JPS63104474A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the space between emitter and base from being electrically short-circuited by any etched metal dust scattering in the direction around 45 deg.C to be rebonded onto the sidewalls of step difference parts by a method wherein polycrystalline silicon is etched in chlorine base gas using emitter.base electrodes to be ion-milled for removing any metal dust rebonded. CONSTITUTION:A base region 2, an emitter region 3, an insulator 4, a polycrystalline silicon 5, an emitter electrode 6 and base electrodes 7 are formed on a semiconductor substrate 1. Metal dust 8 is a rebonding metal. Conventionally, any etched material is scattered in the direction of around 45 deg.C during ionmilling process. Later, polycrystalline silicon is dryetched in chlorine base gas using the emitter base electrodes 6, 7 as masks. Then, the metal dust 8 is removed by the second time ion milling process. Through these procedures, the space between emitter base electrodes can be widened by etching the polycrystalline silicon not to be subjected to short circuit even during repeated rebonding processes.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing L9 semiconductor devices t' using accelerated ions. [Prior Art] The manufacturing process of semiconductor devices varies from wet process to dry process. However, the ion milling method has become mainstream in the electrode formation process.

In particular, for structures such as ultra-high frequency transistors in which the emitter-to-pace distance is on the order of several micrometers, the wet process is unstable because it is extremely difficult to control the amount of side etching. On the other hand, since the ion milling method provides conditions with no side etching, it has become possible to obtain the dimensional finish of the mask pattern 9.

[Problem that the invention seeks to solve]

In the conventional ion milling method described above, as shown in Figure 2, argon ions accelerated at a high voltage of several degrees Celsius hit the main surface of the semiconductor substrate perpendicularly, so etched metal scraps are scattered in a direction of approximately 45 degrees, causing the sidewalls of the stepped portions to be damaged. This has the disadvantage that it re-attaches to the surface and causes an electrical short between E and B.

[Means for solving problems]

The ion milling method of the present invention is characterized by etching polycrystalline silicon using a chlorine-based gas using the emitter/base electrode as a mask, and then performing ion milling to remove all redeposited metal debris.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) to 1(C) are longitudinal sectional views of an embodiment of the present invention. 1 is a semiconductor substrate, 2 is a base region, 3 is an emitter region, 4 is an insulator, 5 is polycrystalline silicon, 6 is an emitter electrode, 7 is a base electrode, and 8 is a redeposited metal. Conventionally,
When ion milling is performed, the material to be etched is scattered in a direction of about 45 degrees. (FIG. (a)) shows that dry etching is then performed using a polycrystalline silicon all-chlorine gas using the emitter and base electrodes as masks. (Figure (b)) At this time, since the amount of side etching cannot be controlled with acid-based wet etching, it cannot be applied to devices with small alignment margins such as ultra-high frequency transistors. Next, ion milling is performed again to remove metal debris 8. (Figure (C)
) [Effects of the Invention] As explained above, the present invention is effective in etching polycrystalline silicon by widening the distance between the emitter and the paste electrode.
There is an effect that short-circuits will not occur even if the long material layer is applied again.

[Brief explanation of the drawing]

FIGS. 1A to 1C are vertical cross-sectional views showing the manufacturing process of the present invention, and FIG. 2 is a vertical cross-sectional view showing conventional ion milling.

Claims (1)

[Claims] In a semiconductor device manufacturing method that uses ion milling to form electrodes on a semiconductor substrate, the ion milling process and the dry etching of polycrystalline silicon with chlorine gas using the emitter and base electrodes as masks are performed. A method for manufacturing a semiconductor device, characterized by performing ion milling.