JPH088268B2 - Semiconductor device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a wiring and a soldering land in an insulating substrate on which a semiconductor chip is mounted.

2. Description of the Related Art FIG. 2 is a cross-sectional view of an LCC (Leadless Chip Carrier) type semiconductor device in which an external terminal is provided on a side wall of an insulating substrate in the conventional example, where 1 is an insulating substrate and 2 is an insulating substrate 1. A semiconductor chip mounted on the substrate 3, a bonding wire 4 for connecting the bonding pad 4 of the insulating substrate 1 and an electrode of the semiconductor chip 2, 5 is an external terminal, and 6 is a metal wiring for connecting the bonding pad 4 and the external terminal 5. .

In the case of an electric circuit that handles high-frequency signals, normal signal transmission is not possible unless the end of the transmission line is terminated with a resistor having the same value as the characteristic impedance of the transmission line through which the signal flows.
Therefore, when the semiconductor device is mounted on a printed circuit board and used, the signal transmission path is terminated with a resistor near the external terminal 5 of the semiconductor device to which a signal is input. However, when the distance between the external terminals 5 becomes narrower, such as 0.5 mm or 0.25 mm, the resistance is larger than those, so if the external terminals 5 for input are close to each other, the resistance The resistor cannot be connected unless the position of is considerably separated from the semiconductor device. Therefore, in such a case, the wiring portion from the position terminated by the resistor to the external terminal 5, the external terminal 5 inside the semiconductor device, the bonding pad 4 and the portion of the metal wiring 6 between them are signaled in a state of characteristic impedance mismatch. Will be transmitted and normal transmission will not be performed.

Also, when a bypass capacitor for power supply is connected, the distance from the position of the capacitor to the bonding pad 4 inside the semiconductor device becomes long, and the effect of stabilizing the power supply of the bypass capacitor for power supply becomes weak due to the impedance thereof. .

Problems to be Solved by the Invention As described above, when a semiconductor device is mounted on a printed circuit board and a signal is terminated by a resistor on the printed circuit board, the distance from the termination position to the bonding pad inside the semiconductor device becomes long and normal. Signal transmission is stopped. Also, in the case of a power supply bypass capacitor, the effect is similarly weakened.

The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a semiconductor device capable of contacting a terminating resistor and a power supply bypass capacitor near a bonding pad.

Means for Solving the Problems The present invention has been made to solve the above problems, and a soldering land is provided on the rear surface of a semiconductor device to connect a terminating resistor, a power supply bypass capacitor, and the like. The bonding pads corresponding to these are connected through through holes.

By connecting the bonding pad to the soldering land on the back side of the semiconductor device through the through hole and connecting the termination resistor or power supply bypass capacitor between the soldering land for bias power supply on the back side of the semiconductor device. The distance between the component connection position and the bonding pad can be shortened. Further, in the case of resistance termination, the characteristic impedance can be maintained up to the bonding pad.

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

FIG. 1 is a drawing of an LCC type semiconductor device in one embodiment of the present invention, FIG. 1A is a sectional view, and FIG. 1B is a plan view seen from the back surface. However, the mounted parts are included. The same numbers as in the conventional example indicate the same.

7,71,72 are component lands for soldering terminating resistors and bypass capacitors, and 8 are component lands 7,71,72
Power supply land for soldering the above parts between
Reference numeral 9 is a through hole, 10 and 11 are termination resistors, and 12 is a bypass capacitor.

In this example, the component lands 7 and 71 correspond to signal input terminals, and the component lands 72 correspond to power supply terminals. It is not always necessary to provide these through holes 9 and component lands 7, 71, 72 for other output terminals and the like, and they may be provided only for input terminals and power supply terminals that require termination. Power is supplied to the power land 8 from the outside. In the case of this example, although the land is the same, if a plurality of power supplies are required, a plurality of power supply lands may be provided correspondingly.

For example, in the case of an ECL level input, a bias voltage of −2V and a terminating resistor of 50Ω are connected to the input end. In such a case, −2V is externally supplied to the power supply land 8 and the terminating resistors 10 and 11 are connected. Should be a resistance of 50Ω.

Further, the external terminal 5, the metal wiring 6, and the through hole 9 are set to have a desired characteristic impedance, that is, if the termination resistance is 50Ω as in the present embodiment,
Naturally, the characteristic impedances of the above three parties are set to 50 according to it.
If Ω is set, normal signal transmission up to the bonding pad 4 can be performed. Since the terminating resistors 10 and 11 are on the back side,
It is possible to terminate much closer to the bonding pad 4 than when terminating on the printed circuit board outside the semiconductor device.

When connecting the bypass capacitor 12 as in the case of the termination, it is better to be as close to the bonding pad 4 as possible. The closer it is, the more effective it is in stabilizing the power supply. Therefore, it is more effective to connect on the back surface of the semiconductor device as in this example than to connect on the printed circuit board.

EFFECTS OF THE INVENTION As described above, according to the present invention, a normal high-frequency signal can be transmitted to the bonding pad, and the stabilization effect by bypassing the power supply can be increased, and its practical effect is large. is there.

[Brief description of drawings]

1A is a sectional view of an LCC type semiconductor device according to an embodiment of the present invention, FIG. 1B is a plan view of the same device seen from the back side, and FIG. 2 is a sectional view of a conventional LCC type semiconductor device. 1 ... Insulating substrate, 2 ... Semiconductor chip, 3 ... Bonding wire, 4 ... Bonding pad, 5 ... External terminal, 6 ... Metal wiring, 7 ... Component land, 8 ... Power supply land , 9 ... Through hole, 10 ... Termination resistor,
12 ... Bypass capacitor.

Claims (2)

[Claims] 1. An insulating substrate and a semiconductor chip mounted on the substrate, each bonding pad and a corresponding electrode being connected by a metal wire, and the bonding pad is provided outside a side surface of the insulating substrate. It is connected to a terminal with a metal wiring and is connected to a soldering land on the back surface of the insulating substrate through a through hole provided in the vicinity of the bonding pad. The through-hole on the signal propagation side that should be connected to the termination resistor is provided with another termination land that can be soldered to the termination land and can be connected to an external power supply line. The semiconductor device, wherein the metal wiring and the external terminal have a characteristic impedance of the same value as the terminating resistor. 2. An insulating substrate and a semiconductor chip mounted on the substrate, each bonding pad and a corresponding electrode being connected by a metal wire, the bonding pad being outside the side surface of the insulating substrate. It is connected to a terminal with a metal wiring and is connected to a soldering land on the back surface of the insulating substrate through a through hole provided in the vicinity of the bonding pad. A semiconductor device, wherein a bypass capacitor can be soldered to the use land, and another solder land to which a power line from the outside can be connected is provided.