ceramic substrate 1. Since the outer lead terminal 3 is bonded so that an end part of a lead conductor presses the outer lead terminal attached part 2 approximately at right angles, a length (l) of the outer lead terminal is minimized. A long side part of the outer lead terminal 3 is led out in parallel to a surface of the ceramic substrate 1 from a position higher than the ceramic frame body 4; therefore, an increase of a lead length caused by bend process can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a mounting structure for external lead terminals in a high frequency semiconductor device.

[Prior Art] FIGS. 6 and 7 respectively show the structure of the external lead terminal mounting part 2 of a ceramic package in a conventional high-frequency semiconductor device. The inner wiring on the ceramic substrate 1 is installed by using the step 9 provided at the edge of the lead or the gap between the bent part 10 provided at the tip of the lead and the external lead terminal attachment part 2 as brazing material. connected to.

As described above, all conventional mounting structures for external lead terminals are characterized by forming a brazing material temperature in order to ensure lead strength. There are two ways to form the brazing material temperature: one is to process and mold the ceramic substrate side, and the other is to bend and mold the lead side. In the case of the method of bending and molding the lead side, as shown in Figure 7, The angle is usually set at a relatively shallow angle of 10 to 20 degrees.

[Problems to be Solved by the Invention] However, no matter which structure is adopted, in order to ensure the adhesive strength of the leads, the length of the external lead terminal mounting portion 2 on the package must be determined! must be set to at least 0.75 mm. Since processing technology constraints are also added to the setting of the length a, it is usually about 1 mm in packages actually used. Furthermore, in this external lead terminal mounting structure, as is clear from FIGS. 6 and 7, the external lead terminal 3 is attached to the mounting portion 2.
Since it is pulled out at the same height as the surface of the ceramic frame 4, it is necessary to bend it toward either the ceramic substrate 1 side or the ceramic frame 4 in order to facilitate mounting on a circuit board or the like. This lead bending process is normally performed by 0.5 to 1.0 mm from the edge of the ceramic substrate 1, taking into consideration mechanical precision issues and relaxation of stress applied to the leads. Since it is performed at a distance of On++n, the total length of the external lead terminal 3 is 1
．． The length is about 5 to 2.0 mm, resulting in redundancy.

Generally, in a high-frequency semiconductor device, the package is made to have a small external shape in order to ensure high-frequency characteristics, so the wiring length inside the package is also short. Therefore, even though the length of the external lead terminal mounting portion 2 is only 1 mm, which may seem short, the signal transmission loss in this portion has become non-negligible. Furthermore, this lead attachment structure has a structural drawback in that the lead length is made redundant due to bending of the lead, which further adds to signal transmission loss.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a semiconductor device in which the structural defects of the conventional external lead terminal mounting portion, which cause an increase in signal transmission loss, are improved.

[Means for Solving the Problems] According to the present invention, a semiconductor device has a ceramic package structure in which external lead terminals are arranged on the outer edge of a ceramic substrate, and the external lead terminals are formed into an L-shape. At the same time, one tip thereof is brazed and bonded so as to abut against the surface of the external lead terminal attachment portion on the ceramic substrate.

[Function] According to the present invention, the external lead terminal is molded into an L-shape and is brazed by abutting one end of the external lead terminal against the lead terminal mounting portion on the ceramic substrate. This shortens the required length to the minimum required length and minimizes the overall length of the lead up to the circuit board on which it is mounted, making it possible to reduce signal transmission loss due to external node terminals.

[Example] The present invention will be described in detail below with reference to the drawings.

FIGS. 1 and 2 are a perspective view of a ceramic package and an enlarged structural view of an external lead terminal mounting portion thereof, respectively, showing an embodiment of the present invention. According to this embodiment, the external lead terminal 3 has an L-shape in which the short side is molded to a length exceeding the height of the ceramic frame 4, and the short side is formed along the side wall of the ceramic frame 4. The ceramic substrate 1 is vertically erected and solder-bonded with the tips of the short sides abutting the surface of the external lead terminal mounting portion 2 disposed on the outer periphery of the ceramic substrate 1 . Here, 5 indicates a metal brazing material such as Ag-Cu used for this bonding. According to this embodiment, the external lead terminal 3 connects the tip of the lead conductor to the external lead terminal mounting portion 2.
Since the external lead terminal attaching portion 2 is bonded in such a manner that it abuts at a substantially right angle, the length β of the external lead terminal attaching portion 2 can be shorter than that of the conventional case. In other words, even if the length 2 of the external lead terminal attachment part 2 is set to about 0.5n+m, which is half of the conventional length,
A sufficient strength of about 100 g is ensured. In addition, since the long side portions of the external lead terminals 3 are pulled out in a direction parallel to the surface of the ceramic substrate 1 from a position higher than the ceramic frame 4, there is no need to make the lead length redundant due to bending as in the conventional case.
It becomes possible to mount it on a circuit board in this state.

FIG. 3 is a diagram showing how the semiconductor device of the above embodiment is mounted on a circuit board, and the total length of the external lead terminal 3 is set to 1.0 to 1.5 mm.
The inductance of the wiring from the internal wiring of the package to the circuit board 6 and the inter-wiring capacitance C are respectively lowered than those of the conventional structure, and the resonant frequency f between opposing wirings is reduced.
. This shows that it is possible to increase For example, L'=4.2
nH.

The conventional values of C# 0.2pF, f, = 3.9GHz are respectively changed to L# 3.8nH, C# 0.18pF, f
Since a can be set to 4.8 GHz, signal transmission loss due to the external lead terminal 3 can be reduced.

FIG. 4 and FIG. 5 are a perspective view of an external lead terminal mounting portion and a processed molding view of the lead terminal, respectively, showing other embodiments of the present invention.

According to this embodiment, a case is shown in which the L-shaped external lead terminal 3 is molded so that the length of the short side does not exceed the height of the ceramic frame 4. In this case, the tip of the short side part 7 is processed into a thin arc shape, but this is done by preparing a piece of lead conductor shaped as shown in FIG.
It can be easily manufactured by bending it by 90 degrees in either direction up or down in the direction of the arrow from A', and then cutting it out from the half-etched part 8 provided at the tip of the short side part 7. If the tip of the short side portion 7 is arcuate as in this embodiment, the brazing material may creep onto the side wall surface of the ceramic frame 4 when soldered onto the external lead terminal mounting portion 2. It can have the function of suppressing the rise.

[Effects of the Invention] As described above in detail, according to the present invention, the tips of the external lead terminals are butt-connected to the external lead terminal mounting portions on the ceramic substrate. The length can be set short. It also solves the issue of redundant lead lengths when mounting on a circuit board, making it easy to set the wiring length from the internal wiring of the package to the circuit board to the shortest length to reduce inter-wiring capacitance and wiring inductance. can be achieved. That is, by reducing the inductance L and inter-wiring capacitance C of the wiring from the package internal wiring to the mounted circuit board, the resonant frequency f between opposing wirings is achieved. Therefore, it is possible to provide a semiconductor device that can easily achieve compatibility with a circuit board.

[Brief explanation of drawings]

FIGS. 1 and 2 are a perspective view of a ceramic package and an enlarged structural view of the external lead terminal mounting portion of the ceramic package showing an embodiment of the present invention, respectively, and FIG. The mounting state diagram, FIGS. 4 and 5 are respectively a perspective structural diagram of an external lead terminal attachment part and a processed molding diagram of the lead terminal, respectively showing another embodiment of the present invention, and FIGS. 6 and 7 are respectively a conventional one. FIG. 2 is an enlarged structural diagram of an external lead terminal mounting portion of a ceramic package in a high-frequency semiconductor device. DESCRIPTION OF SYMBOLS 1... Ceramic board, 2-- External lead terminal attachment part, 3... External lead terminal, 4... Ceramic frame, 5... Metal brazing material, 6... Circuit board, 7...・
・Short side (of external lead terminal), 8...-half etching groove.

Claims (1)

[Claims] In a semiconductor device having a ceramic package structure in which external lead terminals are disposed on the outer edge of a ceramic substrate, the external lead terminals are formed into an L shape, and one end thereof is attached to the surface of the external lead terminal mounting portion on the ceramic substrate. A semiconductor device characterized by low adhesive bonding so as to abut against the top.