JPH0430568A - Semiconductor device - Google Patents

Abstract

PURPOSE:To To increase circuit operation mergin by enabling capacitance determined by an electrode surface area to be increased and eliminating any trouble on a circuit design by forming a laminating type capacitor part. CONSTITUTION:An impurity diffusin layer 2 is formed by injecting P or As into a capacitor part formation region of a principal surface of a semiconductor substrate 1 by a sleeve diffusion method using a photoresist process. Then, an insulating film 3 comprising SiO2 and the like is formed over the entire surface, and thereafter a contact opening is formed in the diffusion layer 2 through a photoresist process. Then a metal thin film comprising aluminum and polycrystalline silicon is formed on the insulating film 3 and the contact opening, and a lower electrode 4 for storage of electric charges is formed after a photoresist process. Then, a pluarlity of grooves 5 are formed in the lower electrode 4. Then, an insulating film 6 as an interelectrode dielectric of the capacitor part is formed on the lower electrode 4 and the insulating film 3 with SiO2 and the like, and further an upper electrode 7 is formed on the insulating film 6 with aluminum and polycrystalline silicon. Hereby, the capacitor part is employed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a semiconductor device having a stacked capacitor section.

[Conventional technology]

Conventionally, a stacked capacitor section formed in a semiconductor device is composed of a lower electrode 4 formed on a diffusion layer, an insulating film 6, and an upper electrode 7, as shown in FIG. 2, and the upper surface thereof is smooth. The patterning was also done based on straight lines, and each etched surface was formed into a single plane.

[Problem to be solved by the invention]

Since the capacitive part of the conventional semiconductor device described above has a smooth surface with no unevenness, the capacitance value determined by the surface area in contact with the insulating film of the electrode is small, and as the pattern of semiconductor devices becomes finer, the area of the capacitive part becomes smaller. At the same time, the capacitance value becomes even smaller, which becomes an obstacle in circuit design and reduces the margin of circuit operation, and at the same time causes a decline in the yield and quality of manufactured semiconductor devices.

[Means to solve the problem]

A semiconductor device of the present invention has a stacked capacitor section including a lower electrode, an insulating film, and an upper electrode sequentially formed on a semiconductor substrate, wherein the stacked capacitor section is formed in an uneven shape. It is something that exists.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1A to 1C are cross-sectional views of a semiconductor chip shown in the order of manufacturing steps to explain one embodiment of the present invention.

First, as shown in FIG. 1(a), P or As is introduced into the capacitor formation region on the main surface of the semiconductor substrate 1 to form an impurity diffusion layer 2 by selective diffusion using a photoresist process. Next, after forming an insulating film 3 made of SiO2 or the like over the entire surface, contact openings are formed on the diffusion layer 2 through a photoresist process.

Next, as shown in FIG. 1(b), a metal thin film such as aluminum or polycrystalline silicon is formed on the insulating film 3 and the contact opening, and a lower electrode 4 for charge storage is formed through a photoresist process. do. Next, a plurality of grooves 5 are formed in this lower electrode 4.

Next, as shown in FIG. 1(c), an insulating film 6 which is to be a dielectric between the electrodes of the capacitive part is placed on the lower electrode 8ii4 and the insulating JI3.
A capacitor section is completed by forming an upper electrode 7 made of aluminum or polycrystalline silicon on the insulating film 6.

As described above, according to this embodiment, since the capacitor portion is formed in an uneven shape, the capacitance value becomes large.

〔Effect of the invention〕

As described above, the present invention can increase the capacitance value determined by the surface area of the electrode by forming the stacked capacitor portion in an uneven shape. Therefore, it is possible to obtain a semiconductor device that eliminates obstacles in circuit design, provides a large margin for circuit operation, and is fully compatible with fine patterning.

[Brief explanation of drawings]

FIGS. 1(a) to (c) are sectional views for explaining one embodiment of the present invention, and FIG. 2 is a sectional view of a conventional example. DESCRIPTION OF SYMBOLS 1... Semiconductor substrate, 2... Diffusion layer, 3... Insulating film, 4... Lower electrode, 5... Groove, 6... Insulating film, 7
...Top electrode.

Claims (1)

[Claims] A semiconductor device having a stacked capacitor section including a lower electrode, an insulating film, and an upper electrode sequentially formed on a semiconductor substrate, wherein the stacked capacitor section is formed in an uneven shape. Device.