STUDY OF INTERCONNECT STRUCTURES FOR ULTR-HIGH-SPEED LSI'S

One of the most essential issues of constructing ultra high speed LSI's is to establish alow-resistivity,highreliability metalization schem. We have developed abvanced metalization schemes using eitherpure aluminum films或pure copper films by newly-developed “Low-Kinetic-Energy Particle ”“The copper films deposited by this过程exibited a very low resistivity of 1.80 .cm ”几乎等于电影的加密结构。such as the (100)-orientation or the (111)-orientation is able to be selected by just controllingthe ion-bombardment energy. Such films wafers epitaxially grown on silicon wafers. the Schottky diodes格式by depositing Cu films directly of n-type (100) Siat room temperature exibited ideal diodecharacteristics. The fact demonstrates that an ideal metal-semiconductor contact is able to be格式without any alloying heat cycles. Excellent adhesion of Cu films on sio_2 was also realizedby this process without any glue layer inbetween. Much more advanced metalization scheme was alsoestablished for pure aluminum metalization. The aluminum films formed with optimum conditionexibited a hillock-free feature up to a 500 C annealing temperature. Furthermore，a good step coverage at small contact holes is also obtained. It was also found that no degradeteoccurs in MOSFET's subjected to such low-energy ion bombardment.The establishment of such advancedpure Al or Cu metalization is of paramount importance for future ultra-high speedultra-high density LSI's。

One of the most essential issues of constructing ultra high speed LSI's is to establish a low-resistivity, high-reliability metalization schem. We have developed abvanced metalization schemes using either pure aluminum films or pure copper films by employing a newly-developed "Low-Kinetic-Energy Particle Process,"The copper films deposited by this process exibited a very low resistivity of 1.80 .cm nearly equal to the bulk resistivity. It was found that the crystal structure of film, such as the (100)-orientation or the (111)-orientation is able to be selected by just controlling the ion-bombardment energy. Such films were epitaxially grown on silicon wafers. The Schottky diodes formed by depositing Cu films directly of n-type (100) Siat room temperature exibited ideal diode characteristics. The fact demonstrates that an ideal metal-semiconductor contact is able to be formed without any alloying heat cycles. Excellent adhesion of Cu films on SiO_2 was also realized by this process without any glue layer inbetween. Much more advanced metalization scheme was also established for pure aluminum metalization. The aluminum films formed with an optimum condition exibited a hillock-free feature up to a 500゜C annealing temperature. Furthermore, a good step coverage at small contact holes is also obtained. It was also found that no degradete occurs in MOSFET's subjected to such low-energy ion bombardment.The establishment of such advanced pure Al or Cu metalization is of paramount importance for future ultra-high speed, ultra-high density LSI's.