JPH0430461A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To improve a semiconductor integrated circuit in degree of integration without enlarging a printed board in area and to prevent a ringing waveform from occurring by a method wherein a damping resistor is provided just under a bonding pad. CONSTITUTION:A damping resistor 2 such as a diffusion resistor or a polysilicon wiring formed of material possessed of a resistive component realized in a semiconductor manufacturing process is provided under a bonding pad 1 formed of an aluminum film. A contact window 3 used for connecting the electrode of the bonding pad 1 to the the damping resistor 2 is provided protruding outside of the edge of the bonding pad 1 so as to protect the edge of the damping resistor 2 against damage caused by the impact of wire bonding or to protect an interlaminar film against damage caused by impact induced by the nonuniform step of the interlaminar film between the damping resistor and the bonding pad 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to, for example, C0M5. The present invention relates to a semiconductor integrated circuit using a damping resistor that effectively prevents ringing that occurs in an output waveform in a TTL or other logic output circuit.

Conventional technology As the speed of electronic devices increases, the operating frequency of semiconductor integrated circuits also increases, and the output waveform of the output stage also increases.
High-speed rising and falling waveforms reaching up to 2 ns are now required. As a result, overshoot and undershoot of the logic output waveform from high level (High) to low level (Low) or from low level (Low) to high level (High), which previously did not pose a problem or was very slight. In other words, ringing has become a problem. The problems are unnecessary side radiation emitted into space during ringing, and malfunctions in the next stage logic circuit that occur when the ringing waveform is transmitted to the next stage.

FIG. 4 shows an output waveform in which ringing occurs when there is no damping resistor. If the overshoot causes the input threshold of the next stage, a malfunction will occur, and furthermore, the steep overshoot and undershoot waveforms will generate unnecessary side radiation that causes interference noise.

In conventional technology, a damping resistor to prevent this ringing is installed on a printed circuit board outside the semiconductor integrated circuit.

Problems to be Solved by the Invention Conventional techniques require an additional external resistor, which requires extra cost. For example, in the case of an output bus of a microcomputer, the number of buses required depends on the bit width, and the latest computers require about 32 buses. This resistor group not only increases its own cost, but also requires extra area on the printed circuit board, which increases cost and hinders miniaturization of the device.

An object of the present invention is to provide a semiconductor integrated circuit that solves these problems.

Means for Solving the Problems The semiconductor integrated circuit of the present invention has a structure in which a damping resistor for preventing ringing is provided directly under a bonding pad within the semiconductor integrated circuit, and no special formation region exclusively for the damping resistor is provided.

Effect: According to the semiconductor integrated circuit of the present invention, there is no need to provide a formation region exclusively for the damping resistor (ringing of the output waveform can be prevented).

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

FIG. 1 is a plan view showing the configuration of a semiconductor integrated circuit according to the present invention. Directly below the bonding pad 1 formed of an aluminum film, a damping resistor 2 made of a material having a resistance component that can be realized in a semiconductor manufacturing process, such as a diffused resistor or a polysilicon wiring, is formed via an insulating film. In order to avoid the edges of the damping resistor 2 being destroyed by the impact during wire bonding, and the interlayer film being destroyed by the impact caused by the uneven step of the glabellar membrane between the damping resistance generated at the edge and the bonding pad 1. The contact window 3 for connecting the electrode of the bonding pad 1 and the damping resistor 2 is designed to protrude outside the bonding pad edge. The signal of the output transistor inside the chip 4 is input from the aluminum electrode wiring layer 5, and the contact window 3 with the damping resistor 2 is input.
, passes through the tamping resistor 2 directly below the bonding pad 1 , passes through the contact window 3 between the damping resistor 2 on the end side of the chip 4 and the bonding pad 1 , and reaches the bonding pad 1 . FIG. 2 shows a circuit diagram corresponding to the plan view of FIG. 1. Resistor 7 is damping resistor 2 in Figure 1.
In this case, the output terminal 6 corresponds to the bonding pad 1. However, the output transistor 7 is not clearly shown in FIG. 1, and can be considered to be on the extension line of the aluminum electrode wiring 5.

Figure 3 shows the output waveform when a damping resistor is inserted. Ringing is suppressed by damping resistance.

As described in detail, according to the semiconductor integrated circuit of the present invention,
By forming a damping resistor directly under the bonding pad, the degree of integration is increased, and the printed board area does not increase compared to the case where the damping resistor is added outside the IC (and the cost increases due to the corresponding increase in the resistor printed board area). Therefore, ringing waveforms can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of a semiconductor integrated circuit according to the present invention, FIG. 2 is a circuit diagram of an output section according to an embodiment of the present invention,
FIG. 3 is an output waveform diagram when a damping resistor is provided, and FIG. 4 is an output waveform diagram of a conventional example. 1... Bonding pad, 2... Damping resistor, 3... Contact window, 4...
... Chip, 5 ... Aluminum electrode wiring layer, 6 ... Output terminal corresponding to bonding pad, 7 ... Damping resistor, 8 ...
...Output transistor. Name of agent: Patent attorney Shigetaka Awano

Claims (1)

[Claims] A resistor is formed directly under the bonding pad via an insulating film, and a contact window connecting the bonding pad and the resistor is formed at an end of the bonding pad or adjacent to the bonding pad. Semiconductor integrated circuit.