JPH0817817A - Method for forming sog film and sog coater - Google Patents

Abstract

PURPOSE:To form an ideal shape where the circumferential part of SOG film slightly retreats inside from a wafer edge. CONSTITUTION:A rotary circular plate 12 rotating in one piece with a wafer W, a discharge nozzle 14 for discharging an SOG source onto the wafer W, a rare HF liquid nozzle 16 for discharging the rare HF liquid, and a rinse liquid nozzle 18 for discharging the edge rinse liquid are provided. An exhaust/ waste means 22 for unloading the SOG source liquid, rare HF liquid, and rinse liquid and at the same time exhausting a cup is provided at the bottom of a cup 20 with an opening at the upper part. Further, an acid exhaust duct 24 is provided to exhaust such gas as HF gas generated from the rare HF liquid. The nozzle ports of the rare HF nozzle and rinse liquid nozzle are positioned so that they face the edge part of a wafer mounted on the rotary circular disk.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SOG coater for spin-coating an SOG film on a wafer. More specifically, when spin-coating an SOG film on a wafer, the peripheral edge of the SOG film is more or less than the wafer edge part. The present invention relates to an SOG coater in which an SOG film is formed so as to recede inward.

[0002]

2. Description of the Related Art SOG (Sp
The in on glass) film is often used as an interlayer insulating film or for flattening the formed film. The SOG film is
A chemical solution called a source in which SiO _X is dissolved in a volatile organic solvent such as alcohol is flown down onto the wafer, and the wafer is rotated at a high speed, so that the film is spread over the entire surface of the wafer. An apparatus called an SOG coater is used to spin-coat an SOG film on a wafer.

FIG. 3 is a sectional structural view schematically showing a conventional SOG coater. The conventional SOG coater includes a rotating disk 12 on which a Si wafer W is placed and integrally rotates, and a rotating mechanism (not shown) for rotating the rotating disk 12 in a direction of an arrow.
And a discharge nozzle 1 for discharging the SOG source onto the wafer W.
4 and a rinse liquid nozzle M for discharging the edge rinse liquid, and a metal cup N accommodates them. Further, at the bottom of the cup N, the SOG source liquid and the rinse liquid which are scattered on the side wall of the cup are discharged and the cup 1 is discharged.
Evacuation / waste liquid means 22 for exhausting 8 is provided.

In order to prevent the generation of particles, which will be described next, the SOG film is slightly recessed (preferably about 3 mm) inward from the wafer edge, as shown in FIG. 2A. Is desirable. However, when the SOG film is formed using the SOG coater, if the SOG film is still spin-coated, the SOG film extends from the upper surface of the wafer along the side edge of the wafer edge portion as shown in FIG. 2B. Film is formed in an overhang state. The wafer on which the SOG film is formed in such a state is transferred to the subsequent step, and when the peripheral edge of the SOG film comes into contact with the parts and parts of the apparatus there, the overhanged portion of the SOG film is chipped and the wafer is emitted. There is a problem that dust and particles are generated. Therefore, during the spin coating, isopropanol alcohol (IP
An organic solvent such as A) or cyclohexanone (CH ₂ (CH ₂ ) ₄ O) is jetted to the wafer edge to dissolve and remove the unnecessary SOG film overhanging the wafer edge.

[0005]

However, when edge rinse is performed using an organic solvent, the SOG film immediately after coating has
The viscosity thereof is reduced by the effect of the organic solvent, and the pressure of the edge rinse liquid pushes it back inward as shown in FIG. 2 (c). Therefore, the raised portion is formed along the wafer edge portion, and the same problem as the above-described particle generation occurs. Therefore, an object of the present invention is to form an ideal shape in which the peripheral portion of the SOG film is slightly recessed inward from the wafer edge without forming an overhang or a raised portion near the wafer edge. An object of the present invention is to provide an SOG film forming method and an SOG coater.

[0006]

In order to achieve the above object, a method for forming an SOG film according to the present invention is such that an SOG source is made to flow down onto the upper surface of a wafer placed on a rotating plate orthogonal to a vertical rotation axis. In a method of spin-coating by rotating a wafer together with a rotating plate to form an SOG film on the wafer, SO extending near the edge of the rotating wafer is used.
Dilute HF liquid is brought into contact with the G film for etching, and further diluted HF
It is characterized in that the rinse liquid is made to flow to rinse the SOG film portion in contact with the liquid.

The concentration of the diluted HF liquid is SOG due to the diluted HF liquid.
It is determined according to the etching rate of the film peripheral portion. Any rinsing liquid may be used as long as it can wash the diluted HF liquid, and, for example, pure water is used.

Further, the SOG coater according to the present invention for carrying out the above-mentioned film forming method has a rotating plate having a rotating surface orthogonal to the vertical rotating shaft and an SO on the upper surface of a wafer placed on the rotating surface.
In a SOG coater that includes a discharge nozzle that discharges a G source, and that spin-coats an SOG film on the upper surface of a wafer, a dilute HF liquid nozzle and a rinse liquid nozzle with nozzle openings facing the edge of the wafer on a rotating plate. And a cup surrounding the rotary plate is formed of an acid resistant material.

The nozzle opening of the dilute HF solution nozzle and the nozzle opening of the rinse solution nozzle are formed by etching with the dilute HF solution.
The SOG film is positioned such that the peripheral portion of the SOG film has an ideal positional relationship with the wafer edge as shown in FIG. The acid-resistant material forming the cup is not particularly limited as long as it is a material having durability against a dilute HF liquid, and for example, a synthetic resin such as PTFE or a metal material lined with an acid-resistant synthetic resin can be used. .

Another SOG coater according to the present invention comprises a rotating plate having a rotation surface orthogonal to the vertical rotation axis, and a discharge nozzle for discharging an SOG source on the upper surface of a wafer placed on the rotation surface. In an SOG coater that spin-coats an SOG film on the upper surface of a wafer, another liquid nozzle with a nozzle opening facing the edge of the wafer on the rotary plate is provided, and a cup surrounding the rotary plate is formed of an acid-resistant material. This is characterized in that the dilute HF liquid is discharged from another nozzle for each wafer, and then the rinse liquid is discharged.

A preferred embodiment of the apparatus of the present invention is characterized in that an acid exhaust duct having an exhaust port is provided at a position close to both the wafer edge and the nozzle port of the dilute HF liquid nozzle, or a nozzle different from the wafer edge is provided. It is characterized in that an acid exhaust duct having an exhaust port is provided at a position close to both of the nozzle ports. The acid exhaust duct is connected to a suction device, and is provided to suck and exhaust HF gas and other generated gas.

[0012]

The SOG film is made of SiO ₂ . According to the present invention, when the peripheral portion of the SOG film is etched with a dilute HF solution,
The following chemical formula utilizes the phenomenon that SiO _{2 that} comes into contact with the diluted HF solution dissolves in the diluted HF solution. SiO ₂ + 4HF = SiF ₄ + 2H ₂ O Then, a rinse liquid such as pure water is flown to the contact portion with the diluted HF liquid to wash the excess diluted HF liquid and the generated SiF ₄ . As a result, the edge of the SOG film recedes inward from the wafer edge.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the accompanying drawings. FIG. 1 shows the S according to the present invention.
It is a typical sectional view showing composition of one example of an OG coater. Of the parts and parts shown in FIG. 1, the same parts as those shown in FIG. 3 are designated by the same reference numerals. The SOG coater 10 of the present embodiment has a rotating disk 12 on which a wafer W is placed and integrally rotates, a rotating mechanism (not shown) for rotating the rotating disk 12 in a direction of an arrow, and an SOG on the wafer W. A discharge nozzle 14 that discharges a source, a diluted HF liquid nozzle 16 that discharges a diluted HF liquid, and a rinse liquid nozzle 1 that discharges an edge rinse liquid.
8 and.

Further, the SOG coater 10 uses PTFE (polytetrafluoroethylene) to accommodate them.
It is provided with a cup 20 having an opening at the top of the product. Further, the bottom of the cup 20 is provided with an exhaust / waste liquid means 22 for discharging the SOG source liquid, the diluted HF liquid and the rinse liquid which are scattered to the side wall of the cup and exhaust the cup 20. Further, an acid exhaust duct 24 is provided to exhaust the generated gas such as HF gas generated from the diluted HF liquid.

The nozzle opening of the discharge nozzle 14 is the rotary disk 1.
It is located at a position facing the center of 2. The nozzle openings of the dilute HF liquid nozzle 16 and the rinse liquid nozzle 18 are respectively arranged at positions facing the edge portion of the wafer W placed on the rotating disk 12, and the peripheral edge portion of the SOG film is etched by the dilute HF liquid, as shown in FIG. As shown in (a), the wafer is positioned so as to recede inward from the wafer edge by about 3 mm. The suction port 26 of the acid exhaust duct 24 is provided at a position close to both the wafer edge portion and the nozzle port of the discharge nozzle 14, and the other end of the acid exhaust duct 24 is connected to a vacuum suction device. As a result, the acid exhaust duct 24 can suck and exhaust the HF gas and other generated gas discharged from the dilute HF liquid nozzle 14.

In order to form an SOG film using the SOG coater 10, first, an appropriate amount of SOG source is ejected from the ejection nozzle 14. When the SOG source is extended to the wafer edge portion by spin coating, the diluted HF liquid is discharged from the diluted HF liquid nozzle 16 to dissolve the peripheral edge portion of the SOG film overhanging the wafer edge portion. Then, the rinse liquid is discharged from the rinse liquid nozzle 18 to remove the excess diluted HF liquid and the melted SOG film. In this embodiment, the dilute HF solution is an aqueous solution having a concentration of several%, and the rinse solution is pure water. As a result, the edge of the SOG film on the wafer is
As shown in (a), since it recedes inward from the wafer edge portion, when the SOG film is formed using this SOG coater, the wafer has a problem that particles are generated in a later step. do not do.

A control device is provided to discharge the SOG source from the discharge nozzle 14 and the diluted HF from the diluted HF liquid nozzle 16.
It is common to perform sequence control of operations such as discharge of liquid and discharge of rinse liquid from the rinse liquid nozzle 18. Also,
In this embodiment, the dilute HF liquid nozzle and the rinse liquid nozzle are different nozzles, but the same nozzle may be used for switching. When the exhaust of the HF gas and other generated gas can be replaced by the exhaust / waste liquid means 22, the acid exhaust duct 24 may be omitted.

[0018]

According to the method and apparatus of the present invention, the unnecessary SOG film formed on the wafer edge is dissolved and removed by the dilute HF solution, so that the SOG film formed on the wafer in the subsequent step. It is possible to prevent a problem that particles are generated due to lack of particles. Further, since the SOG film on the wafer edge is removed and the peripheral edge of the SOG film is shaped at the same time when the SOG film is formed, the number of steps does not increase and the work efficiency is high. Further, according to the method and the device of the present invention, it is possible to avoid the viscosity change of the SOG film due to the conventional edge rinse treatment.
It is possible to prevent a phenomenon in which the film thickness of the SOG film near the wafer edge becomes thicker than the flat portion and rises, which is caused by the conventional film forming method.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of an embodiment of an SOG coater according to the present invention.

FIGS. 2A, 2B and 2C are schematic views showing the relationship between a wafer edge portion and an SOG film peripheral portion.

FIG. 3 is a schematic cross-sectional view showing the configuration of a conventional SOG coater.

[Explanation of symbols]

 10 SOG Coater 12 Rotating Disk 14 Discharge Nozzle 16 Dilute HF Liquid Nozzle 18 Rinse Liquid Nozzle 18 20 Cup 22 Exhaust / Waste Liquid Means 24 Acid Exhaust Duct 26 Suction Port

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/31 Z

Claims (5)

[Claims] 1. An SOG source is made to flow down onto the upper surface of a wafer placed on a rotary plate orthogonal to a vertical axis of rotation, and the wafer is rotated together with the rotary plate for spin coating to form an SOG film on the wafer. In the method, a diluted HF solution is brought into contact with an SOG film extending near the edge of a rotating wafer to perform etching, and a rinse solution is flown to rinse the SOG film portion in contact with the diluted HF solution for rinsing. Method of forming SOG film. 2. A rotating plate having a rotation surface orthogonal to the vertical rotation axis, and a discharge nozzle for discharging an SOG source onto the upper surface of the wafer placed on the rotation surface, and the upper surface of the wafer includes S.
An SOG coater that spin-coats an OG film is equipped with a dilute HF liquid nozzle and a rinse liquid nozzle with nozzle openings facing the edge of the wafer on the rotary plate, and the cup surrounding the rotary plate is made of an acid-resistant material. SOG coater characterized by 3. The SOG coater according to claim 2, wherein an acid exhaust duct having an exhaust port is provided at a position close to both the wafer edge portion and the nozzle port of the dilute HF liquid nozzle. 4. A rotating plate having a rotation surface orthogonal to the vertical rotation axis, and a discharge nozzle for discharging an SOG source onto the upper surface of the wafer placed on the rotation surface, and the upper surface of the wafer is provided with S.
An SOG coater that spin-coats an OG film is equipped with another liquid nozzle with a nozzle opening facing the edge of the wafer on the rotating plate, and a cup surrounding the rotating plate is made of an acid-resistant material. The SOG is characterized in that the dilute HF liquid is discharged from a different nozzle for each nozzle, and then the rinse liquid is discharged.
Coater. 5. The SOG coater according to claim 4, wherein an acid exhaust duct having an exhaust port is provided at a position close to both the wafer edge and the nozzle port of another nozzle.