JPH0810683B2 - Wet etching equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet etching apparatus, and more particularly to a wet etching apparatus that automatically performs etching in a manufacturing process of a compound semiconductor device.

2. Description of the Related Art As a conventional wet etching apparatus for automatically etching semiconductors, an apparatus that moves a carrier on which a plurality of substrates are placed between chemical baths by a carrier is used, as is used in the etching of Si substrates. .

A conventional wet etching apparatus will be described below with reference to FIG.

In FIG. 16, 1601 is a carrier capable of mounting a plurality of machine boards, 1602 is a semiconductor substrate mounted on the carrier 1601, 1603
Is a hanger for holding the carrier 1601, 1604 is a carrier, 16
05a is the first etching tank, 1605b is the second etching tank, 16
06a is a first rinse tank, 1606b is a second rinse tank, 1607a is a first etching solution, 1607b is a second etching solution, 1608a is a first rinse solution, and 1608b is a second rinse solution. Semiconductor substrate 1
The etching of 602 is performed by first locating the carrier 1601 on the first etching tank 1605a and immersing the carrier 1601 in the first etching solution 1607a for a predetermined time. To stop the etching, move the carrier 1601 to the first rinse tank 1606a,
It is performed by immersing it in the rinse liquid 1608a. Similarly, the subsequent etching is performed by moving the carrier 1601 to the second etching tank 1605b and the second lith tank 1606b. The wet etching apparatus configured as described above is mainly used in substrate pretreatment etching at the time of process introduction in the manufacturing process of SiIC and LSI, and mass processing is performed automatically.

On the other hand, in a manufacturing process of a compound semiconductor device such as a semiconductor laser using a GaAs-based or InP-based material, a groove is formed in order to form another stripe-shaped active layer for pretreatment etching of the substrate before epitaxially growing the double hetero structure. Alternatively, wet etching is the mainstream because it has an etching step such as mesa structure forming etching, and good element characteristics have not been obtained with good reproducibility by dry etching such as RIE (reactive ion etching).

However, the etching process in the manufacturing process of the semiconductor laser or the like has a problem that the conventional wet etching apparatus cannot be used because of the following reasons.

That is, if the chemical is left in the air in the pre-treatment etching before the epitaxial growth of the CaAs or InP substrate and the solution is left in the air, the surface becomes cloudy and the mirror-like state cannot be obtained, and the metamorphism occurs on the surface in a relatively short time. Because,
For example, it was necessary to gradually replace the etching solution with pure water so that the substrate was not exposed to the air as much as possible. This is the same in the etching for forming the groove or the mesa structure for forming the stripe-shaped active layer. In addition, since the etching rate of the commonly used etching solution is relatively large, it is necessary to form it to a predetermined width or depth. Needs to quickly replace the etching solution, and in the conventional wet etching system, while the carrier moves from the etching tank to the rinse tank by the carrier, the etching solution is exposed to the air while adhering to the substrate. It was difficult to quickly replace the etching solution with the rinse solution.

In general, wet etching in the compound semiconductor device manufacturing process such as a semiconductor laser is first compared to that in the Si semiconductor device manufacturing process, because the size of the GaAs or InP substrate to be used is small and the above-mentioned groove formation or mesa is taken into consideration in consideration of the substrate plane orientation. Since the structure forming etching is more complicated and requires controllability, the apparatus used in the Si semiconductor field cannot be used as it is, and the automation of the etching process has not been achieved.

In view of the above-mentioned conventional techniques, the present invention prevents generation of a metamorphic substance when a substrate is exposed to air while the etching liquid remains attached, and controllability of groove formation or mesa structure formation in a semiconductor laser manufacturing process or the like. It is also an object of the present invention to provide a novel wet etching apparatus capable of automatically performing good etching even in the case of requiring etching and using a mixed etching solution.

Means for Solving the Problems The technical solution of the present invention for achieving the above object is to provide an etching treatment tank for performing etching with a chemical solution input tank and a chemical solution preparation tank connected by a chemical solution introduction line,
Further, in a configuration in which a waste liquid preliminary tank and a chemical liquid waste tank are connected by a chemical liquid discharge line, the chemical liquid input tank or the chemical liquid is placed in a state in which a sample holding portion holding a sample to be etched is located in the etching treatment tank. A chemical liquid supply / discharge control unit is provided to control the start and stop of introduction of the chemical liquid from the mixing tank into the etching treatment tank and the start and stop of the chemical liquid discharge from the etching treatment tank to the waste liquid preliminary tank and the chemical liquid waste liquid tank. In addition to enabling automated preparation, the chemical solution is continuously passed through the etching treatment tank to carry out etching without moving the sample to be etched.

With the above-described configuration, the present invention enables automatic mixing of a mixed chemical liquid by controlling the introduction of the chemical liquid from the chemical liquid feeding tank to the chemical liquid mixing tank in the chemical liquid feeding / discharging control unit, and at the same time, the chemical liquid feeding tank or the chemical liquid mixing tank. By controlling the introduction of the chemical solution into the etching treatment tank and the discharge of the waste fluid from the etching treatment tank to the waste liquid preliminary tank and the chemical liquid waste tank, all the etching is performed in the etching treatment tank. When discharging the chemical liquid, the chemical liquid is smoothly discharged because it is discharged to each chemical liquid waste liquid tank after receiving the chemical liquid in one of the waste liquid preliminary tanks, and therefore the chemical liquid is replaced in the etching treatment tank in a very short time. Therefore, it is possible to prevent the generation of metamorphic substances due to the sample being exposed to the air while being attached to the reagent, and to obtain a good controllability of etching.

Example (Example 1) Example 1 will be described below with reference to FIG.

In FIG. 1, 101 is a sample holding part, 102 is a sample, 103 is an etching treatment tank, 104a, 104b, 104c, 104d, 104e, 104f are chemical solution input tanks, and 105a, 105b, 105c, 105d, 105e, 105f are chemical solution input. Charged chemicals charged in the tanks 104a to 104f, 106a, 106b, 10
6c, 106d, 106e, 106f, 106ab, 106cd are chemical liquid introduction lines, 107
ab, 107cd is a chemical compounding tank, 105ab is a compounded solution prepared from the chemical solutions 105a and 105b in the chemical solution mixing tank 107ab, 105cd is a chemical solution prepared from the chemical solutions 105c and 105d in the chemical solution mixing tank 107cd, 108ab, 108cd, 108e and 108f are chemical solutions 105ab and 105c, respectively.
Chemical liquid waste tanks that store d, 105e, 105f waste liquids, 109a-f, 109ab
cd, 109ef, 109ab, 109cd, 109e, 109f are chemical liquid discharge lines, 11
0abcd, 110ef is a waste liquid reserve tank, 111 is a chemical liquid supply / discharge control unit, 112
a, 112b, 112c, 112d, 112e, 112f, 112ab, 112cd are chemical liquid introduction valves, 113ab, 113cd, 113e, 113f are chemical liquid introduction pumps 114a-
f, 114abcd, 114ef, 114ab, 114cd, 114e, 114f are chemical liquid discharge valves, and 115a-f are chemical liquid discharge pumps.

In the wet etching apparatus having the configuration according to the present embodiment, first, predetermined chemicals 105a to 105f are charged into the chemical injection tanks 104a to 104f, respectively. Chemicals 105a and 105b and
105c and 105d are chemical liquids to be used after being mixed, and these are chemical liquid introduction valves 112a and 112b and 112c and 112d, respectively.
Is controlled to be opened / closed by the chemical liquid supply / discharge control unit 111, and the chemical liquid mixing tank is passed through the chemical liquid introduction lines 106a and 106b and 106c and 106d.
Prepared in 107ab and 107cd respectively
And 105 cd. Here, for example, the drug solution 105e is the prepared drug solution 1
If the chemical solution 105f is the rinse solution of 05ab, and the chemical solution 105f is the rinse solution of the mixed chemical solution 105cd, and the etching is first performed by the mixed chemical solution 105ab and then performed by the mixed chemical solution 105cd, first, the chemical solution supply / discharge control unit 111 causes the chemical solution introduction valve. 112ab is opened, and the chemical solution introduction pump 113ab operates in conjunction with each other to introduce a prescribed quantity of the mixed chemical solution 105ab into the etching treatment tank 103 through the chemical solution introduction line 106ab. After the etching is performed for a predetermined time, the chemical liquid supply / discharge control unit 111 opens the chemical liquid discharge valves 114a-f, 114abcd, 114ab to open the chemical liquid discharge pump 115.
a-f works in conjunction with each other, and the mixed chemical solution 105ab is a chemical solution discharge line.
It is first discharged into the waste liquid preliminary tank 110abcd through 109a-f and 109abcd, and then discharged into the chemical liquid waste liquid tank 108ab through the waste liquid discharge line 109ab. Etching tank 103 here
And chemical liquid discharge line 109a-f, 109 that connects the waste liquid backup tank 110abcd
It is desirable that the abcd be as short as possible and have a large pipe diameter, and that the waste liquid preliminary tank 110abcd is located immediately below the etching treatment tank so that its capacity is large, so that the blended chemical solution 105ab is smooth. Then, it is discharged from the etching treatment tank 103. Immediately after the mixed solution 105ab is discharged, this time the solution discharge valve 1 is controlled by the solution supply / discharge control unit 111.
14a-f are closed and the liquid chemical introduction valve 1
12e is opened, the chemical liquid introducing valve 113e is operated in conjunction with each other, and the chemical liquid 105e as a rinse liquid is introduced into the etching treatment bath 103 through the chemical liquid introducing line 106e by a predetermined amount. The chemical liquid discharge valve 114abcd may be appropriately closed while the rinse is performed, and the chemical liquid discharge valve 114abcd may be appropriately closed when the mixed chemical liquid 105ab is discharged to the chemical liquid waste tank 108ab. After rinsing for a predetermined time, the chemical liquid supply / discharge control unit 111 in turn supplies chemical liquid discharge valves 114a-f, 114ef, 114.
The chemical liquid discharge pumps 115a-f are operated in conjunction with the opening of e, and the chemical liquid 105e is sequentially discharged from the etching treatment tank 103 to the waste liquid preliminary tank 110ef and the chemical liquid waste liquid tank 108e. Here again, it is desirable that the waste liquid discharge line 109ef is a short pipe having a thick pipe diameter, and the waste liquid preliminary tank 110ef is located immediately below the etching treatment tank and has a large capacity, as described above. After rinsing with the chemical liquid 105e by the valve operation by the chemical liquid supply / discharge control unit 111 for an appropriate number of times, the prepared chemical liquid is operated by the same valve operation as described above.
The etching process is completed by performing etching with 105 cd and rinsing with the chemical solution 105 f.

In this embodiment, the introduction and discharge of the chemicals are all performed automatically by the valve operation and the pump operation by the chemicals supply / discharge control unit 111, and the chemicals are sequentially smoothly introduced and discharged into the etching treatment tank. The time required for replacement is extremely short. In particular, arranging a waste liquid backup tank means, for example, if there is no such a tank, there will be multiple chemical liquid waste tanks, and the pipe from the etching tank to each chemical liquid waste tank will become long and the pipe diameter must be increased. Since it is difficult to connect the pipes in space, it takes time to discharge the chemical liquid, whereas it is possible to discharge the chemical liquid to the waste liquid reserve tank located immediately below the etching treatment tank in a short time. Has become a means to do effectively. Regarding the introduction of the chemical solution, the chemical solution introduction valve (here, 112ab, 112cd, 112e, 112f) immediately before the etching treatment tank can be arranged as close to the etching treatment tank as possible to facilitate the introduction of the chemical solution. It is desirable that each tank such as the chemical solution input tank and the chemical solution preparation tank be hermetically sealed in consideration of evaporation of the chemical solution, and each tank and each pipe are made of a material that is not corroded by the chemical solution such as Teflon.

FIG. 2 is a diagram showing an etching process in which stripe-shaped groove forming etching is performed on an InP substrate using the wet etching apparatus in this embodiment. The sample is provided with a SiO ₂ film 202 as an etching mask on a (100) plane-oriented InP substrate 201 as shown in a in the figure, and a window is opened in stripes in the <001> direction by using a normal photolithography technique. A resist 203 is provided. Here, as the chemical solution shown in FIG.
5b NH ₄ F, 105c HCl, 105d H ₃ PO ₄ , 105e pure water, 105f
Acetone is used to prepare NF: NH ₄ F = 1: 9 in the chemical solution mixing tank 107ab, and HCl: H ₃ PO _{4 in the} chemical solution mixing tank 107cd.
Mix so that it becomes = 1: 1. When the preparation is ready, first, as shown in Fig. 2b, the preparation liquid HF + NH ₄ F (105a
In b), the SiO ₂ film 202 is etched using the resist 203 as a mask. After replacing this with pure water 105e and thoroughly washing,
The resist 203 is removed with acetone 105f as shown in FIG. Cleaning with pure water and removal of the resist with acetone may be carried out sufficiently by repeating introduction and discharge. After then similarly washed with pure water, this time as shown in FIG d SiO ₂ film 20
In using 2 + as an etching mask with HCl + H ₃ PO ₄ (105 cd)
Grooves 204 are formed in the P substrate 201 by etching. After washing again with pure water, the SiO ₂ film 202 is removed with NF + NH ₄ F (105ab) as shown by e in the figure, and finally pure water washing is completed.
Here, all of the above processes are automatically performed by the valve control of the chemical liquid supply / discharge control unit 111, but as described above, the chemical liquid can be replaced promptly,
After the groove 204 is formed, it is immediately replaced with pure water.
For example, good reproducibility can be obtained in terms of groove depth control.

As described above, in the wet etching apparatus in the present embodiment, the etching process can be performed automatically including the preparation of the chemical solution, and the sample does not move between the chemical solution tanks as in the conventional case, but the sample is The chemical solution is automatically automatically introduced and discharged into the retained etching treatment tank in order.In particular, the provision of a waste solution reserve tank facilitates the chemical solution to be discharged, and the chemical solution can be replaced in a very short time.
In etching a compound semiconductor such as InP or InP, it is possible to prevent the generation of the above-mentioned metamorphism and to obtain good controllability in etching such as groove formation or mesa structure formation.

(Embodiment 2) In the present embodiment, the wet etching apparatus according to the first embodiment has a configuration including a temperature control unit for controlling the temperature of each of the chemical bath, the chemical preparation bath, and the etching bath and the etching bath. By adding a sonic vibration mechanism and controlling the temperature of each chemical in the bath, etching can be performed in consideration of temperature dependence, and the ultrasonic vibration mechanism increases the uniformity of etching, and rinse after etching (cleaning with pure water, etc.) It is an object of the present invention to provide a wet etching apparatus capable of reliably performing the above.

The second embodiment will be described below with reference to FIG.

FIG. 3 shows the chemical liquid feeding tank 104 in the configuration shown in FIG.
It is the figure which showed the partial structure of a, 104b, the chemical | medical solution mixing tank 107ab, and the etching process tank 103 using the same code | symbol as FIG.
301 is a temperature control unit, 302a, 302b, 302ab, 302E are temperature control water tanks, 3
Reference numeral 03 is an ultrasonic oscillator, and 304 is a power source for the ultrasonic oscillator 303. Temperature control water circulates in the temperature control water tanks 302a, 302b, 302ab, 302E, and the temperature control unit 301 controls the temperature of the chemical liquid in each tank to be uniform. The power source 304 of the ultrasonic oscillator is linked with the chemical liquid supply / discharge control unit so that when the chemical liquid is introduced into the etching treatment tank, ultrasonic vibration is appropriately applied to the etching treatment tank. In the present embodiment, when a chemical solution having an etching rate different depending on the temperature is used, since the temperature of each of the chemical solution introducing tank, the chemical solution preparing tank and the etching treatment tank is controlled, the etching can be performed by grasping the etching rate of the chemical solution. In particular, when using a prepared chemical solution, heat may be generated during preparation, which may cause a large difference from the etching rate at room temperature, or the composition of the chemical solution may change due to evaporation.
According to the present embodiment, it is possible to perform the preparation so that the temperature of the prepared chemical solution does not become extremely high, and the etching treatment can be performed after the temperature of the prepared chemical solution is set to a predetermined temperature. Further, since ultrasonic vibration is applied to the etching treatment tank, rinsing after etching can be surely performed. For example, as in the etching process described in FIG. The process can be reliably performed when removing.

As described above, in the wet etching apparatus according to the present embodiment, the temperature of the chemical liquid including the mixed chemical liquid can be controlled to a predetermined temperature before performing the etching, and the ultrasonic vibration mechanism is added to the etching treatment tank, so that the etching uniformity can be improved. And the rinsing can be surely performed, so that etching that requires more controllability is made possible.

(Third Embodiment) In this embodiment, in addition to the structure of the wet etching apparatus in the second embodiment, a chemical solution stirring mechanism is provided in each of the chemical solution feeding tank and the chemical solution mixing tank to keep the chemical solution in each tank uniform. It is an object of the present invention to provide a wet etching apparatus that enables the above.

The third embodiment will be described below with reference to FIG.

FIG. 4 is a view showing a partial configuration of the chemical liquid feeding tanks 104a, 104b and the chemical liquid mixing tank 107ab in the wet etching apparatus in the second embodiment, and other reference numerals are the same as those shown in the drawings. Are the same. In the figure, 401 is a chemical liquid circulation line, 402 is a circulation line valve, and 403 is a circulation pump. In FIG. 4, a means for circulating a chemical solution is used as a chemical solution stirring mechanism, and an example in which this means is provided in the chemical solution mixing tank 107ab is shown. The circulation line valve 402 and the circulation pump 403 are interlocked with the chemical liquid supply / discharge control unit 111 so as to operate when the mixing of the chemical liquids 105a and 105b is started. In the above configuration, by circulating the chemical solution until the prepared chemical solution 105ab reaches a predetermined temperature and before being introduced into the etching treatment tank, it is possible to maintain a uniform state. It will be possible. Therefore, since it also has the effect of preventing deterioration of the chemical liquid over time, preparation of the chemical liquid including preparation and etching can be adjusted in time, and the time from the preparation of the chemical liquid to the end of etching can be set with a margin. .

(Embodiment 4) In this embodiment, in the structure of the wet etching apparatus according to the third and third embodiments, the sample holder is provided with a swinging mechanism or a rotating mechanism to increase the uniformity of etching performed in the etching treatment tank. It is an object of the present invention to provide a wet etching apparatus capable of performing uniform etching even when a chemical liquid in which etching is controlled by diffusion rate is used.

The fourth embodiment will be described below with reference to FIG.

FIG. 5 is a view showing only an etching treatment tank portion in the structure of the wet etching apparatus in the fourth embodiment.
In the figure, 501a and 502b are sample holders having a swinging or rotating mechanism. The sample holding part 501a is indicated on the upper part of the etching treatment tank 103 as shown in a in the figure, so that the sample 102 can be vertically swung or rotated in the etching treatment tank as shown in the figure. Here is an example. The sample holding unit 501b is supported by the lower portion of the etching treatment bath 103 and is an example in which it can be rotated. In the above-described structure, since the chemical liquid introduced into the etching treatment tank can be stirred, the chemical liquid around the sample 102 becomes uniform and the etching uniformity can be increased. That is, when the etching is controlled by diffusion rate control, the sample 102
There is, in the present embodiment, while enabling this, and also when using a chemical solution controlled by the reaction rate, in general, the reaction rate-determining process has a large temperature dependence, so that the temperature around the sample changes, Although the etching rate changes, the temperature change of only the peripheral portion of the sample can be suppressed by stirring the chemical solution, so that etching with more controllability can be performed.

(Embodiment 5) In this embodiment, the sample holder in Embodiment 4 is divided into a basket capable of accommodating a plurality of samples and a basket holding rod having a swinging mechanism for holding the baskets or a rotating mechanism. An object of the present invention is to provide a wet etching apparatus capable of etching a plurality of samples by facilitating the installation and removal of the samples.

The fifth embodiment will be described below with reference to FIG.

FIG. 6 is a sectional view showing the structure of this embodiment in which the basket is positioned in the etching treatment tank. 601a, 601b in the figure
Is a basket capable of storing a plurality of samples, and 602a and 602b are basket holding rods. The basket 601a is one in which the samples can be arranged vertically as shown in a in the drawing, and the basket holding rod 602a swings up and down to perform etching. In the basket 601b, the samples can be placed side by side as shown in b in the figure, and etching is performed by rotating the basket holding rod 602b. Here, when the samples are arranged vertically like the basket 601a, they should be arranged at a certain interval or more so that the chemical solution can uniformly flow around the sample surface. In the above configuration
Compounds such as GaAs and InP are practically handled in the dynamics. Considering the size of the substrate (rectangular substrate of about 30 mm square), the capacity of the etching treatment tank and the amount of chemical solution used, enough chemical solution can be used up to about four substrates. It is possible to carry out the etching smoothly with the replacement, and by removing the basket, the sample can be easily set and taken out.

At least the portions of the basket and the basket holding rod exposed to the chemical liquid or the chemical liquid should be made of Teflon or coated with Teflon so as not to be corroded by the chemical liquid.

(Example 6) In this example, in the wet etching apparatus having the configuration of Example 5, the shape of the etching treatment tank has a funnel-shaped inclined surface at the upper and lower portions, and the chemical liquid introduction line is in contact with the upper inclined surface. An object of the present invention is to provide a wet etching apparatus in which the chemical liquid is smoothly introduced into and discharged from the etching treatment tank by arranging them.

The sixth embodiment will be described below with reference to FIG. In FIG. 7, reference numeral 701 denotes an etching treatment tank having a funnel-shaped inclined surface at the upper and lower portions, and other reference numerals are the same as those in the above drawing. For example, as shown in the figure, the chemical liquid introduction line 10 is provided on the upper inclined surface of the etching treatment tank 701.
Place 6ab, 106cd, etc. in contact with this. Further, the chemical solution discharge valves 114a-f are provided directly below the etching treatment tank 701. In the above configuration, when the chemical solution is introduced,
Since it drops smoothly from the upper inclined surface of the etching treatment tank 701, the introduction is smooth, and it is possible to prevent the droplets from becoming uneven and adhering to the sample before the prescribed amount of the chemical solution is introduced. Further, the volume of the etching treatment tank is reduced by the configuration in which the inclined surface is provided in the lower portion, and it is not necessary to use the chemical liquid more than necessary, and the chemical liquid is smoothly discharged without remaining in the lower portion. Therefore, in the present embodiment, the introduction and discharge of the chemical liquid can be made smooth and the chemical liquid can be replaced.

(Embodiment 7) In this embodiment, in the wet etching apparatus having the configuration of Embodiment 6, a pure water introduction line is provided in each of the chemical solution feeding tank, the chemical solution mixing tank, and the etching treatment tank, and each tank is cleaned after the etching process is completed. It is an object of the present invention to provide a wet etching apparatus that makes it possible to dilute the charged chemical liquid while facilitating the above.

The seventh embodiment will be described below with reference to FIG. In FIG. 8, reference numerals 801a and 801b are pure water introduction lines provided in the chemical liquid feeding tanks 104a and 104b, 801ab is a pure water introduction line provided in the chemical liquid mixing tank 107a, and 801E is an etching treatment tank 701.
Pure water introduction line provided in, 802a, 802b, 802ab, 802E is a pure water introduction valve provided in each pure water introduction line,
The other reference numerals are the same as those shown in the drawings. Introduction valves 802a, 802b, 802ab, 80 of each pure water introduction line
2E is controlled to be opened / closed by the chemical liquid supply / discharge control unit. In the above-mentioned configuration, it is possible to easily wash pure water in each tank after the etching process is completed, it is possible to dilute the input chemical liquid, and the pure water introduction line provided in the etching treatment tank is It can be used when pure water is used as the rinse liquid, and it is not necessary to use one of the chemical liquid feeding tanks as the pure water tank as in the etching process described in FIG.

(Embodiment 8) In this embodiment, in the configuration of Embodiment 7, among the chemical liquid introduction lines connected to the etching treatment tank, the rinse water introduction line is placed in contact with the upper inclined surface of the etching treatment tank and the etching treatment. To provide a wet etching apparatus that is divided into a shower-like spray from the upper part of the bath and quickly removes the chemical solution adhering to the sample when the chemical solution is discharged, thereby increasing the controllability of etching stop. With the goal.

The eighth embodiment will be described below with reference to FIG.

FIG. 9 is a view showing only the etching treatment tank in the configuration of the seventh embodiment. In the figure, reference numeral 901 indicates the upper portion of the etching treatment tank divided by the pure water introduction line 801E provided in contact with the inclined surface of the upper portion of the etching treatment tank. With the pure water shower provided,
The other reference numerals are the same as those shown in the drawings. In the case of using pure water as the rinse liquid in the above configuration, the pure introduction line 8 is generated by ejecting the pure water from the pure water shower 901 almost at the same time as the chemical liquid is discharged.
The pure liquid introduced from 01E can be roughly washed off before the chemical solution attached to the sample is filled. As a result, it is possible to set the time in which the chemical solution is left in the air while the chemical solution is attached to the sample to almost O, and it is possible to completely prevent generation of the above-mentioned metamorphic material, and to stop etching with good controllability. .

Generally, in the actual etching process, pure water is often used as the rinse liquid, but in the case of using the rinse liquid other than this, shower introduction of the rinse liquid may be provided with the same configuration.

(Embodiment 9) In this embodiment, a dry air jetting mechanism is provided on the upper part of the etching treatment tank to dry and remove the rinse liquid adhering to the sample after rinsing and its peripheral portion, and rinse the etching liquid introduced next. An object of the present invention is to provide a wet etching apparatus capable of preventing compositional change and heat generation due to liquid mixture and performing more strict etching.

The ninth embodiment will be described below with reference to FIG.

FIG. 10 is a diagram showing a structure in which a dry air injection nozzle 1001 is added to the upper part of the etching treatment tank 701 in the structure of the eighth embodiment. The dry air jet nozzle 1001 is made to interlock with a chemical liquid supply / discharge control unit so that dry air is appropriately jetted when the chemical liquid (particularly, rinse liquid) is discharged.

In the above-described configuration, for example, a pure water introduction line 801E and a pure water shower 90 are used as a rinse after etching.
Pure water is introduced from 1 to perform pure water rinsing, the pure water is discharged when the rinsing is completed, and dry air is jetted from the dry air jet nozzle 1001 before the next etching, and adheres to the sample and the wall surface of the etching treatment tank. It is possible to remove the formed water droplets. Water droplets can be removed from the sample by moving the basket holding rod 602a up and down.However, when using a prepared chemical solution that requires a strict mixture ratio, or when using a chemical solution that generates heat due to water droplets, the method, In the embodiment, since water droplets can be removed including the peripheral portion of the sample, composition change and heat generation due to mixing of water droplets can be prevented, which is effective for more strict etching.

(Embodiment 10) In the present embodiment, in the configuration of Embodiment 9, a plurality of chemical liquid discharge bypass lines that connect the chemical liquid supply tank, the chemical liquid preparation tank and the chemical liquid waste liquid tank are provided to discharge the residual liquid after the etching process and It is an object of the present invention to provide a wet etching apparatus that simplifies cleaning of each tank.

The tenth embodiment will be described below with reference to FIG. FIG. 11 is a schematic diagram showing the configuration of this embodiment.
a, 1101b, 1101c, 1101cb are chemical solution input tanks 104a, 104b,
104c, chemical liquid mixing tank 107ab and chemical liquid waste liquid tanks 108ab, 108cd, waste liquid discharge biopsy line, 1102a, 1102b, 1102c, 1102ab
Is a bypass discharge valve provided in each bypass line, and other reference numerals are the same as those shown in the drawings. Each bypass discharge valve 1102a, 1102b, 1102c,
1102ab is controlled by a chemical liquid supply / discharge control unit and is appropriately controlled to be opened and closed after the etching process is completed. In the above-described configuration, for example, when the residual liquid in each tank is discharged or each tank is washed, it is possible to simultaneously discharge the residual liquid and cleaning water in each chemical liquid waste liquid tank. That is, in the case where there is no chemical solution discharge bypass line, the chemical solution passes through the etching treatment tanks, and therefore it is not possible to discharge or wash all the residual liquids in each tank at the same time, which requires time, but in this embodiment, this time can be shortened. It was made possible and facilitated.

(Embodiment 11) In the present embodiment, in the configuration of Embodiment 10, the opening / closing control is performed by the chemical solution introduction speed control valve and the heart sound level detection of the prepared chemical solution in the chemical solution introduction line connecting the chemical solution introduction tank and the chemical solution preparation tank. An object of the present invention is to provide a wet etching apparatus which is provided with an electromagnetic valve to prevent compositional changes and heat generation during preparation of a chemical solution, and which can accurately prepare a prepared chemical solution at a predetermined ratio.

The eleventh embodiment will be described below with reference to FIG. In FIG. 12, 1201 is a chemical liquid introduction speed control valve, 12
02 is a temperature sensor, 1203 is a temperature detection valve control unit, 1204
Is an electromagnetic valve whose opening and closing is controlled by the temperature detecting valve 1203 at a predetermined temperature, and other reference numerals are the same as those shown in the drawings. Here temperature control valve control unit
1203 is interlocked with the chemical liquid supply / discharge control unit. In the above-mentioned configuration, for example, H ₂ SO ₄ is added to the chemical liquid charging tank 104a, 104b
The _{(H 2 O 2 + H 2} O) were charged, at chemical preparation tank 107ab (H ₂
(SO ₄ + H ₂ O ₂ + H ₂ O) When preparing a mixed solution, first, (H ₂ O ₂ + H ₂ O) is introduced into the solution mixing tank 107ab, and then H ₂ SO ₄
To introduce. At this time, if a large amount of H ₂ SO ₄ is introduced at one time, heat will be generated, so the temperature will rise rapidly even if the temperature of the chemical liquid mixing tank 107ab is controlled, and the desired mixing ratio cannot be obtained due to the decomposition of H ₂ O _2. Will end up. Therefore, while adjusting the introduction flow rate of H ₂ SO ₄ by the chemical solution introduction speed control valve 1201, the electromagnetic valve 1204 is closed to stop the introduction of H ₂ SO _{4 when} the temperature of the prepared chemical solution becomes higher than a certain temperature. Make sure to open it again when it goes down. By doing so, preparation can be performed without raising the temperature of the prepared chemical solution to a certain temperature or higher, and the prepared chemical solution can be prepared at a predetermined ratio. As described above, in the present embodiment, even when heat is generated during the preparation, it is possible to prepare the preparation liquid medicine at a desired ratio without changing the composition of the preparation liquid.

In the configuration of (Example 12) This example Example 11, HCl as the chemical charging _{tank, H 2 SO 4, H 2} O 2, provided with four tanks acetone, H ₂ SO ₄ bath as the chemical blending tank, 1 connected from two H ₂ O ₂ tanks
Two tanks are provided, and HC, (H ₂ SO ₄ + H ₂ O ₂ ),
It is an object of the present invention to provide a wet etching apparatus capable of forming a stripe-shaped groove on a sample to be an InP / InGaAsP epitaxial substrate with good controllability by providing three tanks of acetone.

The twelfth embodiment will be described below with reference to FIG. FIG. 13 is a configuration diagram of this embodiment, and all reference numerals in the drawing are the same as those shown in the above drawings. Here the chemical solution input tank 10
It is assumed that 4a is an H ₂ SO ₄ tank, 104b is an H ₂ O ₂ tank, 104c is an HClu tank, 104d is an acetone tank, and a chemical solution mixing tank 107ab mixes H ₂ SO ₄ and H ₂ O ₂ . As will be described later, what is used as the etching solution is (H ₂ SO ₄ + H ₂ O ₂ + H ₂ O = 3: 1: 1) preparation solution and HCl, and the chemical solution preparation tank 107ab containing these is prepared.
The chemical bath 104c and the etching treatment bath 501 are provided with temperature baths to keep the etching temperature constant, but the chemical baths 104a (H ₂ SO ₄ bath) and 104b (H ₂ O ₂ bath) are especially It is sufficient even if it is not the embodiment, so it is not provided. Acetone is used to remove the resist, and it is sufficient to keep the temperature constant.
(H ₂ SO ₄ + H ₂ O ₂ + H ₂ O = 3: 1: 1) Prepared solution was first charged with pure water from the pure water introduction line 801b and then the same amount
H ₂ O ₂ is charged into the chemical liquid charging tank 104b. (H ₂ O ₂ + H ₂ O) is first introduced into the chemical liquid mixing tank 107ab, and while circulating in the chemical liquid circulation line 401, a predetermined amount of H ₂ SO ₄ is gradually introduced from the chemical liquid input tank 104a. At this time, in order to prevent sudden heat generation due to the introduction of H ₂ SO ₄ , the opening / closing control of the electromagnetic valve 1204 by the chemical liquid introduction speed control valve 1201 and the temperature detection valve control unit is appropriately adjusted.

The above operations are set to be performed by valve operation in each line of the chemical liquid supply / discharge control unit 111, except for the initial injection of the chemical liquid. Preparation is completed and the temperature of the chemical solution is 25 ° C.
When the temperature is controlled so that the temperature is set to 0 and the preparation is completed, etching is performed according to the etching process shown in FIG. FIG. 14 is a diagram showing the groove forming etching process of the BS structure semiconductor laser, and the sample is as shown in a in the figure (100).
n-InP layer 1402 (2 μm), p-
InP layer 1403 (1 μm), n-InP layer 1402 (2 μm), n-InGa
The AsP layer 1405 (0.2 μm) and the epitaxially grown one were formed with a stripe-shaped pattern of about 1 μm in the <011> direction by ordinary photolithography technology.
06 is a resist in which a stripe pattern is formed.
This is attached to the sample holder and first prewashed with pure water (introduction parts 901, 801E). This is a dry air injection nozzle 10
Remove water droplets at 01, then (H ₂ SO ₄ + H ₂ O ₂ + H ₂ O = 3: 1: 1)
Is introduced through the chemical solution introduction line 106ab, and the n-InGaAsP layer 1405 is etched for 10 seconds using the resist 1406 as a mask.
At this time (H ₂ SO ₄ + H ₂ O ₂ + H ₂ O = 3: 1: 1), InGaAsP is etched and InP is hardly etched. As shown in FIG. -InGaAsP
Layer 1405 is side etched to the left and right by about 0.3 μm each. 10s
Immediately after the etching of ec, washing with pure water is performed, and then acetone (introduction line 106d) is introduced to remove the resist 1406 (c in the figure). At this time, ultrasonic vibration is applied to the etching-treated layer, and the introduction and discharge of acetone are repeated several times. Next, after sufficiently washing with water to remove water droplets, this time, HCl (introduction line 106c) was introduced, and n-I
Each InP layer is etched for 40 seconds using the nGaAsP layer 1405 as a mask. Since HCl etches InP and hardly etches InGaAsP, the n-InGaAsP layer 1405 is used as an etching mask. By etching for 40 seconds, a groove 1407 having a width of 1.7 μm and a depth of 4 μm is formed as shown in FIG. Immediately after the etching, washing with pure water is performed to complete the process. The above processes are all performed by chemical liquid supply / discharge control including etching and cleaning time settings.

FIG. 15 is a diagram showing the relationship between the in-plane position of the substrate central portion and the groove depth when similar groove formation etching is performed on a 26 mm × 18 mm size sample (stripe pattern forming portion 20 mm × 18 mm, stripe interval 300 μm). Is. As shown in the figure, the groove depth is almost uniform over the surface for each etching time. Depth d = for etching time of 40 seconds
4.3 ± 0.2 μm, which is equivalent to or better than the control without etching using a wet etching system, but the reproducibility is better when using a wet etching system. It was The groove width is W = 1.7 ± for each etching time.
It has a good controllability of 0.1 μm, and it is possible to perform groove formation etching with a uniform width and depth.

As described above, the present embodiment has good controllability and reproducibility in the groove forming etching of the semiconductor laser, and therefore has an effect of improving the manufacturing yield.

EFFECTS OF THE INVENTION As described above, the effects of the present invention are as follows. Firstly, by adopting the configuration shown in FIG. 1, it is possible to perform an etching process automatically including the preparation of a chemical solution, and to hold a sample. The chemical solution is automatically and automatically introduced into the etched layer.
The chemical solution is discharged smoothly by providing the waste liquid preliminary layer, and the replacement of the chemical solution takes only a short time.Therefore, the etching of compound semiconductors such as GaAs and InP can be controlled with good control, It has an effect that etching can be performed by preventing generation. Secondly, the temperature dependence is taken into consideration by providing a temperature control unit for controlling the temperature of each of the chemical liquid charging tank, the chemical liquid mixing tank, and the etching treatment tank and an ultrasonic vibration mechanism for applying ultrasonic vibration to the etching treatment tank. It has an effect that the etching can be performed and the uniformity of the etching is increased, and the rinse after the etching can be surely performed. Third
By providing a chemical liquid stirring mechanism in each of the chemical liquid feeding tank and the chemical liquid mixing tank, it is possible to prevent the chemical liquid from deteriorating with time and maintain it in a uniform state. Fourthly, by providing the sample holder with a swinging mechanism or a rotating mechanism, the chemical can be agitated in the etching treatment tank, so that the chemical around the sample becomes uniform and the etching is controlled by diffusion rate or reaction rate. Even if it is performed, it has an effect that etching can be performed with good controllability. Fifth, if the sample holder is divided into a basket capable of accommodating a plurality of samples and a basket holding rod, a plurality of etchings can be performed, and the sample can be installed.
It has the effect of being easy to remove. Sixth, the etching tank shape has a funnel-shaped inclined surface at the upper and lower parts, and the chemical solution introduction line is placed in contact with the upper inclined surface, so that the chemical solution can be smoothly introduced without dropping droplets during introduction. It is possible and has the effect that the chemical solution can be smoothly discharged without remaining in the lower part. Seventh, by providing a pure water introduction line for each of the chemical solution input tank, the chemical solution preparation tank, and the etching treatment tank, cleaning of each tank after the etching process is facilitated and the input chemical solution can be diluted and used. In the case of rinsing with other pure water, there is an effect that it is not necessary to specially provide a chemical solution introducing tank for pure water. Eighthly, the rinsing liquid introduction line is divided into one that is placed in contact with the inclined surface of the upper portion of the etching treatment tank and one that is ejected in a shower shape from the upper portion of the etching treatment tank. The rinse liquid introduced from the upper inclined surface of the etching treatment tank is promptly removed before the etching treatment tank is filled with the chemicals, which has the effect of improving the controllability of the etching stop. Ninth, by providing a dry air jetting mechanism on the upper part of the etching treatment tank, the rinse liquid adhering to the sample after rinsing and its peripheral portion is removed, and the composition of the etching liquid due to the mixing of the rinse liquid when the next etching liquid is introduced It has the effect of preventing changes and heat generation. The tenth effect is that by providing a chemical liquid discharge bypass line that connects these chemical liquid input tanks, chemical liquid mixing tanks, and chemical liquid waste tanks, it is possible to easily discharge the residual liquid and cleaning water after the etching process and reduce the time. Have. Eleventh, by providing a chemical solution introduction speed control valve and an electromagnetic valve that is controlled to open and close by detecting the temperature of the prepared chemical solution in the chemical solution introduction line that connects the chemical solution input tank and the chemical solution mixing tank, composition change during chemical solution preparation and It has the effect of preventing heat generation. Twelfthly, in the wet etching system having the configuration shown in FIG. 13, (H ₂ SO ₄ + H ₂ O ₂ + H
_{The use of 2} O), HCl, and acetone has the effect that the InP / InGaAsP epitaxial substrate can be subjected to groove formation etching in the semiconductor laser manufacturing process with high yield.

[Brief description of drawings]

FIG. 1 is a block diagram of a wet etching apparatus according to the first embodiment of the present invention, and FIG. 2 is an etching for performing stripe-shaped groove forming etching on an InP substrate using the wet etching apparatus having the configuration of FIG. FIG. 3 is a diagram showing a process, FIG. 3 is a partial configuration diagram of a wet etching apparatus according to a second embodiment of the present invention, and FIG. 4 is a partial configuration diagram of a wet etching apparatus according to a third embodiment of the present invention. Is a partial configuration diagram of a wet etching apparatus in a fourth embodiment of the present invention, FIG. 6 is a partial configuration diagram of a wet etching apparatus in a fifth embodiment of the present invention, and FIG. 7 is a sixth embodiment of the present invention. FIG. 8 is a partial configuration diagram of a wet etching apparatus in an example, FIG. 8 is a partial configuration diagram of a wet etching apparatus in a seventh embodiment of the present invention, and FIG. 9 is an eighth embodiment of the present invention. Partial configuration diagram of a wet etching apparatus, Fig. 10 No. 9 partial configuration diagram of a wet etching apparatus in the embodiment of FIG. 11 is a partial structural view of a wet etching apparatus according to the present invention a tenth embodiment of the present invention,
12 is a partial configuration diagram of the wet etching apparatus in the embodiment of FIG. 11 of the present invention, FIG. 13 is a configuration diagram of the wet etching apparatus in the embodiment of FIG. 12 of the present invention, and FIG. 14 is FIG. Figure showing the etching process for performing stripe-shaped groove formation etching on InP / InGaAsP epitaxial substrates using the wet etching system consisting of
FIG. 15 is a diagram showing the relationship between the depth of the stripe-shaped groove formed in the etching process shown in FIG. 14 and the in-plane position of the substrate, and FIG. 16 is a block diagram of a conventional wet etching apparatus. 102 …… Sample, 103,701 …… Etching tank, 111 ……
Chemical liquid supply / discharge control unit, 301 ... Temperature control unit, 401 ... Chemical liquid circulation line, 601a, 601b ... Basket, 602a, 602b ... Basket holding rod, 801a, 801b, 801ab, 801E ... Pure water introduction line, 901 ... pure water shower, 1001 ... dry air injection nozzle, 1101a, 1101b, 1101c, 1101ab ... chemical solution discharge bypass line, 1201 ... chemical solution introduction speed control valve, 1203 ... temperature detection valve control unit.

Claims (13)

[Claims] 1. A sample holding part for holding a sample to be etched, an etching treatment tank for performing etching, a plurality of chemical solution introducing tanks, a plurality of chemical solution introducing lines connecting each chemical solution introducing tank and the etching treatment tank, and the chemical solution. A plurality of chemical liquid mixing tanks connected between the input tank and the etching treatment tank by the chemical liquid introducing line, a plurality of chemical liquid waste liquid tanks, and a plurality of chemical liquid discharge lines connecting the chemical liquid waste liquid tanks and the etching treatment tank. A plurality of waste liquid reserve tanks connected between the etching solution tank and the chemical solution waste tank and connected by the chemical solution discharge line, and a chemical solution from the chemical solution input tank to the chemical solution preparation tank or the etching process tank through the chemical solution introduction line Starting and stopping the introduction and starting the discharge of the chemical liquid from the etching treatment tank to the waste liquid preliminary tank or the chemical liquid waste tank through the chemical liquid discharge line. And a chemical liquid supply and discharge control unit for controlling the stop, wet etching apparatus, wherein said that the etching treatment tank sequentially continuously chemical liquid is etched through is performed with automating preparation of drug solution. 2. A temperature control mechanism for controlling the temperature of each chemical bath in order to control the temperature of each chemical in the chemical bath, the chemical preparation bath, and the etching bath, and the etching bath contains a rinse after etching. The wet etching apparatus according to claim 1, wherein an ultrasonic vibration mechanism is provided to surely perform the above. 3. The wet etching apparatus according to claim 2, wherein each tank is provided with a chemical solution stirring mechanism so as to make the chemical solution in each tank uniform. 4. The wet etching apparatus according to claim 3, wherein the sample holder is provided with a swinging mechanism or a rotating mechanism so that the sample is uniformly etched in the etching treatment tank. 5. The sample holder is divided into a basket capable of accommodating a plurality of samples to be etched and a basket holding rod having a swinging mechanism or a rotating mechanism for connecting the baskets. Wet etching equipment. 6. The basket is made of Teflon or quartz, and at least a portion of the basket holding rod which is exposed to the chemical or is exposed to the chemical vapor is coated with Teflon in the etching tank.
The wet etching apparatus described. 7. The chemical solution introduction tank has an inclined surface for arranging a chemical solution introduction line at the upper opening, and has a funnel shape that gradually decreases with inclination from the central portion where the etching process is performed at the lower part. The wet etching apparatus according to claim 5, wherein the discharge is promptly performed. 8. The wet etching apparatus according to claim 7, wherein a pure water introduction line is provided in each of the chemical solution introducing tank, the chemical solution preparing tank, and the etching treatment tank. 9. A chemical liquid introduction line connected to an etching treatment tank, wherein a rinse liquid introduction line is arranged in contact with an inclined surface of an etching treatment tank upper portion, and a chemical solution introduction line is showered from the upper portion of the etching treatment tank. The wet etching device according to claim 8, wherein the wet etching device is divided. 10. The wet etching apparatus according to claim 9, further comprising a sample, a sample holder, and a dry air jetting mechanism for removing the rinse liquid adhering to the inner wall of the etching treatment tank, which is provided above the etching treatment tank. 11. A plurality of chemical liquid discharge bypass lines connecting the chemical liquid supply tank, the chemical liquid mixing tank and the chemical liquid waste tank are provided to simplify the residual liquid discharge after the etching process and the cleaning of each tank. 11. The wet etching device according to claim 10. 12. The chemical liquid introduction line connecting the chemical liquid feeding tank and the chemical liquid mixing tank is provided with a chemical liquid introduction speed control valve and an electromagnetic valve which is controlled to open and close by detecting the temperature of the mixed chemical liquid. Wet etching equipment. 13. A chemical solution input tank having _four tanks of HCl, H ₂ SO ₄ , H ₂ O ₂ and acetone, and a chemical solution mixing tank of H ₂ SO ₄ tank and H ₂ O.
_{It has} one tank connected from _two tanks of two tanks, and has three tanks of HCl, (H ₂ SO ₄ + H ₂ O ₂ ) and acetone as a chemical liquid waste tank, and InP / InGaAsP as a sample to be etched. 13. The wet etching apparatus according to claim 12, wherein an epitaxial substrate is used.