JP3162157B2 - Film formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming method.

[0002]

2. Description of the Related Art In the technical field of semiconductor devices in recent years, research and development of 64-Mbit DRAMs have been advanced.
Exposure techniques for line widths of 3 microns or less have become necessary. Therefore, in a step-and-scan exposure apparatus (stepper) generally used in the exposure technology, the wavelength of a light source used from a g-line to an i-line is being shortened from the viewpoint of improving resolution. In addition, due to the use of stacked capacitors and multilayer wiring, there are cases where the unevenness of the resist surface provided at the time of pattern exposure exceeds 1 micron. For example, integration of semiconductor devices (three-dimensional structure)
As a result, an insulating film (interlayer insulating film) is appropriately buried in the surface of the trench structure having a high aspect ratio (vertical length / horizontal length) constituted by the conductive layer provided on the surface of the semiconductor wafer. However, a large step occurs on the entire surface of the insulating film after the burying. This step can be as large as 1 micron for devices with a resolution of about 0.3 microns.

For example, the insulating film is tetraethyl orthosilicate _{(Si (OC 2 H 5)} 4; TEOS ( TEOS)) mixed gas of ozone _{(O 3) (TEOS / O} 3)
According to the reaction using TEOS / O ₃ , since the silicon film has high fluidity, the step coverage formed by the conductive layer is conformally formed. (The deposition amount of the step covering portion is uniform). However, even though the step covering portion can be embedded conformally, the entire surface of the insulating film is not necessarily flat. Therefore, when a resist for exposure is provided on the surface of this insulating film,
Large unevenness occurs on the entire surface of the resist.

[0004]

In the case where the surface of the resist has asperities as large as 1 micron as described above,
NA of Stepper Lens with Shorter Wavelength in Exposure Equipment
Since the depth of focus becomes shallow due to the increase in the (aperture ratio), so-called blur occurs, and it is difficult to properly expose the entire surface of the resist.

Accordingly, an object of the present invention is to provide a film forming method capable of forming a flat film on an uneven surface.

[0006]

In order to achieve the above objects, the film forming method of the present invention has the following features. (1) In a film forming method for forming a flat film on an uneven surface, after a film is provided on the uneven surface, an ultrafine particle is brought into contact with the surface of the film to interact with the ultrafine particle. Is characterized in that the film is flattened in the atomic order. (2) When the ultrafine particles are brought into contact with the surface of the film, a conductive gas is interposed near the contact surface. (3) In a film forming method for forming a flat film on an uneven surface, after forming a film on the uneven surface using a coating liquid containing a film forming material in a highly fluid hydrophilic medium. The method is characterized in that ultrafine particles are brought into contact with the surface of this film, and the film is flattened in the atomic order by the interaction between the film surface and the ultrafine particles.

[0007]

According to a film forming method, after a film is provided on an uneven surface, ultrafine particles are brought into contact with the surface of the film and the film is flattened on the atomic order by the interaction between the film surface and the ultrafine particles. An extremely flat film is formed. In addition, when the ultrafine particles are brought into contact with the surface of the film, an adverse effect due to triboelectric charging can be sufficiently removed by interposing a conductive gas near the contact surface, and a flat film can be reliably formed. Can be.

Further, a film is formed on an uneven surface by using a coating solution containing a film-forming material in a high-fluidity hydrophilic medium, and then ultrafine particles are brought into contact with the surface of the film to form a film surface. According to the film forming method in which the film is flattened in the atomic order by the interaction between the particles and the ultrafine particles, a flat film can be formed with high efficiency. Therefore, for example, a flat resist surface without a step can be formed on the surface of an uneven insulating film formed on the surface of a semiconductor wafer having a trench structure with a high aspect ratio, and the depth of focus becomes small (NA Even when a large stepper lens is used, it is possible to properly expose the entire surface of the resist without causing so-called blur.

[0009]

[Embodiment 1] In this embodiment, an embodiment corresponding to claim 1 will be described.
In the film forming method of this embodiment , a flat film is formed on an uneven surface.
In the film forming method to be formed, a film was provided on a surface having irregularities
Then, the ultrafine particles are brought into contact with the surface of this
Flatten the film in atomic order by interaction with particles
It is characterized by that. This flattening means is a so-called EE
M (Elastic Emission Machine)
ing) method. This EEM method has two types of
When solids are brought into contact, the bonding force at the formed interface
Occurs, and when these are separated, one surface atom is no longer
One of the solid surface atoms may be removed.
This is a technology applied to flattening. That is, for example,
Ultrafine particles of submicron size or less are supplied to the film surface and transported.
Movement and separation, the phase between the membrane surface and the ultrafine particles
The interaction can planarize the film in atomic order.
Wear.

Electron state at the interface between the film surface and the ultrafine particles
State reduces the bonding force between the film surface atoms and the second layer atoms
In this case, efficient planarization is achieved. this
According to the EEM method, flattening can be performed on an atomic basis,
Removal of an atom accompanied by a decrease in the bonding strength of the atom
When the ultrafine particles move relative to each other on the film surface,
Flattening progresses as spontaneous behavior of atoms.
Yes, very ideal both geometrically and physically
It is possible to obtain high leveling accuracy.

As the ultrafine particles, for example, zirconium oxide
(ZrO ₂ ) etc., with a particle size of less than 0.1 μm
Fine particles can be used.

When contacting ultrafine particles with the surface of the film,
It is preferable to interpose a conductive gas near the contact surface of
No. This conductive gas prevents static electricity from being generated,
Dielectric breakdown when electricity is generated can be sufficiently prevented.
Wear. As the conductive gas, for example, carbon dioxide gas (C
O ₂ ), carbon monoxide gas (CO), etc. can be used.
However, the present invention is not limited to this.

FIG . 1 can be used in this embodiment.
The outline of a film forming apparatus is shown, and the film forming apparatus has an aspect ratio of
Of trenches with insulating film provided on the surface of high trench structure
To flatten the surface of the insulating film of a semiconductor wafer
belongs to. Reference numeral 1 denotes a processing chamber.
Fine particle supply means 7 and inlet for conductive gas such as carbon dioxide
8, a drain port 3, and a substrate holder 4 are provided.
You. The substrate holder 4 is provided with an uneven insulating film.
Semiconductor wafer 5 is fixed. Ultra fine particle supply means
7 is, for example, a polyurethane plate having a large number of ejection ports 72.
For example, zirconium oxide (ZrO ₂ )
Ultra-fine particles are filled, and these ultra-fine particles are ejected.
It is supposed to be. The ultrafine particles are, for example, in a suspension
It may be in a dispersed state. As these ultrafine particles
Is the surface binding (activation required for dissociation) energy of the membrane surface
And the interaction with the ultrafine particle surface
Choose something that can promote separation .

The conductive gas such as carbon dioxide (CO ₂ )
Suppresses the generation of static electricity when fine particles come into contact with the film surface
It is introduced in order to.

The semiconductor wafer 5 is rotated by the substrate holder 4.
In the state of being rotated, from the ejection port 72 of the ultrafine particle supply means 7
While squirting the ultrafine particles or its suspension,
The polyurethane plate 71 of the particle supply means 7 is connected to the semiconductor wafer 5
Close to the surface of the insulating film, and apply ultra-fine particles to the surface of the insulating film.
Make contact. At this time, the rotation speed of the semiconductor wafer 5 and the contact speed
The distance and the type and amount of ultrafine particles depend on the film thickness of the surface to be polished.
It is appropriately selected depending on the type. Ultra fine particles on insulating film surface
When making contact, the semiconductor wafer 5 is cooled or heated.
You may.

According to the film forming method of this embodiment, the aspect ratio
Provided on the surface of a semiconductor wafer with a high-ratio trench structure
Make the surface of the uneven insulating film extremely flat.
Can be. Therefore, the surface of this insulating film can be
By forming a more resist film, a flat resist
NA (opening) where a film can be formed and the depth of focus becomes shallow
When using a stepper lens with a large aperture ratio,
The entire surface of the strike film can be properly adjusted without causing so-called blur.
Exposure becomes possible. In addition, based on this embodiment,
And a semiconductor wafer with a trench structure having an aspect ratio of 3
Surface of insulating film with irregularities of up to 1 μm provided on the surface
The ultrafine particles in contact with the surface of the insulating film and the phase of the ultrafine particles.
After flattening the insulating film in atomic order by interaction,
The surface roughness was measured and found to be within 30 °.

[Embodiment 2] As shown in FIG.
For example, inside the polyurethane roll 73 having a spout
Filled with ultrafine particles such as zirconium oxide (ZrO ₂ )
This polyurethane roll 7
3 is similar to the relative movement to the film surface of the semiconductor upper lobe 5
Using a film-forming device that ejects ultra-fine particles from
The film forming method may be performed in the same manner as in the first embodiment. Real truth
According to the embodiment, a flat film can be formed as in the first embodiment.
Can be.

[Embodiment 3] In this embodiment, an embodiment corresponding to claim 3 will be described.
In the film forming method of this embodiment, a flat film is formed on an uneven surface.
In a film forming method, a film is formed on a highly fluid hydrophilic medium.
Use a coating solution containing the material to form a film on uneven surfaces
After providing the film, the ultrafine particles are brought into contact with the surface of this
Interaction between the surface and the ultrafine particles makes the film in atomic order
It is characterized by flattening.

As the hydrophilic medium having high fluidity, water, aluminum
Those selected from coal are preferred.
It can be preferably used. Ultrapure water has a resistivity of 1
8MΩ · cm or more water, which contains almost all impurities
Not what it is. Therefore, in semiconductor devices
It is a suitable material for film formation. Also, as alcohol
For example, use methyl alcohol, ethyl alcohol, etc.
Can be.

The film forming material is made of a resist.
Is preferably used. This film forming material is used for forming a film.
It is appropriately selected depending on the type. As a resist,
“CEL” (Contrast Enhanced Materia
(Contrast Enhanced Material)
ial)) can be used. In the coating solution,
The mixing ratio of the highly fluid hydrophilic medium and the film forming material
Is appropriately selected according to the type of the film to be formed.

FIG . 3 can be used in this embodiment.
An outline of a film forming apparatus is shown. 1 is a processing chamber, and this processing chamber
First, a film-forming material is contained in a highly fluid hydrophilic medium.
The inlet 2 for the coating liquid, the outlet 3 and the substrate holder 4
Is provided. That is, the film forming apparatus shown in FIG.
Room 1, inlet 2, drain 3 and basic holder 4
And the film forming apparatus shown in FIG.
Connected via a heat valve 9 to enable continuous processing
Things.

The substrate holder 4 has, for example, an electrostatic chuck
The semiconductor wafer 5 is fixed by the above method. This board
The rudder 4 can be cooled or heated,
It can be rotated further.

The coating liquid inlet 2 is provided with a highly fluid hydrophilic medium.
Coating solution prepared by premixing body and film forming material
Toward the semiconductor wafer 5 on the substrate holder 4.
It is something to make. The inlet 2 is provided with a pair of semiconductor wafers 5.
It is provided on the surface. Highly fluid hydrophilic that constitutes the coating solution
As the conductive medium, for example, ultrapure water is used.
For example, a resist is used. Ultrapure water and resist
Is appropriately selected.

Using this film forming apparatus, for example,
Thus, the film forming method of this embodiment can be performed. Processing room
1, a substrate holder to which a semiconductor wafer 5 is fixed
-4 is rotated at an appropriate speed and applied from inlet 2
Spout the liquid. Also, while spraying the coating liquid,
Cool or heat the semiconductor wafer 5 according to the type of liquid
Is also good. The coating is solidified by cooling or heating to form a film.
You. According to such a film forming method, high fluidity of ultrapure water can be achieved.
Therefore, the step coverage portion in the insulating film on the semiconductor wafer surface
Is sufficiently buried, and the entire insulating film is
First, a flat resist film is formed. This resist film
The thickness is preferably, for example, about 0.5 to 1 μm, which is thicker than usual.
Good.

The insulating film on the surface of the semiconductor wafer is, for example,
For example, tetraethyl orthosilicate ( Si (OC ₂ H ₅ )
₄ ; mixed gas of TEOS and ozone (O ₃ )
CVD method using (TEOS / O ₃ ) as source gas
Can be formed. The TEOS / O ₃ using
According to the conventional CVD method, the fluidity of the silicon film is high.
In addition, the step covering part can be embedded conformally
You.

According to the film forming method of this embodiment, the flatness is further improved.
The formed film can be efficiently formed. The book
Based on the embodiment, a trench structure having an aspect ratio of 3
Unevenness of maximum 1 μm formed on the surface of semiconductor wafer
Forming a resist film having a thickness of 50 μm on the surface of the insulating film;
The ultrafine particles are brought into contact with the surface of this resist
The resist film is formed by the interaction between the film surface and the ultrafine particles.
After flattening in atomic order, the surface roughness was measured.
At this time, it was within ± 5 °.

[0027]

As described above, according to the present invention,
The following effects are obtained. (1) After providing a film on an uneven surface,
Contact between ultrafine particles and the interaction between film surface and ultrafine particles
By flattening the film in the atomic order,
In addition, a flat film can be formed. (2) When ultrafine particles are brought into contact with the surface of the film, the contact
Friction electrification by interposing conductive gas near the surface
Can be sufficiently removed to ensure flatness
A large film can be formed. (3) High-fluidity hydrophilic medium containing film-forming material
After providing a film on the uneven surface using a coating solution, this film
Phase of ultrafine particles by contacting ultrafine particles to the surface of the film
By flattening the film in atomic order by interaction,
It is possible to efficiently form an extremely flat film
You.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a film forming apparatus used in Example 1.

FIG. 2 is a schematic view of a film forming apparatus used in Example 2.

FIG. 3 is a schematic view of a film forming apparatus used in Example 3.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Processing chamber 2 Application liquid inlet 3 Drainage port 4 Substrate holder 5 Semiconductor wafer 6 Perforated nozzle 7 Ultrafine particle supply means 71 Polyurethane plate 72 Spout port 73 Polyurethane roll 8 Conductive gas inlet 9 Gate valve

────────────────────────────────────────────────── (5) References JP-A-64-50422 (JP, A) JP-A-61-121441 (JP, A) JP-A-62-219923 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 7/16 G03F 7/26 511

Claims (3)

(57) [Claims] In a film forming method for forming a flat film on an uneven surface, a film is provided on an uneven surface, and ultrafine particles are brought into contact with the surface of the film to form a film between the film surface and the ultrafine particles. A film forming method, wherein the film is flattened in an atomic order by interaction. 2. A film forming method according to claim 1 , wherein, when the ultrafine particles are brought into contact with the surface of the film, a conductive gas is interposed near the contact surface. 3. A film forming method for forming a flat film on an uneven surface, wherein the film is provided on the uneven surface by using a coating liquid containing a film forming material in a highly fluid hydrophilic medium. And then contacting the surface of the film with ultrafine particles to flatten the film on the atomic order by the interaction between the film surface and the ultrafine particles.