Enhancement of Selective Chemical Vapor Deposition of Copper by Nitrogen Plasma Pretreatment

Abstract

Selective chemical vapor deposition of copper on TiN in the presence of borophosphosilicate glass (BPSG) was achieved by RF N2 plasma pretreatment. Without N2 plasma pretreatment, the copper films deposited on BPSG as well as TiN at the deposition temperature of 170°C, while N2 plasma treatment prior to copper deposition led to the significant suppression of the copper nucleation on BPSG. As the plasma pretreatment temperature was increased, the suppression of the copper nucleation on BPSG was increased. The results of time-of-flight secondary ion mass spectroscopy (TOF-SIMS) indicated that N2 plasma treatment decreased the content of hydroxyl groups on BPSG surface, suggesting that the reduction of the surface hydroxyl groups contributed to the selective deposition of copper on TiN/BPSG substrates.

Current Trends in Patterning with Copper

“…However, nonselective deposition and poor film conformity are the disadvantages of plasma-assisted CVD . Also, the plasma can cause damage to the underlying substrate . Laser-assisted CVD is potentially useful for direct-write applications; a laser is used to heat a substrate, inducing pyrolysis of the Cu precursor …”

“…Some precursors will selectively deposit Cu on conductive surfaces such as metals but not on dielectric surfaces, for example, SiO 2 . Examples of this are (hfac)Cu(COD), which deposits indiscriminately on both tungsten and SiO 2 surfaces, whereas (hfac)Cu(VTMS) can selectively deposit on tungsten in the temperature range 120−420 °C. , Selectivity is clearly determined by the nature of the ligands which surround the metal, and it can also be achieved by exploiting the fact that dielectric surfaces require a higher deposition temperature than conductive materials. , Therefore, by carefully controlling the substrate temperature, Cu can be deposited selectively on conducting materials …”

Preparation of thin copper films from the vapour phase of volatile copper(I) and copper(II) derivatives by the CVD method

“…It was assumed that it is this step that determines the overall process selectivity. 387 Hence, the simplest solution for the selectivity problem can involve suppressing the nucleation 396 or providing conditions where adsorption of molecules of the CCC on the dielectric surface is suppressed, while that on the metal surface is not suppressed. However, this solution also involves certain difficulties.…”

A Process for Copper Film Deposition by Pyrolysis of Organic Copper Materials

“…The Cu films have been deposited by plating, 6,7 sputtering, 8,9 and metallorganic chemical vapor deposition (MOCVD) techniques. [10][11][12][13][14][15][16][17] In the electroplating techniques, the Cu seed layer is needed on barrier metals and is deposited by sputtering technique. 8 As for the MOCVD technique, copper hexafluoroacetylacetonate vinyltrimethylsilane [(C 5 HF 6 O 2 )Cuи(CH 3 ) 3 Si-CHϭCH 2 , Cu 1ϩ (hfac)(vtms)] has been mainly used as the Cu 1ϩ precursor.…”

“…8 As for the MOCVD technique, copper hexafluoroacetylacetonate vinyltrimethylsilane [(C 5 HF 6 O 2 )Cuи(CH 3 ) 3 Si-CHϭCH 2 , Cu 1ϩ (hfac)(vtms)] has been mainly used as the Cu 1ϩ precursor. [10][11][12][13][14][15][16] The Cu films have been deposited at the substrate temperatures ranging from 130 to 250ЊC. Misawa et al have revealed that the resistivity of Cu films deposited at 200ЊC was 2.05 ⍀-cm, and it decreased to 1.98 and 1.88 ⍀-cm by annealing at 300 and 500ЊC, respectively.…”