JPS5946047A - Forming method for multilayer wiring of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the defective connection of the connecting section of upper and lower layer wirings by adding a metal M, which reduces Al2O3 while forming MO and M2O3 by itself, into Al of the upper layer wiring. CONSTITUTION:Al2O3 is chemically stable, but can be reduced. An Al alloy containing 0.1-0.3% of the metal Th, La, Be, Mg, Ca, Ba or the like of strong oxidizability capable of reducing Al2O3 is used as an upper layer wiring material. The dissociation energy of the oxides of these metals is larger than Al2O3, they are chemically stable, and they can reduce Al2O3 into Al. A sintering temperature of 400-500 deg.C used for forming the connection of the upper and lower wirings is sufficient for reduction. MO and M2O3 formed take several massive shapes, and the lower layer Al wiring with Al2O3 naturally formed on the surface and the upper layer Al alloy wiring are Al-Al connected. An effect is not displayed when the quantity of the metal being added is less than 0.01%, and MO and M2O3 obstruct connection when it is 0.3% or more.

Description

【発明の詳細な説明】 〔発明の技術分野〕 この発明は半導体装置の多層配線形成方法に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for forming multilayer wiring in a semiconductor device.

〔発明の技術的背景〕[Technical background of the invention]

従来、半導体装置の配線材料としてはＡ１．（アルミニ
ウム）を用いるが、Ａ１は非常に酸化し７やすいため、
ＬＳＩなどの多層配線構造を有する半導体装置に於ては
上層配線と下層配線との１λＩ：６’ｊｌ：　ｊｌｌり
分に於て接続不良を生じることが予力・った。Conventionally, A1. (Aluminum) is used, but since A1 is very easy to oxidize,
In a semiconductor device having a multilayer wiring structure such as an LSI, it is expected that a connection failure will occur in a distance of 1λI:6'jl:jll between the upper layer wiring and the lower layer wiring.

〔背景技術の問題点〕[Problems with background technology]

Ａｌは非常に酸化されやすいため、蒸着の貞空条注下の
ようなかなり冒度の真空中（で放ｉねシた場合でも、そ
の表面は少なくとも数十穴以上のｊマさのアルミナ膜が
生じる。アルミナ（Ａ１２０３）は絶縁性の高い物質で
あるため、これが配線中や配線の接続部に生じると、配
線が断線した状態となったり、あるいは配線抵抗が著し
く高くなって半導体装置を実質的に不能化してしまう。Al is very easily oxidized, so even if it is left alone in a fairly extreme vacuum, such as during vapor deposition, its surface will be covered with an alumina film with at least several tens of holes. Since alumina (A1203) is a highly insulating substance, if it occurs in the wiring or at the connections of the wiring, the wiring will become disconnected or the wiring resistance will increase significantly, causing the semiconductor device to be damaged. It becomes physically impossible.

従りてＡ１を用いて多層配線を形成する場合には上層配
線を被着させる直前に稀フッ酸洗浄などの表面１処理を
することが行われているが、そｉｔでも」二層配線全形
成前又は形成中に下層配線の表面には必ず微小厚さのア
ルミナ膜が生じており、」一層配線と下層配線との接続
部に於゛Ｃ接続不良もしく（１断線を１１じ、その結果
、特にスルーポール接続点が数十万個もあるような半導
体装置の製造歩留りを低下させるという問題点が提起さ
れている。Therefore, when forming multilayer wiring using A1, surface 1 treatment such as dilute hydrofluoric acid cleaning is carried out immediately before depositing the upper layer wiring, but even with that, the entire second layer wiring is Before or during formation, a microscopic alumina film is always formed on the surface of the lower-layer wiring, and the connection between the first-layer wiring and the lower-layer wiring is caused by poor connection or disconnection (11). As a result, a problem has been raised in that the manufacturing yield of semiconductor devices, especially those having hundreds of thousands of through-pole connection points, is reduced.

〔発明の目的〕[Purpose of the invention]

この発明の目的は、前記の如き問題点、すなわち上層配
線と下層配線との接続部によ、・ける接続不良の発生を
防止しつる新規な多層配線形成方法ン：提供することで
ある。It is an object of the present invention to provide a novel method for forming multilayer interconnections that can prevent the above-mentioned problems, namely, the occurrence of connection failures caused by connections between upper layer interconnections and lower layer interconnections.

〔発明の棚、要〕[Shelf of inventions, essential]

この発明の方法は上層配線材としてＡｌよりも被酸化性
の強いＴｈ　、　Ｌａ　、　Ｂｅ　、Ｍｇ　、　Ｃａ　
、　Ｅａ等の金属’ｉｏ、０１〜０３％含有しブヒＡ１
合金を用いるとともに１層配線利としてＡｔを用いるこ
とケ特徴とｊる。この発明では、Ａｌ２Ｏ３を還元して
ＡＩにするため［Ｔｈ　、　Ｌａ、　、　Ｂｅ　＋　Ｍ
ｇ　、　Ｃａ　、　Ｂａ等の金属を用い、上層配線と下
層配線との接続部に存在するＡｌ２Ｏ３を分解さ−（−
ｉＪｌ　従来の半導体装置製造工程ケ著Ｉ−２〈改変す
ること攻く、前記の問題点を解決できるという利点があ
る。The method of the present invention uses Th, La, Be, Mg, and Ca, which are more oxidizable than Al, as upper layer wiring materials.
, containing 01-03% of metals such as Ea, Buhi A1
The characteristics are that an alloy is used and At is used for the first layer interconnection. In this invention, in order to reduce Al2O3 to AI, [Th, La, , Be + M
Using metals such as g, Ca, and Ba, Al2O3 existing at the connection between the upper layer wiring and the lower layer wiring is decomposed.
iJl Conventional Semiconductor Device Manufacturing Process Book I-2〈It has the advantage of being able to solve the above-mentioned problems without modification.

〔発明の実施例〕[Embodiments of the invention]

以下に本発明の実施例について説明するが、その前に従
来方法の間）唄点について図面を参照Ｌ７て簡単に説明
する。Embodiments of the present invention will be described below, but before that, the conventional method) will be briefly described with reference to the drawings.

第１図（イ）乃至（−９は半導体装置の製造工１ｌｊＩ
”（ａ於゛て−Ｌ層配線と下層配線との接続部Ｖｃオ、
−ける接に不良の発生状況不・示したものである。Figures 1 (a) to (-9 are semiconductor device manufacturing workers 1ljI
”(a) - Connection part Vc between L layer wiring and lower layer wiring,
- It shows the situation in which the defect occurred in the contact area.

第１図に於て２はＳｉ基板１上に成長さぜたＳｉＯ３膜
、６は５ＩＯ２膜２」、−に被着された純又はＳｉ含有
Ａｌから成る下層配線である。下層配線６の形成後、そ
の表面には薄いＡｌ２Ｏ３の）換４が生じるが、こｙｔ
はもちろん意図して発生させたものではない。下層配線
の形成後に全面に層間絶縁膜５が被着されたイ〔、：、
下層配線乙の上方の層間杷わ！＜　ｌｌｐ、’、３５が
フォトエツチングによって除去され、スルーポールすな
わち接続用開口部５ａが形成される。次に層ｍＪ絶縁１
摸５の上に上層配線６が被着され、該接続用開口部５ａ
に於て上層配線６と下層配線ろとが接続さシ］、るがＡ
ｌ２Ｏ３の股４が右在才るため、電気的には接続不良と
なる、 この発明ＶＣ，ｌ−′−いては、多層配線の工程でＡ１
２０３ｊ摸の発生を防止することは外部環境の制御のみ
では不可能であること、Ａｌ２Ｏ３は化学的に安シ１で
はあるが還元することは可能であること等に渚目し、Ａ
１よりも被酸化性が強い一金属、すなわち次式のように
ＡＩ。０３を還元すると、−もに自身ＭＯ２Ｍ２ｏ３を
形成する金属Ｍを上層配線材料のＡｌ中に添加すること
りこより、前記問題点を解決したものである。In FIG. 1, 2 is a SiO3 film grown on a Si substrate 1, and 6 is a lower layer wiring made of pure or Si-containing Al deposited on the 5IO2 film 2''. After forming the lower layer wiring 6, a thin layer of Al2O3) is generated on its surface.
Of course, this was not intentional. After forming the lower layer wiring, the interlayer insulating film 5 is deposited on the entire surface.
The layer between the layers above the lower layer wiring B! <llp,', 35 is removed by photoetching to form a through pole, that is, a connection opening 5a. Then layer mJ insulation 1
Upper layer wiring 6 is deposited on the pattern 5, and the connection opening 5a
The upper layer wiring 6 and the lower layer wiring are connected at
Since the crotch 4 of l2O3 is bent on the right side, electrical connection will be poor.
Considering that it is impossible to prevent the occurrence of 203j by controlling the external environment alone, and that although Al2O3 is chemically unstable, it is possible to reduce it,
A metal that is more oxidizable than 1, that is, AI as shown in the following formula. The above-mentioned problem was solved by adding the metal M, which itself forms MO2M2o3 when O3 is reduced, to the Al of the upper layer wiring material.

Ａｌ２Ｏ：（＋３Ｍ（２１’ｖｆ）→２Ａｌ＋３ＭＯ（
１＼／１２０３）下層配、線上に自然形成されたＡ１２
ｏ３ば」１式のようにＡＩに還元されるが、この還元条
件は上層及び下層配線の接続形成に通常行わオしている
４００〜５００℃のゾンタリング温度条件で十分である
。Al2O: (+3M(21'vf) → 2Al+3MO(
1\/1203) Lower layer wiring, A12 naturally formed on the line
It is reduced to AI as shown in formula 1, and the zontering temperature condition of 400 to 500° C., which is normally used to form connections between upper and lower layer wiring, is sufficient for this reduction.

また形成した■〜１０若しくはＭ２Ｏ３の酸化物は、」
二式反応によって自然酸化したＡ１゜０３膜のように下
層配線の被覆膜として残存１−２ないでいくつ刀・の固
まりとして残存するから、下層上層配線の接続面はＡｌ
−Ａｌの接続が形ＤＩできる。In addition, the formed oxide of ■~10 or M2O3 is
Like the A1゜03 film that is naturally oxidized by a two-way reaction, it remains as a coating film for the lower layer wiring, but remains as a lump of 1-2, so the connection surface of the lower layer and upper layer wiring is covered with Al.
-Al connections can be made in DI form.

このようにＡ１□ｏ、’を還元する被酸化性の強い金属
は１：と（−１てア、ルノノリ土’ｉ’：’１．！金属
、土類金属に属するものが多く、例えはＬａ　ｌ　Ｂｅ
　、　Ｍｇ　、　Ｃａ　、　１３ａ及びＴｈなどが前記
条件を満た］、ている、こパ１、らの金属の酸化物はＡ
ｌ　Ｏよりも解離エネルギーΔＦ０□９８２　　：（ が大きく、化学的に安定でＡＩ。０３を還元してＡ１に
することができる。第１表に上記の各金属酸化物の２０
　’Ｃ（２９８″Ｋ）における解離エネルギーンーＡｌ
２Ｏ３のそれに比較して示す（詳卸１は誠文堂新丸社発
行「金属イオ料の加〃（と酸化」参照）、第１表 −Ｌ層配線月料としてＡＩに添加する」１記金属の添加
量はＯＯ■〜０３重量係である。０．０１％未満である
と本発明の効果が現れず、また０３％を超えては生成す
るＭＯ（Ｍ２Ｏ３）が接続を阻害するふそれが生じるか
らである。In this way, the highly oxidizable metals that reduce A1□o,' are 1: and (-1tea, lunonori earth 'i':'1.! Many of them belong to metals and earth metals, for example, La l Be
, Mg, Ca, 13a and Th satisfy the above conditions], oxides of metals such as Copa 1, etc. are A
The dissociation energy ΔF0□982:( is larger than that of lO, it is chemically stable, and AI.03 can be reduced to A1.
Dissociation energy at 'C (298''K) - Al
A comparison with that of 2O3 is shown below. The amount of metal added is in the range of OO■ to 03% by weight.If it is less than 0.01%, the effect of the present invention will not appear, and if it exceeds 0.03%, the generated MO (M2O3) will inhibit the connection. This is because

以下にその実施例の一つ全記載する。One of the examples will be fully described below.

第２図の如く下層配線６として純Ａｌ’Ｔｈ用いて配線
を行った後、層間絶え、月摸５の形成とフォトエツチン
グとを行って層間絶縁膜５にスルーホール５ａを設けた
。」Ｌ層配線材としてＡｌＯ中に０１％のＣａミラ加（
７たＡ１合金を蒸着発生源に用いて」二層配線７を行っ
た後、４００〜５００°ＣのＮ２ガス雰囲気中で熱処理
を行った。熱処理後、上層配線７と下層配線６との接続
部について調査したところ、が、導通試、’、ＩＨＴ４
の結果、これらのＣａＯは全く電気的には障害となっ”
τいないことがわかった。After wiring was performed using pure Al'Th as the lower layer wiring 6 as shown in FIG. 2, the layers were separated, a moon pattern 5 was formed, and a through hole 5a was formed in the interlayer insulating film 5 by photoetching. ”01% Ca mira added in AlO as L layer wiring material (
After the two-layer wiring 7 was formed using the A1 alloy 7 as a vapor deposition source, heat treatment was performed in an N2 gas atmosphere at 400 to 500°C. After the heat treatment, the connection between the upper layer wiring 7 and the lower layer wiring 6 was investigated, and a continuity test was performed.
As a result, these CaOs do not pose any electrical problem.
It turned out that there was no τ.

〔発明の効果〕〔Effect of the invention〕

以上のよう１へ、この発明によれば、従来、接続不良を
生じゃ才力・った多層配線が接続不良な生じることなく
形成−ｙｉｔ、従、って半導体装置の歩留り及びイを軸
性を改善することができる。As described above, according to the present invention, multi-layer wiring, which conventionally requires a lot of effort to avoid connection failures, can be formed without connection failures, thereby increasing the yield of semiconductor devices. can be improved.

なお、実施例では、この発明を半導体素子の多層配線に
適用する場合のみを示したが、本発明が半導体素子ばか
りでなく、他の電子部品等にも適用しうろことは明らか
であイ）。In addition, in the examples, only the case where the present invention is applied to multilayer wiring of semiconductor elements is shown, but it is clear that the present invention can be applied not only to semiconductor elements but also to other electronic parts etc.) .

【図面の簡単な説明】[Brief explanation of the drawing]

第１図（イ）乃至（ハ）は半導体装置の製造工程Ｖｒ、
丸・ける配線形成工程と該工程で生じる問題点とを説ツ
］するための図、第２図は本発明の方法により配線形成
を行った半導体装置の断面図である。 １・・・基板、２・・・ＳｉＯ２膜、６・・下層配線、
４・・・Ａｌ２Ｏ３の膜、５・・・層間絶縁ｊ良、６．
７・・・上層配線。 特許出願人　東京芝浦軍気株式会月 第１図 （ハ） 第２図FIGS. 1(A) to 1(C) show the semiconductor device manufacturing process Vr,
FIG. 2 is a cross-sectional view of a semiconductor device in which wiring is formed by the method of the present invention. 1... Substrate, 2... SiO2 film, 6... Lower layer wiring,
4... Al2O3 film, 5... Good interlayer insulation, 6.
7... Upper layer wiring. Patent applicant: Tokyo Shibaura Gunki Co., Ltd. Figure 1 (c) Figure 2

Claims (1)

【特許請求の範囲】 １　下層配線を形成した後−Ｆ層配線全形成し、両配線
の一部を接触させて半導体装置の多層配線を形成するに
あたり、下層配線拐料としてＡＩヲ用いるとともに、上
層配線拐料としてＡＩよりも被酸化性の強いＴｈ、Ｌａ
、Ｂｅ、、Ｍｇ。 Ｃａ　、　Ｊ３ａ等の金属ｐ　０．０１〜０．３％含有
しｒｖＡ］合金を用いることを特徴とする半導体装置の
多層配線形成方法、[Scope of Claims] 1. After forming the lower layer wiring, all the F layer wiring is formed, and a part of both wirings are brought into contact to form a multilayer wiring of a semiconductor device. In addition, AI is used as a lower layer wiring material, Th and La, which are more oxidizable than AI, are used as upper layer wiring materials.
, Be, , Mg. A method for forming a multilayer interconnection of a semiconductor device, characterized by using an alloy containing 0.01 to 0.3% of metal p such as Ca, J3a, etc.