JPS584338B2 - How to prevent resist peeling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing resist peeling during contact exposure.

When performing close exposure of extremely fine patterns in the manufacture of semiconductor devices such as semiconductor integrated circuits, slight damage to the mask pattern can be a fatal defect in the electrical characteristics and reliability of the semiconductor device. , Chromium (Cr) has higher hardness and greater wear resistance than emulsion masks.
Chromium trioxide (Cr2O3), ferric oxide (Fe2
A hard mask with a pattern formed using O3) or the like is generally used.

However, if this hard mask is used as it is for contact exposure, the hardness of the mask is high, so the impact when the semiconductor substrate and the mask are pressed together may cause small damage to the resist film, or the resist particles that are peeled off at that time may be damaged. may adhere to the mask, causing abnormalities in the pattern when exposing the substrate in the next process, and furthermore, the mask pattern and resist will rub during crimping, resulting in abrasion of the pattern and shortening the life of the mask. was there.

Therefore, in the past, the patterned surface of the mask was made to a thickness of about 5000 Å using a resin such as polyvinyl alcohol (PVA), which is transparent and has buffering properties and is generally known as a mask protective resin. A method has been used in which contact exposure is performed using a hard mask that is covered with a buffering property to prevent the resist from peeling off due to impact during pressure bonding.

However, since this mask protection resin has a slight adhesiveness, adhesion between the mask and the resist occurs during close exposure, and when the semiconductor substrate is separated from the mask, a 5 to 100 μm adhesiveness occurs.
A new problem has arisen in which resist peeling with a size of about m is generated on the substrate.

The present invention provides a method for eliminating such problems and preventing peeling of the resist during contact exposure using a hard mask.

That is, in the present invention, during close exposure using a hard mask,
This resist peeling prevention method is characterized by using a hard mask whose patterned surface is covered with a transparent resin protective film having a buffering property and a fluorine bonding layer formed on the surface.

Examples will be described in detail below.

The drawing is a conceptual diagram of the cross-sectional structure of a hard mask used in the present invention, in which a mask pattern 2 is formed on one side of a glass plate 1 using chromium (Cr-containing trichromium dioxide (Cr2O3), ferric oxide (Fe2O3), etc.). 5,000 ml of a mask protective resin (e.g. polyvinyl alcohol, etc.) that is transparent and has cushioning properties is applied to the patterned surface.
After the mask is coated to a thickness of approximately 100 Å, plasma etching is performed using a plasma etching device in tetrafluoromethane (Freon) without a shield metal tube and directly exposed to electric discharge. As shown in the figure, a portion 4 in which resin and fluorine are chemically bonded is formed on the surface layer of the protective resin film.

This fluorine bonding layer exhibits properties similar to those of ordinary fluororesins,
It is chemically extremely stable and has strong water repellency.

A hard mask with such a protective film has buffering properties during close exposure and does not have adhesive properties with the resist, so resist peeling is significantly reduced compared to conventional methods, and the occurrence rate is lower than that of conventional negative resists. For positive resists, which have extremely brittle properties, we were able to reduce the resistivity to about 180 compared to conventional resists.

Although the above embodiment describes contact exposure of a semiconductor substrate, the present invention is also extremely effective when applied to the manufacture of exposure masks.

As explained above, according to the present invention, it is possible to significantly reduce resist peeling during close exposure to a fine pattern, thereby preventing defects in the exposed pattern due to resist defects and adhesion of the peeled resist to the mask. This has the effect of reducing defective electrical characteristics of semiconductor devices such as integrated circuits, improving manufacturing yield, and improving product reliability.

[Brief explanation of drawings]

The figure is a conceptual diagram of the cross-sectional structure of the hard mask used in the present invention. 1 is a glass plate, 2 is a mask pattern, 3 is a protective resin film,
4 indicates a fluorine bonding layer.

Claims (1)

[Claims] 1. A resist for contact exposure, characterized by the use of a hard mask (metal deposition mask) whose patterned surface is covered with a protective film made of a resin that is transparent and has buffering properties, on which a fluorine bonding layer is formed. How to prevent peeling.