RU2591237C1 - Method of making semiconductor device - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: invention relates to semiconductor devices production process, in particular to technology of making contacts with lowered resistance. In method of semiconductor device making contacts are formed on basis of platinum. For this film of platinum with thickness of 35-45 nm is applied by electron-beam evaporation on silicon substrate, heated prior to 350 °C, at rate of deposition of 5 nm/min. Then heat treated in three stages: 1 step is carried out at temperature of 200 °C for 15 minutes, 2 step is carried out at temperature of 300 °C for 10 minutes and 3 stage is at 550 °C for 15 min in forming gas, with mixture of gases N₂:H₂=9:1.

EFFECT: proposed method of semiconductor device making provides reduced contact resistance, high technological effectiveness, improved parameters of devices, high quality and yield.

1 cl, 1 tbl

Description

The invention relates to the field of production technology of semiconductor devices, in particular to the technology of manufacturing contacts with low resistance.

A known method of manufacturing a semiconductor device [US Pat. 5345108 USA, MKI HO1L 23/48] with multilayer conductors, where Al Si Cu layers alternate with TiN layers. At the interface of the layers, Ti and Al interact and intermetallic compounds are formed, which envelop the metal grains with a very thin layer and separate the structural layers of the conductors, thereby sharply increasing their resistance to the formation of tubercles and the formation of gaps due to electromigration. In such semiconductor devices, due to the low technological processes, the spread of parameters increases, the quality and reliability of the devices decrease.

A known method of manufacturing a semiconductor device [US Pat. 5317187 USA, MKI HO1L 49/00] by creating contact between conductive elements located at different levels. A through window is created in the dielectric layer. Then, sequential deposition of Ti / TiN / Ti layers is carried out. Next, heat treatment of the structure is carried out, as a result of which titanium silicide is formed at the metal-semiconductor interface. Al is applied over Ti to reduce contact resistance.

The disadvantages of the method are:

- high contact resistance;

- low manufacturability;

- increased density of defects.

The problem solved by the invention is to reduce contact resistance, ensure manufacturability, improve instrument parameters, improve quality and increase yield.

The problem is solved by the formation of a Pt platinum film with a thickness of 35-45 nm by electron beam evaporation onto silicon substrates, with a deposition rate of 5 nm / min, preheated to 350 ° C, followed by annealing in three stages: stage 1 at a temperature of 200 ° C for 15 minutes, stage 2 - at a temperature of 300 ° C for 10 minutes and stage 3 - at a temperature of 550 ° C for 15 minutes in a forming gas, with a mixture of gases N ₂ : H ₂ = 9: 1.

The technology of the method consists in the following: according to standard technology, regions of a semiconductor device are formed on a silicon wafer with (100) orientation. Subsequently, contacts are formed on the basis of platinum silicide. For this, a Pt film 35-45 nm thick is deposited by electron beam evaporation on a silicon substrate, preheated to 350 ° C, with a deposition rate of 5 nm / min. Then annealing is carried out in three stages: stage 1 - at a temperature of 200 ° C for 15 minutes, stage 2 - at a temperature of 300 ° C for 10 minutes and stage 3 at a temperature of 550 ° C for 15 minutes in forming gas, gas mixtures N ₂ : H ₂ = 9: 1. In this case, the entire Pt layer interacts with silicon. In structures annealed sequentially at three temperatures, in a forming gas, the reaction between Pt and Si proceeds completely, and a PtSi layer is formed. Annealing in the forming gas promotes the formation of a uniform PtSi layer. On top of the PtSi layer, we apply an aluminum film according to standard technology.

According to the proposed method, semiconductor structures were manufactured and investigated. The results are presented in the table.

Experimental studies have shown that the yield of suitable devices on a batch of plates formed in the optimal mode increased by 15.7%.

Effect: reduction of resistance, ensuring manufacturability, improving the parameters of devices, improving quality and increasing yield.

The stability of the parameters over the entire operating temperature range was normal and consistent with the requirements.

The proposed method for manufacturing a semiconductor device by forming a platinum film with a thickness of 35-45 nm by electron beam evaporation onto silicon substrates followed by annealing in three stages: stage 1 at a temperature of 200 ° C for 15 minutes, stage 2 at a temperature of 300 ° C in for 10 min and stage 3 at a temperature of 550 ° C for 15 min in a forming gas, with a gas mixture of N ₂ : H ₂ = 9: 1, allows you to increase the percentage of suitable devices and improve their reliability.

Claims (1)

A method of manufacturing a semiconductor device, including the processes of deposition, heat treatment, formation of silicide, characterized in that the silicide is formed by applying a platinum film with a thickness of 35-45 nm by electron beam evaporation on a silicon substrate, heated to a temperature of up to 350 ° C, with a deposition rate of 5 nm / min followed by heat treatment in three stages: Stage 1 - at a temperature of 200 ° C for 15 minutes, Stage 2 - at a temperature of 300 ° C for 10 minutes and Stage 3 - at a temperature of 550 ° C for 15 minutes in forming gas , with a mixture of gases N ₂ : H ₂ = 9: 1.