KR960011471B1 - Manufacturing method of semiconductor memory device - Google Patents

Abstract

forming a gate region(2) by ion-implantation after forming a device isolation insulating film(3) on the semiconductor substrate(1); forming an active region(5) of a thin film transistor by etching after forming a gate insulating film(4) and depositing a polysilicone layer on the gate insulating film(4); forming a source/drain region(5A) of the thin film transistor with the exposed active region by ion-implantation; forming a first contact hole(15) by etching a first insulating film(7) on the source/drain region; forming a bit line(8); forming a second contact hole(16) by etching the first and the second insulating film(7,8); forming a charge storage electrode(10); and forming a capacitor insulating film(11) and a plate electrode(12) in sequence around the charge storage electrode(10).

Description

Semiconductor Memory Manufacturing Method

1 is a layout diagram for manufacturing a semiconductor memory device according to the present invention.

2A to 2D are sectional views showing a process of manufacturing a semiconductor memory device according to the present invention.

* Explanation of symbols for main parts of the drawings

1: semiconductor substrate 2: gate area (word line)

3: device isolation insulating film 4: gate insulating film

5: active area 6: photoresist mask

7: first insulating film 8: bit line

9: second insulating film 10: charge storage electrode

11 capacitor insulating film 12 plate electrode

13 bit line contact region 14 charge storage electrode contact region

15 and 16: first and second contact holes

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor memory device using a thin film transistor (TFT). In particular, a semiconductor memory capable of solving a short circuit problem between a bit line and a charge storage electrode by forming a gate electrode on a semiconductor substrate. It relates to a device manufacturing method.

In general, in the DRAM structure, as the integration becomes higher, the gap between the bit line and the word line, and the gap between the charge storage electrode and the word line decreases rapidly, causing a short circuit problem between them. There is almost no state.

Therefore, in order to solve the above problems, the present invention first forms a word line as an active region on a semiconductor substrate and then forms a TFT (thin film transistor) with polysilicon thereon so that the word line is a bit line contact region and a charge storage electrode contact. It is an object of the present invention to provide a method for manufacturing a semiconductor memory device which can be isolated from an area.

The semiconductor memory device manufacturing method of the present invention for achieving the above object comprises the steps of forming a device isolation insulating film 3 on a semiconductor substrate 1 and then forming a gate region 2 by an ion implantation method. A gate insulating film 4 is formed on the device isolation insulating film 3 and the gate region 2, and then polysilicon is deposited on the gate insulating film 4, and then a predetermined portion of the polysilicon is etched to form a thin film transistor. Forming an activation region 5 and arranging the photoresist mask 6 on the activation region 5 corresponding to the gate region 2 in a predetermined width from the step; 5) forming the source / drain regions 5A of the thin film transistor, removing the photoresist mask 6 from the step, and depositing a first insulating film 7 on the active region 5. Etching a predetermined portion of the first insulating layer 7 over the source / drain region 5A of the next thin film transistor to form a first contact hole 15; and from the step, the first contact hole 15 Filling and patterning the conductors to form bit lines 8, and from the step, forming a second insulating film 9 on the first insulating film and the bit lines 7 and 8, and then forming the thin film transistor. Etching the first and second insulating layers 7 and 9 over the source / drain regions 5A of the semiconductor substrate to a predetermined width to form a second contact hole 16, and from the step, the second contact hole 16. And filling the conductive material with the conductor 16 to form a charge storage electrode 10, and sequentially from the step the capacitor insulating film 11 and the plate electrode 12 around the charge storage electrode 10. Characterized in that it comprises a step of forming.

According to the present invention, the polysilicon deposited on the gate insulating film may be heat treated to form single crystal silicon, and then a thin film transistor may be formed.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

FIG. 1 is a layout for manufacturing a semiconductor memory device according to the present invention, in which a region in which a word line 2, a bit line 8 and a charge storage electrode 10 are to be located is shown. Denotes a portion connected to the source / drain region, and the charge storage electrode contact region 14 indicates a portion to which the charge storage electrode 10 and the source / drain region 5A are connected, and the thin film transistor active region 5 Represents a region operated as a thin film transistor.

2A through 2D are cross-sectional views showing a process for manufacturing a semiconductor memory device according to the present invention, and FIG. 2A shows a device isolation insulating film 3 formed on a semiconductor substrate 1 with the device isolation insulating film 3 as a mask. As a result, the gate region 2 is formed by the ion implantation method. Since the gate region 2 is used as a word line (2 in FIG. 1) of the memory device, the resistance should be as low as possible.

FIG. 2B illustrates a gate insulating film 4 formed on the gate region and the device isolation insulating films 2 and 3 by thermal oxidation or chemical vapor deposition in the structure of FIG. 2A, and then polysilicon is deposited on the gate insulating film 4. After etching a predetermined portion in the state to form an activation region 5 of the thin film transistor, a photoresist mask having the same width as the gate region 2 is formed on the activation region 5 corresponding to the gate region 2. 6) is a cross-sectional view of a source / drain region 5A of the thin film transistor formed by an ion implantation method. The region of the lower portion of the photoresist mask 6 becomes the channel region 5B of the thin film transistor.

On the other hand, under the structure of FIG.

2C illustrates that the photoresist mask 6 is removed, the first insulating film 7 is deposited on the active region 5, and the first insulating film 7 on the source / drain region 5A is formed to have a predetermined width. The first contact hole 15 is formed by etching, followed by filling and patterning the first contact hole 15 with a conductor to form a bit line 8.

FIG. 2D illustrates first and second upper portions of the source / drain regions 5A after forming the second insulating layer 9 on the first insulating layer and the bit lines 7 and 8 after forming the bit line 8. In the state in which the insulating films 7 and 9 are etched to a predetermined width to form a second contact hole 16 and a conductor is filled in the second contact hole 16 and then patterned to form the charge storage electrode 10. It is sectional drawing of the state where the capacitor insulating film 11 and the plate electrode 12 were formed in order around the charge storage electrode 10. FIG.

As described above, according to the present invention, a thin film transistor is applied to the memory device to form a word line on the silicon substrate, thereby completely eliminating a short circuit problem between the bit line and the charge storage electrode, thereby increasing the process margin. Since the activation region is separated into a silicon substrate, a neighboring activation region, and an insulating layer, the leakage current problem can be solved, thereby improving yield and improving memory device characteristics.

Claims (2)

In the semiconductor memory device, forming a device isolation insulating film 3 on a semiconductor substrate 1 and then forming a gate region 2 by an ion implantation method, and from the step, the device isolation insulating film 3 and the gate region. (2) forming a gate insulating film 4 on the upper side, and then depositing polysilicon on the gate insulating film 4, and then etching a predetermined portion of the polysilicon to form an active region 5 of the thin film transistor; From the step, the photoresist mask 6 is arranged on the activation region 5 corresponding to the gate region 2 in a predetermined width, and the active region 5 exposed by the ion implantation method is provided with the cathode / drain of the thin film transistor. Forming the region 5A, removing the photoresist mask 6 from the step, depositing a first insulating film 7 over the active region 5, and then source / drain region 5A of the thin film transistor. Etching a predetermined portion of the upper first insulating layer 7 to form a first contact hole 15, and filling and patterning a conductor in the first contact hole 15 from the step to form a bit line ( 8) and a second insulating film 9 formed on the first insulating film and the bit lines 7 and 8 from the step, and then on top of the source / drain region 5 of the thin film transistor. Etching the first and second insulating layers 7 and 9 to a predetermined width to form a second contact hole 16, and filling the second contact hole 16 with a conductor from the step, and then Forming a charge storage electrode 10 and sequentially forming a capacitor insulating film 11 and a plate electrode 12 around the charge storage electrode 10 from the step. Method of manufacturing semiconductor memory device. The method of manufacturing a semiconductor memory device according to claim 1, wherein the polysilicon (5) on the gate insulating film (4) is heat treated to form single crystal silicon and then a thin film transistor is formed.