JP2924022B2 - Resist stripping solution for chemically amplified resist and resist stripping method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a resist stripper for a chemically amplified resist,
And a resist stripping method. The resist stripping solution of the present invention can be widely used for stripping various chemically amplified resists. For example, a resist used in a photolithography technique or the like used for forming an electronic material or another material of a semiconductor device or the like can be used for removing the resist. In particular, the present invention provides a resist stripping solution and a resist stripping method capable of easily stripping and removing a chemically amplified resist which has conventionally been difficult to strip.

[Summary of the Invention]

The resist stripping solution of the present invention, and a resist stripping method,
Hexamethylphosphoric triamide, dimethyl sulfoxide, and at least one solvent arbitrarily selected from a compound group consisting of sulfolane,
With this configuration, a chemically amplified resist which has conventionally been difficult to remove by a solvent can be easily removed.

[Conventional technology]

A resist is used in various processing techniques. For example, a resist is patterned by a photolithography technique, and a desired pattern is obtained by etching using the resist as a mask, or an impurity is doped only at a necessary place by ion implantation.

These resists must be removed after the necessary steps have been completed.

However, some resists are not always easy to remove.

For example, a resist after etching or a resist after ion implantation at a high dose may be difficult to peel off for various reasons such as progress of curing due to irradiation with high energy.

Conventionally, an ashing technique using oxygen plasma has been used to remove such a resist that is difficult to peel. However, these methods using plasma have an adverse effect such as driving impurities into a substrate or the like. For this reason, recently, the impurities originally contained in the resist are reduced to prevent the impurities from entering even when the plasma processing is performed.
Another goal is to reduce the ashing method itself. However, the treatment using high energy such as plasma as described above inevitably affects an object to be processed such as a substrate, and the possibility of causing damage cannot be wiped out.

[Problems to be solved by the invention]

As described above, the plasma treatment as described above should be avoided as much as possible in order to keep the object and the object to be processed such as the substrate clean without hitting the impurity and to prevent any adverse effects such as damage. preferable. Therefore, a resist stripper has been developed to remove the resist with a solvent. These are collectively called removers. The components of these removers include those based on phenol,
Examples thereof include strong alkali liquids and solvents such as ethanolamines.

However, these conventional resist stripping solutions called removers are not always versatile, and may not exhibit sufficient stripping action, for example, for resists that are difficult to remove as described above. For example, when sufficient peeling is performed, heating is required at the time of peeling, and in many cases, a problem associated with the heating occurs, or handling is dangerous in many cases.

Some resists are difficult to peel off due to the nature of the resist itself, and so-called chemically amplified resists, which have been receiving attention in recent years, are difficult to sufficiently peel off with conventional stripping solutions.

An object of the present invention is to solve the above problems and provide a versatile resist stripping solution that is easy to handle and has a large stripping action, and thus can easily strip a resist that was conventionally difficult to remove. I do.

[Means for solving the problem]

The resist stripping solution of the present invention includes hexamethylphosphoric triamide (chemical formula: [[CH ₃ ) ₂ N] ₃ PO), dimethyl sulfoxide (chemical formula: (CH ₃ ) ₂ SO), and sulfolane A resist stripping solution for a chemically amplified resist containing at least one solvent arbitrarily selected from the group consisting of the compounds consisting of: a resist stripping method of the present invention, wherein the resist stripping solution is used for stripping a chemically amplified resist. Thing,
With this configuration, the object described above has been achieved.

The resist stripping solution of the present invention may contain at least one of the above three compounds as an effective main component for stripping the resist.

Each of the above three compounds is easy to handle and can be used as is without any problem.
Can be preferably used. Of course, the above compounds,
Alternatively, it may be used by being mixed with another solvent.

All of the above three compounds are easily soluble in water and can be washed and removed with water, so that they are easy to handle. No toxicity.

In any case, hexamethylphosphoric triamide (hereinafter abbreviated as “HMPA” as appropriate) is most preferable from the viewpoint that the vapor pressure is relatively low, handling properties are good in this respect, and the vapor pressure is low.

[Action]

The resist stripping solution of the present invention has a high stripping ability and is relatively difficult to strip (such as a resist after etching or ion implantation) or a resist that is originally difficult to strip (for example, a so-called chemically amplified resist). Can easily be peeled off under neutral conditions at room temperature.

The reason that the resist stripping solution of the present invention exhibits such excellent stripping performance for various resists, especially for chemically amplified resists, is not necessarily clear, but this is derived from the properties of each compound in the present invention as a solvent. Conceivable. Further, advantages such as handleability are also based on the properties of each compound.

〔Example〕

Next, examples of the present invention will be described. However, needless to say, the present invention is not limited to the embodiments described below, but can take various forms.

Example 1 In this example, a stripping solution containing HMPA as a main component was used as a resist stripping solution. In particular, the resist stripping solution of the present embodiment is 100% without mixing other solvents with HMPA.
Was used as a stripping solution using HMPA as is.

In this embodiment, the following three types of resists were removed.

A pattern formed from a novolak-naphthoquinonediamide general-purpose positive resist (specifically, TSMR-V3 manufactured by Tokyo Ohka Co., Ltd.), and a resist pattern after plasma etching in a CF ₄ reaction gas .

The same resist turn as above, with arsenic on the substrate
A resist pattern after using As when a high dose (specifically, 10 ¹⁵ / cm ² ) ions are implanted.

Using a novolak resin as a base resin, a photoacid generator,
Chemically amplified resist containing hexamethylolmelamine as a polymerization agent (specifically, SAL 601 manufactured by Shipley)
-ER7) resist pattern.

That is, the above is the case where the rest of the resist pattern used as the etching mask is removed, and the above is the case where the resist pattern used as the mask for ion implantation at a high dose is removed. Conventionally, all of them have been difficult to remove and must be removed by oxygen plasma ashing which may damage the base. The above is difficult to remove as a property of the resist itself.

In this example, the above-mentioned HMPA was used as a resist stripping solution according to the present invention, and a shiplay 11 comprising an N-methylpyrrolidone-based solvent was used as a comparative resist stripping solution.
12A (Shipley) and a 1: 1 dilution of this with water were used.

Processing conditions are 50 ° C for the comparative resist stripper.
For 3 minutes, 80 ° C. and 5 minutes. For the resist stripper HMPA according to the present invention, 3 minutes at 25 ° C. and 3 minutes at 25 ° C.
Performed under conditions. In addition, as for the comparative stripping solution, stripping was attempted under the same conditions as in the case where the resist stripping solution according to the present invention was used, but stripping was not possible with any resist.

The results are shown in Table 1 below. In Table 1, the evaluation of the peeling result was as follows.

A: The resist was sufficiently removed, and the resist was completely removed.

…: Resist peeling was good. However, some residues may remain.

Δ: The resist is generally peeled off, but a residue remains and the peeling is not sufficient, making it impractical.

×: Difficult to remove resist.

As understood from Table 1, various resists can be stripped and removed at room temperature under neutral conditions according to the resist stripping solution of the present invention. In particular, the resist pattern after etching, which has conventionally been considered difficult to remove, and the resist pattern after ion implantation can be favorably stripped, and in addition to this, such as a chemically amplified resist pattern that has recently attracted attention. Even resists that are difficult to remove themselves can be removed under neutral conditions at room temperature.

That is, as is clear from Table 1, the patterns of the resists used as the resists to be peeled are as follows.
When a conventional resist stripping solution is used, the resist cannot be stripped, or practical resist removal cannot be achieved even when the resist is treated at a high temperature such as 80 ° C. for 5 minutes. That is, Shipley 11 which is a comparative resist stripping solution
When 12A is used as a pure solution (100%), the peeling force is somewhat better than that of the diluting solution, but it does not reach the resist removing solution according to the present invention, and practical resist removal cannot be achieved. On the other hand, with the resist stripping solution according to the present invention, under a room temperature condition of 25 ° C., that is, without requiring special heating or the like, the resist stripping can be performed in a short time of 3 minutes, and in particular, conventionally, practically practical The stripping of the chemically amplified resist, which was difficult to strip, can be favorably achieved. Further, by applying ultrasonic waves used in the case of ultrasonic cleaning or the like, the removal effect can be more completely improved.

In addition, HMPA used in the present example, like dimethyl sulfoxide and sulfolane, falls off cleanly with water,
Subsequent processing is also easy. Easy to handle in terms of toxicity and vapor pressure.

Further, since there is no need to use a dangerous substance for the eyes as in the case of a conventional alkaline stripping liquid, and more particularly, it is not necessary to use it after heating, it is safe in many respects.

In this example, only one type of chemically amplified resist was tested, but three components of a photoacid generator, a so-called chemically amplified resist, a crosslinking agent, and a base resin (or For a chemically amplified resist composed of two components, see, for example, Ao Yamaoka and Masashi Nishigame, "New Positive Deep UV Resist", Press Semiconductor, Monthly Semiconductor World, 1988.
For example, see pages 44 to 46 of September, 2002).

Example 2 A resist was stripped in the same manner as in Example 1, except that dimethyl sulfoxide (DMSO) was used as a resist stripping solution according to the present invention at 100% without being mixed with another solvent. In this example, substantially the same resist stripping effect as in Example 1 was obtained.

Example 3 In this example, the resist was stripped in the same manner as in Example 1, except that sulfolane was used as a resist stripping solution according to the present invention at 100% without being mixed with another solvent. In this example, substantially the same resist stripping effect as in Example 1 was obtained.

〔The invention's effect〕

As described above, the resist stripping solution of the present invention is easy to handle and has a large stripping action, and thus can easily strip a resist which has conventionally been difficult to remove. This has the effect of providing a highly versatile resist stripping solution.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03F 7/42

Claims (5)

(57) [Claims] 1. A resist stripping solution for a chemically amplified resist, comprising at least one solvent arbitrarily selected from the group consisting of hexamethylphosphoric triamide, dimethyl sulfoxide, and sulfolane. 2. A method according to claim 1, wherein at least one solvent selected from the group consisting of hexamethylphosphoric triamide, dimethylsulfoxide and sulfolane is used.
The resist stripping solution for a chemically amplified resist according to claim 1, wherein the resist stripping solution is used at 0%. 3. A resist stripping solution containing at least one solvent arbitrarily selected from a compound group consisting of hexamethylphosphoric triamide, dimethyl sulfoxide, and sulfolane is used for stripping a chemically amplified resist. A method for removing a chemically amplified resist. 4. A method according to claim 1, wherein at least one solvent selected from the group consisting of hexamethylphosphoric triamide, dimethyl sulfoxide and sulfolane is used.
4. The method for stripping a chemically amplified resist according to claim 3, wherein the resist is used at 0%. 5. The method according to claim 3, wherein the resist is stripped under the condition of applying ultrasonic waves.