JPH04107278A - Wet etching device - Google Patents

Abstract

PURPOSE:To carry out fast and uniform etching without breaking the device by providing a turbulent flow generating means between a liq. etchant outlet having a uniform flow forming nozzle and a substrate to be treated in the etchant. CONSTITUTION:A substrate 3 to be etched is passed through a liq. etchant 2 by a conveyor 4 provided in an etchant tank 1. Meanwhile, a nozzle 16 for forming a uniform flow 18 contg. a punched metallic sheet 17 to straighten the etchant flow is set at the outlet of an etchant feed pipe 10. The etchant outlet is set below the surface of the etchant 2, and a turbulent flow generating means 19 is provided between the etchant and the substrate 3 on the conveyor 4. The means 19 is formed by plural globular or columnar bodies arranged at regular intervals. As a result, the uniformity in etching is enhanced, the etching rate is increased, and the mechanical damages are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a wet etching apparatus used for etching substrates such as liquid crystal devices and semiconductor devices. A typical example of a leaf etching device is shown in FIG. In the figure, an etching liquid tank 101 contains an etching liquid 102.
Although the substrate to be etched 103 is moved by a substrate transport device 104 and etched one by one, the problem with this device is that when the substrate to be etched 103 moves within the etching solution 102, the etching occurs as shown in FIG. A velocity boundary layer 1.5 is generated on the etching surface of the substrate 103. This velocity boundary layer 105 is caused by the etching in the direction of the etching substrate 103 indicated by the arrow in FIG. 5 because the etching solution is not circulated. show. In the figure, the etching liquid 202 in the etching liquid tank 201 is
It is collected from the cleaning liquid recovery pipe 208 provided at the bottom of the cleaning liquid tank 201, and is supplied to the shower nozzle 206 via the cleaning liquid supply pipe 210 by the circulation pump 209, and becomes the shower flow 207.
Even if 7 drops collide with the etching surface of the substrate to be etched 203 being transported by the substrate transport device 204 and etching is performed, this method always supplies fresh etching liquid 202 to the substrate to be etched 203 in the form of a shower to increase the etching speed. The problem to be solved by the present invention is to improve the etching process.Here, in this etching method, the state in which the shower flow 207 collides with the substrate 203 to be etched is schematically shown. In the figure, the shower flow 207 forms a mixture of two forms: a droplet shape as shown in FIG. As long as the etching liquid collides with the substrate, the etching liquid does not flow on the substrate except for a flow component 214 that flows along the substrate and remains there (component 213). The etching speed varies between the parts of the substrate 203 to be etched where the etching liquid is flowing and the parts where it is stagnant, and even with this method, uneven etching occurs within the surface of the substrate. Due to the water hammer action, an impact pressure proportional to P = ρCV (ρ: tight seal of the etching liquid C: sound velocity in the etching liquid v: collision speed of the etching liquid) is generated, and this is the gas-liquid interface 215 of the etching liquid. Even if the impact velocity V of the etching liquid is 10 m/s, the impact pressure ζ that acts on the portion reaches a value of 10 Pa or more, causing mechanical damage to the substrate 203 to be etched, and causing etching to be formed on the substrate 203 to be etched. The above-mentioned etching non-uniformity ζ, which was one of the causes of device destruction during etching, is a major problem especially when the substrate to be etched is large, and it is difficult to fabricate devices without characteristic variations over the entire surface of a large substrate. 1. Even though the current practice is to sacrifice some cost to form a film using a material with a high selectivity as a base layer, and to perform etching under conditions that result in over-etching at the edges of the substrate, it also prevents the destruction of the devices being formed. In order to prevent this, a process with a slow etching speed had to be selected, which contributed to lowering the etching throughput.In view of the above problems, the present invention eliminates etching non-uniformity in wet etching and improves device configuration. By eliminating the formation of unnecessary films for etching and enabling high-speed etching without causing device destruction, we solve four problems with the aim of lowering the cost of manufactured devices. The wet etching apparatus of the present invention has an etching liquid outlet having a uniform flow forming nozzle disposed in the etching liquid, and a turbulent flow generating means is provided between the etching liquid outlet and the substrate to be processed in the etching liquid. AM action In the wet etching apparatus of the present invention, the etching liquid collides with the turbulent flow generating means installed in the etching liquid, and the vortex action generated at the wake of the turbulent flow generating means causes etching on the substrate to be etched. It is possible to prevent liquid from stagnation.

EXAMPLE Hereinafter, an embodiment of a wet etching apparatus of the present invention will be described with reference to the drawings. FIGS. 1 and 2 show a schematic configuration of an embodiment of a wet etching apparatus of the present invention. A transport device 4 for transporting the substrate 3 to be etched is attached to the etching liquid tank 1 containing the etching liquid 2. Even when the substrate 3 to be etched passes through the etching liquid 2, the etching liquid tank 1 An etching liquid recovery pipe 8 is installed on the bottom of the etching liquid recovery pipe 8, and the etching liquid 2 recovered from this is sent to an etching liquid supply pipe 10 via a circulation pump 9. Even though a uniform flow forming nozzle 16 with a built-in punching metal plate 17 for rectifying the liquid is installed, this etching liquid outlet is installed below the surface of the etching liquid 2 in the etching liquid tank l, Although the turbulent flow generating means 19 is provided between the liquid outlet and the substrate to be etched 3 on the substrate transport device 4, this turbulent flow generating means 193 is
As shown in FIG. 2, the etching liquid may be formed of a plurality of spheres 20 or a plurality of cylinders 21 arranged at equal intervals d2. 2 is recovered from the etching liquid recovery pipe 8 by the circulation pump 9, passed through the etching liquid supply pipe 10, the nozzle 16, the punching metal 17, and returned to the etching liquid 2 to form a uniform flow 18. First class IEN-! , collides with the turbulence generating means 19 and passes through the turbulence gap,
At this time, the uniform flow 1 hits the substrate 3 to be etched that is being moved by the conveyance device 4, and there is no need to perform etching.
The velocity of 8 is the speed at which the etching liquid flow forms a turbulent flow by colliding with the sphere 20 or cylinder 21 of the turbulence generating means 19. In other words, the diameter of the sphere 20 or cylinder 21 of the turbulence generating means 19 d+, the Reynolds number defined by the velocity of the uniform flow 18 and the viscosity of the etching liquid 2 is set to be 2320 or more. The distance between the sphere 20 or cylinder 21 and the substrate 3 to be etched is set to about 1.5 to 3 degrees 0 times the diameter d1 of the sphere 20 or cylinder 21. Figure 3 shows the concept of forming a turbulent flow in the etching liquid flow using the above-mentioned turbulence generating means.

When the etching liquid, which has been rectified by the punching metal 17 and becomes a uniform flow 18, collides with the sphere 20 or cylinder 21 of the turbulent flow generating means 19, a large number of turbulent flow separation areas are formed in the downstream part of the sphere 2o or cylinder 21. These vortices 22 (Table 1) generate vortices 22 (Table 1).Since these vortices 22 have various velocity components, the etching liquid impinges on the substrate 3 to be etched from various angles. Since the etching solution collides with the etching solution, there is no stagnation of solution that caused mechanical damage in the conventional example.
'Y.

As described above, the wet etching apparatus of the present invention (which generates a vortex having many velocity components with the turbulence generating means installed between the etching liquid supply nozzle and the substrate to be etched,
By effectively utilizing this, the uniformity of etching has been dramatically improved, and the etching speed has been improved compared to conventional etching equipment, and the mechanical damage caused by the shower etching method has been solved. However, it is not possible to achieve high product quality and cost reduction by improving throughput and yield. 5-3. Force length set to around 0 times For cases outside this range, first 1.5
When the etching rate is less than 2 times, the substrate 3 to be etched enters the downstream dead zone of the sphere 2o or the cylinder 21, so the etching speed is slow in that part. In the case of Ω times or more, the dead area disappears, but many vortices 22 dry up, various velocity components are killed, and the collection of jets that have flowed between the spheres 2o or cylinders 21 reaches the substrate 3 to be etched. Because of the collision,
An etching distribution occurs between the areas where the jet collides and the areas where the jets do not collide, and the effect of the turbulence generating means I9 is reduced. In this embodiment, etching is performed while moving the substrate to be etched using a substrate transport device. Etching may be performed by stopping the substrate to be etched (~Effects of the Invention The wet etching apparatus of the present invention (a friend of the present invention) produces a turbulent flow between the etching liquid supply nozzle and the substrate to be etched. By installing a means, a vortex having many velocity components is generated,
Dramatically improves etching uniformity. Mechanical damage to the substrate to be etched is also prevented, resulting in higher quality products and lower costs by improving throughput and yield.

[Brief explanation of drawings]

FIG. 1 shows the schematic structure of a wet etching apparatus in one embodiment of the present invention. FIG. 2 shows the structure of the turbulence generating means in the same embodiment. FIG. 3 shows the concept of turbulence generation in the same embodiment. 5 shows the schematic structure of a conventional wet etching device. FIG. 5 shows the operation of etching using the same conventional wet etching device. FIG. 6 shows the schematic structure of another conventional wet etching device. This is an explanatory diagram of the action of etching by an etching device.
Substrate to be etched 4...Transport device 8...Etching liquid recovery view 9...Circulation bond IO...Etching liquid supply 16...Uniform flow formation nozzle/kl?・・・
...Punching Meta/Ni 19... Name of agent for turbulence generating means Patent attorney Haruaki Ogata Two people Figure 2 −One plow/θ乎Fig.Fig.

Claims (4)

[Claims] (1) Consisting of an etching liquid tank, an etching liquid recovery pipe, and an etching liquid supply pipe, the etching liquid outlet of the etching liquid supply pipe is used as a uniform flow forming nozzle, and the etching liquid outlet is used as the etching liquid outlet in the etching liquid tank. A wet etching apparatus characterized in that a turbulent flow generating means is disposed below the surface of the etching liquid and between a substrate to be etched in the etching liquid and an outlet of the etching liquid. (2) Claim 1, wherein the turbulence generating means is formed by a plurality of cylinders or a plurality of spheres arranged at equal intervals.
Wet etching equipment described. (3) The distance between the cylinder or sphere constituting the turbulence generating means and the substrate to be etched is 1.5 of the diameter of the cylinder or sphere.
3. The wet etching apparatus according to claim 2, wherein the wet etching apparatus is set to 3.0 times. (4) The Reynolds number defined by the velocity and viscosity of the etching liquid flowing out from the uniform flow forming nozzle and colliding with the turbulent flow generating means is set to 2320 or more.
4. The wet etching apparatus according to any one of 3 to 3.