Method for etching of aluminium film (al)

FIELD: technological processes.

SUBSTANCE: invention is related to technology of semiconductor instruments manufacture. Method for etching of aluminium film includes etching of aluminium film from the surface of siliceous plates by means of their processing in etchant, which contains nitric, phosphorous and acetic acids at the ratio of components that is accordingly equal to 1:50:12 at temperature of 405C, for 155 minutes, at that difference in aluminium thickness layer makes 4.55.0%.

EFFECT: provision of smooth profile relief and reduced time and temperature of etching.

 

The invention relates to a technology of manufacturing of the power transistor, in particular for etching aluminum in the process of forming the base contact and emitter regions.

Known methods of etching the aluminum film, the essence of which consists in etching aluminum contact areas [1, 2].

The main disadvantage of this method is rough terrain profile, the duration of the process (30-40 minutes), high temperature etching (70-80C).

The aim of the invention is to obtain smooth terrain profile and reducing the time and temperature of the etching.

This goal is achieved using the provide the Etchant, which consists of the following main components: nitric acid, phosphoric acid, acetic acid in the ratio 1: 50:12.

The essence of the method lies in the fact that on the surface of silicon wafers is to achieve uniformity and speed of etching the aluminum film by adding acetic acid and the use of phosphoric acid (85%), the full release of aluminum from the surface of the substrate not protected by the photoresist layer, and the minimal impact of provide the Etchant on the film of photoresist.

Summary of the invention the following examples.

EXAMPLE 1. The process carried out at the facility chemical processing in the ratios of components:

HNO3:H3RO 4:CH3COOH=1:50:15.

The provide the Etchant temperature of 405C., the etching time of 155 minutes.

The variation in thickness of aluminum layer is 6.57,0%.

EXAMPLE 2. The method is carried out analogously to example 1. The process is carried out at a ratio of components:

HN3:H3RHO4:CH3COOH=1:50:13.

The provide the Etchant temperature of 405C., the etching time of 155 minutes.

The variation in thickness of aluminum layer is 5.56,0%.

EXAMPLE 3. The method is carried out analogously to example 1. The process is carried out at a ratio of components:

HN3:H3RHO4:CH3COOH=1:50:12.

The variation in thickness of aluminum layer is 4.55,0%.

The provide the Etchant temperature of 405C., the etching time of 155 minutes.

Thus, the proposed method is compared with the prototype provides uniform and complete etching of aluminum at a lower temperature and with less time etching process.

Literature

1. Ahikereru, Win. Production technology of semiconductor devices and integrated circuits. - M.: Higher school". 1986. - P. 166.

2. Ezzel, Fpprec. Planar silicon technology devices. - M.: "Energy". 1974. - S.

The method of etching the aluminum film, comprising etching the aluminum film from the surface of silicon wafers by processing silicon wafers to provide the Etchant consisting of nitric, phosphoric and acetic acids, characterized in that the processing is performed at a mixing ratio of nitrogen, phosphate and acetic acid = 1:50:12, at a temperature of 405C for 155 min, the variation in thickness of aluminum layer is 4.55,0%.



 

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