JP2002110623A - Wet-etching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method of a wet-etching manufacture process for improving the quality of products, and for solving the problem of the excess and shortage of etching time. SOLUTION: This wet-etching method is applies on a semiconductor wafer layer, and includes procedures (a), (b), (c), (d), (e), and (f). In the procedure (a), a wet-etching reaction tank should be provided. In the procedure (b), film thickness loss (ΔH) should be obtained by setting or calculation. In the procedure (c), prompt etching speed (ER (C, T)) should be obtained by an etching speed function, based on concentration (C) and temperature (T) of the wet- etching reaction tank. In the procedure (d), etching time (Time) is to be obtained, by automatic calculation based on an equation Time=ΔH/ER (C, T) for the wet-etching reaction tank. In the procedure (e), a semiconductor wafer is to be put in the wet-etching reaction tank. In the procedure (f), the layer of the semiconductor wafer is etched according to the etching time calculated based on the automatic calculation in the wet-etching reaction tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to wet etching, and more particularly to a method for performing wet etching on a semiconductor wafer layer.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, control of wet etching ability has a great effect on product quality and element function. In a well-known wet etching method, a fixed etching time is set according to a current etching rate of a wet etching reaction tank, and a required etching film thickness is achieved. The wet etching process can be well controlled within a short time, but the etching rate changes with the aging of the concentration and temperature of the wet etching reactor. Therefore, it is very difficult to control the etching process. In addition, since there is a difference in the wafer state between lots or the wafer state between lots, if the same etching time is set for each wafer, there is a problem that the time is exceeded or insufficient. appear.

[0003]

SUMMARY OF THE INVENTION In the present invention, the "wet etching method" of the present invention was finally developed on the basis of the indomitable spirit of research in consideration of the drawbacks of the well-known technology, and on the basis of indomitable research spirit.

It is a primary object of the present invention to provide a controllable wet etching manufacturing process.

It is a secondary object of the present invention to provide a method for improving product quality.

Another object of the present invention is to provide a method for solving the problem of excessive or insufficient etching time.

[0007]

SUMMARY OF THE INVENTION Based on the above objects, the present invention provides, on the one hand, a method of wet etching, applied on the loss of fixed film thickness (ΔH) during etching on a semiconductor wafer layer. You. It involves the following steps: a) providing a wet etching reactor; b) setting the fixed thickness loss (ΔH); and for the wet etching reactor, its concentration (C) and temperature (T). An instantaneous etch rate (ER (C, T)) is determined by an etch rate function based on
The etching time is obtained by an automatic calculation based on im = △ H / ER (C, T). d) The semiconductor wafer is put into the wet etching reaction tank. e) The wet etching reaction tank is calculated based on the automatic calculation. Performing the etching with the fixed thickness loss on the layer of the semiconductor wafer according to the determined etching time.

The fixed thickness loss (ΔH) is set by the wet etching reaction tank.

[0009] The measured concentration value is obtained by measurement with a concentration measuring device of the wet etching reaction tank.

[0010] The measured temperature value is obtained by measurement using a thermocouple (Thermal Couple) device of the wet etching reaction tank.

In the above concept, the etching rate function is: ER (C, T) = ER ₀ * C * exp (−Ea / RT)
+ A C: Concentration of wet etching reaction tank T: Temperature of wet etching reaction tank Ea: Etching activation energy R: Gas reaction constant (= 8.314 J / K) ER ₀ : Constant A: Constant

Based on the above object, the present invention also provides a wet etching method from another side, which is applied to a fixed remaining film thickness (H _r ) when etching a semiconductor wafer layer. To do so, the following steps are performed: a) providing a wet etching reactor, b) setting the fixed remaining thickness (H _r ), and simultaneously measuring the pre-etch thickness (H _b ) of the layer, For the wet etching reaction tank, an immediate etching rate (ER (C, T)) is obtained by an etching rate function based on the concentration (C) and the temperature (T). C) For the wet etching reaction tank, the equation T
_{ime = (H b -H r)} / ER (C, T) by an automatic calculation based on, obtains the etching time (Time), d) putting the semiconductor wafer in the wet etching reaction vessel, e) the wet etching reaction Performing, in the tank, the layer of the semiconductor wafer with the fixed remaining film thickness using the etching time calculated based on the automatic calculation.

The fixed remaining film thickness (H _r ) is set by the wet etching reaction tank.

The pre-etch thickness (H _b ) of the layer is obtained by measuring the wet etching reaction tank.

The thickness (H _b ) of the layer before etching is measured by an ellipsometer.

The measured value of the concentration is obtained by measurement by a concentration measuring device of the wet etching reaction tank.

The measured temperature value is obtained by measuring a thermocouple device of the wet etching reaction tank.

The etching rate function is given by: ER (C, T) = ER ₀ * C * exp (−Ea / RT)
+ A C: Concentration of wet etching reaction tank T: Temperature of wet etching reaction tank Ea: Etching activation energy R: Gas reaction constant (= 8.314 J / K) ER ₀ : Constant A: Constant

Based on the above object, the present invention also provides a method for wet etching from another side, and a method for performing a fixed layer height (Stepph) for etching on a semiconductor wafer layer.
right, X). It comprises the following steps: a) providing a wet etching reactor; b) setting the fixed story height (X); c) for the wet etching reactor, the fixed story height (X). And the film thickness loss (△ H
(X)), and for the wet etching reaction tank, based on the concentration (C) and the temperature (T), an immediate etching rate (ER (C,
T)), and d) Equation T for the wet etching reactor.
im) = automatic calculation based on H (X) / ER (C, T) to determine the etching time (Time); e) placing the semiconductor wafer in the wet etching reactor; f) in the wet etching reactor. Performing the etching of the fixed layer height on the layer of the semiconductor wafer according to the etching time calculated based on the automatic calculation.

The fixed floor height (X) is set by the wet etching reaction tank.

When the layer requiring etching is located on a plurality of relatively high film thicknesses, the film thickness loss (ΔH (X)) is ΔH (X) = H _h -H l _-X H _h: total H l of a plurality of thickness higher before _etching: the sum of the plurality of film thickness relatively low before etching X: horizontal after etching is performed to etch layer This value is obtained by subtracting the horizontal height of a plurality of relatively low film thicknesses before etching from the height.

When the layer requiring etching is located on a plurality of relatively thin film thicknesses, the film thickness loss (ΔH (X)) is ΔH (X) = X− _{(H h -H l) H h} : total of a plurality of thickness higher before etching H _l: total relatively low multiple layer thickness before etching X: before etching of a plurality of relatively low This value is obtained by subtracting the horizontal height after the etching layer is etched from the horizontal height of the film thickness.

The sum of the relatively high film thicknesses (H
_h ) and the sum of the plurality of relatively low film thicknesses (H ₁ )
Is obtained by measurement in the etching reaction tank.

The sum of the relatively high film thicknesses (H
_h ) and the sum of the plurality of relatively low film thicknesses (H ₁ )
Is measured by an ellipse thickness meter.

The measured value of the concentration is obtained by the measurement of the concentration measuring device in the wet etching reaction tank.

The measured temperature value is obtained by measuring a thermocouple device in the wet etching reaction tank.

The etching rate function is given by: ER (C, T) = ER ₀ * C * exp (−Ea / RT)
+ A C: Concentration of wet etching reaction tank T: Temperature of wet etching reaction tank Ea: Etching activation energy R: Gas reaction constant (= 8.314 J / K) ER ₀ : Constant A: Constant

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The objects and functions of the present invention will be described in detail with preferred embodiments with reference to the accompanying drawings.

As described above, the etching rate is changed as the concentration and temperature of the wet etching reaction tank change with time. Therefore, it is very difficult to control the wet etching process. If the wet etch bath is capable of estimating the instantaneous etch rate (ER (C, T)) and the thickness loss (△ H) obtained by setting or calculation, the wet etch bath has the formula Time = △ H / ER
Since the etching time (Time) can be automatically calculated based on (C, T), the wet etching tank can achieve automated production and good control of the wet etching process.

Accordingly, the present invention provides one method of wet etching, which is applied on a semiconductor wafer layer. It involves the following steps: a) providing a wet etching reactor; b) determining the thickness loss (ΔH) by setting or calculation; c) for the wet etching reactor, its concentration (C) and temperature ( Based on T), an immediate etching rate (ER (C, T)) is obtained by an etching rate function. D) For the wet etching reaction tank, an equation T
im) = automatic calculation based on H / ER (C, T) to determine the etching time; e) put the semiconductor wafer into the wet etching reaction tank; f) calculate in the wet etching reaction tank based on the automatic calculation Etching the layer of the semiconductor wafer according to the determined etching time.

The etching rate (ER (C,
T)) indicates the following etching rate function, and the parameters Ea, ER and A are obtained by solving a ternary simultaneous equation under three different etching conditions for the concentration and temperature of the wet etching reaction tank.

ER (C, T) = ER ₀ * C * exp (-
Ea / RT) + AC: Concentration of the wet etching reaction tank. It can be obtained by measurement with a concentration measuring device in a wet etching reaction tank.

T: Temperature of the wet etching reaction tank. Obtained by measurement of a thermocouple device in a wet etching reaction tank.

Ea: Etching activation energy R: Gas reaction constant (= 8.314 J / K) ER ₀ : Constant A: Constant Regarding film thickness loss (ΔH), it is necessary to confirm the necessity of the manufacturing process. Yes, there are some differences in the measurement or calculation method.

The application of the present invention to a wet etching process will be described in detail with reference to the following examples.

Example 1 (Fixed Film Thickness Loss) FIG. 1 is a sketch drawing of the wet etching of the fixed film thickness loss. This wet etching is most commonly applied to semiconductor manufacturing processes. The film thickness loss in the wet etching is a fixed constant value, and the fixed film thickness loss (ΔH) is set by the wet etching reaction tank. Further, the wet etching reaction tank obtains an immediate etching rate (ER (C, T)) from an etching rate function based on the concentration (C) and the temperature (T). / ER (C, T) automatically calculates the etching time.

ΔH = H _b −H ₀ = constant Time = ΔH / ER (C, T) (Example 2 (Fixed Residual Film Thickness)) FIG. 2 is a sketch drawing of the fixed residual film thickness. In consideration of the manufacturing process, the remaining film thickness of the wet etching needs to be maintained at a fixed constant value in some cases. The wet etching reaction tank can determine a film thickness loss (ΔH) based on the measured film thickness H _b before etching and the remaining film thickness H _r set by the wet etching reaction tank. Further, the wet etching reaction tank obtains an immediate etching rate (ER (C, T)) from an etching rate function based on the concentration (C) and the temperature (T).
The etching time (Time) is automatically calculated from ΔH / ER (C, T).

ΔH = H_b-H_r  H_b: Film thickness before etching. Determined by measurement.

H _r : remaining film thickness. Constant value. Time = ΔH / ER (C, T) (Example 3 (Fixed Layer Height)) FIG. 3 is a sketch drawing of wet etching at a fixed layer height (Step Height). In consideration of the manufacturing process, it is necessary to maintain the fixed layer height of the wet etching at a fixed constant value in some cases. Based on the measured values of the plurality of other layer thicknesses before etching and the fixed layer height (X) set value,
The thickness loss (ΔH (X)) is calculated. Further, the wet etching reaction tank obtains an immediate etching rate (ER (C, T)) from an etching rate function based on the concentration (C) and the temperature (T). (X) / ER (C,
According to T), the etching time (Time) is automatically calculated. ΔH (X) = (H ₄ + H ₅ ) − (H ₁ + H ₂ + H ₃ ) −
_{X = H h -H l -X H} 1, H 2, H 3, H 4: thickness of the non-etching layer. Determined by measurement.

H ₅ : film thickness of the layer to be etched. Determined by measurement.

H _h : the sum of a plurality of relatively high film thicknesses.

H ₁ : The sum of a plurality of relatively thin film thicknesses.

X: Hierarchy height (Step Height)
t). Constant value.

When the horizontal height of the fifth layer after etching and the first layer are to be controlled to be the same, X = 0.

In a case where the horizontal height of the fifth layer after the etching is controlled to be higher than the first layer, X> 0.

If the horizontal height of the fifth layer after etching is to be controlled to be lower than the first layer, X <0. Time = △ H / ER (C, T) Naturally, the three embodiments are only given as examples, and the film thickness loss (△ H (X)) is not limited to the three embodiments. If the film thickness loss (△ H (X)) can be calculated from the fixed layer height (X) set value, the wet etching reaction tank is expressed by the equation Time = △ H (X) / ER (C,
By T), the etching time (Time) can be automatically calculated.

[0047]

According to the wet etching method of the present invention,
The well-known problem of excess or short wet etching time can be solved, and the quality of the product is improved. In this regard, the present invention is superior to various existing technologies, and has extremely great industrial value.

[Brief description of the drawings]

FIG. 1 is a sketch drawing of wet etching of a fixed film thickness loss.

FIG. 2 is a sketch drawing of wet etching of a fixed remaining film thickness.

FIG. 3 is a sketch drawing of wet etching at a fixed layer height.

[Explanation of symbols]

H _b etching thickness before H _a film thickness after etching △ H film thickness loss H _r residual film thickness H ₁ of the first layer thickness H ₂ second layer thickness H ₃ third layer thickness H ₄ of the total total H _l relatively low multiple of the thickness of the film thickness X hierarchy height H _h higher plurality of the film thickness of the fourth layer thickness H ₅ fifth layer of

 ────────────────────────────────────────────────── 72 Continuing on the front page (72) Inventor Chen Yi Masan No. 23, 60 Alley, Dongshan Street, Hsinchu, Taiwan Term (reference) 4K057 WA14 WA19 WJ10 5F043 DD24 GG10

Claims (21)

[Claims] 1. A fixed film thickness loss (半導体) on a semiconductor wafer layer.
H) The wet etching method of the present invention applied above, comprising: a) providing a wet etching reactor; b) setting the fixed thickness loss (ΔH); Based on the concentration (C) and the temperature (T), an immediate etching rate (ER (C, T)) is obtained by an etching rate function. C) For the wet etching reactor, the equation T
The etching time is obtained by an automatic calculation based on im = △ H / ER (C, T). d) The semiconductor wafer is put into the wet etching reaction tank. e) The wet etching reaction tank is calculated based on the automatic calculation. Performing the etching with the fixed thickness loss on the layer of the semiconductor wafer according to the determined etching time. 2. The wet etching method according to claim 1, wherein the fixed thickness loss (ΔH) is set by the wet etching reaction tank. 3. The wet etching method according to claim 1, wherein the measured concentration value is obtained by measuring with a concentration measuring device of the wet etching reaction tank. 4. The wet etching method according to claim 1, wherein the measured temperature value is obtained by measuring a thermocouple device of the wet etching reaction tank. 5. The etching rate function is: ER (C, T) = ER ₀ * C * exp (−Ea / RT)
+ A C: Concentration of wet etching reaction tank T: Temperature of wet etching reaction tank Ea: Etching activation energy R: Gas reaction constant (= 8.314 J / K) ER ₀ : Constant A: Constant The wet etching method according to claim 1, wherein 6. A wet etching method applied on a fixed remaining film thickness (H _r ) during etching on a semiconductor wafer layer, the method comprising: a) providing a wet etching reaction tank; and b) providing the fixed remaining film. The thickness (H _r ) is set, and at the same time the pre-etch thickness (H _b ) of the layer is measured. Based on the concentration (C) and temperature (T) of the wet etching reaction tank, an etching rate function is used. Determine the immediate etch rate (ER (C, T)); c) For the wet etch reactor, equation T
_{ime = (H b -H r)} / ER (C, T) by an automatic calculation based on, obtains the etching time, d) put the semiconductor wafer in the wet etching reaction vessel, e) in the wet etching reaction vessel, A wet etching method comprising: performing etching with the fixed remaining film thickness on the layer of the semiconductor wafer based on the etching time calculated based on the automatic calculation. 7. The wet etching method according to claim 6, wherein the fixed remaining film thickness (H _r ) is set by the wet etching reaction tank. 8. The wet etching method according to claim 6, wherein the pre-etch thickness (H _b ) of the layer is obtained by measuring the wet etching reaction tank. 9. The wet etching method according to claim 6, wherein the thickness (H _b ) of the layer before etching is measured by an ellipsometer. 10. The wet etching method according to claim 6, wherein the measured concentration value is obtained by measuring with a concentration measuring device in the wet etching reaction tank. 11. The wet etching method according to claim 6, wherein the measured temperature value is obtained by measuring a thermocouple device of the wet etching reaction tank. 12. The etching rate function is: ER (C, T) = ER ₀ * C * exp (−Ea / RT)
+ A C: Concentration of wet etching reaction tank T: Temperature of wet etching reaction tank Ea: Etching activation energy R: Gas reaction constant (= 8.314 J / K) ER ₀ : Constant A: Constant The wet etching method according to claim 6, wherein 13. A wet etching method applied on a fixed level height when etching on a layer of a semiconductor wafer, the method comprising: a) providing a wet etching reaction vessel; and b) providing the fixed level height (X). C) Calculate based on the fixed layer height (X) for the wet etching reaction tank, and calculate the film thickness loss (ΔH
(X)), and for the wet etching reaction tank, based on the concentration (C) and the temperature (T), an immediate etching rate (ER (C,
T)), and d) Equation T for the wet etching reactor.
im) = automatic calculation based on H (X) / ER (C, T) to determine the etching time; e) placing the semiconductor wafer in the wet etching reactor; f) automatically calculating in the wet etching reactor Performing the etching of the fixed layer height on the layer of the semiconductor wafer by the etching time calculated based on the above. 14. The wet etching method according to claim 13, wherein the fixed layer height (X) is set by the wet etching reaction tank. 15. When the layer requiring etching is located on a plurality of relatively high film thicknesses, the film thickness loss (ΔH (X)) is ΔH (X) = H _h -H l _-X H _h: total H l of a plurality of thickness higher before _etching: the sum of the plurality of film thickness relatively low before etching X: horizontal after etching is performed to etch layer 14. The wet etching method according to claim 13, wherein a value obtained by subtracting a horizontal height of a plurality of relatively thin film thicknesses before etching from the height is obtained. 16. When the layer requiring etching is located on a plurality of relatively thin film thicknesses, the film thickness loss (ΔH (X)) is ΔH (X) = X _{- (H h -H l) H} h: total H _l of a plurality of thickness higher before etching: the sum of the plurality of film thickness relatively low before etching X: relatively low plurality before etching 14. The wet etching method according to claim 13, wherein a value obtained by subtracting the horizontal height after the etching of the etching layer from the horizontal height of the film thickness is obtained. 17. The sum (H _h ) of the relatively high plurality of film thicknesses and the sum (H H) of the relatively low plurality of film thicknesses.
The wet etching method according to claim 15, wherein _l ) is obtained by measuring the etching reaction tank. 18. The method according to claim 1, wherein the sum of the relatively high thicknesses (H _h ) and the sum of the relatively low thicknesses (H ₁ ) are measured by an ellipsometer. The wet etching method according to claim 15, wherein: 19. The wet etching method according to claim 13, wherein the measured concentration value is obtained by measuring with a concentration measuring device of the wet etching reaction tank. 20. The temperature measurement value is a thermocouple of the wet etching reaction tank.
14. The apparatus according to claim 13, wherein the apparatus is obtained by measuring the apparatus.
The described wet etching method. 21. The etching rate function is: ER (C, T) = ER ₀ * C * exp (−Ea / RT)
+ A C: Concentration of wet etching reaction tank T: Temperature of wet etching reaction tank Ea: Etching activation energy R: Gas reaction constant (= 8.314 J / K) ER ₀ : Constant A: Constant The wet etching method according to claim 13, wherein