JPS62221111A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To omit two mask aligning processes, by providing a photo masks, which has a specified opening pattern and an opening part pattern having a diameter shorter than the wavelength of an exposing light beam, on a resist film, performing exposure, and removing the exposed part with a resist-film removing agent. CONSTITUTION:On a resist film, the following parts are provided: an exposing pattern region 14 having an opening part 13 in a specified form; a pattern region 16 having a circular opening part 15, which has a diameter shorter than the wavelength of an exposing light beam; and a photo mask 18 having a pattern region 17 comprising a non-opening part region. After exposure, the exposed part is removed by using a resist removing agent. Then, a staircase shaped resist film 19 is formed. Thereafter, B<+> atom ions are implanted, and a channel region 20 is formed. The remaining resist film 19A is removed by ashing. With the resist film 19B as a mask, the B<+> atom ions are implanted, and two channel regions 20 and 21 having different impurity atom concentrations are formed.

Description

[Detailed Description of the Invention] [Summary] A pattern region having openings formed in a predetermined pattern, a pattern region having a circular or rectangular opening having a diameter or one side shorter than the wavelength of an exposure light beam; By placing an exposure mask consisting of a non-opening area on the resist film, exposing it to light, and then removing it with a resist film remover, a thick layer can be formed on the same substrate using one mask and one exposure process. By forming resist films with different thicknesses and using these resist films as masks to introduce impurity atoms into the substrate,
Forming regions of different concentrations on the substrate.

[Industrial application field]

The present invention relates to a resist film pattern forming method, and more particularly, to a method for forming regions with different impurity atom concentrations on a substrate while reducing the number of exposure masks used and the number of mask alignments required in the exposure process.

For example, when forming an MO3 type semiconductor device, the source and drain regions or channel regions of a MOS transistor are formed using an ion implantation method. A resist film is used as a mask.

In particular, in order to form MO5 type transistors with different dark value voltages on a single silicon (Si) wafer, the dark value voltage is MOS type transistors of different types are formed.

(Prior Art) Conventionally, in order to form channel regions having different concentrations of implanted impurity atoms, as shown in FIG. As shown in the figure, a photomask 4 having an opening 3 of a predetermined area is placed in a resist film removing solution, and the resist film 2 is exposed to ultraviolet rays from the mask 4.

Next, the exposed portion of the resist film is removed using a resist film remover to form a resist film pattern 2A shown in FIG.

Next, using the patterned resist film 2A as a mask, B+ atoms are ion-implanted into the substrate at a dose of 1X10'' atoms/cI02 as shown by the arrows to form the channel region 5.
form.

Next, as shown in FIG. 1O, the resist film 2A shown in FIG. 9 is exposed to ultraviolet light using a photomask 7 having an opening 6 with a larger area than the opening 3 of the mask 4 shown in FIG. 8. Then, the exposed area is removed with a resist film removing solution to form a resist film pattern 2B shown in FIG.

Next, using this resist lll2B as a mask, B+ atoms are ion-implanted at a dose of 2×10 5 atoms/cm 2 to form a channel region 8 .

Then, the channel region 9 contains B+ atoms with a dose of 2X1.
The region is ion-implanted with a dose equal to the sum of 0 atoms/c112 and 1×1O atoms/a12.

In this way, by forming 2M type regions with different impurity atom concentrations as the channel regions 8 and 9, MO3 type semiconductor devices with two different threshold voltages can be formed in one Si wafer. Ta.

[Problem that the invention seeks to solve]

However, such a method requires two photomasks and two exposure steps, that is, two mask alignment steps.

This mask alignment process requires a lot of time, and reducing the mask alignment process is necessary to reduce the number of steps for manufacturing semiconductor devices.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a semiconductor device that solves the above problems, reduces the number of mask alignments, and reduces the number of manufacturing steps.

[Means for solving problems]

A method for manufacturing a semiconductor device according to the present invention includes: an exposure pattern having an opening in a predetermined area on a substrate coated with a resist film; a diameter shorter than the wavelength of an exposure light source;
Alternatively, an exposure pattern in which a circular or rectangular minute opening with one side is formed and an exposure mask consisting of a non-opening area are placed on the resist film, and the exposure mask is passed through each pattern area from above the exposure mask. A light beam for exposure is irradiated onto the resist film.

Next, the resist film in the area exposed through the exposure pattern having openings is removed with a resist film removing liquid to form an opening, and the resist film in the area exposed through the exposure pattern having minute openings is removed. Remove to a predetermined thickness.

Next, impurity atoms are introduced into the substrate through the openings in the patterned resist film.

Further, the resist film in the area exposed through the pattern area of the minute opening is removed to form an opening in the resist film, and the unexposed resist film is removed to a predetermined thickness.

Further, impurity atoms are introduced into the substrate through the openings formed in the pattern of the minute openings.

[Effect]

The resist sun exposure method of the present invention involves installing a photomask having a predetermined opening pattern and an opening pattern having a diameter shorter in wavelength than that of the exposure light onto the resist, and exposing the photomask to a resist film remover. By removing the resist film, a step-like resist film having openings of two different sizes and partially different thicknesses is formed with one mask and one mask alignment process.

By introducing impurity atoms through these two types of openings with different dimensions, two types of regions with different concentrations are formed in the substrate.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

First, as shown in FIG. 1, a positive resist film 12 is coated on an N-type Si substrate 11.

Next, as shown in FIG. 2, an opening 1 of a predetermined shape is formed in the center.
3, and a circular opening 15 whose diameter is a dimension l shorter than the wavelength of the exposure light beam.
A photomask 1 having a second pattern region 16 having a non-opening region and a third pattern region 17 having a non-opening region.
8 is placed on the resist film 12 and exposed, and then the exposed portion is removed using a resist film remover such as choline.

Then, the cross-sectional view of the patterned resist film is shown in the third figure.
As shown in the figure, the resist film 19A in the area below the opening 13 is removed, the resist film 19A in the area below the pattern area 16 having the opening 15 is removed by a predetermined thickness, and the resist film 19A in the area below the pattern area 16 having the opening 15 is removed, and the resist film 19A in the area below the pattern area 16 having the opening 15 is removed, and The lower part remains as a resist film 19B and has a stepped cross-sectional structure.
9 is formed.

As shown in FIG. 4, such a resist 11m111
9, B+ atoms are ion-implanted at a dose of lXl0 atoms/e1m2 to form the channel region 2.
form 0.

Furthermore, this substrate is introduced into a reaction vessel, and is ashed and removed in an oxygen gas plasma atmosphere to the extent that the remaining resist film 19^ can be removed.

Then, as shown in FIG. 5, the resist 19B remains.

Next, as shown in FIG. 6, using the resist film 19B as a mask, a dose of 2×lθ″' atoms/
By ion-implanting B+ atoms at the port 2, a channel region 21 with an ion implantation amount of 2×10 atoms/cf112,
A channel region 22 with a combined ion implantation amount of 2×10 atoms/cI2 and 1×10 atoms/cI112 is formed, and two channel regions 2 with different impurity atom concentrations are formed.
0.21 are formed respectively.

In this way, with one mask and one exposure process,
Two regions with different concentration regions are formed, and the number of steps for manufacturing a semiconductor device can be reduced compared to conventional methods.

Note that in the above embodiments, the resist film was formed in two thicknesses, and two regions with different impurity concentrations were formed. As a result, two or more regions having different impurity concentrations are formed.

Further, in the photomask used in this example, for convenience of explanation, the pattern region 14 having the opening 13 and the pattern region 16 having the opening 15 were formed adjacent to each other, but the respective pattern regions 14 and 16 are separated by a distance. They may be formed separately.

〔Effect of the invention〕

As described above, according to the method of the present invention, the number of man-hours for mask alignment in the exposure process of the resist film, which serves as a mask for forming regions with different impurity concentrations, is reduced, so the number of man-hours for manufacturing semiconductor devices is reduced. There is an effect that can be done.

[Brief explanation of drawings]

1 and 3 to 6 are cross-sectional views showing an embodiment of the method of the present invention in the order of steps, FIG. 2 is a plan view of a photomask used in the method of the present invention, FIGS. 7 and 9 11 are cross-sectional views showing the conventional method in the order of steps, and FIGS. 8 and 10 are plan views of photomasks used in the conventional method. In the figure, 11 is a Si substrate, 12 is a resist film, 13.15 is an opening, 14 and 16 are pattern areas, 17 is a non-opening area,
18 is a photomask, 19.19A and 19B are resist films, and 20.21.22 is a channel region. 71 Jlj0I￥1iP
1st figure of engineering 2nd l 2FN! -θ attack 2: pis bitoki ≧ E energy ￥furi 3rd drawing (/Ji'l-Ter Jingo 4-chom@5 Figure 6 Figure U/1 and Zipass I-H encounter 1's daughter I trfJ @ 7 Figure @ 8 Figure @ 9 Figure

Claims (1)

[Claims] A substrate (11) on which a resist film (12) is coated.
An exposure pattern area (14) having an opening (13) in a predetermined area on the top, and a circular or rectangular opening (15) having a diameter or one side shorter than the wavelength of the exposure light source. Formed exposure pattern area (16)
and an exposure mask (18) consisting of a non-opening area (17).
) is placed on the resist film (12), and the exposure mask (
18) A step of irradiating the resist film (12) with an exposure light beam from above through the pattern regions (14) and (16), and converting the resist film in the area exposed through the pattern region (14) of the mask (18) into a resist film. While removing with a film removal liquid to form an opening, the pattern area (16)
a step of removing the resist film in the area exposed through the pattern to a predetermined thickness; a step of introducing impurity atoms into the substrate through the opening of the patterned resist film;
6) removing the resist film in the exposed area to form an opening in the resist film and removing a predetermined thickness of the unexposed resist film; A method for manufacturing a semiconductor device, comprising a step of introducing atoms.