JPH0287147A - Resist removing method - Google Patents

Abstract

PURPOSE:To enable removal of a resist using no organic solvent by decomposing the resist attached to a semiconductor substrate by oxygen dissolved in pure water into carbon dioxide and water to remove the resist. CONSTITUTION:The resist is removed by heating the pure water 9 in a pressurized vessel 8 with a heater to a temperature of about 200 - 300 deg.C, operating a pressurizing device to raise the air pressure to about 50 - 100kg/cm<2>, and dipping a plurality of the substrates 10 of the semiconductor held with a carrier 11 into the pure water 9 in the vessel 8, thus permitting the resist to be removed without using organic solvent, and environmental pollution due to waste water to be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for removing resist in a PR process in the manufacture of semiconductors such as ICs and LSIs.

[Conventional technology]

One of the important processes in semiconductor manufacturing is a PR (Photo Re5ist) process in which an insulating film on a semiconductor substrate is selectively removed to form a window for selective diffusion. This PR process is generally performed in (a) in Figure 2.
) to (f).

That is, FIG. 2(a) shows an insulating film (2) formed on a semiconductor substrate (wafer), and in this state, first, as shown in FIG. 2(b), a resist (3) is formed. ) is covered with a mask (5) in which an opaque portion (4) is selectively formed on the lower surface of a transparent glass substrate, and light (ultraviolet rays) is irradiated vertically from above the mask (5) to form a resist 1-(3). is selectively exposed to light, and the exposed areas are hardened and altered by photopolymerization reaction. next,
The mask (5) is removed and the resist (3) is developed to remove the non-exposed areas and the window holes (6) are opened as shown in FIG. 2(d).
) to form. Afterwards, the insulating film (2) seen through the window hole (6) is selectively removed by etching the remaining resist (3) as a corrosion-resistant mask as shown in Figure 2(e). Form the desired window hole (7) and finally (
As shown in ), the resist (3) is dissolved and removed with an organic solvent.

[Problem to be solved by the invention]

By the way, since the resist (3) in the PR process in semiconductor manufacturing has conventionally been removed by dissolving it with an organic solvent as described above, the following problems have arisen. That is, after removal, in order to remove the organic solvent attached to the semiconductor substrate (1), it is necessary to wash it in the order of methyl ketyl ketone (MEK), isopropyl alcohol (IPA), and pure water, which takes a lot of man-hours. There were a lot of problems, and productivity was bad. Furthermore, it is difficult to dispose of the waste liquid of the used organic solvent, and there is also a risk that the waste liquid may cause environmental pollution. Furthermore, manufacturing costs are high because large quantities of organic solvents and pure water must be used.

[Means to solve the problem]

This invention was made in view of the above problems, and its purpose is to provide a resist removal method that does not use an organic solvent.

In order to achieve the above object, this invention immerses a semiconductor substrate to which a resist is attached in pure water that is heated to a high temperature and pressure, and the resist is oxidized by dissolved oxygen in the pure water that has been heated and pressurized. It is something that is decomposed.

[Effect]

By the above means, the resist attached to the semiconductor substrate is oxidized and decomposed into carbon dioxide and water by dissolved oxygen in pure water and removed.

〔Example〕

The resist removal method according to the present invention will be explained below with reference to a specific implementation apparatus shown in FIG.

In Figure 1, (8) is a pressure vessel with pure water (9) inside.
) is stored, and a heater and an internal pressure booster are attached, although not shown in the drawings. When the heater is heated, the temperature of the pure water (9) stored in the pressure vessel (8) is gradually raised, and when the pressure increase device in the vessel is operated, the temperature inside the pressure vessel (8) is increased. The pressure is gradually increased.

(lO) is a semiconductor substrate from which the resist is to be removed, and is held in large numbers in a carrier (11).

To explain the operation in the above configuration, the heater is heated to raise the temperature of the pure water (9) stored in the pressure vessel (8) by about 200 to 300°C G4, and the pressure booster is activated. Activate the pressure in the pressure volume "H (8) to 50 ~
100) Increase the pressure to about [g-f / cffl,
A large number of semiconductor substrates (10) (10)... are held in a carrier (11) while pure water (9) is poured into a pressure vessel (8).
) to remove the resist. This resist removal is carried out as follows by using pure water (8) which is activated by increasing temperature and pressure and by its dissolved oxygen. That is, the resist [CxHy] deposited on the semiconductor substrate (10) is oxidized and decomposed into carbon dioxide (COZ) and water (UZO) by the dissolved oxygen [0□] of the pure water (8) as shown in the following equation.

mcxlly +n02 −+ 0CO2+P)1
．． 0 In this reaction step, the resist (Cxlly) attached to the semiconductor substrate (10) is removed.

For example, using a semiconductor substrate (10) to which a positive resist of 0.2-thickness is attached, the water temperature of pure water (9) is set to 250"C.
1 Pressure inside pressure vessel (8) is 70Kg -f/c+f
The experiment was conducted under the conditions of i. As a result, a semiconductor substrate (10
) adhering to the top! It was possible to completely remove 0.2 μm of positive resist.

〔Effect of the invention〕

According to the present invention, it is possible to remove the resist without using an organic solvent, and therefore there is no need for cleaning after removal, reducing the number of steps in the PR process and improving productivity. In addition, since the resist is removed using pure water, waste liquid treatment is very easy, and CO□ and 11
．． Since it decomposes to zero, there is no risk of environmental pollution caused by waste liquid, and manufacturing costs can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a specific implementation apparatus for the resist removal method according to the present invention, and FIG. 2 is an enlarged cross-sectional view of each step to explain the PR process in detail. (8) -Pressure vessel, (9)--Pure water, (10
)...Semiconductor substrate, (IIL-carrier.

Claims (1)

[Claims] (1) A semiconductor substrate with a resist attached thereto is immersed in purified water at a high temperature and pressure, and the resist is oxidized and decomposed by dissolved oxygen in the purified water at a high temperature and pressure. How to remove resist.