JPH1197437A - Manufacture of semiconductor device and equipment therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an equipment of manufacturing of a semiconductor device in which surface flatness of an SOG(spin-on glass) film prepared on a semiconductor substrate is improved, by spin-coating the SOG solution onto a substrate, planarizing the layer of the coated SOG solution, and further by applying ultrasonic vibration to the substrate. SOLUTION: In the equipment, an evacuation path 14, which runs to an open end in a suction pad 13, is provided inside a rotary axis 12 of a rotary chuck 11. An ultrasonic-wave generating transducer 15 is embedded in the suction pad 13, so that the ultrasonic vibration is applied to a substrate 16 in the direction normal to the surface of the substrate 16 which is vacuumchucked on the suction pad 13. An interlayer insulator film is prepared on the substrate wafer 16 in the following way: An SOG solution is dripped onto the central part of the wafer 16, and the rotary chuck 11 is rotated to spread out the SOG solution onto the whole surface area of the wafer 16. Then, the ultrasonic-wave transducer 15 is operated to apply ultrasonic vibration to the wafer 16. The solution is dried while the wafer 16 is rotating. After the wafer 16 having the SOG film is rinsed, thickness of the interlayer insulator film is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for manufacturing a semiconductor device, and more particularly to a method and an apparatus for forming an interlayer insulating film of a semiconductor device.

[0002]

2. Description of the Related Art Methods for forming an interlayer insulating film of a semiconductor device include a thermal oxidation method, a CVD method, and a sputtering method.
For forming the iO ₂ film, any of these methods, a phosphorus silicate film (PSG film), a boron phosphorus silicate film (BP)
An SG film) and a silicon nitride film are generally formed by a CVD method. However, the flatness of the interlayer insulating film formed by these methods was not always good.

A method for forming an interlayer insulating film having good surface flatness is S
There is a method called an OG (spin on glass) method. In this method, an SOG solution in which an additive such as a silicon compound and a binder is dissolved in an organic solvent is spin-coated on the surface of a semiconductor substrate, and then heat-treated to form an inorganic SiO ₂ film on the substrate. When the SOG solution is spin-coated on the substrate, the solution is thick in the concave portions of the steps and thin in the convex portions on the substrate, and a film is formed so as to reduce the steps.
For this reason, the step coverage of the film formed on the upper layer can be improved.

[0004]

However, the flatness of the film formed by the conventional SOG method is not sufficient, and needs to be improved. An object of the present invention is to improve the conventional SOG method so as to further improve the surface flatness of a formed film.

[0005]

In order to achieve the above object, a method of manufacturing a semiconductor device according to the present invention comprises applying an SOG solution onto a semiconductor substrate by spin coating, and then applying ultrasonic vibration to the semiconductor substrate. A step of flattening the applied SOG solution.

An apparatus for manufacturing a semiconductor device according to the present invention is characterized in that an ultrasonic vibrator is embedded in a rotary chuck for vacuum-sucking and rotating a semiconductor substrate.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an SOG solution is applied to the surface of a semiconductor substrate using a spin coater, and ultrasonic vibration is applied to the semiconductor substrate before the applied SOG solution solidifies. Promotes the flow of As a result, the flatness of the formed film is improved. The present invention is particularly effective for forming an interlayer insulating film of a semiconductor device.

In order to apply ultrasonic vibration to a semiconductor substrate,
The apparatus according to the present invention embeds an ultrasonic vibrator in a rotary chuck, such as a spin coater, which vacuum-adsorbs and rotates a semiconductor substrate. This makes it possible to effectively apply ultrasonic vibration to the semiconductor substrate at a necessary time in the process of forming the interlayer insulating film.

[0009]

【Example】

(Comparative Example) A silicon wafer having a diameter of 6 inches was vacuum-adsorbed to a rotary chuck of a conventional spin coater. As shown in FIG. 1, elements 2 such as transistors and diodes and aluminum wirings 3 for these elements are formed on this silicon wafer 1, and furthermore, at predetermined positions on the aluminum wiring 3, interlayer wirings are formed. This is a stage where the metal plug 4 is formed. Reference numeral 5 denotes an insulating film. The height and width of the plug 4 are 0.7 μm and 1 respectively.
The minimum distance between the plugs 4 in the chip is 0.8 μm.

3 ml of an SOG solution (Type-10, Tokyo Ohka Co., Ltd.) is dropped at the center of the wafer, and the rotating chuck is rotated at 100 rpm for 0.5 seconds and further at 3500 rpm for 1 second to spread the SOG solution over the entire surface of the wafer. I let it. The rotation was further continued, and the solution was dried, rinsed, and the like, and finally rotated at 2000 rpm for 13 seconds. The wafer was removed from the rotary chuck, and heat treatment was performed for one minute per hot plate using two 80 ° C. hot plates, two 150 ° C. hot plates, and two 230 ° C. hot plates to form an interlayer insulating film.

The flatness of the interlayer insulating film was measured. As an index of flatness, the maximum step d of the interlayer insulating film 6 shown in FIG.
And the maximum inclination angle θ of the surface of the maximum step portion 7 was adopted.
The step becomes large where the distance between the plugs is large. In this comparative example, the maximum step d is 0.28 μm, and the maximum inclination angle θ
Was 17 degrees.

(Embodiment) FIG. 3 shows an embodiment of the apparatus of the present invention. The suction pad 1 is provided on the rotating shaft 12 of the rotating chuck 11.
3 is provided with a vacuum path 14 that opens to the surface of the pad in communication with 3. The ultrasonic vibrator 15 is attached to the suction pad 13.
Is embedded, and it is possible to apply ultrasonic vibration in the thickness direction to the wafer 16 that is vacuum-sucked on the suction pad 13.

An interlayer insulating film was formed using the same silicon wafer as the comparative example. 3 ml of SOG solution is dropped on the center of the wafer, and the rotating chuck is rotated at 100 rpm.
The SOG solution was spread over the entire surface of the wafer by rotating the wafer at 0.5 m for 0.5 second and further at 3500 rpm for 1 second. And the ultrasonic vibrator is operated while rotating at the same number of rotation points,
Ultrasonic vibration of 2 MHz (output 25 W) was applied to the wafer for 1 second. Thereafter, while rotating the wafer, drying and rinsing of the solution were performed as in the comparative example.
Rotated at 00 rpm for 13 seconds. Remove the wafer from the rotating chuck, 2 hot plates at 80 ° C, 150 ° C
Using two hot plates at 230 ° C. and two hot plates at 230 ° C., heat treatment was performed for one minute per hot plate to form an interlayer insulating film.

The flatness of the interlayer insulating film was measured. In this example, the maximum step d was 0.17 μm and the maximum inclination angle θ was 10 degrees, the step was shallow and gentle, and the flatness was significantly improved as compared with the comparative example. The output of the ultrasonic vibrator must be at least 5 W to obtain the flat effect, and from the practical viewpoint, an output of about 30 W is sufficient.

It is apparent that the apparatus shown in FIG. 3 can be used not only for forming an SOG film in a semiconductor device manufacturing process but also for spin coating in general.

[0016]

As described above, according to the present invention, the flatness of the interlayer insulating film can be improved. Therefore,
For example, a wiring layer formed thereover does not require excessive step coverage and does not cause disconnection or the like at a step portion, so that the performance or manufacturing yield of the semiconductor device as a whole can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a surface shape of a wafer on which an interlayer insulating film is formed.

FIG. 2 is a diagram illustrating the surface flatness of an interlayer insulating film.

FIG. 3 shows an embodiment of the device according to the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon wafer 2 Element 3 Aluminum wiring 4 Plug 5 Insulating film 6 Interlayer insulating film 7 Maximum step 11 Rotation chuck 12 Rotation shaft 13 Suction pad 14 Vacuum path 15 Ultrasonic transducer 16 Wafer

Claims (2)

[Claims] 1. A method of manufacturing a semiconductor device, comprising: after spin-coating an SOG solution on a semiconductor substrate, applying ultrasonic vibration to the semiconductor substrate to flatten the applied SOG solution. . 2. An apparatus for manufacturing a semiconductor device, wherein an ultrasonic vibrator is embedded in a rotary chuck for vacuum-sucking and rotating a semiconductor substrate.