JPH01270322A - Formation of insulating film - Google Patents

Abstract

PURPOSE:To form a flattened insulating film by a method wherein a substrate being heated is sputtered to form a reflow glass while discharging sputtering gas. CONSTITUTION:A target which selects the composition out of the compositions such as PbO; 30-70wt.%Pb, SiO2: 50-20wt.% Si, P2O5: 4-8wt.% P conforming to arbitrary flow temperature is used. The substrate heating temperature in a sputtering device with even heat kept on is set up at the flowing temperature of PbSG. Then, the substrate to form reflow glass is carried to a sputtering chamber while the heating temperature of this substrate is kept at the set up flowing temperature. In such a state, PbO-SiO2-P2O5 target is sputtered to be deposited on the substrate. At this time, the substrate temperature being set up at the flow temperature, the PbSG deposited on the substrate starts to flow simultaneously to form a flattened PbSG film on the spot. Through these procedures, a flattened insulating film in excellent quality containing little gas and producing no bubbles at all can be formed in only one process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a flattened insulating film that is commonly used in the manufacture of semiconductor devices.

[Summary of the invention]

In the method of forming an insulating film, the present invention performs sputtering while heating the substrate and forms reflow glass while releasing sputtering gas, thereby eliminating the generation of air bubbles, performing deposition and flow at the same time, and flattening the glass on the spot. This makes it possible to form a chemically oxidized insulating film.

[Conventional technology]

In a semiconductor device, a flattening film made of adhesive flow glass such as Pb5G (lead silicate glass) is used as an interlayer insulating film for multilayer wiring.

P b S Gll containing pbo and 5iOz is Ar
After forming a deposited film by sputtering method such as gas,
It is formed by reflowing at the required temperature. Pb5G film is
Reflow is performed at a temperature of 350'' to 600° C. by adjusting the pbo to 30 to 70 wt% pb at 11 degrees.

As another method for forming a flattening film, there is also known a method in which a deposited film is formed by sputtering in the same chamber, and then etching is performed by reverse sputtering to flatten the film.

[Problem to be solved by the invention]

By the way, in the method of forming a flattening film in which a deposited film such as PBSC is formed by sputtering and then heat-treated and reflowed, impurities such as Ar gas are incorporated into the deposited film during sputtering at room temperature or below the reflow temperature.
Reflow generates gas pores such as Ar gas, making it impossible to obtain a uniform film. Even if a uniform film is obtained, two steps are required: forming a deposited film and reflow treatment, which takes time. It takes.

On the other hand, in the case of a method that combines deposited MI film formation and etching in the same chamber, poor step coverage during sputtering and a decrease in formation speed due to etching are unavoidable, and reverse sputtering such as A'' is unavoidable. If flattening is performed by etching using a photoresist, it is likely to generate particles and leave haze (cracks) in the deposited film, while methods such as RF bias sputtering may leave damage in the deposited film.
In order to remove this, high temperature annealing (approximately 600° C. or higher) is required. Therefore, it cannot be used after forming AA', which will become a wiring, and although it is necessary to suppress the bias in order to eliminate damage, the degree of planarization deteriorates at this time.

In consideration of the above points, the present invention provides a method for forming an insulating film that can form a high-quality glue-flow glass film by flattening the film at the same time as it is deposited.

[Means to solve the problem]

In the present invention, reflow glass is formed on the substrate while sputtering the substrate without heating it and releasing sputtering gas.

[Effect]

Since sputtering is performed while heating the substrate, a reflow glass film is always deposited in a degassed state, and is simultaneously flowed and flattened. Therefore, an insulating film can be obtained that is planarized on the spot or made of flow glass. Since the reflow glass film is deposited in a degassed state, the content of the sputtering gas in the reflow glass film is small and no air bubbles are generated, resulting in a high quality reflow glass film. Further, the process of forming such a planarizing insulating film is also simplified.

〔Example〕

Examples of the method for forming an insulating film according to the present invention will be described below.

A sputtering device capable of heating the substrate to about 350° C. to 600° C. is used as the device. Sputtering can be done by ordinary illumination, with RF bias on the substrate side.

The so-called loading method for loading the substrate (i.e., semiconductor wafer) on which an insulating film is to be formed, which does not require the application of a DC bias, may be an oven funnel or a load rotor, but from the standpoint of device stability, a load rotor is preferable. The heating may be resistance heating, infrared lamp heating, high frequency heating, laser heating, or the like.

This example is a case in which the formation of PBSC was successful.

First, a target having the following composition is prepared.

Composition PbO: 30 to 70 wt% pb St (h: 50 to 20 wt% 5i P205: 4 to 8 vt% P In other words, a target whose composition is selected from among these compositions according to an arbitrary flow temperature is used. The substrate is heated by maintaining uniform heat of about ±0.5 to 5 degrees Celsius.
Set the temperature to a point where it flows.

Then, the substrate on which reflow glass is to be formed is transported to a sputtering chamber, and the heating temperature of this substrate is maintained at a set flow temperature. In this state, the above PbO-5i (h-P205
A target is sputtered and deposited onto the substrate. At this time, since the substrate temperature is set to the flow temperature, the Pb5C film is flowed on the substrate at the same time as the )'bSG is deposited, and a flattened Pb5C film is formed on the spot. Thereafter, the substrate is taken out, cooled, and returned to the carrier socket.

According to the above method, since sputtering is performed while heating the substrate to the flow temperature of Pb5G, the Pb5G film is always deposited in a gaseous state and is flattened at the same time. Therefore, the obtained Pb5Glfi can be used for example A
The r content is also low, and the formation of air spores is eliminated, resulting in a high-quality film. Since it is flowed simultaneously with sputtering, a flattened Pb5G film can be obtained in that case, and the process can also be simplified. The flattened p b s GM'A can be formed at the same speed as the Toichi sputtering process. In addition, fewer particles and haze are generated, and damage to the Pb5G film caused by Arfi sputtering as in the conventional method and Ar content can be reduced.

By adding 4 to 8 wt% of P2O5 to the target, a gettering effect on alkali metal impurities can be obtained at the same time.

In particular, since it is planarized at the same time as the formation of the Pb5G film, it is suitable for forming an insulating film between the eyebrows of multilayer wiring. When used as a glabellar insulating film on Al wiring, the substrate temperature is desirably up to about 500°C.

Although the method was applicable to the formation of Pb5Glli, which can be reflowed at low temperatures, it can also be applied to the formation of insulating films using other reflow glasses.

〔Effect of the invention〕

According to the present invention, since the substrate is sputtered while heating to form the rifumi glass, deposition and flow are performed simultaneously, and a flattened insulating film can be obtained in step (2). and,
In this sputtering, the svanta gas is released while being deposited, so the resulting insulating film has a small amount of gas and no air bubbles, resulting in a high-quality film. Therefore, the present invention is particularly suitable for forming glabellar insulating films for multilayer wiring in semiconductor devices.

Claims (1)

[Claims] A method for forming an insulating film, which comprises sputtering a substrate while heating it and forming reflow glass while releasing a sputtering gas.