Semiconductor device manufacturing: process – Making passive device – Stacked capacitor
Reexamination Certificate
2002-12-10
2004-11-16
Zarneke, David A. (Department: 2829)
Semiconductor device manufacturing: process
Making passive device
Stacked capacitor
C438S399000, C438S627000
Reexamination Certificate
active
06818522
ABSTRACT:
BACKGROUND
1. Technical Field
Methods for forming capacitors of semiconductor devices are disclosed, and more particularly, methods for forming capacitors are disclosed wherein the capacitors comprise a contact plug, a diffusion barrier film, a lower electrode formed of ruthenium (hereinafter, referred to as ‘Ru’), a dielectric film formed of high dielectric constant material and an upper electrode, and wherein the diffusion barrier film prevents diffusion of oxygen atoms during a deposition process and thermal treatment of the dielectric film to reduce degradation of characteristics of the device.
2. Description of the Related Art
A conventional diffusion barrier film is composed of TiN, TiAlN, TiSiN or TaSiN. A lower electrode composed of Ru or platinum is formed on the diffusion barrier film. A dielectric film is formed on the lower electrode using high dielectric constant materials such as BST or tantalum oxide film.
Here, the deposition process of dielectric film having high dielectric constant is carried out under oxygen atmosphere using a high thermal treatment method. As a result, oxygen atoms diffuse into the lower electrode and oxidize the diffusion barrier film.
In addition, when the lower electrode is composed of Ru film, molecular structure of Tris(2,4-octanedionato) ruthenium which is a source material must be broken down to allow the deposition of Ru film. Here, oxygen used as a reaction gas penetrates into the Ru film and diffuses through the lower electrode during the subsequent thermal process, thereby oxidizing a diffusion barrier film under the lower electrode. The oxidized diffusion barrier film degrades electrical characteristics of device.
SUMMARY OF THE DISCLOSURE
Accordingly, methods for forming capacitors of semiconductor devices are disclosed wherein the capacitors comprise a diffusion barrier film having strong chemical bond, amorphous structure without rapid diffusion path of oxygen and low electrical resistance in order to prevent degradation of characteristics of device during the subsequent high temperatures thermal process.
In order to produce the above-described capacitors one disclosed method comprises:
(a) forming a diffusion barrier film, wherein the diffusion barrier film includes a RuTiN film or RuTiN/RuTiO stacked film on a contact plug for a capacitor;
(b) thermally processing the diffusion barrier film via RTP under O
2
gas atmosphere; and
(c) sequentially forming a lower electrode, a dielectric film and an upper electrode on the diffusion barrier film.
It is preferable that the RuTiN/RuTiO stacked film further comprises a plurality of RuTiN/RuTiO stacked films.
It is preferable that the step of thermally processing the diffusion barrier film further comprises a step of making the surface of the diffusion barrier film dense using ionized gas.
It is preferable that the step of forming a diffusion barrier film comprises a CVD process for forming the RuTiN film having a thickness ranging from 200 to 1000 Å performed at a temperature ranging from 100 to 900° C.
It is preferable that the RuTiN film comprises Ru ranging from about 50 to about 90 atom %, Ti ranging from about 10 to about 50 atom % and N ranging from about 1 to about 80 atom %.
It is more preferable that the RuTiN film comprises Ru ranging from about 60 to about 90 atom %, Ti ranging from about 10 to about 40 atom % and N ranging from about 5 to about 40 atom %.
It is preferable that the step of forming a diffusion barrier film comprises a CVD process for forming the RuTiO film having a thickness ranging from 200 to 1000 Å performed at a temperature ranging from 100 to 900° C.
It is preferable that the RuTiO film of RuTiN/RuTiO stacked film comprises Ru ranging from about 50 to about 90 atom %, Ti ranging from about 10 to about 50 atom % and 0 ranging from about 1 to about 50 atom %.
It is preferable that the RuTiO film of RuTiN/RuTiO stacked film comprises Ru ranging from about 60 to about 90 atom %, Ti ranging from about 10 to about 40 atom % and O ranging from about 5 to about 40 atom %.
It is preferable that the step of forming the diffusion barrier film further comprises a purge process using a purge gas selected from the group consisting of N
2
, He, Ne, Ar, H
2
and mixed gas thereof.
It is preferable that the step of forming the diffusion barrier film employs a Ru precursor selected from the group consisting of RuX
2
and RuX
3
(where, X is selected from the group consisting of H, F, Cl, Br, I, C
1
-C
10
alkyl, C
2
-C
10
alkenyl, C
1
-C
8
alkoxy, C
6
-C
12
aryl, C
1
-C
8
alkylcyclopentadienyl, cyclopentadienyl, &bgr;-diketonates, C
1
-C
10
alkyl substituted with halogen, C
2
-C
10
alkenyl substituted with halogen, C
1
-C
8
alkoxy substituted with halogen, C
6
-C
12
aryl substituted with halogen, C
1
-C
8
alkylcyclopentadienyl substituted with halogen, cyclopentadienyl substituted with halogen and &bgr;-diketonates substituted with halogen).
It is preferable that the Ru precursor comprises Bis(ethylcyclopentadienyl) ruthenium, Tris(2,4-octanedionato)ruthenium or Tris(6-methyl-2,4-heptanedionato) ruthenium.
It is preferable that the step of forming the diffusion barrier film employs a Ti precursor selected from the group consisting of TiY
4
and TiY
2
(where, Y is selected from the group consisting of H, F, Cl, Br, I, C
1
-C
10
alkyl, C
2
-C
10
alkenyl, C
1
-C
8
alkoxy, C
6
-C
12
aryl, C
1
-C
8
alkylcyclopentadienyl, cyclopentadienyl, &bgr;-diketonates, C
1
-C
10
alkyl substituted with halogen, C
2
-C
10
alkenyl substituted with halogen, C
1
-C
8
alkoxy substituted with halogen, C
6
-C
12
aryl substituted with halogen, C
1
-C
8
alkylcyclopentadienyl substituted with halogen, cyclopentadienyl substituted with halogen and &bgr;-diketonates substituted with halogen).
It is preferable that the Ti precursor comprises Titanium tetrachloride or Titanium tetraisopropoxide.
It is preferable that the diffusion barrier film is formed using a reaction gas selected from the group consisting of O
2
, NH
3
, H
2
O, H
2
O
2
, ROH, RCOOH, C
2
-C
10
diol and mixtures thereof (where, R is selected from the group consisting of H, C
1
-C
10
alkyl, C
2
-C
10
alkenyl, C
1
-C
8
alkoxy, C
6
-C
12
aryl, C
1
-C
10
alkyl substituted with halogen, C
2
-C
10
alkenyl substituted with halogen, C
1
-C
8
alkoxy substituted with halogen and C
6
-C
12
aryl substituted with halogen).
It is preferable that the thermally processing the step (b) is performed under a gas atmosphere selected from the group consisting of O
2
gas, mixture gas of Ar and O
2
, mixture gas of N
2
and O
2
and combinations thereof.
It is preferable that the step of making the surface of the diffusion barrier film dense using ionized gas comprises (i) process comprising the steps of impacting the diffusion barrier film with ionized O
2
, ionized Ar, ionized Ar and O
2
, ionized N
2
and ionized N
2
and O
2
; thermally treating the diffusion barrier film; and forming a uniform oxide layer on the surface of the diffusion barrier film using O
2
ion, (ii) process comprising the steps of thermally treating the diffusion barrier film under NH
3
gas atmosphere, NH
3
plasma or NH
3
/O
2
plasma atmosphere; and forming a uniform oxide layer on the surface of the diffusion barrier film using O
2
ion, (iii) process comprising steps of thermally treating the diffusion barrier film using UV-O
3
to form a surface layer or (iv) combinations thereof.
It is preferable that the thermally processing the diffusion barrier film is performed at a temperature ranging from 100 to 650° C. for a time period ranging from 1 to 5 minutes.
It is preferable that the dielectric film is selected from the group consisting of a Ta
2
O
5
film, a BST film, a PZT film, a SBT film, a BLT film and mixtures thereof.
A diffusion barrier film is formed that has an oxidation tolerance at high temperature under oxygen atmosphere, which prevents degradation of characteristic of device during the subsequent thermal process.
A diffusion barrier film is required to prevent diffusion of oxygen atoms and must be oxidation-resistant.
Marshall & Gerstein & Borun LLP
Sarkar Asok Kumar
Zarneke David A.
LandOfFree
Method for forming capacitor of semiconductor device with... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for forming capacitor of semiconductor device with..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for forming capacitor of semiconductor device with... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3300914