| 摘要 |
1279741 Semi-conductor devices; printed circuits INTERNATIONAL BUSINESS MACHINES CORP 1 Jan 1970 [15 Jan 1969] 136/70 Headings H1K and H1R [Also in Division C7] A conductive track on a substrate consists of aluminium alloyed with copper which acts to reduce current-induced mass transport therein. The tracks may function as electrodes of electronic devices or as interconnections in hybrid thin film circuits, or on passivated chips. A typical use is to form a pattern of multi-layer interconnections between junction-isolated components formed by diffusion into a silicon chip utilizing alumina, silica or silicon nitride as passivating and inter-layer insulation. The tracks may be etched using photoresist techniques from films deposited by vacuum evaporation or RF sputtering, the aluminium and copper being derived from a common or from separate sources. A preferred method is to deposit a sequence of thin layers Al-Cu-Al. Distribution of the copper is improved by depositing with the substrate maintained at a high temperature, or by subsequent annealing at 250-560‹ C. To retard alloying to the silicon within apertures in the passivation 3% by weight of silicon may be added to the aluminium alloy and adhesion improved by varying the amount of copper throughout the thickness so that the aluminium is substantially free of copper adjacent the silicon. Mechanical strength can be improved by addition of 0À1-0À25% chromium, the consequent reduction in corrosion resistance being minimized by use of a protective coating of pure aluminium. The effect of the amount of copper (preferred range being 0À1-10%), annealing temperature and time on the median lifetime of the tracks is discussed in detail. Use of specific copper-aluminium alloys which also contain one or more of manganese, magnesium, chromium and silicon is suggested. |
