JPH0273A - pattern forming material - Google Patents

Abstract

PURPOSE:To prevent poor resolution and poor O2 etchability by incorporating a specified resin having a specified group, a specified compound, and a solvent. CONSTITUTION:The pattern forming material comprises the resin obtained by polymerizing a phenol derivative by the medium of silicon atoms, a naphthoquinone diazide compound, and the solvent. The silicon atom only serves as a binder for forming the polymer, and decreases in freedom and it cannot approach and combine with the hydroxy group in the resin, thus permitting the pattern forming material to be made soluble in alkali like ordinary novolak resins and enhanced in sensitivity as the resist, and reduced in an amount of light to take a detour, so to prevent poor resolution, and further, to prevent poor etchability due to the rise of silicon content.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to lithography technology for semiconductors, etc., and relates to a pattern forming material containing St gold as an upper layer when forming a resist pattern with a two-layer structure.

2. Description of the Related Art As semiconductor devices become smaller and more highly integrated, pattern formation becomes difficult when using a normal single-layer pattern forming material (resist).

Under these circumstances, a two-layer pattern forming method has been devised. This is a method in which the base substrate is flattened with a lower flattening layer, and the lower layer is etched by o2RIE (reactive ion etching) using a Si-containing resist pattern formed on the upper layer as a mask to form a pattern. It is. According to this method, if the upper resist layer is formed with good resolution and has sufficient O2 etching resistance to etch the lower layer, a fine pattern with a high aspect ratio can be formed.

Conventionally, many silicon-containing pattern forming materials (resists) having oxygen resistance (02) RIE (reactive ion etching) properties have been devised for use in forming turns in such a two-layer resist.

Among these, a positive type resist made of a naphthoquinonediazide compound and a resin in which a silicon-containing group is introduced into the benzene ring of a novolac resin has been devised as a resist with particularly high resolution.

This type of resist reacts by the same reaction mechanism as normal UV positive resists. That is, in the unexposed area, the novolak resin containing a silicon group is prevented from being dissolved in dialkali by the action of naphthoquinone diazide, and in the exposed area, the indene carboxylic acid produced by the reaction between the novolac resin and naphthoquinone diazide is dissolved in alkali, It becomes a positive resist.

However, such conventional resists have poor alkali solubility in exposed areas, that is, poor sensitivity, and this also results in poor pattern shapes.

A pattern forming method using a conventional pattern forming material (resist) will be described with reference to FIG.

Positive resist on substrate 1 (Sibley MP1400)
A resist layer 2 is formed by applying 2.0 μm of resist and hardening it by open baking for 200-030 minutes (Figure 3a).
. Next, a conventional pattern forming material having the following composition was applied to a thickness of 0.5 .mu.m, and a resist layer 9 was formed by hot plate baking at 90"C for 2 minutes (FIG. 3b).

The formed resist layer 9 was used as a Q-ray stepper using N5R manufactured by Kon Co.
1505G4C; NAo, 42), resist pattern 9A was formed by IJ/ffl exposure through Manuk 4 (Fig. 3C) and 60 seconds paddle development using MF-319 alkaline developer (Sibley) (Fig. 3C). Figure d). However, this pattern 9A was a defective pattern having a nearly triangular shape with dimensions varying by about 20% because the sensitivity was too low and the exposure light also entered the mask portion. After this, 02RI
Although anisotropic etching was carried out using E, the pattern 9A in the upper layer with varying dimensions and a poor shape was transferred to the lower resist layer, resulting in a pattern 2B with a poor shape in which the dimension variation was 3% of the desired pattern. (Figure 3e).

Such a defective pattern is expected to be further transferred in a subsequent process using pattern 2B as a mask, resulting in larger dimensional variations, leading to a reduction in yield in semiconductor manufacturing. As described above, pattern formation using conventional pattern forming materials has been problematic.

In addition, conventionally, as a positive resist with high resolution as a St-containing resist used for two-layer resist formation, a resist (pattern forming material) was made by mixing a mixture of Si resin and novolac resin with naphthoquinone diazide as a photoreceptor. (For example, Noh Ueno, 4th Photopolymer Conference 7)
7 Rennes Abstracts, p. 107 (1985)).

However, such conventional positive type St-containing resists had poor pattern shapes and did not have sufficient 02R resistance.

That is, a third pattern is formed using conventional pattern forming materials such as:
As a result of conducting the same experiment as shown in the figure, the same defective pattern was obtained.

The causes of such a defective pattern are considered to be that the resist pattern was defective and its resistance to 02 RIE was low, so that it did not function as a complete mask for etching the lower layer.

In terms of materials, Si-containing resin in conventional pattern-forming materials inhibits the pattern shape, and S in pattern-forming materials
It is thought that the small amount of i component inhibited the 02RIE resistance.

It is clear that such a degraded pattern with poor dimensional accuracy causes a decrease in yield in subsequent steps, which is a cause for concern.

Furthermore, conventional resists have been devised in which a naphthoquinonediazide compound is mixed with a siloxane or novolac resin containing St (for example, RG
-a5oOp (Hitachi Chemical)], these were found to be insufficient in resolution and etching resistance.

A pattern forming method using a conventional pattern forming material will be described with reference to FIG.

RG-3900B as a flattening layer on the substrate 1 with steps
(Hitachi Chemical) with a thickness of 1.9 μm (Figure 4a)
. Next, RG-asooP (Hitachi Chemical), which is a conventional pattern forming material containing Si, is formed to a thickness of 0.5 μm (FIG. 4b). Q-line (4se) with lens numerical aperture 0.42
Figure 4C
), alkaline developer NMD-3 (Tokyo Ohka) SO
Pattern 10A was formed using a second paddle (Figure 4d)
. However, in the pattern 1oA, although 0.5 μm lines and spaces were formed, the resolution was poor and the pattern was semicircular. Thereafter, the lower layer was etched using 02 etching using this pattern 1oA as a mask, but the defective pattern in the upper layer affected the pattern in the lower layer by changing its pattern dimension, and since the upper layer resist had originally low O2 etching resistance, it was difficult to obtain a good result. The resulting lower layer pattern 2C has a line with a dimension variation of 0.3 μm and a film reduction of 20 μm.
It was very large (Fig. 4, 8).

Problems to be Solved by the Invention The defective patterns produced by the conventional methods as described above will cause pattern variations in subsequent processes such as etching and ion implantation, which will cause a decrease in the yield of device manufacturing. It was a big problem since then.

An object of the present invention is to solve problems such as poor resolution and poor 02 machining resistance and soching properties that conventional pattern forming materials containing Si have.

Means for Solving the Problems In order to solve the problems of conventional pattern forming materials, the present invention provides a pattern comprising a resin containing silicone and a phenolic compound, a naphthoquinone diazide compound, and a solvent. It provides a forming material.

That is, in order to solve the problems of conventional pattern forming materials, the present invention uses a resin obtained by polymerizing a phenolic compound through Si, and mixes this with a naphthoquinone diazide compound to form a resist (pattern forming material). material).

Effect The research of the present inventors has shown that the phenolic compound polymerized through Si as in the present invention has good solubility in alkaline solutions, which is no different from that of ordinary novolac resins. As a result, I found it. That is, by using the resin having St according to the present invention in a pattern forming material, the exposed area can be dissolved in an alkaline developer with the same level of sensitivity (approximately 100 m T /crl) as a normal positive resist. Moreover, the pattern shape was also improved.

The remarkable improvement in sensitivity and pattern shape according to the present invention is considered as follows.

That is, in conventional materials, since the Si group is close to the OH group of the resin in terms of molecular coordination, a certain type of intramolecular bond of ~OH...Si- occurs, and this causes O ) (It is thought that the alkali solubility of the group was inhibited. On the other hand, in the material of the present invention, St only acts as a binder to form polymerization, and this Si atom is a silicon atom with few degrees of freedom. , cannot approach (bond to) the OH groups in the resin, and therefore has the same alkaline solubility as ordinary novolac resins, improving the sensitivity of the resist and preventing light from penetrating into unexposed areas. It is thought that this will reduce the amount and improve the shape of the cut.

Embodiments In order to solve the conventional problems, the present invention uses, for example, a copolymer of a phenolic compound and a silicon-containing compound as a resin, and a pattern forming material containing a naphthoquinone diazide compound and a solvent for dissolving these compounds. use

The copolymer resin of a phenolic compound and a silicon-containing compound according to the present invention inevitably has a high Si content in the resin and has improved O2R resistance. That is, in conventional pattern forming materials, the content of SL resin itself could not be increased due to its poor compatibility with novolac resins and solvents, but according to the present invention, since it is originally a copolymer, There is no problem with compatibility with resins (including novolac resins) due to phenolic compounds, and the phenolic resin in the copolymer is more soluble in solvents than when it is a monopolymer. As a result, the St gold-containing copolymer resin has good compatibility with solvents.

As a result, the Si content in the resin according to the present invention was improved, and as a result, the 02RIE properties of the pattern forming material were improved. At the same time, the shape when forming the turn was also improved. Although this has not been clearly considered,
It is thought that this is because the Si copolymer resin reduces the degree of freedom of movement of Si atoms in the material, which can be a factor inhibiting pattern resolution.

The resin related to the material of the present invention described above uses cresol as its starting phenolic compound.

Examples include xylenol, phenol, and of course,
It is not limited to this. The copolymer tree Toshi is
Copolymer resins of these and silicon-containing compound resins such as silane, siloxane, and silseth siloxane may be mentioned, but are not limited to these.

The above naphthoquinonediazide compounds according to the material of the present invention include naphthoquinonediazide sulfonyl chloride and naphthoquinonediazide sulfonic acid ester/L/(1,2,
3-1-lyhydroxybenzophenone, 1,3,1'
, 3'-tetra-hydroxybenzophenone, pinuphenol nato ester/I/), etc., which are
It acts as an alkali dissolution inhibitor for the resin in unexposed areas, and upon exposure, it becomes indenecarboxylic acid and becomes alkali-soluble.

Of course, this is not the case. Of course, it goes without saying that this material is sensitive not only to ultraviolet light but also to various energy rays due to the action of this compound.

The above-mentioned solvent according to the present invention is not particularly limited, but any solvent that can dissolve the resin and the naphthoquinone diazide compound may be used. Examples include ethyl cellosolve acetate, diethylene glycol dimethyl ether, methyl cellosolve acetate, and cyclohexanone.

Incidentally, a sensitizer such as benzophenone or an onium salt, a single silicon-containing phenol compound, or the like may be added to the above-mentioned pattern forming material of the present invention to adjust the sensitivity.

Note that the above-mentioned material of the present invention has a weight ratio of Si in the material that is comparable to that of conventional materials, and has good resistance to 02 RIE.

Further, in order to solve the conventional problems, the present invention provides a turn-forming material characterized by containing a resin containing an OH group having St in the main chain and side chain and a naphthoquinone diazide compound. It is.

When a naphthoquinone diazide compound is added to the resin containing an OH group with Si in the main chain and side chain according to the present invention to form an alkaline dissolution-blocking positive resist, the exposed portion of the resin is soluble in an alkaline developer. - The inventors found that the difference in the unexposed area was very large (about 1° Hiro).

This is considered to be because the Si in the main chain and the Si in the side chains interact to strongly strengthen the bonding state with the naphthoquinone diazide compound in the unexposed area. As a result, there is no possibility that unexposed areas are eroded by development after exposure, and a well-shaped pattern can be formed after all.

The price will be higher than the 1st grade, and the 02RIE of sake will also be good.

In addition, examples of the resin according to the present invention include main chain kasiran, haloxane, silses siloxane, or a mixture thereof. Further, the side chain generally has a phenol group, but of course it is not limited to this.

Examples will be described in detail below.

(Part 1) A pattern forming method using a pattern forming material according to an embodiment of the present invention will be described with reference to FIG.

A positive type GINUTO (Sibley MP1) is applied onto a semiconductor substrate 1.
400) at 2*C)/'m and 200°cS.

A hardened resist layer 2 is formed by open baking for several minutes (FIG. 1a). Note that an insulating or conductive film 1oo is often formed on the semiconductor substrate 1. Next, 0.5% of the pattern forming material according to the present invention having the following composition was added.
The resist layer 3 was formed by applying the resist to a thickness of .mu.m and baking it on a hot plate for 90'02 minutes (FIG. 1b).

A two-layer resist pattern was obtained (FIG. 1e).

Note that similar good results were obtained even when the following resins were used as the resin in the pattern forming material of the present invention. Of course, the formed resist layer 3 is not limited to these.
to the q-ray stepper made by Kon Co., Ltd. N5R1505G4C; N
Ao, 42) [jRemask 4 to desired pattern li light 5(2o.

mJ/CWI)L (Figure 1C) and MF-319 alkaline developer (Sibley) 60 seconds paddle development to form resist pattern 3A (Figure 1D).

The obtained pattern 3A was a 0.5 μm line-and-space pattern with no dimensional variation compared to the mask pattern, and its shape was also a sharp rectangular pattern. After that, anisotropic etching was performed by 02RIE, but the upper layer pattern 3A was transferred as it was without any dimensional change and a good shape was obtained.(m, n are integers) (m, n are integers) It is not something that will be done.

(m and n are integers) (Part 2) An experiment similar to Example (Part 1) was conducted using the following pattern forming material of the present invention, and good results similar to those in (Part 1) were obtained.

In addition to the example of the pattern forming material of the present invention in this example, similar good results were obtained when the following materials were used. Of course, the present invention (part 3) will be described with reference to FIG. 2 about an example of a pattern forming method using the pattern forming material of the present invention. The composition of the pattern forming material of the present invention was as follows.

RG- is applied as a flattening layer on a substrate 6 such as a semiconductor with steps.
3900B (Hitachi Chemical) 1.9 μm thick (Fig. 2a). Note that the membrane 100 in FIG. 1 is omitted. Next, K, apply the above pattern forming material of the present invention and bake on a hot plate for 90"02 minutes to give a 0.5"
A resin film 8 having a thickness of μm is formed (FIG. 2b). Selectively irradiate Q-ray (436 nm) light 5 with a lens numerical aperture of 0.42 through a mask 4 (Fig. 2C), and remove with an alkaline developer NMD-3 (Tokyo Ohka) using a paddle for 60 seconds. Turn 8A was formed (Figure 2d). Nokuturn 8A was a 0.6 μm line and space with no membrane edges and an aspect ratio of 90'. After that, the lower layer 7 was etched by 02 using this pattern 8A as a mask (second
Figure e). Because the upper layer Nokuturn 8A had good O2 etching resistance and a good Nokuturn shape,
The resulting Notuturn 7A was a 0.5 μm line and space pattern with no film periphery or dimensional variation. It should be noted that an unetched layer of pattern 8A remained on the top of No. 7A (7).

Incidentally, examples of the pattern forming material of the present invention include the following. Of course, the present invention is not limited to these.

diethyleneglyco-tV-)methylny, -/L/
42. Effects of the O/I Invention As described above, the present invention is a Si-containing resist that has never existed before, has good solubility in the developing solution in the exposed area, and has excellent etching resistance of the material, so it can have a good shape. It becomes possible to form a desired fine regimen pattern with less film loss. Therefore, by using the material of the present invention, fine submicron patterns can be formed as desired, and the present invention greatly contributes to the production of ultra-high density semiconductor integrated circuits. That is, the use of the pattern forming material of the present invention leads to improvements in productivity and yield υ in the semiconductor manufacturing process, and has high industrial value.

[Brief explanation of the drawing]

1 and 2 are process cross-sectional views of an example of a pattern forming method using the pattern forming material of the present invention, and FIGS. 3 and 4 are process steps of a pattern forming method using a conventional pattern forming material. FIG. 1...Substrate, 2...Thermoset positive resist, 3.8...Pattern forming material according to the present invention, 4...Mask, 6 . . . Q-ray light, 6 . . . Substrate with steps, 7 . . . Flattening layer (RG-3900B). Name of agent: Patent attorney Shigetaka Awano and one other person C pattern

Claims (9)

[Claims] (1) A pattern forming material comprising a resin containing silicone and a phenolic compound, a naphthoquinonediazide compound, and a solvent. (2) The pattern forming material according to claim 1, comprising a resin in which a phenolic compound is polymerized via silicone, a naphthoquinone diazide compound, and a solvent. (3) The pattern forming material according to claim 1, which contains a resin obtained by copolymerizing a phenolic compound and a silicon-containing compound, a naphthoquinone diazide compound, and a solvent. (4) The pattern forming material according to claim 2 or 3, wherein the phenolic compound is any one of cresol, xylenol, and phenol. (5) The pattern forming material according to claim 3, wherein the silicon-containing compound is one of silane, siloxane, silseth siloxane, or a combination thereof. (6) The pattern forming material according to claim 1, which contains a resin containing an OH group with Si in its main chain and side chain, and a naphthoquinone diazide compound. (7) The pattern forming material according to claim 6, wherein the main chain is composed of silane, siloxane, silcesiloxane, or a mixture thereof. (8) The pattern forming material according to claim 6, wherein the side chain has a phenol group. (9) The pattern forming material according to claim 2, 3, or 6, wherein the naphthoquinonediazide compound is naphthoquinonediazide sulfonyl chloride or a naphthoquinonediazide sulfonic acid ester compound.