CN104054162A - Etching process chambers for the manufacture of semiconductor light-emitting diodes - Google Patents

Abstract

The purpose of the present invention is to improve the structure of an etching chamber for manufacturing a semiconductor LED, such that a failure rate due to byproducts, which are deposited by being generated in an etching step, falling on a wafer is remarkably lowered and the decline in productivity caused by frequent cleaning of the chamber is reduced. The present invention enables: a wafer to be provided on the ceiling of the upper part of the chamber to face the bottom thereof; a vacuum pump to be formed at a vertical lower portion; and a device for generating plasma to be arranged under the vacuum pump, wherein a vertical lower part is opened such that byproducts can be immediately discharged through the vacuum pump without falling on the wafer.

Description

Etching process chambers for the manufacture of semiconductor light-emitting diodes

technical field

The present invention relates to the plasma etching process (etching; etching) in the process for manufacturing semiconductor light-emitting diodes, in particular, through the epoch-making structure improvement of the etching treatment chamber (chamber), greatly reduce the And the accumulation of byproducts (byproducts) falling to the wafer caused by bad problems, thereby reducing the decline in productivity caused by frequent cleaning of the processing chamber.

Background technique

As we all know, in order to manufacture semiconductors, multiple processes such as oxidation process, photoresist, exposure, development, etching, ion implantation, chemical vapor deposition, metal wiring, etc. are required, and the present invention relates to the use of Plasma dry etching.

As shown in Figure 1, in the prior art, the general etching treatment room of light-emitting diode (LED) utilizing plasma has following structure: source insulator (101; source insulator) is set on the upper part of treatment room (100), then in it An RF induction coil (102) is arranged above, a gas injection port (103) is provided at the center of the source insulator (101) to inject an etching gas (BCl ₃ ), and at the bottom of the processing chamber (100), a bias insulator (biasinsulator) (104), the tray (110) with the sapphire wafer (WAFER) installed is fixed to the chuck (chuck) (120), and a row of Air channel (105) and is connected with vacuum pump (130).

In the above structure, a vacuum is maintained inside the processing chamber (100), and helium gas is filled between the tray (110) and the chuck (120), so that the processing chamber (100) can also realize heat transfer in a vacuum state. In such a state, at first, the etching gas is supplied to the inside of the processing chamber (100) through the gas injection port (103), and then the source power is applied to the RF induction coil (102) on the top, so that plasma is generated and reacted with the gas (BCl ₃ ) Molecules produce inelastic conflicts, thereby producing a large number of ion-active gas molecules and atomic groups. At this time, the active gas molecules chemically react with the surface of the adjacent object to be etched to cause etching, but the sapphire wafer is chemically stable, so chemical etching hardly occurs.

In the state as described above, RF power is applied to the chuck (102) at the lower end of the tray (110) to apply attractive force to the plasma ions (ION) generated in the upper part, thereby giving physical potential energy (potential) to the ions , The ions with physical force collide with the sapphire wafer as the object to be etched to achieve etching.

Fragments of the etched object produced in such a process combine with ions to produce byproducts, which are typically volatile species. That is, the gas (BCl ₃ ) acts on sapphire (Al ₂ O ₃ ), which is the material of the wafer, to generate AlCl ₃ and B ₂ O ₃ .

Due to such a problem, when the number of etching processes is accumulated, by-products accumulate on the surface affected by the plasma in the processing chamber. Generally, when the number of processes exceeds 80, the by-products form a layer, the structure becomes weak, and the by-products deposited on the wall surface Redissociation by plasma, during which by-product lumps fall off resulting in defective wafers.

Therefore, usually the processing chamber should be cleaned before the by-products accumulated on the source insulator fall, and the current cycle does not exceed 100 operations, so the waste of time required for frequent cleaning results in a problem that the production efficiency is greatly reduced .

Contents of the invention

technical issues

The present invention has been accomplished in view of the above problems. The purpose of the present invention is to minimize the generation of defects caused by by-products in the plasma etching process, and greatly prolong the cleaning cycle of the processing chamber, thereby improving productive.

means of solving problems

In order to achieve the above object, the present invention is characterized in that on the upper ceiling of the processing chamber, the wafer is arranged in a downward manner, a vacuum pump is provided directly below, a device for generating plasma is provided below it, and the directly below is opened, so that When the by-products are dropped, they are directly discharged to the vacuum pump without being disturbed, and the device for fixing the wafer tray is configured to have the elasticity of the spring, and the clamps pull the tray upward to fix it, so that the wafer tray can be easily and quickly While the movement is fixed, it prevents the pallet from being damaged due to excessive clamping.

Invention effect

In the present invention, the position of the chuck becomes the ceiling of the processing chamber, and the etching is realized with the wafer facing downward, thereby possessing an advantageous advantage, and the wafer will not be subjected to the side effects of being piled up on the inner wall of the processing chamber and then falling. The influence of the product, thereby having the conditions that can greatly reduce the defective rate of the wafer caused by the drop of by-products.

In addition, since the defect rate of wafers can be greatly reduced, the cycle of cleaning the processing chamber can be greatly extended, and thus the etching operation time can be increased, thereby greatly improving production efficiency.

In particular, the present invention is in a straight-down exhaust mode in which the chuck coincides with the central axis of the vacuum pump, and has a structure in which the chuck is located at the top and the bottom is completely opened, so it is characterized by particle flow with mean free path (Mean freepath) In the PSS etching process (Etching Process) of the pressure treatment method (Process Pressur), the exhaust structure is the most ideal.

As mentioned above, when the exhaust structure is ideal, the pumping efficiency is improved, and a small-capacity pump can be used, so the cost can be reduced, the device can be miniaturized, and the dropped by-products can be easily disposed of, and the waste of by-products can also be reduced. accumulation. In addition, since the structure of the device is simplified, it also has the effect of shortening the cleaning time.

Description of drawings

FIG. 1 is a cross-sectional view showing the structure of a conventional general processing chamber.

Fig. 2 is a schematic diagram showing the overall structure of the present invention.

3a, 3b, and 3c are sectional views showing part of the clamping device of the present invention.

Figure 3a is a state diagram at the time of release.

Figure 3b is a state diagram when rising once.

Fig. 3c is a state diagram of being fully clamped by elastic action.

Fig. 4 is a sectional view taken along line A-A of Fig. 2 .

Detailed ways

Hereinafter, according to the accompanying drawings, the preferred embodiments for realizing the present invention will be described in detail.

The processing chamber (1) of the present invention is basically constituted as follows: the inner ceiling of the processing chamber (1) is provided with a chuck (20) for installing a tray (10), and the tray (10) is used for loading wafers. When the wafer is directed downward, an insulator (21) is set between the chuck (20) and the processing chamber (1) on the upper part of the chuck (20).

A channel (2) is formed on the side directly below the chuck (20) on the upper part of the processing chamber (1), and the channel (2) allows the tray (10) loaded with wafers to enter and exit sideways.

Under the upper chuck (20), at a position at a certain interval, after the insulating cylinder (31) is provided with a diameter wider than that of the chuck (20), the insulating cylinder (31) A cylindrical RF induction coil (30) is arranged on the outside, so that the directly below the chuck (20) on which the tray (10) is arranged is completely penetrated downward.

Below the RF induction coil (30), after the inclined surface (3) is formed in a reduced diameter manner, a vacuum valve (40) and a vacuum pump (41) are provided at the lower part. The vacuum pump (41) is a turbomolecular vacuum pump capable of realizing high vacuum.

More specifically, each part of the present invention is structured as follows.

First, in the device for fixing the tray (10) to the chuck (20), a cylinder (50) fixed to the support table (4) is provided on the upper part of the processing chamber (1), and then the work of the cylinder (50) And the lifting rod (51) of lifting penetrates to the inside of the processing chamber (1), and when the clamps (52) are fixed at the lower end of the lifting rod (51) and the tray (10) is fixed, the cylinder (50) makes the lifting rod (51) Lift the clamp (52) to fix the pallet (10) on the chuck (20). When releasing, the lifting rod (51) is lowered, and the pallet (10) and the chuck (20) are clamped by the clamp (52). separated.

More specifically, a lifting plate (53) is set on the rod (50') of the air cylinder (50), then the lifting rod (51) is penetrated through the lifting plate (53), and a fixed block ( 54) After that, a spring (55) is set between the fixed block (54) and the lifting plate, so that when the lifting plate (53) rises, the spring (55) pushes the fixed block (54) up, so that the lifting rod (51) Ascent, when stopping the ascension of the lifting rod (51), the spring (55) is compressed from this moment on.

Reference numeral 56 is a guide rod, and 57 is a bellows.

As shown in Fig. 5, it is preferable that described elevating bar (51) and clamp (52) are arranged 3 on the periphery of chuck (20) with equal angle, when pallet (10) enters wherein 2 clamps ( 52) when designing the channel (2), if the tray (10) enters horizontally, the clamps (52) can directly lift the tray (10) and fix it, so this is the preferred way.

Below the channel (2) of the processing chamber (1) is formed an upper inclined surface (5) that reduces the diameter of the inner space of the processing chamber (1), and in the middle of the upper inclined surface (5) forms a Gas inflow port (6) inside the processing chamber (1).

Reference numeral 7 is a helium gas line, and 8 is a dry pump line for initial vacuum.

The functions of the present invention constituted as described above are as follows.

Through the channel (2), the tray (10) with wafers is installed into the interior of the processing chamber (1) that is always kept in a high vacuum in a straight line, and enters between the 2 clamps (52), when the entry is completed , the tray (10) is located in the center between the three clamps (52).

Before the pallet (10) enters, the air cylinder (50) descends, so that the lifting plate (53) and the lifting rod (51) descend, so that the clamp (53) is also located below the pallet (10) entered.

When the pallet (10) has entered, the cylinder (50) acts immediately to lift the lifting plate (53), and the lifting plate (53) pushes the spring (55) up, so that the spring (55) pushes the fixed block (54) up, Thereby the lifting rod (51) fixed to the fixed block (54) rises, and the clamp (52) at the end pulls up the pallet (10) to make it cling to the chuck (20).

When the clamp (52) lifts the tray (10) and clings to the chuck (20) (referring to Figure 3b), from now on the lifting rod (51) and the clamp (52) can no longer rise, so the lifting plate ( 53) Compress the spring (55) and go up a little more. (See Figure 3c). Therefore, the elastic force of the spring (55) acts on the elevating rod (51) and the clamp (52), thereby fixing the tray (10) firmly and stably, and preventing the ceramic tray from being damaged.

Etching gas for plasma is injected into the processing chamber (1) through the gas injection port.

Plasma is generated when the RF induction coil (30) is connected to a power source, and inelastic collisions are generated with the molecules of the etching gas, thereby generating a large number of ions-active gas molecules (excited) and atomic groups.

RF power is applied to the chuck (20) at the upper end of the processing chamber (1), to apply attractive force to the ions of the plasma generated in the lower part, and to give the ions a physical potential energy (POTENTIAL) in the direction opposite to the gravitational force, so that the etched The object (sapphire wafer) is etched, and the byproducts (byproducts; AlCl ₃ and B ₂ O ₃ ) produced in such a process undergo Brownian motion in the interior of the processing chamber (1) and then gradually accumulate to the inner walls, after accumulation , even if it falls according to gravity, the by-products will not be blocked in the middle and directly discharged through the vacuum pump (41), so there is no impact on the wafer.

After finishing the etching, the cylinder (50) descends to make the lifting plate (53) descend, then before the lifting rod (51) descends, at first realize the relaxation effect corresponding to the compression amount of the spring (55), and then the lifting rod (51) The jaws (52) are lowered to separate the tray (10) from the chuck (20), after which the tray (10) is discharged through the channel (2) in the opposite direction from the entry.

Claims (6)

1. an etching treatment chamber for manufacturing semiconductor light-emitting diodes, characterized in that, A chuck on which a wafer loading tray is mounted facing downward is installed on the inner ceiling of the processing chamber, and a vacuum pump is installed directly below the center line of the chuck. 2. The etching treatment chamber for manufacturing semiconductor light-emitting diodes according to claim 1, characterized in that, Clamps are arranged in three directions around the chuck to form a channel so that the pallet enters between the two clamps. When the pallet enters, the clamps rise to fix the pallet. 3. The etching treatment chamber for manufacturing semiconductor light-emitting diodes according to claim 1 or 2, characterized in that, On the lower side of the chuck, an insulating cylinder is arranged at a position separated by a certain interval, and an RF induction coil is arranged outside the insulating cylinder, so that the lower part of the chuck is completely opened. 4. The etching treatment chamber for manufacturing semiconductor light-emitting diodes according to claim 1 or 2, characterized in that, A structure for lifting the tongs is formed. A lifting rod that moves up and down according to the action of the cylinder and connected with the inside of the processing chamber is arranged on the upper part of the processing chamber, and a clamp is arranged at the lower end of the lifting rod. 5. The etching treatment chamber for manufacturing semiconductor light-emitting diodes according to claim 4, characterized in that, The rod of the air cylinder is connected to the lifting plate, and the lifting rod is installed through the lifting plate. A spring is arranged between the upper end of the lifting rod and the lifting plate. After the pallet is tightly attached to the chuck through the clamp, the spring is compressed and the lifting plate is raised. , thereby securing the tray. 6. The etching treatment chamber for manufacturing semiconductor light-emitting diodes according to claim 1 or 2, characterized in that, An upper inclined surface that reduces the diameter of the inner space of the processing chamber is formed under the channel of the processing chamber, and a gas inflow port for the etching gas to flow into the processing chamber is formed in the middle of the upper inclined surface.