JP2008243907A - Composition for forming cavity between conductive layers, sacrifice film for forming cavity between conductive layers, and method of forming cavity between conductive layers - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming cavity between conductive layers, capable of forming a film which is excellent in heat resistance and mechanical strength with less residue after ashing, and to provide a sacrifice film for forming a cavity between conductive layers that uses the polymer and a method of forming cavity between conductive layers. <P>SOLUTION: The composition for forming the cavity between conductive layers contains (A) a polymer of aromatic polyarylene and aromatic polyarylene ether or either of them, and (B) organic solvent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a composition for forming a cavity between conductive layers, a sacrificial film for forming a cavity between conductive layers, and a method for forming a cavity between conductive layers.

In recent years, the manufacture of micromechanical elements using manufacturing methods developed for semiconductor electronic components has attracted attention. One area that has received attention is the technology of using such devices to switch current. Techniques for fabricating micromechanical structures include silicon bulk micromachining, or surface micromachining using sacrificial layer technology, which can be used to create freestanding or lift-off structures. Is commonly used. And (patent document 1, 2) has disclosed the resist and the phosphosilicate glass as a material of a sacrificial layer.
JP 2002-170470 A JP 2002-23073 A

  However, in the method disclosed in the above publication, the intended structure is maintained as a result of thermal decomposition of the organic resist having low heat resistance during high-temperature annealing applied after creating a structure in which the conductive layer is filled with an organic resist or a silica compound. In addition, as a result of the organic resist having low mechanical strength being deformed by stress applied during processing of the conductive layer, the intended structure may not be maintained. In addition, when an organic resist or silica compound is removed by etching or ashing to form a cavity, the organic resist or silica compound remains between the conductive layers, resulting in a short circuit between the conductive layers or outgassing, resulting in device reliability. May deteriorate. Furthermore, it may be corroded by the cleaning liquid used at the time of structure creation.

  An object of the present invention is to provide a composition for forming a cavity between conductive layers, which is excellent in heat resistance and mechanical strength, and can form a film with little residue after ashing, and between conductive layers using the polymer. It is to provide a sacrificial film for forming a cavity and a method for forming a cavity between conductive layers.

・・・・・（１）
［式中、Ｚは下記一般式（２）で表される２価の芳香族基であり、Ｙは、下記一般式（３）で表される２価の芳香族基および下記一般式（４）で表される２価の芳香族基から選ばれる少なくとも１種の２価の芳香族基である。］

・・・・・（２）
（式中、Ｒ^１およびＲ^２は独立に、−ＣＱＱ’−（ここで、Ｑ、Ｑ’は同一であっても異なっていてもよく、ハロゲン化アルキル基、アルキル基、水素原子、ハロゲン原子またはアリール基を表す。）で示される基、フルオレニレン基、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＣＯＮＨ−、−Ｓ−、−ＳＯ_２−または式：

で表される２価の基を表し、Ｒ^３、Ｒ^４およびＲ^５は独立に、炭素原子数１〜２０の炭化水素基、シアノ基、ニトロ基、炭素原子数１〜２０のアルコキシル基またはアリール基を表し、ａは１〜３の整数を示し、ｂ、ｃおよびｄは独立に０〜４の整数を示す。）

・・・・・（３）

・・・・・（４）
（式中、Ｒ^６およびＲ^７は独立に−ＣＱＱ’−（ここで、Ｑ、Ｑ’は同一であっても異なっていてもよく、ハロゲン化アルキル基、アルキル基、水素原子、ハロゲン原子またはアリール基を表す。）で示される基、フルオレニレン基、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＣＯＮＨ−、−Ｓ−、−ＳＯ_２−を表し、Ｒ^８、Ｒ^９、Ｒ^１０およびＲ^１１は独立に、炭素原子数１〜２０の炭化水素基、シアノ基、ニトロ基、炭素原子数１〜２０のアルコキシル基またはアリール基を表し、ｅは０〜３の整数を示し、ｆ、ｇ、ｈおよびｉは独立に０〜４の整数を示す。） The composition for forming a cavity between conductive layers according to one embodiment of the present invention contains (A) a polymer having a repeating unit represented by the following general formula (1), and (B) an organic solvent.

(1)
[In the formula, Z is a divalent aromatic group represented by the following general formula (2), Y is a divalent aromatic group represented by the following general formula (3) and the following general formula (4 And at least one divalent aromatic group selected from divalent aromatic groups. ]

(2)
(Wherein R ¹ and R ² are independently —CQQ′— (wherein Q and Q ′ may be the same or different and are a halogenated alkyl group, an alkyl group, a hydrogen atom, a halogen atom, Or an aryl group)), a fluorenylene group, —O—, —CO—, —COO—, —CONH—, —S—, —SO ₂ — or a formula:

R ³ , R ⁴ and R ⁵ are independently a hydrocarbon group having 1 to 20 carbon atoms, a cyano group, a nitro group, an alkoxyl group having 1 to 20 carbon atoms, or Represents an aryl group, a represents an integer of 1 to 3, b, c and d independently represent an integer of 0 to 4; )

(3)

(4)
(Wherein R ⁶ and R ⁷ are independently —CQQ′— (wherein Q and Q ′ may be the same or different and are a halogenated alkyl group, an alkyl group, a hydrogen atom, a halogen atom or Represents an aryl group.), A fluorenylene group, —O—, —CO—, —COO—, —CONH—, —S—, —SO ₂ —, and R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ independently represents a hydrocarbon group having 1 to 20 carbon atoms, a cyano group, a nitro group, an alkoxyl group having 1 to 20 carbon atoms or an aryl group, e represents an integer of 0 to 3, f, g, h and i each independently represents an integer of 0 to 4.)

  The sacrificial film for forming cavities between conductive layers according to one embodiment of the present invention is obtained by applying the above-mentioned composition for forming cavities between conductive layers to form a coating film and firing the coating film.

  In the sacrificial film for forming cavities between the conductive layers, the weight loss when heated at 350 ° C. for 1 hour in an inert gas atmosphere or a vacuum atmosphere can be 5 mass% or less.

  The sacrificial film for forming cavities between the conductive layers may have an elastic modulus at 25 ° C. of 5 GPa or more.

Residue after performing ashing for 180 seconds at 350 ° C. under a pressure of 100 Pa using H ₂ and Ne (H ₂ : He = 350 scm / 3500 scm) as an ashing gas in the sacrificial film for forming a cavity between the conductive layers. The product can be 100 ppm or less.

  In the sacrificial film for forming cavities between the conductive layers, the change in film thickness after immersion for 60 seconds at 25 ° C. using a 1.0 wt% hydrofluoric acid aqueous solution can be 3% or less.

A method for forming a cavity between conductive layers according to one embodiment of the present invention includes:
Using the composition for forming a cavity between the conductive layers, forming a sacrificial film for forming a cavity on the first conductive layer;
Patterning the sacrificial film for cavity formation to form a pattern in the sacrificial film;
Forming a second conductive layer on the sacrificial film;
Forming a cavity between the first conductive layer and the second conductive layer by removing the sacrificial film;
including.

  Since the composition for forming cavities between conductive layers includes a polymer for forming cavities between conductive layers having a repeating unit represented by the general formula (1), heat resistance and mechanical properties can be improved by using the composition. It is possible to form a film having excellent mechanical strength, little residue generated at the time of removal by ashing, and mechanical strength that can sufficiently cope with the conductive layer processing process at a heat resistant temperature or lower. In addition, it has sufficient resistance to cleaning liquid and is highly adaptable to general semiconductor device manufacturing processes. Therefore, by using the above composition for forming a cavity between conductive layers, a cavity can be easily formed between conductive layers (wirings, electrodes, contacts, etc.) in a semiconductor element, a MEMS element or the like.

  Hereinafter, a composition for forming a cavity between conductive layers, a sacrificial film for forming a cavity between conductive layers, and a method for forming a cavity between conductive layers according to an embodiment of the present invention will be described in detail.

1. Composition for forming cavities between conductive layers A composition for forming cavities between conductive layers according to one embodiment of the present invention is a polymer for forming cavities ((A) component) between conductive layers according to one embodiment of the present invention. B) Contains an organic solvent (component (B)).

  The sacrificial film for forming cavities between conductive layers according to an embodiment of the present invention is obtained by applying a composition for forming cavities between conductive layers according to this embodiment to form a coating film, and firing the coating film. It is done.

  The total solid content concentration of the composition is preferably 2 to 30% by mass, and is appropriately adjusted according to the purpose of use. When the total solid content concentration of the composition is 2 to 30% by mass, the film thickness of the coating film is in an appropriate range, and the storage stability is more excellent.

1.1. Polymer (component (A))
The component (A) is a polymer for forming cavities between conductive layers having a repeating unit represented by the following general formula (1).

・・・・・（１）
［式中、Ｚは下記一般式（２）で表される２価の芳香族基であり、Ｙは、下記一般式（３）で表される２価の芳香族基および下記一般式（４）で表される２価の芳香族基から選ばれる少なくとも１種の２価の芳香族基である。］

・・・・・（２）
（式中、Ｒ^１およびＲ^２は独立に、−ＣＱＱ’−（ここで、Ｑ、Ｑ’は同一であっても異なっていてもよく、ハロゲン化アルキル基、アルキル基、水素原子、ハロゲン原子またはアリール基を表す。）で示される基、フルオレニレン基、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＣＯＮＨ−、−Ｓ−、−ＳＯ_２−または式：

で表される２価の基を表し、Ｒ^３、Ｒ^４およびＲ^５は独立に、炭素原子数１〜２０の炭化水素基、シアノ基、ニトロ基、炭素原子数１〜２０のアルコキシル基またはアリール基を表し、ａは１〜３の整数を示し、ｂ、ｃおよびｄは独立に０〜４の整数を示す。）

・・・・・（３）

・・・・・（４）
（式中、Ｒ^６およびＲ^７は独立に−ＣＱＱ’−（ここで、Ｑ、Ｑ’は同一であっても異なっていてもよく、ハロゲン化アルキル基、アルキル基、水素原子、ハロゲン原子またはアリール基を表す。）で示される基、フルオレニレン基、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＣＯＮＨ−、−Ｓ−、−ＳＯ_２−を表し、Ｒ^８、Ｒ^９、Ｒ^１０およびＲ^１１は独立に、炭素原子数１〜２０の炭化水素基、シアノ基、ニトロ基、炭素原子数１〜２０のアルコキシル基またはアリール基を表し、ｅは０〜３の整数を示し、ｆ、ｇ、ｈおよびｉは独立に０〜４の整数を示す。） 1.1.1. Structure of polymer The polymer has a repeating unit represented by the following general formula (1).

(1)
[In the formula, Z is a divalent aromatic group represented by the following general formula (2), Y is a divalent aromatic group represented by the following general formula (3) and the following general formula (4 And at least one divalent aromatic group selected from divalent aromatic groups. ]

(2)
(Wherein R ¹ and R ² are independently —CQQ′— (wherein Q and Q ′ may be the same or different and are a halogenated alkyl group, an alkyl group, a hydrogen atom, a halogen atom, Or an aryl group)), a fluorenylene group, —O—, —CO—, —COO—, —CONH—, —S—, —SO ₂ — or a formula:

R ³ , R ⁴ and R ⁵ are independently a hydrocarbon group having 1 to 20 carbon atoms, a cyano group, a nitro group, an alkoxyl group having 1 to 20 carbon atoms, or Represents an aryl group, a represents an integer of 1 to 3, b, c and d independently represent an integer of 0 to 4; )

(3)

(4)
(Wherein R ⁶ and R ⁷ are independently —CQQ′— (wherein Q and Q ′ may be the same or different and are a halogenated alkyl group, an alkyl group, a hydrogen atom, a halogen atom or Represents an aryl group.), A fluorenylene group, —O—, —CO—, —COO—, —CONH—, —S—, —SO ₂ —, and R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ independently represents a hydrocarbon group having 1 to 20 carbon atoms, a cyano group, a nitro group, an alkoxyl group having 1 to 20 carbon atoms or an aryl group, e represents an integer of 0 to 3, f, g, h and i each independently represents an integer of 0 to 4.)

・・・・・（５）
（式中、Ｒ^１〜Ｒ^５、ａ、ｂ、ｃおよびｄは、上記一般式（２）に関して定義したとおりであり、Ｘは水酸基、ハロゲン原子、−ＯＭ基（Ｍはアルカリ金属である）、−ＯＳＯ_２Ｚ基（Ｚはアルキル基、ハロゲン化アルキル基またはアリール基）を表わす。）

・・・・・（６）

・・・・・（７）
（上記一般式（６）および上記一般式（７）中、Ｒ^６〜Ｒ^１１、ｅ、ｆ、ｇ、ｈおよびｉは、上記一般式（３）または一般式（４）に関して定義したとおりである。） 1.1.2. Production of Polymer The polymer is, for example, selected from the group consisting of a compound represented by the following general formula (5), a compound represented by the following general formula (6), and a compound represented by the general formula (7). It can be produced by polymerizing at least one compound in the presence of a catalyst.

(5)
(Wherein R ^{1 to} R ⁵ , a, b, c and d are as defined in relation to the above general formula (2), X is a hydroxyl group, a halogen atom, and an —OM group (M is an alkali metal). , —OSO ₂ Z group (Z represents an alkyl group, a halogenated alkyl group or an aryl group).

(6)

(7)
(In the general formula (6) and the general formula (7), R ^{6 to} R ¹¹ , e, f, g, h, and i are as defined for the general formula (3) or the general formula (4). is there.)

Of Q and Q ′ constituting R ¹ and R ² in the general formula (5), examples of the alkyl group include a methyl group, an ethyl group, an i-propyl group, an n-propyl group, a butyl group, and a pentyl group. A halomethyl group such as a trifluoromethyl group and a pentafluoroethyl group; an arylalkyl group such as a benzyl group and a diphenylmethyl group; and an aryl group such as a phenyl group and a biphenyl group , Tolyl group, pentafluorophenyl group and the like.

As the Z constituting a -OSO 2 _Z in the general formula (5), as the alkyl group, methyl group, ethyl group; Examples of the halogenated alkyl group, a trifluoromethyl group, etc. pentafluoroethyl group; Examples of the aryl group include a phenyl group, a biphenyl group, a p-tolyl group, and a p-pentafluorophenyl group. R ¹ and R ² in the general formula (5) are preferably —O— and —CO—.

Examples of the compound represented by the general formula (5) include 1,2-bis (2-bromophenoxy) benzene, 1,2-bis (2-iodophenoxy) benzene, 1,2-bis (3- Bromophenoxy) benzene, 1,2-bis (3-iodophenoxy) benzene, 1,2-bis (4-bromophenoxy) benzene, 1,2-bis (4-iodophenoxy) benzene, 1,3-bis ( 2-bromophenoxy) benzene, 1,3-bis (2-iodophenoxy) benzene, 1,3-bis (3-bromophenoxy) benzene, 1,3-bis (3-iodophenoxy) benzene, 1,3- Bis (4-bromophenoxy) benzene, 1,3-bis (4-iodophenoxy) benzene, 1,4-bis (3-bromophenoxy) benzene, 1,4-bis (3- Dophenoxy) benzene, 1,4-bis (2-bromophenoxy) benzene, 1,4-bis (2-iodophenoxy) benzene, 1,4-bis (4-bromophenoxy) benzene, 1,4-bis (4 -Iodophenoxy) benzene,
1- (2-bromobenzoyl) -3- (2-bromophenoxy) benzene, 1- (2-iodobenzoyl) -3- (2-iodophenoxy) benzene, 1- (3-bromobenzoyl) -3- ( 3-bromophenoxy) benzene, 1- (3-iodobenzoyl) -3- (3-iodophenoxy) benzene, 1- (4-bromobenzoyl) -3- (4-bromophenoxy) benzene, 1- (4- Iodobenzoyl) -3- (4-iodophenoxy) benzene, 1- (3-bromobenzoyl) -4- (3-bromophenoxy) benzene, 1- (3-iodobenzoyl) -4- (3-iodophenoxy) Benzene, 1- (4-bromobenzoyl) -4- (4-bromophenoxy) benzene, 1- (4-iodobenzoyl) -4- (4-iodophenoxy) ) Benzene,
2,2′-bis (2-bromophenoxy) benzophenone, 2,2′-bis (2-iodophenoxy) benzophenone, 2,4′-bis (2-bromophenoxy) benzophenone, 2,4′-bis (2 -Iodophenoxy) benzophenone, 4,4'-bis (2-bromophenoxy) benzophenone, 4,4'-bis (2-iodophenoxy) benzophenone, 2,2'-bis (3-bromophenoxy) benzophenone, 2, 2'-bis (3-iodophenoxy) benzophenone, 2,4'-bis (3-bromophenoxy) benzophenone, 2,4'-bis (3-iodophenoxy) benzophenone, 4,4'-bis (3-bromo Phenoxy) benzophenone, 4,4′-bis (3-iodophenoxy) benzophenone, 2,2′-bis (4-bromophenoxy) ) Benzophenone, 2,2′-bis (4-iodophenoxy) benzophenone, 2,4′-bis (4-bromophenoxy) benzophenone, 2,4′-bis (4-iodophenoxy) benzophenone, 4,4′- Bis (4-bromophenoxy) benzophenone, 4,4′-bis (4-iodophenoxy) benzophenone,
2,2′-bis (2-bromobenzoyl) benzophenone, 2,2′-bis (2-iodobenzoyl) benzophenone, 2,4′-bis (2-bromobenzoyl) benzophenone, 2,4′-bis (2 -Iodobenzoyl) benzophenone, 4,4'-bis (2-bromobenzoyl) benzophenone, 4,4'-bis (2-iodobenzoyl) benzophenone, 2,2'-bis (3-bromobenzoyl) benzophenone, 2, 2′-bis (3-iodobenzoyl) benzophenone, 2,4′-bis (3-bromobenzoyl) benzophenone, 2,4′-bis (3-iodobenzoyl) benzophenone, 4,4′-bis (3-bromo Benzoyl) benzophenone, 4,4′-bis (3-iodobenzoyl) benzophenone, 2,2′-bis (4-bromobenzoyl) ) Benzophenone, 2,2′-bis (4-iodobenzoyl) benzophenone, 2,4′-bis (4-bromobenzoyl) benzophenone, 2,4′-bis (4-iodobenzoyl) benzophenone, 4,4′- Bis (4-bromobenzoyl) benzophenone, 4,4′-bis (4-iodobenzoyl) benzophenone,
3,4′-bis (2-bromophenoxy) diphenyl ether, 3,4′-bis (2-iodophenoxy) diphenyl ether, 3,4′-bis (3-bromophenoxy) diphenyl ether, 3,4′-bis (3 -Iodophenoxy) diphenyl ether, 3,4'-bis (4-bromophenoxy) diphenyl ether, 3,4'-bis (4-iodophenoxy) diphenyl ether, 4,4'-bis (2-bromophenoxy) diphenyl ether, 4, 4′-bis (2-iodophenoxy) diphenyl ether, 4,4′-bis (3-bromophenoxy) diphenyl ether, 4,4′-bis (3-iodophenoxy) diphenyl ether, 4,4′-bis (4-bromo) Phenoxy) diphenyl ether, 4,4′-bis (4-iodophenoxy) diphe Ether,
3,4′-bis (2-bromobenzoyl) diphenyl ether, 3,4′-bis (2-iodobenzoyl) diphenyl ether, 3,4′-bis (3-bromobenzoyl) diphenyl ether, 3,4′-bis (3 -Iodobenzoyl) diphenyl ether, 3,4'-bis (4-bromobenzoyl) diphenyl ether, 3,4'-bis (4-iodobenzoyl) diphenyl ether, 4,4'-bis (2-bromobenzoyl) diphenyl ether, 4, 4'-bis (2-iodobenzoyl) diphenyl ether, 4,4'-bis (3-bromobenzoyl) diphenyl ether, 4,4'-bis (3-iodobenzoyl) diphenyl ether, 4,4'-bis (4-bromo Benzoyl) diphenyl ether, 4,4′-bis (4-iodobenzoyl) diphe Ether and the like. These compounds may be used individually by 1 type, or may use 2 or more types simultaneously.

  Examples of the compound represented by the general formula (6) include 4,4′-diethynylbiphenyl, 3,3′-diethynylbiphenyl, 3,4′-diethynylbiphenyl, and 4,4′-diethynyl. Diphenyl ether, 3,3′-diethynyl diphenyl ether, 3,4′-diethynyl diphenyl ether, 4,4′-diethynyl benzophenone, 3,3′-diethynyl benzophenone, 3,4′-diethynyl benzophenone, 2,4 , 4'-triethynyl diphenyl ether and the like. These compounds may be used individually by 1 type, or may use 2 or more types simultaneously.

  Examples of the compound represented by the general formula (7) include 1,2-diethynylbenzene, 1,3-diethynylbenzene, 1,4-diethynylbenzene, 2,5-diethynyltoluene, 3, 4-diethynyltoluene and the like can be mentioned. These compounds may be used individually by 1 type, or may use 2 or more types simultaneously.

  The polymer of the present invention catalyzes at least one compound selected from the group consisting of the compound represented by the general formula (5) and the compound represented by the general formula (6) and the general formula (7). Of the compound represented by the general formula (5), the compound represented by the general formula (6) and / or the compound represented by the general formula (7). The proportion of use is such that the total amount of the latter compound is 0.8-1.2 mol, preferably 0.9-1.1 mol, particularly preferably 0.95-1. 05. When the total amount of the latter compound is less than 0.8 mol or exceeds 1.2 mol, the molecular weight of the resulting polymer is unlikely to increase.

In the method for producing a polymer, these compounds are preferably polymerized in the presence of a catalyst containing a transition metal compound, more preferably a catalyst containing a transition metal compound and a basic compound. ), (B) and (c) are particularly preferred.
(A) a substance capable of binding to a palladium salt and palladium as a ligand or forming a complex (including a complex ion) by supplying a group (atomic group) that binds as a ligand (hereinafter referred to as coordination) Or a palladium complex (a ligand former may be added if necessary)
(B) Monovalent copper compound (c) Basic compound

  Examples of the palladium salt include palladium chloride, palladium bromide, palladium iodide and the like. Examples of the ligand-forming body include triphenylphosphine, tri-o-tolylphosphine, tricyanophenylphosphine, tricyanomethylphosphine, and the like. Of these, triphenylphosphine is preferable. These compounds may be used alone or in combination of two or more.

  Examples of the palladium complex include dichlorobis (triphenylphosphine) palladium, dibromobis (triphenylphosphine) palladium, diiodobis (triphenylphosphine) palladium, dichlorobis (tri-o-tolylphosphine) palladium, dichlorobis (tricyanophenylphosphine) palladium. Dichlorobis (tricyanomethylphosphine) palladium, dibromobis (tri-o-tolylphosphine) palladium, dibromobis (tricyanophenylphosphine) palladium, dibromobis (tricyanomethylphosphine) palladium, diiodobis (tri-o-tolylphosphine) palladium, Diiodobis (tricyanophenylphosphine) palladium, diiodobis (tricyanomethylphosphine) para Um, tetrakis (triphenylphosphine) palladium, tetrakis (tri--o- tolyl phosphine) palladium, tetrakis (tricyanophenylphosphine) palladium, tetrakis (tricyanomethylphosphine) palladium. Of these, dichlorobis (triphenylphosphine) palladium and tetrakis (triphenylphosphine) palladium are preferable. These compounds may be used alone or in combination of two or more.

  Examples of the monovalent copper compound include copper (I) chloride, copper (I) bromide, copper (I) iodide and the like. These compounds may be used alone or in combination of two or more.

  The usage ratio of the catalyst is as follows.

  The use ratio of the palladium salt is preferably 0.0001 to 10 mol, more preferably 0.001 to 1 mol, with respect to 1 mol of the total amount of the compounds represented by the general formulas (5) to (7). is there. If the amount is less than 0.0001 mol, polymerization may not proceed sufficiently. On the other hand, if it exceeds 10 mol, purification may be difficult.

  Moreover, the usage-amount of a ligand formation body becomes like this. Preferably it is 0.0004-50 mol with respect to 1 mol of total amounts of the compound represented by said general formula (5)-(7), More preferably, it is 0.004. ~ 5 moles. If the amount is less than 0.0004 mol, polymerization may not proceed sufficiently. On the other hand, if the amount exceeds 50 mol, purification may be difficult.

  The use ratio of the palladium complex is preferably 0.0001 to 10 mol, more preferably 0.001 to 1 mol, with respect to 1 mol of the total amount of the compounds represented by the general formulas (5) to (7). . If the amount is less than 0.0001 mol, polymerization may not proceed sufficiently. On the other hand, if it exceeds 10 mol, purification may be difficult.

  The proportion of the monovalent copper compound used is preferably 0.0001 to 10 mol, more preferably 0.001 to 1 mol, based on 1 mol of the total amount of the compounds represented by the general formulas (5) to (7). Is a mole. If the amount is less than 0.0001 mol, polymerization may not proceed sufficiently. On the other hand, if it exceeds 10 mol, purification may be difficult.

  Examples of the basic compound include pyridine, pyrrole, piperazine, pyrrolidine, piperidine, picoline, trimethylamine, triethylamine, monoethanolamine, diethanolamine, dimethylmonoethanolamine, monomethyldiethanolamine, triethanolamine, diazabicyclooctane, dia Examples include zabicyclononane, diazabicycloundecene, tetramethylammonium hydroxide, diethylamine, ammonia, n-butylamine, and imidazole. Of these, diethylamine, piperidine, and n-butylamine are preferable. These compounds may be used alone or in combination of two or more.

  The use ratio of the basic compound is preferably 1 to 1000 mol, more preferably 1 to 100 mol, with respect to 1 mol of the total amount of the compounds represented by the general formulas (5) to (7). If the amount is less than 1 mol, polymerization may not proceed sufficiently, while if it exceeds 100 mol, it is not economical.

In the production of the polymer, a solvent can be used as necessary. Although there is no restriction | limiting in particular as a polymerization solvent, For example, halogen-type solvents, such as chloroform, a dichloromethane, 1, 2- dichloroethane, chlorobenzene, dichlorobenzene;
Aromatic hydrocarbon solvents such as benzene, toluene, xylene, mesitylene, diethylbenzene; ether solvents such as diethyl ether, tetrahydrofuran, dioxane, diglyme, anisole, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether; acetone, Ketone solvents such as methyl ethyl ketone, 2-heptanone, cyclohexanone, and cyclpentanone; ester solvents such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl lactate, ethyl lactate, butyl lactate, and γ-butyrolactone; N, N Examples include amide solvents such as dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone. These solvents are preferably used after sufficiently dried and deoxygenated. These solvents may be used alone or in combination of two or more.

  In the production of the polymer, the monomer (polymerization component) concentration in the polymerization solvent is preferably 1 to 80% by mass, and more preferably 5 to 60% by mass. The polymerization temperature is preferably 0 to 150 ° C, more preferably 5 to 100 ° C. The polymerization time is preferably 0.5 to 100 hours, more preferably 1 to 40 hours.

1.2. Organic solvent (component (B))
In the composition for forming cavities between conductive layers according to this embodiment, the component (A) is dissolved or dispersed in the component (B).

  As the component (B), for example, n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, 2,2,4-trimethylpentane, n-octane, i-octane, Aliphatic hydrocarbon solvents such as cyclohexane and methylcyclohexane; benzene, toluene, xylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propyl benzene, i-propyl benzene, diethylbenzene, i-butylbenzene, triethylbenzene, di-i -Aromatic hydrocarbon solvents such as propyl benzene, n-amyl naphthalene, trimethylbenzene; methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n- Pentanol, -Pentanol, 2-methylbutanol, sec-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, heptanol-3 , N-octanol, 2-ethylhexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethylheptanol-4, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec -Heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, phenylmethyl carbinol, diacetone alcohol, creso Monoalcohol solvents such as ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, pentanediol-2,4, 2-methylpentanediol-2,4, hexanediol-2,5, heptanediol Polyhydric alcohol solvents such as -2,4,2-ethylhexanediol-1,3, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin; acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl -N-butyl ketone, diethyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-i-butyl ketone, trimethylnonanone, cyclohexanone, 2-hex Ketone solvents such as sanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, fenchon; ethyl ether, i-propyl ether, n-butyl ether, n-hexyl ether, 2-ethylhexyl Ether, ethylene oxide, 1,2-propylene oxide, dioxolane, 4-methyldioxolane, dioxane, dimethyldioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono -N-hexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, ethyl Glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol di-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol di-n -Butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, tetrahydrofura Ether solvents such as 2-methyltetrahydrofuran; diethyl carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, acetic acid sec-butyl, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, aceto Methyl acetate, ethyl acetoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol acetate -N-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, glycol diacetate, Methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, malon Ester solvents such as diethyl acetate, dimethyl phthalate and diethyl phthalate; N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetate Nitrogen-containing solvents such as toamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone; dimethyl sulfide, diethyl sulfide, thiophene, tetrahydrothiophene, dimethyl sulfoxide, sulfolane, 1,3 -Sulfur-containing solvents such as propane sultone. These solvents can be used alone or in combination of two or more.

1.3. Other Components The composition for forming cavities between conductive layers according to the present embodiment comprises components such as colloidal silica, colloidal alumina, organic polymer other than the component (A), a surfactant, a silane coupling agent, and a triazene compound. Furthermore, you may contain.

  Colloidal silica is, for example, a dispersion in which high-purity silicic acid is dispersed in a hydrophilic organic solvent. Usually, the average particle size is 5 to 30 μm, preferably 10 to 20 μm, and the solid content concentration is 10 to 10 μm. It is about 40% by mass. Examples of colloidal silica include methanol silica sol and isopropanol silica sol (manufactured by Nissan Chemical Industries, Ltd.), Oscar (manufactured by Catalyst Chemical Industries, Ltd.), and the like.

  Examples of the colloidal alumina include Alumina Sol 520, 100, 200 (Nissan Chemical Industry Co., Ltd.), Alumina Clear Sol, Alumina Sol 10, 132 (Kawaken Fine Chemical Co., Ltd.), and the like.

  Examples of the organic polymer include polymers having a sugar chain structure, vinylamide polymers, (meth) acrylic polymers, aromatic vinyl compound polymers, dendrimers, polyimides, polyamic acids, polyamides, polyquinoxalines, poly Examples thereof include oxadiazole, a fluorine-based polymer, and a polymer having a polyalkylene oxide structure.

Examples of the polymer having a polyalkylene oxide structure include polymers having a polymethylene oxide structure, a polyethylene oxide structure, a polypropylene oxide structure, a polytetramethylene oxide structure, a polybutylene oxide structure, and the like. Specifically, polyoxymethylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, ethylene oxide derivative of alkylphenol formalin condensate, polyoxyethylene poly Ether type compounds such as oxypropylene block copolymer, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene fatty acid alkanolamide sulfate, etc. Ether ester type compound, polyethylene glycol fatty acid ester, ethylene glycol fat Esters, fatty acid monoglycerides, polyglycerol fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, ether-ester type compounds such as sucrose fatty acid esters and the like. Examples of the polyoxyethylene polyoxypropylene block copolymer include compounds having the block structure shown below.
− (X ′) _p − (Y ′) _q −
-(X ') _p- (Y') _q- (X ') _r-
[Wherein, X ′ represents a group represented by —CH ₂ CH ₂ O—, Y ′ represents a group represented by —CH ₂ CH (CH ₃ ) O—, and p represents a number of 1 to 90. Q represents a number from 10 to 99, and r represents a number from 0 to 90. ]

  Among these, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, etc. The ether type compound is a more preferred example. These may be used alone or in combination of two or more.

  Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and further, fluorine surfactants, silicone surfactants, Polyalkylene oxide surfactants, poly (meth) acrylate surfactants and the like can be mentioned, and fluorine surfactants and silicone surfactants can be preferably mentioned.

  Examples of the fluorosurfactant include 1,1,2,2-tetrafluorooctyl (1,1,2,2-tetrafluoropropyl) ether, 1,1,2,2-tetrafluorooctyl hexyl ether, Octaethylene glycol di (1,1,2,2-tetrafluorobutyl) ether, hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl) ether, octapropylene glycol di (1,1,1, 2,2-tetrafluorobutyl) ether, hexapropylene glycol di (1,1,2,2,3,3-hexafluoropentyl) ether, sodium perfluorododecylsulfonate, 1,1,2,2,8, 8,9,9,10,10-Decafluorododecane, 1,1,2,2,3,3-hexafluorodecane, N- [3- (perfluoro Kutansulfonamido) propyl] -N, N'-dimethyl-N-carboxymethyleneammonium betaine, perfluoroalkylsulfonamidopropyltrimethylammonium salt, perfluoroalkyl-N-ethylsulfonylglycine salt, bis (N-perfluorophosphate) Octylsulfonyl-N-ethylaminoethyl), monoperfluoroalkylethyl phosphate ester and the like, a fluorosurfactant comprising a compound having a fluoroalkyl or fluoroalkylene group at at least one of its terminal, main chain and side chain Can be mentioned. Commercially available products include Megafax F142D, F172, F173, and F183 (above, manufactured by Dainippon Ink and Chemicals, Inc.), Ftop EF301, 303, and 352 (manufactured by Shin-Akita Kasei Co., Ltd.). ] Fluorad FC-430, FC-431 [manufactured by Sumitomo 3M Co., Ltd.], Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (manufactured by Asahi Glass Co., Ltd.), BM-1000, BM-1100 (manufactured by Yusho Co., Ltd.), NBX-15 (Neos Co., Ltd.) and other commercially available fluorines There may be mentioned system surfactants. Among these, the above-mentioned Megafac F172, BM-1000, BM-1100, and NBX-15 are particularly preferable.

  As the silicone-based surfactant, for example, SH7PA, SH21PA, SH30PA, ST94PA (all manufactured by Toray Dow Corning Silicone Co., Ltd.) can be used. Of these, SH28PA and SH30PA are particularly preferable. The usage-amount of surfactant is 0.00001-1 weight part normally with respect to 100 weight part of (A) component. These may be used alone or in combination of two or more.

  Examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-aminoglycidyloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 1 -Methacryloxypropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3 -Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarboni -3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-triethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1, 4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N- Bis (oxyethylene) 3-aminopropyl trimethoxysilane, etc. N- bis (oxyethylene) -3-aminopropyltriethoxysilane and the like. These may be used alone or in combination of two or more.

  Examples of the triazene compound include 1,2-bis (3,3-dimethyltriazenyl) benzene, 1,3-bis (3,3-dimethyltriazenyl) benzene, and 1,4-bis (3,3 -Dimethyltriazenyl) benzene, bis (3,3-dimethyltriazenylphenyl) ether, bis (3,3-dimethyltriazenylphenyl) methane, bis (3,3-dimethyltriazenylphenyl) sulfone, Bis (3,3-dimethyltriazenylphenyl) sulfide, 2,2-bis [4- (3,3-dimethyltriazenylphenoxy) phenyl] -1,1,1,3,3,3-hexafluoro Propane, 2,2-bis [4- (3,3-dimethyltriazenylphenoxy) phenyl] propane, 1,3,5-tris (3,3-dimethyltriazenyl) ben 2,7-bis (3,3-dimethyltriazenyl) -9,9-bis [4- (3,3-dimethyltriazenyl) phenyl] fluorene, 2,7-bis (3,3- Dimethyltriazenyl) -9,9-bis [3-methyl-4- (3,3-dimethyltriazenyl) phenyl] fluorene, 2,7-bis (3,3-dimethyltriazenyl) -9, 9-bis [3-phenyl-4- (3,3-dimethyltriazenyl) phenyl] fluorene, 2,7-bis (3,3-dimethyltriazenyl) -9,9-bis [3-propenyl- 4- (3,3-dimethyltriazenyl) phenyl] fluorene, 2,7-bis (3,3-dimethyltriazenyl) -9,9-bis [3-fluoro-4- (3,3-dimethyl) Triazenyl) phenyl] fluorene, 2,7-bis ( , 3-Dimethyltriazenyl) -9,9-bis [3,5-difluoro-4- (3,3-dimethyltriazenyl) phenyl] fluorene, 2,7-bis (3,3-dimethyltriazeni) ) -9,9-bis [3-trifluoromethyl-4- (3,3-dimethyltriazenyl) phenyl] fluorene. These may be used alone or in combination of two or more.

1.4. Film Manufacturing Method As described above, the sacrificial film for forming a cavity between conductive layers according to this embodiment is obtained by applying the above composition to form a coating film and baking the coating film.

When the composition is applied to a substrate such as a silicon wafer, SiO ₂ wafer, or SiN wafer, for example, a coating means such as spin coating, dipping, roll coating, or spraying can be used.

  As the dry film thickness, the thickness of the coating film is preferably about 0.05 to 1.5 [mu] m by one coating and about 0.1 to 3 [mu] m by two coatings. After forming the coating film, it is dried at room temperature, or heated at a temperature of about 80 to 600 ° C. and usually dried for about 5 to 240 minutes to form a coating film (cured film) that becomes an interlayer insulating film. can do. As a heating method at this time, a hot plate, an oven, a furnace, or the like can be used, and a heating atmosphere is performed in the air, a nitrogen atmosphere, an argon atmosphere, a vacuum, a reduced pressure with a controlled oxygen concentration, or the like. Can do. Moreover, a coating film can be formed also by irradiating an electron beam or an ultraviolet-ray.

1.5. Sacrificial film for forming cavities between conductive layers The sacrificial film for forming cavities between conductive layers according to this embodiment has a weight loss of 5% by mass or less when heated at 350 ° C. for one hour in an inert gas atmosphere or vacuum atmosphere. (Preferably 3% by mass or less, more preferably 1% by mass or less). The sacrificial film for forming cavities between the conductive layers according to this embodiment has a mechanical strength that can sufficiently cope with the conductive layer processing process at a temperature lower than the heat resistant temperature. Therefore, by forming the sacrificial film for forming the cavities between the conductive layers according to the present embodiment using the polymer according to the present embodiment, it is possible to easily form cavities between the conductive layers in the semiconductor element, the MEMS element, and the like. it can.

  Here, examples of the inert gas include nitrogen and the like in addition to rare gases such as helium, neon, argon, krypton, xenon, and radon. As the inert gas to be used, those having a purity of 99.9% or more are usually used, those having a purity of 99.99% or more are preferred, and those having a purity of 99.999% or more are particularly preferred. As the inert gas used, nitrogen, argon and helium are preferable. The vacuum atmosphere is usually 100 Torr or less, preferably 10 Torr or less, particularly preferably 1 Torr or less.

  Moreover, hydrogen, oxygen, ammonia, water, etc. can be mixed in the inert gas atmosphere for the purpose of promoting the decomposition of the polymer according to the present embodiment. The mixing component is not particularly limited in the mixing amount, but is usually used in an amount of 50% by volume or less, preferably 25% by volume or less. The polymer has a good thermal decomposability at 500 ° C. or less, and can be removed by simple heat treatment without the need for complicated operations such as etching and ashing that are usually used in the production of semiconductor devices and MEMS devices. In addition, cavities can be easily formed between conductive layers (wirings, electrodes, etc.) in semiconductor elements and MEMS elements.

  The sacrificial film for forming cavities between conductive layers according to this embodiment has an elastic modulus at 25 ° C. of 5 GPa or more.

Furthermore, the sacrificial film for forming cavities between the conductive layers according to the present embodiment uses H ₂ and Ne (H ₂ : He = 350 scm / 3500 scm) as the ashing gas and ashing at 350 ° C. for 180 seconds at a pressure of 100 Pa. The residue after performing is 100 ppm or less. That is, since the sacrificial film for forming cavities between the conductive layers according to the present embodiment is formed using (A) an aromatic polyarylene and / or an aromatic polyarylene ether, a polymer that is either Excellent in mechanical properties and mechanical strength, and little residue after ashing.

  The sacrificial film for forming cavities between the conductive layers according to the present embodiment has sufficient mechanical strength to withstand processing in the manufacture of semiconductor elements and MEMS elements.

  The sacrificial film for forming cavities between the conductive layers according to the present embodiment has a hardness of usually 0.2 GPa or more, preferably 0.3 GPa or more, particularly preferably 0.4 GPa or more, and usually 5.0 GPa or more, preferably 6.0 GPa. As described above, since the elastic modulus (25 ° C.) is particularly preferably 7.0 GPa or more, it can be applied to processing in manufacturing semiconductor elements such as CMP and MEMS elements.

  The sacrificial film for forming cavities between the conductive layers according to the present embodiment can be processed into a predetermined shape and used as necessary. The sacrificial film for forming cavities between conductive layers according to the present embodiment is prepared by spin coating, dip coating, roll coating after the polymer according to the present embodiment is diluted alone or with an organic solvent as necessary. The film is formed by various methods such as a flow coating method, a spray coating method, and a hot press method, and further, if necessary, by heating to a temperature lower than the thermal decomposition temperature of the polymer according to the present embodiment. It can be obtained by removing an organic solvent.

2. Cavity Formation Method Between Conductive Layers FIGS. 1A to 1C are cross-sectional views schematically showing a method for forming a cavity between conductive layers according to an embodiment of the present invention. By using the polymer for forming cavities between conductive layers according to the present embodiment, cavities can be easily formed between conductive layers in semiconductor elements, MEMS elements, and the like.

  FIGS. 1A to 1C show the case where a multilayer wiring is formed on the semiconductor substrate 1, and the first and second conductive layers 3 and 4 are wiring layers constituting the multilayer wiring. Although the case is shown, the method shown in FIGS. 1A to 1C can also be applied to the formation of a MEMS element.

  For example, a coating film is formed by applying the composition for forming a cavity between conductive layers according to the present embodiment on the surface of the insulating layer 6 formed on the semiconductor substrate 1 by the above-described method, and the coating film is baked. Thus, after forming the cavity forming sacrificial film 2 on the insulating layer 6 between the conductive layers, the sacrificial film 2 is patterned using a normal lithography technique and an etching technique to form an opening (not shown). (See FIG. 1 (a)).

  Next, a metal such as Cu, Al, W, or Mo is embedded in the opening by a method such as normal plating or CVD to form the first conductive layer 3 (see FIG. 1A). When embedding a metal, a nitride layer of a refractory metal such as TaN or TiN can be formed between the sacrificial film 2 and the metal for the purpose of preventing metal diffusion. Alternatively, the surface may be planarized by CMP after embedding a metal. Alternatively, the first conductive layer 3 may be formed by embedding a nitride layer of a refractory metal such as TaN or TiN in the opening instead of the metal. The first and second conductive layers 3 and 4 may have a laminated structure of two or more layers. In the above step, the sacrificial film 2 may be formed after the first conductive layer 3 is formed.

  Next, the second conductive layer 4 is formed on the first conductive layer 3 and the sacrificial film 2 by a method similar to the method of forming the first conductive layer 3 (see FIG. 1B).

  Finally, the sacrificial film 2 is removed by ashing to form a cavity 5 between the first conductive layer 3 and the second conductive layer 4 (see FIG. 1C).

  When the first and second conductive layers 3 and 4 are wiring layers constituting a multilayer wiring, the sacrificial film 2 may be removed for each wiring layer of the multilayer metal wiring, or FIG. After repeating the steps from (a) to FIG. 1 (c), several layers of multilayer wiring may be performed together.

Ashing can be performed, for example, using a known ashing apparatus using H ₂ / He gas and NH ₃ gas as ashing gas at a temperature of room temperature to 350 ° C. and a pressure of 10 to 100 Pa for 60 to 300 seconds. it can.

  According to the method for forming a cavity between conductive layers according to the present embodiment, (A) a sacrificial film is formed using a composition containing a polymer that is an aromatic polyarylene and an aromatic polyarylene ether or one of the above, By removing the sacrificial film by ashing, ashing residue can be reduced.

3. Examples Hereinafter, the present invention will be described more specifically with reference to examples. However, the following description shows the example of an aspect of this invention generally, and this invention is not limited by this description without a particular reason. In addition, unless otherwise indicated, the part and% in an Example and a comparative example have shown that they are a weight part and the mass%, respectively. Various evaluations were performed as follows.

3.1. Evaluation method 3.1.1. Weight reduction By thermogravimetry (TG), the change in weight of the film was measured when the film obtained in each Example and Comparative Example was heated at 350 ° C. for 1 hour in a nitrogen atmosphere.

3.1.2. Elastic modulus The elastic modulus is a film (film thickness: 0. 3) obtained by recoating three times by a nano-indentation method at 25 ° C. by the same film forming method as that used in each example and comparative example. This is a value obtained by measuring an elastic modulus of 5 μm).

3.1.3. Ashing residue The films obtained in each Example and Comparative Example were subjected to ashing under the following conditions.
Ashing device: Shibaura Mechatronics CDE300
Output of ashing device: 1000W
Ashing gas: H ₂ / He
Flow rate of ashing gas: H ₂ / He = 350 scm / 3500 scm
Ashing gas pressure: 100 Pa
Ashing gas temperature: 350 ° C
Ashing time: 180 seconds

Ashing residue was evaluated according to the following criteria.
A: The weight of the residue after ashing is less than 100 ppm with respect to the weight of the film before ashing. B: The weight of the residue after ashing is 100 ppm or more with respect to the weight of the film before ashing.

3.1.4. Wet etching resistance The polymer films obtained in the examples and comparative examples were subjected to a wet etching resistance test under the following conditions.
Cleaning solution: 1.0 wt% hydrofluoric acid aqueous solution immersion condition: rinse at 25 ° C. for 60 seconds, drying condition: spray-cleaned with ultrapure water and then dried on a 120 ° C. hot plate.

Wet etching resistance was evaluated according to the following criteria.
A: Less than 3% change in film thickness before and after wet etching resistance test B: 3% or more change in film thickness before and after wet etching resistance test

3.2. Example 3.2.1. Example 1
To a 1000 ml three-necked flask equipped with a thermometer, an argon gas inlet tube, and a stirrer, 120 ml of tetrahydrofuran, 3.46 g of tetrakistriphenylphosphine palladium, 2.1 g of dichlorobistriphenylphosphine palladium, 1.44 g of copper iodide, 20 ml of piperidine, And 185.72 g of 4,4′-bis (2-iodophenoxy) benzophenone were added. Next, 65.48 g of 4,4′-diethynyl diphenyl ether was added and reacted at 25 ° C. for 20 hours. This reaction solution was reprecipitated twice with 5 liters of acetic acid, then dissolved in cyclohexanone, washed twice with ultrapure water, reprecipitated with 5 liters of methanol, the precipitate was filtered and dried, and the weight average molecular weight was 35,000. Polymer A was obtained.

  A solution obtained by dissolving 3 g of this polymer A in 47 g of cyclohexanone was filtered through a Teflon (registered trademark) filter having a pore size of 0.2 μm to obtain a film-forming composition of Example 1.

  The obtained composition was applied onto a silicon wafer by spin coating, dried on a hot plate at 80 ° C. for 2 minutes and at 180 ° C. for 2 minutes, and further on a hot plate in a nitrogen atmosphere at 390 ° C. Baking for 10 minutes gave the polymer film of Example 1 (thickness 180 nm).

3.2.2. Example 2
The same operation as in Example 1 except that 189.06 g of 4,4′-bis (2-iodobenzoyl) diphenyl ether was used instead of 4,4′-bis (2-iodophenoxy) benzophenone in Example 1. And a polymer B having a weight average molecular weight of 38,000 was obtained.

  A solution obtained by dissolving 3 g of this polymer B in 47 g of cyclohexanone was filtered through a Teflon (registered trademark) filter having a pore size of 0.2 μm to obtain a film-forming composition of Example 2.

  The obtained composition was applied onto a silicon wafer by spin coating, dried on a hot plate at 80 ° C. for 2 minutes and at 180 ° C. for 2 minutes, and further on a hot plate in a nitrogen atmosphere at 390 ° C. The polymer film of Example 2 (thickness 180 nm) was obtained by baking for 10 minutes.

3.2.3. Comparative Example 1
After dissolving 24 g of poly (hydroxystyrene) in 96 ml of acetone, 9.7 g of t-butyl bromoacetate and 7.6 g of potassium carbonate were added, and the mixture was reacted for 8 hours while refluxing with stirring. After completion of the reaction, 100 ml of ethyl acetate was added to the reaction solution and washed with a 5% by weight acetic acid aqueous solution. Then, the solvent was distilled off, the resulting resin was redissolved in acetone, reprecipitated, and vacuum dried at 50 ° C It dried in the container overnight and obtained the acid dissociable group containing resin of the comparative example 1. The obtained resin had a weight average molecular weight of 12,000, and as a result of NMR measurement, 23% of the hydrogen atoms of the phenolic hydroxyl group were substituted with a t-butoxycarbonylmethyl group.

  A solution obtained by dissolving 3 g of this resin in 47 g of ethyl 2-hydroxypropionate was filtered through a Teflon (registered trademark) filter having a pore size of 0.2 μm to remove foreign matters, and applied on a silicon wafer by spin coating. After that, preliminary baking was performed at 100 ° C. for 2 minutes to obtain a resist film (thickness 180 nm) of Comparative Example 1.

3.2.4. Comparative Example 2
After dissolving 77.04 g of methyltrimethoxysilane and 2 g of acetic acid in 290 g of isopropyl alcohol, the solution was stirred with a three-one motor to stabilize the solution temperature at 60 ° C. Next, 84 g of ion-exchanged water was added to the solution over 1 hour. Then, after making it react at 60 degreeC for 2 hours, the reaction liquid was obtained.

  A solution obtained by filtering this reaction solution through a Teflon (registered trademark) filter having a pore size of 0.2 μm was applied onto a silicon wafer by a spin coating method, and then heated on a hot plate at 80 ° C. for 2 minutes at 180 ° C. And then baked on a hot plate in a nitrogen atmosphere at 390 ° C. for 10 minutes to obtain a silica-based film (thickness 180 nm) of Comparative Example 2.

  According to Table 1, the polymer films obtained in Examples 1 and 2 have few ashing residues, are excellent in wet etching resistance, and have an elastic modulus at 25 ° C. of 5 GPa or more, so they have excellent mechanical strength. I can understand that. From the above results, it can be understood that the polymer films obtained in Examples 1 and 2 are suitable as a sacrificial film for forming a space.

FIG. 1A to FIG. 1C are cross-sectional views schematically showing a method for forming a cavity between conductive layers according to an embodiment of the present invention.

Explanation of symbols

1: Semiconductor substrate 2: Sacrificial film for cavity formation 3: First conductive layer 4: Second conductive layer 5: Cavity 6: Insulating layer

Claims (7)

(A) A composition for forming cavities between conductive layers, comprising a polymer having a repeating unit represented by the following general formula (1), and (B) an organic solvent.

(1)
[In the formula, Z is a divalent aromatic group represented by the following general formula (2), Y is a divalent aromatic group represented by the following general formula (3) and the following general formula (4 And at least one divalent aromatic group selected from divalent aromatic groups. ]

(2)
(Wherein R ¹ and R ² are independently —CQQ′— (wherein Q and Q ′ may be the same or different and are a halogenated alkyl group, an alkyl group, a hydrogen atom, a halogen atom, Or an aryl group)), a fluorenylene group, —O—, —CO—, —COO—, —CONH—, —S—, —SO ₂ — or a formula:

R ³ , R ⁴ and R ⁵ are independently a hydrocarbon group having 1 to 20 carbon atoms, a cyano group, a nitro group, an alkoxyl group having 1 to 20 carbon atoms, or Represents an aryl group, a represents an integer of 1 to 3, b, c and d independently represent an integer of 0 to 4; )

(3)

(4)
(Wherein R ⁶ and R ⁷ are independently —CQQ′— (wherein Q and Q ′ may be the same or different and are a halogenated alkyl group, an alkyl group, a hydrogen atom, a halogen atom or Represents an aryl group.), A fluorenylene group, —O—, —CO—, —COO—, —CONH—, —S—, —SO ₂ —, and R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ independently represents a hydrocarbon group having 1 to 20 carbon atoms, a cyano group, a nitro group, an alkoxyl group having 1 to 20 carbon atoms or an aryl group, e represents an integer of 0 to 3, f, g, h and i each independently represents an integer of 0 to 4.)   A sacrificial film for forming cavities between conductive layers obtained by applying the composition for forming cavities between conductive layers according to claim 1 to form a coating film and firing the coating film. In claim 2,
A sacrificial film for forming a cavity between conductive layers, the weight loss of which is 5% by mass or less when heated at 350 ° C. for 1 hour in an inert gas atmosphere or a vacuum atmosphere. In claim 2,
A sacrificial film for forming cavities between conductive layers, having an elastic modulus at 25 ° C. of 5 GPa or more. In claim 2,
Cavities between conductive layers having a residue of 100 ppm or less after ashing at 350 ° C. for 180 seconds at a pressure of 100 Pa using H ₂ and Ne (H ₂ : He = 350 scm / 3500 scm) as ashing gas Sacrificial film for formation. In claim 2,
A sacrificial film for forming cavities between conductive layers, wherein a change in film thickness is 3% or less after immersion for 60 seconds at 25 ° C. using a 1.0 wt% hydrofluoric acid aqueous solution. Using the composition for forming a cavity between conductive layers according to claim 1 to form a sacrificial film for forming a cavity on the first conductive layer;
Patterning the sacrificial film for cavity formation to form a pattern in the sacrificial film;
Forming a second conductive layer on the sacrificial film;
Forming a cavity between the first conductive layer and the second conductive layer by removing the sacrificial film;
A method for forming a cavity between conductive layers.

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