JPH10178008A - Method and apparatus for applying flattening material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flattening material applying apparatus for applying a flattening material such as ceramate dissolved in a volatile solvent to the surface of a semiconductor substrate using a discharge nozzle, and a pot of the discharge nozzle. By constantly setting the atmosphere in the standby pot to the same atmosphere as the solvent in the ceramate, evaporation of the solvent is delayed, and crystallization of the flattening material attached to the discharge port of the discharge nozzle is prevented. A flattening material diluted with a volatile solvent from a discharge nozzle to a rotating semiconductor substrate.
In the method of applying a flattening material for forming a flattening film having a constant thickness on the semiconductor substrate 3, at least the tip of the discharge nozzle 5 is applied except that the flattening material 8 is applied to the semiconductor substrate 3. The discharge nozzle 5 is immersed in the solvent in the solvent reservoir 9 in the standby pot 4 filled with the solvent atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flattening material applying apparatus for applying a flat material such as ceramate dissolved in a volatile solvent to a semiconductor substrate surface.

[0002] The degree of integration of semiconductor devices is becoming stricter year by year. Along with this, multi-layer wiring of semiconductor device circuits is progressing, and a flattening material such as ceramate in which an organic silicon compound is dissolved in a volatile solvent is used as a flattening technique between multilayer wiring layers.

[0003]

2. Description of the Related Art FIGS. 6 to 8 are explanatory views of a conventional art.
7 is a plan view of a conventional coating apparatus, FIG. 7 is a cross-sectional view of a conventional coating apparatus, and FIG. 8 is a cross-sectional view of a conventional standby pot.

FIG. 7 is a cross-sectional view of FIG. 6, in which the coating cup portion is viewed from the left side and the standby pot portion is viewed from the right side. In the figure, 1 is a coating device, 2 is a coating cup, 3 is a semiconductor substrate, 4 is a standby pot, 5 is a discharge nozzle, 6 is a cleaning nozzle, 7 is a solvent supply port, 8 is a flattening material,
Reference numeral 9 denotes a solvent reservoir, 10 denotes a drain, 11 denotes a quartz window, 12 denotes a rotary suction table, and 13 denotes a vacuum suction tube.

Conventionally, as shown in FIGS. 6 and 7, on the side of the coating cup 2 of the coating apparatus 1, the discharge nozzle 5 is used for discharging and coating the flattening material 8 onto the semiconductor substrate 3 of the discharge nozzle 5. A standby pot 4 is provided for storing and waiting for a flattening material 8 such as a ceramate to adhere to the interior of the standby pot 4 as shown in FIG. Is used to inject the solvent to clean the tip of the discharge nozzle 5 with the solvent. The solvent dripping from the cleaning nozzle 6 is stored in a solvent reservoir 9 and is periodically discharged from the drain together with a volatile gas or the like.

For example, a commercially available ceramate used as a flattening material is a flattening material for a semiconductor substrate surface obtained by dissolving a polymer having a structural unit of perhydropolysilazane (SiHxNy) n which is an organic silicon compound in a volatile organic solvent such as xylene. It is.

However, the volatilization of the solvent in the ceramate is rapid, and if the solvent volatilizes, perhydropolysilazane, a component of the ceramate, is crystallized. For this reason, the crystal of the ceramate attached to the tip of the discharge nozzle 5 blocks the discharge port of the discharge nozzle 5, resulting in discharge failure.

[0008]

Therefore, if the ceramate adheres to the tip of the discharge port of the discharge nozzle by the conventional method, the solvent in the ceramate volatilizes and the ceramate crystallizes, causing the discharge nozzle at the tip of the discharge nozzle to be discharged. Blocking has caused problems such as ejection failure.

The present invention is provided for the purpose of delaying the volatilization of the solvent and preventing crystallization of the ceramate by constantly setting the atmosphere in the standby pot to the same atmosphere as the solvent in the ceramate.

[0010]

FIG. 1 is a plan view of a coating apparatus of the present invention, FIG. 2 is a sectional view of the coating apparatus of the present invention, and FIG. 3 is a sectional view of a standby pot of the present invention. The cross-sectional view of FIG. 2 is a view of the application cup portion of FIG. 1 viewed from the left side and the standby pot viewed from the right side.

In the figure, 1 is a coating device, 2 is a coating cup, 3 is a semiconductor substrate, 4 is a standby pot, 5 is a discharge nozzle, 6 is a cleaning nozzle, 7 is a solvent supply port, 8 is a flattening material,
9 is a solvent reservoir, 10 is a drain, 11 is a quartz window, 12 is a rotary suction table, 13 is a vacuum suction tube, and 14 is an O-ring.

In the present invention, as shown in FIGS. 2 and 3, the standby pot 4 is filled with a solvent such as xylene to prevent crystallization due to volatilization of the solvent of the planarizing material such as ceramate. At the time of standby other than the discharge and application of the flattening material from 5, a solvent reservoir 9 is installed below the discharge nozzle 5 inside the standby pot 4, and the discharge nozzle 5 is immersed, so that the tip of the discharge nozzle 5 Prevents clogging of the discharge port with the flattening material.

When the discharge nozzle 5 is on standby, the discharge nozzle 5
In addition, a quartz window 11 for checking the height of the solvent liquid level of the solvent reservoir 9 and the state of the discharge port of the discharge nozzle 5 is attached, and the position of the discharge nozzle 5 and the solvent liquid level are constantly monitored.

As described above, in the present invention, in order to prevent crystallization of the ceramate attached to the tip of the discharge nozzle 5, a solvent reservoir 9 filled with a solvent is provided in the standby pot 4, and the discharge nozzle 5 is filled with the solvent. While soaking, the discharge nozzle 5 is periodically cleaned by the cleaning nozzle 6.

As the solvent in the atmosphere filling the inside of the waiting pot 4, a solvent such as xylene contained in the ceramate is used, and the inside of the waiting pot 4 is closed to delay the volatilization of the solvent. Since the tip of the discharge nozzle 5 is constantly immersed in the solvent during standby, the tip of the discharge nozzle 5 does not dry, thereby preventing crystallization of the ceramate.

The solvent that fills the solvent reservoir 9 in the standby pot 4 is supplied periodically from the lower portion of the standby pot 4, overflows from the solvent reservoir 9 at the time of supply, and is discharged from the drain 10, so that it is constantly replaced with a new solvent. I do.

Further, as described above, by attaching the quartz window 11 to the standby pot 4, the discharge nozzle 5 in the standby pot 4 is provided.
It is possible to check the state of the discharge port at the tip of the nozzle and the amount of the liquid level of the solvent, and it is possible to save the time of checking the conventional apparatus from automatic to manual and to check without stopping the coating process. .

[0018]

FIG. 1 is a plan view of a coating apparatus according to the present invention.
2 is a sectional view of the coating apparatus of the present invention, FIG. 3 is a sectional view of the standby pot of the present invention, FIG. 4 is a crystallized state of the flattening material by the conventional standby pot, and FIG. Is in a crystallized state.

In the drawing, 1 is a coating apparatus, 2 is a coating cup, 3 is a semiconductor substrate, 4 is a standby pot, 5 is a discharge nozzle, 6 is a cleaning nozzle, 7 is a solvent supply port, 8 is a flattening material,
9 is a solvent reservoir, 10 is a drain, 11 is a quartz window, 12 is a rotary suction table, 13 is a vacuum suction tube, and 14 is an O-ring.

An embodiment of the present invention will be described first with reference to FIG. In this embodiment, a commercially available ceramate is used as a planarizing material and xylene is used as a solvent in order to planarize fine irregularities on the surface of the multilayer wiring on the surface of the semiconductor substrate.

Similar to the conventional standby pot 4, first, in order to clean the tip of the discharge nozzle 5 with a solvent, the solvent xylene is discharged from the adjacent cleaning nozzle 6 as shown in FIG. Xylene is poured onto the discharge port at the tip of 5, and the discharge nozzle 5 is washed for several seconds.

In the present invention, as shown in FIG. 3, a solvent line for supplying a solvent to the standby pot 4 is separately provided, and the solvent is supplied to the solvent reservoir 9 so that the standby pot 4 always has a solvent atmosphere. It is supplied from the solvent supply port 7. Since the tip of the discharge nozzle 5 is immersed in the solvent in the solvent reservoir 9, preliminary discharge is performed for about 2 seconds before discharging the ceramate. At that time, the ceramate is discharged into the solvent, and the ceramate crystallizes around the discharge port of the discharge nozzle 5 and does not adhere. The ceramate discharged into the solvent is diluted with the solvent when the solvent is supplied, and flows out to the drain 10.

In order to coat the semiconductor substrate 3 with the ceramate, the discharge nozzle 5 is lifted upward from the solvent reservoir 9 in the standby pot 4, and is rotationally sucked in the coating cup 2 of the coating apparatus by the rotation shaft of the base of the discharge nozzle 5. The semiconductor substrate (wafer) 3 held by vacuum suction by the vacuum suction tube 13 on the base 12 is rotated and moved to the center of the semiconductor substrate (wafer) 3. Then, a 6 ml ceramate is pneumatically supplied from the discharge port at the tip of the discharge nozzle 5.
The liquid is discharged for a second and dropped at the center of the semiconductor substrate. At the same time, the semiconductor substrate 3 held on the vacuum chuck is 4,000 rpm.
While rotating at, the liquid crystal is dropped on the center of the semiconductor substrate 3 and the ceramicate is uniformly enlarged and applied to the entire surface of the semiconductor substrate 3.
At this time, the thickness of the ceramic material as the planarizing material 8 is about 2.2.
00 °.

After the end of the dropping of the flattening material 8, the discharge nozzle 5
Immediately, it is returned to the standby pot 4, lowered as it is, and immersed in the solvent reservoir 9. The cycle of pulling-up → rotating → dropping → rotating → falling down from the solvent reservoir 9 of the discharge nozzle 5 is about 1 minute, and the ceramic coating of the semiconductor substrate 3 is repeated one by one. While immersed in the solvent reservoir for about 55 seconds, the solvent in the solvent reservoir 9 evaporates more and more so that the standby pot 4 becomes an atmosphere of xylene vapor and is constantly exhausted from the drain 10. The reduced amount of xylene in the solvent reservoir 9 is periodically replenished from the solvent supply port 7 below the solvent reservoir 9, and the surface of the solvent reservoir 9 constantly overflows with the solvent.
Make sure that no crystal residue remains.

The height of the liquid surface of the solvent reservoir 9 and the condition of the discharge port at the tip of the discharge nozzle 5 when the solvent is collected are constantly observed from the quartz window 11 fitted into the wall surface of the standby pot 4. The height of the liquid surface of the solvent reservoir 9 is monitored for the presence of crystal deposits of the ceramate, and the discharge port at the tip of the discharge nozzle 5 is monitored so as not to be blocked.

By attaching the quartz window 11 to the standby pot 4, the positional relationship between the discharge nozzle 5 and the liquid level of the solvent can be easily known. In addition, the semiconductor substrate 3
After the ceramate is dropped on the surface of the semiconductor substrate 3, the semiconductor substrate 3 is immediately automatically replaced with the next semiconductor substrate 3, and the coated semiconductor substrate 3 is sent to an adjacent hot plate and heated at 300 ° C. for 70 seconds, and the SiO 2 is heated. a thickness of about 2,000 consisting of _two membrane
The flattening film Å is formed on the multilayer wiring film on the surface of the semiconductor substrate 3.

In order to improve the tightness of the standby pot 4, an O-ring 14 is provided between the discharge nozzle 5 and the standby pot 4, as indicated by a black dot in FIG.

[0028]

The effect of preventing the crystallization of the flattening material ceramate during the standby time of the discharge nozzle will be compared between the case of using the conventional standby pot and the case of using the new standby pot of the present invention. Was done.

The evaluation method is as follows. The time during which the flattening material is applied from the discharge nozzle to the semiconductor substrate and the product waits in the standby pot is set as the discharge nozzle empty interval.
Waiting time for discharge time The state where the flattening material does not crystallize at the discharge port of the discharge nozzle due to the standby time in the pot, the intermediate stage where gelation proceeds to crystallization, and the state where the discharge port is completely crystallized and the discharge port is clogged Observed at stages.

First, as shown in FIG. 4, in a conventional standby pot, depending on the viscosity of the ceramate, the standby time is 10 minutes.
In minutes, gelation starts on the inner wall of the standby pot, which is expressed as a pot. In 15 minutes, both the discharge port at the tip of the discharge nozzle and the pot are gelled, and in 30 minutes or more, both the nozzle and the pot are completely crystallized.

On the other hand, in the standby pot of the present invention shown in FIG. 5, neither the nozzle nor the pot is crystallized even in the standby time of 60 minutes, and the flattening material is applied without any trouble even when the discharge nozzle is in the standby state for a long time. Can be performed.

As described above, according to the present invention, the prevention of crystal adhesion to the discharge nozzle by the ceramate is complete, and the discharge nozzle can be easily cleaned. Thereby, crystallization of the discharge nozzle is prevented, and abnormal application of the flattening material such as ceramate does not occur, and the structure of the standby pot of the coating apparatus of the present invention and the method of applying the flattening material by the discharge nozzle are applied to the flattening film. It greatly contributes to a uniform forming technique.

[Brief description of the drawings]

FIG. 1 is a plan view of a coating apparatus of the present invention.

FIG. 2 is a sectional view of a coating apparatus according to the present invention.

FIG. 3 is a sectional view of a standby pot according to the present invention.

FIG. 4 is a crystallization state of a flattening material in a conventional waiting pot.

FIG. 5 is a crystallization state of a flattening material by the standby pot of the present invention.

FIG. 6 is a plan view of a conventional coating apparatus.

FIG. 7 is a sectional view of a conventional coating apparatus.

FIG. 8 is a sectional view of a conventional standby pot.

[Explanation of symbols]

 In the figure, 1 coating apparatus 2 coating cup 3 semiconductor substrate 4 standby pot 5 discharge nozzle 6 washing nozzle 7 solvent supply port 8 flattening material 9 solvent reservoir 10 drain 11 quartz window 12 rotary suction table 13 vacuum suction tube 14 O-ring

Claims (4)

[Claims] 1. A method of applying a flattening material, wherein a flattening material diluted with a volatile solvent is applied from a discharge nozzle to a rotating semiconductor substrate, and a flattening film having a constant thickness is formed on the substrate. In at least one aspect of the present invention, the discharge nozzle is immersed in the solvent in a solvent reservoir in a standby pot filled with the solvent atmosphere, except when at least the tip of the discharge nozzle is applied to the semiconductor substrate with the planarizing material. A method for applying a flattening material. 2. The flattening method according to claim 1, wherein a solvent reservoir is provided in the standby pot, and the solvent reservoir is immersed in a discharge nozzle in the solvent except when the planarizing material is applied to the semiconductor substrate. Material coating device. 3. The flattening material applying apparatus according to claim 2, wherein the solvent reservoir has a structure in which the solvent is supplied from below the solvent reservoir and overflows and is discharged. 4. The flattening material applying apparatus according to claim 2, wherein a window for monitoring the liquid level of the discharge nozzle and the solvent reservoir is provided on a part of the wall of the standby pot.