JPH02227406A - Flattening material - Google Patents

Abstract

PURPOSE:To obtain a flattening material for substrate having unevenness, providing ideal flattened face by the same process as existing photo resist method, comprising an organic polymer shown by a specific formula and having specific molecular weight. CONSTITUTION:The aimed material comprising an organic polymer (e.g. compound shown by formula II) shown by formula I [R1 and R2 are H or methyl; R3 is monofunctional organic group containing one of vinyl-containing group, ethynyl-containing group and-Si(OR5)3 (R5 is alkyl, aromatic group or substituted silyl); R4 is bifunctional organic group; Ar is phenylene; l and n are >=1; m is 0 or 1] and <=10,000 molecular weight. The polymer shown by formula I is obtained by subjecting styrene (derivative) to anionic polymerization with bis(p-methyllithium)benzene and deactivating the polymerization with a halogen- containing organic compound containing one of vinyl group, ethynyl group and substituted silyl group.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a material for planarizing a substrate having irregularities.

[Prior Art] (In the formula, R5 and R2 are hydrogen atoms or methyl groups, R
, l are required to be vinyl-containing groups, ethynyl-containing groups or subsequent lamination.

However, as the number of conductor layers increases to two or three, the height difference between the conductor layers becomes steeper, and disconnections or short circuits occur where the conductor layers intersect, making it difficult to form a substantial laminated structure.

In order to prevent the above-described disconnection of the conductor layer, it is effective to flatten the surface of the insulating layer before forming the conductor layer.

In contrast, etch-back methods using photoresist or polyimide are conventionally known, but flattening becomes insufficient when the step width is approximately several μm.

In order to improve this, a material with a low heat distortion temperature such as polystyrene or its derivatives with a molecular weight of about 10,000 was spin-coated and then heated above the heat distortion temperature (e.g. 200°C) to flow and flatten an organic resin. Means for Solving the Problems] The present inventors have worked hard to find a flattening material that can reduce the complexity of the process and improve productivity by omitting the ultraviolet curing step in the above method, and can be sufficiently flattened. As a result of study, we have arrived at the present invention.

In other words, the present invention has a general formula: % formula %) [Problems to be Solved by the Invention] However, compared to the etch-back method using photoresist or polyimide, this method requires an additional ultraviolet curing step and the process is slow. It becomes complicated and has low productivity, and
There is a problem in that it is almost impossible to flatten a step having a width of approximately μm.

(In the formula, R3 and R2 are hydrogen atoms or methyl groups, R
3 is a vinyl-containing group, an ethynyl-containing group, or -3i(O
R, ): a monovalent organic group having any one of l, where R6 is an alkyl group, an aromatic group or a substituted silyl group,
R4 represents a divalent organic group, Ar represents a phenylene group, Ln represents an integer of 1 or more, and m represents 0 or 1. ) and is a flattening material made of an organic polymer having a molecular weight of 1OOOO or less.

As R8, -σCH"C)12.-CH"CH2, -CH2CH2
Vinyl-containing groups such as 0CH”CH2, -3i(OCaHs)3-3i(O3i(CHa)3)
Examples include substituted silyl groups such as a.

The divalent organic group of R1 is XtkL~1 and tetramodal spinning panic? T= ty-1 ト@@, 1-4F, A('r, %
1: LL+t knee CH9, ()CH2--CH
Examples include 2CH2CH2CH2-.

The phenylene group of Ar includes 0-phenylene group, m-
It is a phenylene group or a p-phenylene group. (2) and n are usually 1 to 50, preferably 2
~7.

The weight average molecular weight of the organic polymer represented by general formula (1) is usually 500 to 10,000, preferably 500 to 1
It is 500. If the weight average molecular weight is less than 500,
Polymers tend to become fluid even at room temperature, and the longer the spin rotation time during coating, the thinner the film becomes, making it difficult to control the film thickness. Furthermore, if the weight average molecular weight exceeds 10,000, the melt viscosity at 200° C. increases, making it difficult to obtain an ideal flat surface. The molecular weight distribution (Mw/Mn) is about 1.0 to 4.0 for polymers obtained by ordinary polymerization methods, and although they can be used for normal use, it is necessary to narrow the fluidization temperature range and lower the melt viscosity. In order to do so, it is preferably less than 1.5.

Specific examples of the polymer represented by general formula (1) are shown below.

(Flattening material 1) Molecular weight distribution (Mw/Mn) 1.2 Molecular weight distribution (Mw/Mn) 1.2 Weight average molecular weight 900 Molecular weight distribution (Mw/Mn) 1.2 Weight average molecular weight 1400 Molecular weight distribution (Mw/Mn) ) 1.2 Molecular weight distribution (Mw/Mn) 1.2 Weight average molecular weight 1500 Molecular weight distribution (Mw/Mn) 1.2 Weight average molecular weight 1000 Molecular weight distribution (Mw/Mn) ], 2 (However, flattening material 1 (In the formulas representing 7 to 7, 1-Pr represents a methyl group, 1-Pr represents an isopropyl group, and Ph represents a phenyl group.) As a method for synthesizing the polymer represented by the general formula (1), bis(p- Styrene or a styrene derivative is anionically polymerized with a dilithium compound such as lithiated (methyl)benzene, 1,4-dilithiated butane, or a sodium-naphthalene complex to produce a halogen-containing compound having either a vinyl group, an ethynyl group, or a substituted silyl group. Obtained by deactivating polymerization with an organic compound.

The planarization material of the present invention is used by dissolving the organic polymer represented by the general formula (1) in an aromatic hydrocarbon (toluene, xylene, etc.), an ester compound (ethyl cellosolve acetate, etc.), or the like. The solids concentration in this case is usually 10 to 60% by weight.

The method of using the planarizing material of the present invention is as follows.

First, an organic polymer represented by the general formula (1) is applied onto an insulating film substrate having steps by spin coating, spray coating, etc. to a thickness of 0.1 to 10 μm. Next, the organic polymer film is heated at 100 to 200°C using an infrared lamp, hot plate, clean oven, etc. to melt and flow it to obtain a flat surface, and then dried to improve the heat resistance of the organic polymer film. Etching and transferring a flat surface to the insulating film [Example] The present invention will be explained in more detail with reference to Examples below.
The scope of the invention is not limited by these examples.

Example 1 SiO□ was deposited at 800 mm on a semiconductor pattern with a thickness of 6000 mm.
After dissolving the planarization material 1 in xylene on the substrate on which the coating was applied, the shape of the coating film of the organic polymer film remains as it is on SiO.
□ Transferred to the film, the height difference was 750 over the conductor width of 50 μm or more, and an almost ideal flat surface was obtained. (See Table 1) Examples 2 to 7 Experiments were conducted in exactly the same manner as in Example 1, except that only planarization material 1 was replaced with planarization materials 2 to 7.

As a result, as shown in Table 1, almost the same results as in Example 1 were obtained, and the substrate could be planarized.

Comparative Example Using exactly the same method as in Example 1, only the planarizing material 1 was used as a photoresist (Silapray Microposit 140031).
Instead, I conducted an experiment.

As a result, as shown in Table 1, almost no planarization could be achieved.

[Effect of the invention] If planarization is performed by etchback using the planarization material of the present invention, the ultraviolet curing step can be omitted, and the process is similar to the conventional etchback method using photoresist or polyimide, and is extremely ideal. It can be seen that a flattened surface can be obtained. Furthermore, the planarization material of the present invention can be used as a lower layer material (planarization layer material) in a multilayer resist method in a lithography process in the manufacture of semiconductor integrated circuit devices.

Claims (1)

[Claims] 1. General formula: ▲ Numerical formula, chemical formula, table, etc. ▼ (1) (In the formula, R_1 and R_2 are hydrogen atoms or methyl groups, R_3 is a vinyl-containing group, an ethynyl-containing group, or -Si
(OR_5) A monovalent organic group having any one of _3, where R_5 is an alkyl group, aromatic group or substituted silyl group, R_4 is a divalent organic group, Ar is a phenylene group, l,
n represents an integer of 1 or more, and m represents 0 or 1. ) and is characterized by being made of an organic polymer having a molecular weight of 10,000 or less.