JPS63281432A - Coated glass film - Google Patents

Abstract

PURPOSE:To improve wettability, and to prevent polarization resulting from moisture absorption by forming a liquid, in which at least one of compounds containing a specific quantity of fluorine or fluorine ions is added to the raw material solution of an SOG film, as a starting material. CONSTITUTION:Wettability to a foundation of a coating liquid in which an F compound such as HF is mixed into the raw material coating liquid of an SOG film must be increased. Since HF is extremely active and reacts with a large number of inorganic materials, the coating liquid into which HF is mixed dissolves an extremely thin section in the surface of an inorganic foundation material. Wettability with the foundation material of a coating film is improved largely. The effect is remarkable especially when the foundation material is SiO2. It is preferable that the quantity of fluorine contained in the coating liquid extends over 10ppm or more to a raw material solution, for example, 1-20g per 100g calculated in terms of SiO2. When fluorine content is kept within the range, an excellent result is acquired. 1-3.5g fluorine per 100g SiO2 is recognized in an SiO2 film, on which the coating film is coated and which is obtained through heat treatment at approximately 150 deg.C.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a coated glass film used for an interconductor insulating film or passivation of a semiconductor device, and in particular an SOG film suitable for flattening unevenness of a fine structure. This invention relates to a coated glass film using.

[Background of the invention]

SOG coating liquid (hereinafter abbreviated as coating liquid) generally combines some or all of the four OH groups of silanol 5i(OH)a with OR.
(R is an alkyl group) A monomer or polymer of a Si compound having a structure substituted with a group is dissolved in a solvent containing alcohol as a main component. In addition, this coating solution usually contains HCQ, which was used as a catalyst when hydrolyzing the Si compound having the above structure from another Si organic compound (for example, 4-ethyloxysilane), and an organic acid such as formic acid or acetic acid. include. An example of the composition of this coating liquid is Patent Publication No. 60-58180.

Coating liquids having such compositions have heretofore been widely used as inexpensive insulating films capable of flattening unevenness that occurs as a result of stacking a large number of various circuit elements on a semiconductor surface. This coating liquid particularly tends to stay in the four parts and has excellent properties for flattening the fine four parts.

However, recently, as the density of semiconductor devices has increased and wiring patterns have become finer, S
A problem arises in that the OG film is not filled. This is generally considered to be a defect caused by the alcohol used as a solvent for SOG not coating the top surface of the semiconductor device. In order to improve this cutting performance, attempts have been made to change the type of alcohol in the solvent and to change the structure and composition of the 8j compound as a solute, but no effective solution has yet been found. .

In addition, in a field different from the SOG thin film of the present invention, methods for producing large solids of Sj and Oz (raw materials for glass fiber, etc.) by the sol-gel method have been widely researched. Among them, K, Na5san, etc., Journal ofN
on-Crystalline 5olids 82 (
1986) p78-85 uses a mixture of HCQ and HF as the catalyst described above, and when HF is added, the gel compound 1
It is stated that the blistering caused by firing at 000° C. is significantly smaller than when using HCfl alone.

However, in the field of sol-gel method, although some thin film formation methods using the depping method have been considered, there are problems such as film thickness distribution and solution stability, and it is difficult to directly apply it to the formation of thin films used in semiconductor devices. considered difficult.

Further, HF is widely known as a catalyst that promotes polymerization in the field of sol-gel method.

[Purpose of the invention]

An object of the present invention is to form a coated glass film that can satisfactorily flatten the unevenness of the surface of a semiconductor device and form an insulating film.

[Summary of the invention]

The coating liquid is usually a low concentration solution containing at most 4 to 5 g of SiO2 component in 100 mQ of a solvent mainly composed of alcohol. Therefore, the wettability of the coating liquid itself is considered to be comparable to that of alcohol as the main solvent. It is well known that alcohol has very low surface tension and excellent wettability. Therefore, immediately after coating, most of the solvent does not evaporate and while the coating liquid remains on the substrate, the coating liquid remains in the narrow and deep hole, but the high concentration coating liquid remains after the main solvent alcohol has evaporated. The wettability of alcohol is now greatly reduced compared to alcohol. Therefore, as the coating liquid dries, it aggregates and solidifies into islands, which does not form a uniform film.

The present invention aims to increase the wettability of a coating solution, which is obtained by mixing a raw material coating solution with an F compound such as HF, onto a substrate.

For example, HF is very active and reacts with many inorganic substances, so a coating solution containing it dissolves a very thin part of the surface of the inorganic base material, so the wettability of the coating film with the subsurface material is greatly reduced. improve. This effect is particularly remarkable when the base material is SiO2.

The amount of fluorine contained in the coating liquid used in the present invention is preferably 1 g to 20 g per 100 g in terms of 5 iOz, and good results can be obtained if the fluorine content is within this range. After this coating film was applied, it was heat-treated at 150°C, and in the resulting 5iOz film, Ig-3.5g of fluorine was observed per SiOzlOOg.

[Embodiments of the invention]

Examples of the present invention will be shown below.

Example 1 4 moles of acetic acid were added to 1 mole of silicon tetrachloride, and the mixture was thoroughly mixed and stirred. The reaction tank was maintained at 40°C and heated to 1/100 with argon.
Stirring was carried out for 2 hours while bubbling with hydrogen fluoride gas diluted to 30%.

Next, 8 mol of ethyl alcohol was added to this reaction solution, and the reaction tank was maintained at 40° C. and stirred for 2 hours.

Thereafter, the temperature was returned to room temperature, and 13 mol of ethyl alcohol was added thereto, followed by stirring for 2 hours.

Next, the reaction solution was transferred to a sealed container and kept at room temperature for one week.

This raw material solution was applied to a thermally oxidized Si,02 film with fine irregularities formed on the surface of a silicon wafer at
Spin coating was performed at rpm. This was heated gradually in a nitrogen stream, and finally heated to 1000°C. The glass film obtained by coating and heating is homogeneous with a thickness of 0.2 μm, and has flattened irregularities, and has a width of 0.5 μm and a depth of about 1 μm.
The membrane filled even the μm grooves. This coated glass film was used as an insulating film between conductor layers and a passivation film of a semiconductor device. In this example, by bubbling HF, F
The introduction of ions into the solution and the evacuation of CQ ions are carried out effectively.

Example 2 1 mole of tetraethoxysilane and 4 moles of ethyl alcohol are mixed. Separately, prepare 1 mol of distilled water in which 0.3 mol of acetic acid and 0.1 mol of hydrofluoric acid are dissolved, and mix this with the above-mentioned alcohol solution and stir. After stirring for 1 hour, 6 moles of ethyl alcohol are added and stirring is continued for a further 1 hour.

Next, this reaction solution is transferred to a sealed container and kept at room temperature for one week.

This raw material solution was spin-coated and heated in the same manner as in Example] to obtain a homogeneous silica film with a thickness of 0.15 μm. The flattening and fine pattern filling performance were almost the same as in Example 1. This coated glass film is used as a conductor layer 1iJ7 of a semiconductor device.
It was used as an insulating film and a passivation film.

In this example, since HCQ is not used as a catalyst for the hydrolysis reaction, it is possible to prevent CQ ions, which are considered harmful to semiconductor devices, from being mixed in.

Example 3 In Example 2, instead of 0.1 mole of fluorine, 0
．． 2 moles of ammonium fluoride were used. The results obtained are almost the same as in Example 2.

Example 4 In Example 1, 0.04 mol of P2O1) was mixed and stirred in acetic acid in advance. Thereafter, the same procedure as in Example 1 was carried out.

Example 5 Since the SOG film created in the above example can be made thicker without cracking, this property can be used to fill trenches for element isolation in the same layer and to form AQ wiring patterns in the lower layer. After the plasma 5iOz was placed thereon, the SOG films according to Examples 1 to 5 were placed in order to alleviate the remaining steep steps, and furthermore, the plasma SjOx y upper layer AR pattern was placed thereon.

〔Effect of the invention〕

As explained above, according to the present invention, the wettability of the SOG coating liquid with the underlying material is greatly improved. The wettability referred to here is not the wettability of the SOG stock solution itself, but the wettability in a transient state between the liquid remaining after most of the main solvent alcohol evaporates during coating or drying after coating and the underlying material. It is difficult to evaluate this quantitatively. However, F
Conventional SOG coating liquid that does not contain elements has a width of 0.5 μm.
m.

Although it was difficult to fill the SiO2 grooves with a depth of 1 μm, it is considered that the wettability was improved because the coating liquid of the present invention could easily fill the grooves.

In addition, as another effect of the present invention, in the film fired at a low temperature of 60° C. or lower, the decrease in film thickness due to baking compaction was small, and the occurrence of cracks was reduced. In addition, the added F is contained in SiO2, and in particular it replaces the OH groups present on the SiO2 surface, so the water repellency has been greatly improved. Law SOG
It is possible to prevent the occurrence of polarization caused by moisture absorption, which occurs when the material is used as an insulating film.

Such an effect occurs when the weight concentration of F contained in 5iOz is 0.
．． It was found that this becomes noticeable when the amount exceeds 4 mg/g membrane.

Note that the F ions or F atoms can be added at any time between before the hydrolysis reaction and just before coating, and almost the same effect can be obtained.

In addition, although an example in which P was doped was shown in the example, it is possible to easily add elements that can be mixed into glass, such as B and Ge, using a similar method.

Claims (1)

[Claims] 1. Coated glass formed by coating and firing on a substrate, (Spi
10P in the raw material solution of n-On-Glass (SOG) film
1. A coated glass film characterized in that it is formed using a liquid containing a small amount of a compound containing a fluorine or a fluorine ion of PM or higher as a starting material.