JPH05299440A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the manufacturing method of a semiconductor device which does not generate parasitic capacity and has simplified manufacture process. CONSTITUTION:A spacer layer 9 consisting of an insulating film is provided on the semiconductor active layer 2 on a semiconductor substrate 1, and photoresist 10 is applied, and a gate is patterned, and then with this photoresist 10 as a mask, the spacer layer 9 is etched off, and next an insulating film 11 is stacked all over the surface. Furthermore, a T-shaped photoresist 7 is patterned hereon, and the insulating film 11 is etched, and then a recessed region 4 is made by the etching by self alignment using this spacer layer 9 as a mask, and further a T-shaped gate electrode 8 is made and lifted off, whereby it is so arranged that the insulating film, etc., in contact with the recessed region 4 and the gate electrode 8 does not exist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming a gate electrode such as a field effect transistor.

[0002]

2. Description of the Related Art FIGS. 3 (a) to 3 (e) and FIG. 4 (a),
(B) is sectional drawing which showed the manufacturing method of the conventional semiconductor device in order of the manufacturing process. In these figures, 1 is a semiconductor substrate, 2 is a semiconductor active layer formed on the semiconductor substrate 1, 3 is a photoresist, 4 is a recess region formed in the semiconductor active layer 2, and 5 is silicon nitride or the like. Insulating film, 6 and 7 are photoresists, 8 is the recessed region 4
The gate electrode 80 is formed inside, and 80 is a gate electrode metal.

Next, a manufacturing process of a semiconductor device having a T-shaped gate electrode will be described with reference to FIGS. First, as shown in FIG. 3A, a photoresist 3 is formed on the entire surface of the semiconductor active layer 2 formed on the semiconductor substrate 1.
After applying, patterning is performed. Using the photoresist 3 as a mask, the semiconductor active layer 2 is etched by a desired amount to form a recess region 4. Next, FIG. 3 (b)
After removing the photoresist 3, an insulating film 5 made of silicon nitride or the like is formed to a thickness of about 0.3 μm by plasma CVD or the like, as shown in FIG. Next, as shown in FIG. 3C, a photoresist 6 is applied on the insulating film 5,
Patterning for gate formation is performed. At this time, as shown in the figure, the opening of the photoresist 6 by patterning is formed so as to enter the recess region 4. Next, as shown in FIG. 3D, the insulating film 5 is etched using the photoresist 6 as a mask. The etching is anisotropic etching such as RIE (reactive ion etching). In this case, the opening width 1 of the insulating film 5 determines the gate length. Next, as shown in FIG. 3 (e), after removing the photoresist 6, a new photoresist 7 is applied and patterning is performed. Pattern of photoresist 7
The opening is wider than the opening width 1 of the insulating film 5 to obtain the T-shape. Here, it is desirable that the resist profile has a reverse taper in order to improve the lift-off property. Next, as shown in FIG. 4A, the gate electrode metal 8
0 is deposited by vacuum evaporation or the like. Further, as shown in FIG. 4B, the photoresist 7 and the unnecessary gate electrode metal 80 on the photoresist 7 are removed by lift-off to form a semiconductor device having a T-shaped gate electrode 8. To be done. Although FIG. 4B shows the case where the insulating film 5 is not removed, as shown in FIG. 5, the insulating film 5 is left only in the portion in contact with the gate electrode 8, or as shown in FIG. , All may be removed. The insulating film 5 is removed by RIE, plasma etching or the like.

[0004]

Although the conventional semiconductor device is formed as described above, the gate pattern in the recess region 4 is unstable and the gate electrode is T-shaped. 8 and the semiconductor active layer 2 have an extra parasitic capacitance via the insulating film 5. When the insulating film 5 is removed so as not to have an extra parasitic capacitance, there is a problem that damage due to dry etching in the recess region 4 may affect device characteristics. ..

The present invention has been made in order to solve the above-mentioned problems, and it is possible to form a recess area by self-alignment with respect to gate patterning and to prevent an extra parasitic capacitance from occurring. It is an object of the present invention to obtain a method for manufacturing a semiconductor device, which does not have a step of entering a dry etching damage into a region.

[0006]

According to the method of manufacturing a semiconductor device of the present invention, a spacer layer made of an insulating film is provided on a semiconductor active layer on a semiconductor substrate, and a photoresist is applied to the gate pattern. After this, the photoresist layer is used as a mask to etch away the spacer layer, an insulating film is laminated on the entire surface, a resist is applied, and an upper gate pattern is formed into a T shape to form the spacer. Recess regions are formed by etching using the mask layer as a mask, and when forming a T-shaped gate electrode, there is no insulating film in contact with the recess region and the gate electrode after lift-off. Is.

[0007]

In the present invention, since the recess region is formed by interposing the spacer layer and using the spacer layer as a mask, the recess region can be formed by self-alignment with respect to the gate patterning and the gate region can be formed. In the electrode formation, since there is no insulating film in contact with the recess region and the gate electrode, no extra parasitic capacitance is generated and the step of removing the insulating film is unnecessary, so that there is no fear of dry etching damage.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A to 1D and 2A to 2D are process cross-sectional views showing an embodiment of the method for manufacturing a semiconductor device of the present invention. 1 and 2, 1 is a semiconductor substrate,
2 is a semiconductor active layer formed on the semiconductor substrate 1, 4
Is a recess region formed in the semiconductor active layer 2, 7 is a photoresist, 8 is a T-shaped gate electrode, and 9 is a space.
10 is a photoresist, 11 is an insulating film, and 80 is a gate electrode metal.

Next, a manufacturing process of the semiconductor device according to the present invention will be described. First, as shown in FIG. 1A, a semiconductor active layer 2 is formed on a semiconductor substrate 1, and a spacer layer 9 made of silicon nitride or the like is formed on the semiconductor active layer 2.
After stacking about 1 μm, a photoresist 10 is applied,
Perform gate patterning. Next, as shown in FIG. 1B, the spacer layer 9 is formed using the photoresist 10 as a mask.
Are removed by etching. At this time, the etching is anisotropic etching such as RIE. Next, as shown in FIG. 1C, an insulating film 11 having a film quality different from that of the spacer layer 9 is laminated on the entire surface. The role of the insulating film 11 is to prevent the photoresist applied in the next step from mixing with the photoresist 10 which has been subjected to the gate patterning. Next, as shown in FIG. 1D, a photoresist 7 is applied on the insulating film 11 and patterned to determine the upper portion of the T-shape. As in the conventional case, the resist profile is preferably reverse taper. Next, FIG. 2 (a)
As shown in, the insulating film 11 is etched using the photoresist 7 as a mask. The etching at this time may be either wet or dry. Next, FIG.
As shown in (b), the spacer layer 9 is side-etched by a necessary amount in consideration of the improvement of the FET breakdown voltage, and then the spacer is removed.
The semiconductor active layer 2 is etched using the mask layer 9 as a mask,
The recess region 4 is formed. Here, the recess area 4 is
Since it is formed by self-alignment with respect to the top patterning, the instability of mask alignment as in the conventional case is eliminated.
Next, as shown in FIG. 2C, a gate electrode metal 80 is deposited by vacuum evaporation or the like, and then lifted off to remove the photoresists 7, 10 and the insulating film 11, the photoresist 7.
By removing the unnecessary unnecessary gate electrode metal 80, a semiconductor device having a T-shaped gate electrode 8 as shown in FIG. 2D is formed.

[0010]

As described above, according to the present invention,
By interposing a spacer layer under the photoresist for gate patterning, it becomes possible to form a recess region by self-alignment with respect to the gate patterning.
Since there is no insulating film or the like in contact with the recess region and the gate electrode, extra parasitic capacitance is not generated, the step of removing the insulating film is not required, and dry etching damage is also eliminated.

[Brief description of drawings]

FIG. 1 is a process sectional view showing an embodiment of a method for manufacturing a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view showing the manufacturing process of the semiconductor device of the present invention, which is subsequent to FIG.

3A to 3D are process cross-sectional views showing a conventional method for manufacturing a semiconductor device.

FIG. 4 is a process cross-sectional view showing the method of manufacturing the conventional semiconductor device, following FIG. 3;

FIG. 5 is a cross-sectional view showing another conventional semiconductor device.

FIG. 6 is a sectional view showing still another conventional semiconductor device.

[Explanation of symbols]

 1 Semiconductor Substrate 2 Semiconductor Active Layer 4 Recess Region 7 Photoresist 8 Gate Electrode 9 Spacer Layer 10 Photoresist 11 Insulating Film 80 Gate Electrode Metal

Claims (1)

[Claims] 1. A step of forming a spacer layer made of an insulating film on a semiconductor active layer formed on a semiconductor substrate, coating a photoresist on the spacer layer, and then forming a gate pattern.
Process, a process of etching the spacer layer using the gate patterned photoresist as a mask, a layer of an insulating film is laminated on the entire surface, and then a photoresist different from the photoresist is applied to form a T-shape. The step of performing the upper gate patterning, the step of etching the insulating film using the T-shaped photoresist as a mask, the side etching of the spacer layer by a desired amount, and then the spacer layer is removed. The step of etching the semiconductor active layer as a mask to form a recess region, the step of depositing a gate electrode metal on the entire surface, and the unnecessary gate electrode metal on the photoresist, insulating film and photoresist by lift-off. A step of removing the gate electrode to form a T-shaped gate electrode.