JPH0117748B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid dropping device equipped with a nozzle for dropping a solution onto the surface of a workpiece, and in particular to a liquid dropping device that prevents the solution from concentrating or solute from precipitating at the periphery of the nozzle tip. Regarding a dropping device.

2. Description of the Related Art An apparatus that uses a nozzle to drop a solution onto the surface of a workpiece is widely used when applying a solution for forming a photoresist or a metal oxide film, a solution containing a diffusing agent, or the like onto the surface of a workpiece.

For example, in the manufacturing process of ICs, LSIs, etc., an apparatus as shown in FIG. 2 is used to apply a coating liquid such as photoresist or a diffusion agent onto a wafer.
That is, in such an apparatus, a spinner 21 is rotatably arranged in a cylindrical case 20 with an open top, and several drops of a coating liquid are applied from a nozzle 23 to the center of the surface of a wafer 22 placed on the spinner 21. After dropping, the wafer 22 is rotated at high speed by a spinner 21, and the coating liquid is evenly applied to the surface of the wafer 22 by centrifugal force.

When the coating liquid is dripped from the nozzle 23, some of the solution remains on the nozzle tip periphery 23a due to the influence of surface tension and the like. The coating liquid here consists of a solution in which a resin or a diffusing agent, etc. is dissolved in a solvent such as an organic solvent, and since the solvent has a high volatility, the coating liquid remaining on the periphery of the nozzle tip will dissolve over time. Only the solvent is volatilized and gradually concentrated, and finally the solute, such as the resin or the diffusing agent, is precipitated.

If such a concentrated solution or precipitate falls onto the wafer being processed, it will cause uneven coating and variations in film thickness between wafers, resulting in the production of defective products, which is extremely disadvantageous in terms of product yield, etc. be.

In order to eliminate this disadvantage, in the past, the periphery of the nozzle tip was wiped using a sponge, cloth, or something impregnated with a solvent, and the concentrated solution or precipitate fell onto the wafer. It prevents However, such a method requires manual work, and if the space between the nozzle and the spinner head is narrow, the wiping operation becomes difficult. Furthermore, when wiping is performed, there is a high possibility that foreign matter will fall onto the spinner head or the bottom of the spinner case, and when the spinner rotates, this foreign matter will fly up and adhere to the wafer surface. Furthermore, when the coating process and other processes that precede and follow it are made to be continuous, the work is temporarily interrupted during the coating process, making it impossible to plan for automation and hindering the improvement of mass productivity. .

In view of the above-mentioned technical problems, the present inventor has devised the present invention to effectively solve the problems.
The objective is to provide a liquid dropping device that does not cause the solution to concentrate or the solute to precipitate at the periphery of the nozzle tip, even without cleaning the nozzle tip by wiping the tip.

In order to achieve such an object, the present invention forms a shielding chamber by a shielding body surrounding the nozzle tip, and provides a solvent storage part in the shielding chamber to create a solvent vapor atmosphere in the shielding chamber. This is the summary.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the main parts of a liquid dropping device 1 according to the present invention, and 2 is a spinner rotatably supported by a spinner case of the device 1. As shown in FIG. This spinner 2 consists of a rotating shaft 3 and a mounting plate 4. The shaft 3 has a through hole that communicates with a vacuum pump, etc., and the mounting plate 4 has a groove connected to the through hole. , the wafer 5 placed on the mounting plate 4 is fixed by suction.

Further, a nozzle 6 and a shield 7 surrounding this nozzle 6 are arranged above the spinner 2, and this shield 7
This forms a shielding chamber 8 that the tip 6a of the nozzle 6 faces. That is, the shielding body 7 includes a substantially cylindrical side wall 7a, an upper lid 7b provided at the upper end of the side wall 7a and having a nozzle insertion hole 9 formed therein, and the side wall 7a.
It consists of a bottom cover 7c in the shape of a truncated cone, which is provided at the lower end and whose center part rises upward, and a hole 10 is formed in the center of the bottom cover 7c, through which the dripping liquid falling from the nozzle 6 passes. are doing.

As described above, the insertion hole 9 of the upper lid 7b of the shielding body 7 is constituted by the side wall 7a, the upper lid 7b, and the bottom lid 7c.
Pass the nozzle 6 through the nozzle 6, and attach the upper cover 7b to the middle part of the nozzle 6.
are integrally fixed, and the nozzle tip 6a is located in the center of a shielding chamber 8 partitioned by a shielding body 7. A pan 12, which is a reservoir for the solvent 11, is formed by the bottom lid 7c and the side wall 7a.
The nozzle 6 facing the shielding chamber 8 may be inserted into the insertion hole 9 of the upper lid 7b so as to be able to move up and down.

Therefore, the inside of the shielding chamber 8 is saturated with the vapor of the organic solvent etc. evaporated from the pan 12, and the solvent in the solution remaining at the periphery of the nozzle tip due to surface tension etc. does not evaporate.

Next, specific effects of the present invention will be explained using an example in which the apparatus shown in FIG. 1 is used.

Experimental example Ethyl alcohol, an organic solvent, is placed in a solvent pan in advance, and a vapor atmosphere of ethyl alcohol is created in the shielded chamber. A diffusing agent manufactured by Tokyo Ohka Kogyo Co., Ltd. (OCD SiFilm, SiO ₂ concentration 5.9%) is applied through a nozzle with an inner diameter of 1 mm. : The main solvent was ethyl alcohol) was added dropwise.

Even after being left for one hour after dropping, no solid matter was deposited on the periphery of the tip of the nozzle, and no concentration of the diffusing agent solution was observed.

On the other hand, the diffusing agent solution was dropped into the pan in the same manner as above, with the shielding chamber filled with air without putting any organic solvent into the pan. In this case, solid matter had already precipitated around the periphery of the nozzle tip 5 minutes after dropping. The above experimental conditions were a temperature of 25°C and a humidity of 60%.

As is clear from the above description, according to the present invention,
A shielding chamber is formed by surrounding the nozzle with a shielding body,
Since a solvent reservoir is provided in this shielded chamber, the interior of the shielded chamber facing the nozzle tip is always saturated with solvent vapor, which prevents the solvent from evaporating from the solution remaining at the nozzle tip. The solution will not be concentrated or the solute will not precipitate at the nozzle tip.

Therefore, it is possible to prevent solids such as concentrated solutions or solutes from falling onto the surface of the object to be treated,
Product yield can be dramatically improved. Furthermore, there is no need to manually wipe the periphery of the nozzle tip, and the coating process and the processes surrounding it can be integrated into a continuous process, improving mass production and reducing product costs. It offers many advantages such as contributing to

[Brief explanation of drawings]

The drawings show a preferred embodiment of the present invention and a conventional example, and FIG. 1 is a longitudinal sectional side view of the essential parts of the liquid dropping device according to the present invention, and FIG. 2 is a longitudinal sectional side view of the conventional device. In the drawings, 1 is a droplet dropping device, 5 is an object to be treated, 6 is a nozzle, 7 is a shield, 7a is a side wall, 7c is a bottom cover,
8 is a shielded chamber, and 12 is a solvent storage pan.

Claims (1)

[Claims] 1. A nozzle for dropping a solution onto a workpiece, a shielding body that forms a shielding chamber facing the nozzle and having an opening through which the liquid dripped from the nozzle passes, and a solvent vapor atmosphere inside the shielding chamber. The solvent storage pan is composed of a side wall of the shielded chamber, and a truncated conical shape provided at the lower end of the side wall with a central portion rising upward. A liquid dropping device characterized in that it is formed from a bottom lid.