JPS607390B2 - Drive pulse power supply method for charge-coupled semiconductor devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive pulse power supply method for a charge-coupled semiconductor device (hereinafter referred to as a CCD), particularly a large-scale CCD solid-state imaging device.

In recent years, CCDs are being applied to imaging devices as functional devices having a light detection function and a signal transfer function.

In general, many CCD solid-state imaging devices use a polysilicon layer as a transfer electrode in order to improve the degree of integration and light receiving efficiency by realizing fine patterns.
In a three-phase clock CCD using a polysilicon layer as a transfer electrode, a plurality of band-shaped channel stops in the charge transfer direction are arranged under an oxide film in a direction perpendicular to the transfer direction, and the oxide A plurality of band-shaped transfer electrodes in the orthogonal direction are arranged on the top of the film in the transfer direction, and the charge of each channel between the stops is supplied to each of the three-phase transfer electrodes assigned to each channel. It is transferred by the drive pulse.

However, in a large-scale array CCD imaging device that will be used for television in the future, the transfer electrodes will become extremely long and thin, and the resistance value of the polysilicon layer, which has a resistance value of 300/hole, will no longer be negligible. By the way, the aforementioned three-phase CCD is expressed as an equivalent circuit of a distributed constant circuit of capacitance C, resistance R, and inductance L, as shown in FIG.
A pair of three-phase external power supply lines L1 and L2 for the drive pulse in Fig. 1
In the part A near the feeder line LI, the transferred wave shows the same rectangular wave as the pulse wave of the pulse generator, as shown in Figure 3a, but in the part B, which is farther away than the feeder line LI and closer to the feeder line L2 In the part shown in FIG. 3b, the transferred wave becomes extremely distorted.

In addition, in the figure, P1, P2, and P3 indicate each of the three phases. Furthermore, the transfer efficiency of CCD is greatly influenced by the drive pulse waveform.
In the center, the transfer efficiency decreases and the resolution decreases.

In order to solve the above-mentioned conventional drawbacks, this invention
This is an improved method of feeding CCD drive pulses,
Next, this invention will be explained in detail with reference to the drawings from FIG. 4 showing one embodiment thereof. 4 to 6 show a three-phase CCD solid-state imaging device adopting the power feeding method of the present invention, in which a pair of external power feeding lines L1 at one end of the device and a pair at the other end are conventionally shown.
, L2, and also from internal feed lines Li, Lj inside the device. The polysilicon transfer electrode 3 is composed of a low-resistance metal feed line 5 made of aluminum or the like and insulated by an insulating film 4 .

Then, the metal feed line 5 and the transfer electrode 3 to which a drive pulse of the same phase is fed are selectively connected through the contact hole 6, and the external feed lines L1, L2 and the internal feed lines Li, L
i is used to supply the drive pulse.

Note that the charge is transferred on the constituent channels from the top to the bottom of the page. 7 is a silicon semiconductor, and 8 is an oxide film layer of silicon dioxide.

According to this method, drive pulses are supplied to the transfer electrode 3 through the low-resistance metal feed line 5 even in the center of the CCD, so even if the transfer electrode 3 becomes elongated, normal pulses can be uniformly distributed over the entire surface of the CCD. A good uniform resolution can be obtained over the entire surface.

Furthermore, since the low-resistance metal feed line 5 is arranged at the channel stop 3, there is no reduction in the degree of integration. As described above, according to the drive pulse power supply method for a charge-coupled semiconductor device of the present invention, a plurality of band-shaped channel stops in the charge transfer direction are arranged under an oxide film in a direction perpendicular to the transfer direction, and an insulating film is arranged in a direction perpendicular to the transfer direction. A plurality of band-shaped transfer electrodes in the orthogonal direction are arranged in the transfer direction on the top of the oxide film through the charge coupling, and charge in each channel between the stops is transferred by a driving pulse supplied to the transfer electrodes. In the drive pulse power supply method for a type semiconductor device, one end and the other end of the transfer electrodes to which drive pulses of the same phase of each channel are supplied are respectively connected to a pair of external power supply lines for the drive pulses, and the insulating film An internal power supply line is provided at each stop position on the upper part of the input line, and each internal power supply line is selectively connected to each of the transfer electrodes to which the drive pulses of the same phase are supplied through a contact hole. By feeding the drive pulses through the output feed line and each of the internal feed lines, it is possible to feed the drive pulses using not only the external feed line but also the internal feed line, improving transfer efficiency and obtaining good resolution. Moreover, it does not cause a decrease in the degree of integration.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a semiconductor device using a conventional charge-coupled semiconductor device drive pulse power supply method, FIG. 2 is an equivalent circuit diagram of FIG. 1, and FIGS. 3a and 3b are A of the semiconductor device of FIG. 1. , FIG. 4 is a plan view of a semiconductor device employing the drive pulse power feeding method for a charge-coupled semiconductor device of the present invention, FIG. 5 is an enlarged view of FIG. 4, and FIG. A- in Figure 5
FIG. 3 is a partial cross-sectional view taken along line A'. 1...Configuration channel, 2...Channel stop, 3
...Transfer electrode, 4...Insulating film, 6...Metal feeder line, 6...
・Contact hole, 7...Silicon semiconductor, 8...
・Oxide film layer, L1, L2...external power supply line "Li, Li...
・Internal power supply line. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A plurality of band-shaped channel stops extending in the charge transfer direction are arranged under the oxide film in a direction perpendicular to the charge transfer direction, and a plurality of band-shaped transfer electrodes in the orthogonal direction are arranged on the upper part of the oxide film via an insulating film. In a drive pulse feeding method for a charge-coupled semiconductor device, in which the charges of the channels arranged in the transfer direction and between the respective stops are transferred by the drive pulses supplied to the transfer electrodes, the drive pulses of the same phase of the respective channels are arranged. One end and the other end of the transfer electrodes to be powered are connected to a pair of external power supply lines for the drive pulse, and internal power supply lines are respectively provided at the positions of the respective stops on the upper part of the insulating film, and A power supply line is selectively connected to each of the transfer electrodes to which the drive pulses of the same phase are supplied through contact holes, and the drive pulses are supplied by both the external power supply lines and each of the internal power supply lines. Drive pulse power supply method for charge-coupled semiconductor devices.