JPH11154663A - Etching processing device of semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the etching processing device of a semiconductor wafer, which is capable of controlling the amount of etching with high accuracy and stopping the etcing processing with optimal timing. SOLUTION: The following parts are provided. An etching pot 4 is constituted by using a semiconductor wafer 2 at the base plate or at a part of a sidewall, arranging a machining surface 28 at the inner surface, and arranging a non- machining surface 29 at the outer surface. An etching head 5 has a stirring means 51 and a heating means 52 of etching liquid in the opt 4. A thickness measuring sensor 6 is arranged so as to face the non-machining surface 29. A sensor moving device 7 moves the sensor 6. The etching processing of the semiconductor wafer 2 is performed with the thickness of the semiconductor wafer 2 being measured by the thickness measuring sensor 6. When the thickness has reached a specified thickness, the etching work is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for etching semiconductor wafers for manufacturing semiconductor sensors such as pressure sensors and acceleration sensors.

[0002]

2. Description of the Related Art For example, as a pressure sensor or an acceleration sensor, there is a semiconductor sensor manufactured using a chip obtained by processing a semiconductor into a diaphragm shape or the like. As shown in FIGS. 6A and 6B, the semiconductor sensor chip 20 is provided with several hundreds to several thousand concave portions 21 on the semiconductor wafer 2 by etching, and then cuts in accordance with the concave portion forming position. It is manufactured by

As shown in FIG. 6, the semiconductor wafer 2 is composed of a circuit surface (non-processed surface) 29 forming a normal semiconductor circuit 290 and an etching processed surface (processed surface) 28 for providing a sensor shape. Have been. By changing the shape of the mask 3 attached to the processing surface 28, a shape of the concave portion 21 suitable for the function of the sensor can be obtained.

As shown in FIG. 7, the shape of the chip 20 is for a pressure sensor having a concave portion 21 in which the center of the chip is concave, and as shown in FIG. 8, an island-like bulge 215 is left at the center of the chip. There are various shapes such as those for an acceleration sensor in which a concave portion 21 is formed by engraving the periphery. These are formed by devising the mask 3 and melting and removing the non-mask portion with an anisotropic etching solution such as potassium hydroxide.

The performance of various sensors using these chips 20 is determined by the accuracy of the thickness T of the bottom of the recess 21. Therefore, when etching the semiconductor wafer 2, the most important issue is how to control the thickness T of the bottom of the concave portion 21 with high accuracy.

Next, FIG. 9 shows an etching apparatus 9 using a conventional anisotropic etching solution. As shown in the figure, the etching apparatus 9 includes an etching tank 93 for storing an etching solution 8 and a heater 9 for heating the etching tank 93 from below.
And 4. Further, a temperature sensor 941 for controlling the heater 94 and an etching solution 8 are provided in the etching tank 93.
And a holder 96 for exposing and holding the processed surface 28 of the semiconductor wafer 2 in the etching solution 8. Note that a power supply 97 is provided between the semiconductor wafer 2 and the electrode 971 immersed in the etching solution 8 in preparation for performing so-called electrochemical stop etching.

When the semiconductor wafer 2 is etched by using the etching apparatus 9, FIG.
As shown in (1), the etching solution 8 placed in the etching tank 93 is heated to a predetermined temperature by the heater 94. At this time, the heater 94 is accurately controlled using data from the temperature sensor 941 immersed in the etching liquid 8.
Next, while maintaining the etching solution 8 at a predetermined temperature,
The semiconductor wafer 2 set on the jig 96 is immersed in the etching solution 8. Thereby, the semiconductor wafer 2 is gradually etched.

[0008]

By the way, when etching is performed by the conventional etching apparatus 9, as a method for knowing that the thickness T of the bottom of the concave portion 21 of the semiconductor wafer 2 has reached a target thickness, the conventional method 2 is used. Two methods have been devised and implemented. The first method is a time management method, in which the amount of etching per unit time (etching rate) is measured in advance and is estimated from this.

More specifically, as shown in FIG. 10, a graph is created with the etching amount on the vertical axis and the etching time on the horizontal axis. Then, the value obtained by subtracting the target thickness T from the original thickness of the semiconductor wafer 2 is set as the etching amount E, and the etching time t1 is obtained from the graph of FIG. Then, after a lapse of time t1 from the start of the etching process, the etching process is stopped on the assumption that the target thickness T has been reached.

In this method, the reproducibility of the etching rate is very important. However, the etching rate is sensitive to the temperature and concentration of the etching solution, so that it is difficult to control the etching rate, and it is difficult to satisfy the precision required in recent years by a single etching process. for that reason,
The etching process is performed several times, and the actual measurement of the thickness and the etching process are repeated. Therefore, great man-hours are required.

Next, as a second method, there is an electrochemical stop etching method. In this method, as shown in FIG. 9, etching is performed while applying electricity to the circuit surface 18 of the semiconductor wafer 2 by a power supply 97, and a change in current during the etching is monitored by an ammeter 972. Thereby, a graph as shown in FIG. 11 is obtained. In the graph of FIG. 7, the vertical axis indicates the current value during etching, and the horizontal axis indicates the elapsed etching time.

As can be seen from FIG. 1, the current in this case increases as the etching proceeds, and shows a peak p near the target thickness. From this point, the etching process is stopped after waiting for a certain time t2. . In this method, since the influence of the etching rate is less than that of time management, a relatively high-accuracy thickness T can be obtained. However, there is a problem in that a thick object with a thickness of 20 μm or more or an object that is thinner than an epi layer (a layer for forming a semiconductor circuit) cannot be formed in principle. There are problems such as not being able to do. Therefore, in the case of this method as well, it is necessary to perform the etching process and the actual measurement of the thickness in two or more steps.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and provides a semiconductor wafer etching apparatus capable of controlling an etching amount accurately and stopping etching at an optimum timing. It is something to offer.

[0014]

According to a first aspect of the present invention, there is provided an etching pot comprising a semiconductor wafer used as a bottom plate or a part of a side wall, a processing surface of the semiconductor wafer arranged on an inner surface, and a non-processed surface arranged on an outer surface. An etching head having a stirring means and a heating means for an etching solution placed in the etching pot; a thickness measurement sensor disposed on the non-processed surface of the semiconductor wafer; and an optional three-dimensional thickness measurement sensor. A sensor moving device for moving the semiconductor wafer to a position, and performing the etching of the semiconductor wafer while measuring the thickness of the semiconductor wafer from the non-processed surface side of the semiconductor wafer by the thickness measurement sensor. Etching of a semiconductor wafer characterized in that etching is stopped when the thickness of the semiconductor wafer reaches a predetermined thickness. In the processing equipment.

The most remarkable point in the present invention is that the semiconductor wafer to be processed is provided as a part of the etching pot, and the thickness measuring sensor is provided on the non-processed surface of the semiconductor wafer. is there.

The etching pot is formed in a container shape by disposing the semiconductor wafer as a part of a bottom plate or a side wall. However, the position where the semiconductor wafer is provided is a position where the etching liquid is sufficiently immersed in the etching liquid when the etching liquid is put in the etching pot. In addition, the semiconductor wafer is disposed so that its processed surface is exposed to the inner surface and can be directly contacted with the etching solution.

The above-mentioned etching head has a function necessary for progressing the etching process. That is, the etching head has a stirring means and a heating means for the etching liquid. In addition, for example, when performing electrochemical stop etching, a power supply unit or the like can be provided in the etching head.

A thickness measurement sensor is provided on the outer surface (non-processed surface) of the semiconductor wafer provided in the etching pot. As the thickness measuring sensor, a type capable of measuring the thickness from one side of the object is used. For example, there is a type in which the thickness is measured in a non-contact state by irradiating infrared rays or the like.

The thickness measuring sensor is connected to the sensor moving device, and is provided so as to be movable to an arbitrary position in a three-dimensional direction (XYZ direction). This sensor moving device is configured to adjust the optimal position of the thickness measurement sensor in the vertical direction, move the thickness measurement position, and the like.

Next, the operation and effect of the present invention will be described.
The etching apparatus of the present invention uses the etching pot in which a semiconductor wafer to be processed is partially disposed, and has the thickness measuring sensor for measuring the thickness of the semiconductor wafer. The thickness measurement sensor can directly measure the thickness of the processed semiconductor wafer.

Therefore, during the etching process of the semiconductor wafer, the thickness of the processed portion that is melted and removed and becomes thinner can always be grasped. Thus, the etching process can be stopped at the timing when the thickness of the processed portion becomes the optimum thickness. Therefore, the thickness of the processed portion of the obtained semiconductor wafer can be finished with extremely high precision as compared with the case of predictive control based on the conventional etching rate.

Further, since the etching process can be stopped at the optimum timing as described above, it is not necessary to measure the thickness of the semiconductor wafer before processing, which has been required conventionally. Further, it is not necessary to repeat the etching process for improving the accuracy. Therefore, by using the etching apparatus of the present invention, the etching of the semiconductor wafer can be performed with high accuracy and high productivity. Furthermore, it is also possible to specify in advance the portion that can become an abnormal chip at the time of etching processing by using the measurement data of the thickness measurement sensor.

As described above, according to the present invention, it is possible to provide a semiconductor wafer etching apparatus capable of controlling the amount of etching accurately and stopping the etching at an optimum timing.

Next, as in the second aspect of the present invention, the etching apparatus scans a predetermined range on a non-processed surface of the semiconductor wafer after starting the etching of the semiconductor wafer. Preferably, one or more predetermined thickness measurement positions are specified, and then etching is performed while measuring the thickness at the thickness measurement positions.

In this case, by scanning the thickness measurement sensor, the processed shape being etched can be grasped, and a predetermined thickness measurement position (for example, the center of the bottom of the concave portion) can be specified. Therefore, there is no need to strictly control the setting direction and the like when disposing the semiconductor wafer in the etching pot. Therefore, the etching operation can be performed more efficiently.

Further, as in the third aspect of the present invention, it is preferable that the scanning range of the thickness measurement sensor is a range of two or more chips among a plurality of chips obtained from the semiconductor wafer. That is, a large number of recesses corresponding to a plurality of chips to be obtained are provided in a semiconductor wafer. The thickness measurement sensor is scanned in two or more recesses, that is, in an area of two or more chips among the many recesses. As a result, the thickness measurement position can be specified more accurately than when scanning the area of one chip.

According to a fourth aspect of the present invention, the etching apparatus has a control unit in which a desired product shape of the semiconductor wafer is stored in advance, and the control unit is configured to control the thickness of the semiconductor wafer. It is preferable that a configuration is adopted in which a processing shape of the semiconductor wafer is calculated using the measurement data during scanning of the measurement sensor, and the thickness measurement position is specified by comparing the processing shape with the product shape. In this case, the optimum thickness measurement position can be easily specified according to the desired product shape.

According to a fifth aspect of the present invention, in the etching apparatus, a plurality of types of processing conditions are stored in the control unit in advance, and one of the processing conditions is selected at the start of the etching processing. Therefore, it is preferable that a desired etching process is automatically performed.

The above processing conditions include, in addition to basic conditions such as an etching temperature, for example, a thickness measurement position and a target thickness according to a desired product shape. Then, these conditions are stored, for example, for each product shape. Then, at the start of the etching process, one condition according to a desired product shape is selected. As a result, the etching apparatus of the present invention
In addition to controlling the temperature of the etching solution, scanning by the thickness measurement sensor, specification of the thickness measurement position, and processing stop are automatically performed. In this case, it is possible to easily cope with various types of product shapes, so that restrictions on the processing order and the like can be removed, and the productivity can be further improved.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment An embodiment of a semiconductor wafer etching apparatus according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the etching apparatus 1 of the present embodiment uses an etching pot 4 having a semiconductor wafer 2 as a bottom plate, a processing surface 28 of the semiconductor wafer 2 on the inner surface, and a non-processing surface 29 on the outer surface. have.

An etching head 5 having a stirring means 51 and a heating means 52 for the etching liquid 8 put in the etching pot 4, a thickness measuring sensor 6 disposed on the non-processed surface 29 of the semiconductor wafer 2, Sensor moving device 7 for moving measurement sensor 6 to an arbitrary position in three-dimensional direction
And

The etching apparatus 1 performs the etching of the semiconductor wafer 2 while measuring the thickness of the semiconductor wafer 2 from the non-processed surface 29 side of the semiconductor wafer 2 with the thickness measuring sensor 6. The etching process is stopped when a predetermined thickness is reached. The details are described below.

As shown in FIG. 1, the etching pot 4 is formed by combining a ring-shaped pot base 41, a cylindrical body 42 combined therewith, and the semiconductor wafer 2 to be processed. The pot base 41 has a ring shape having a through hole 410 at the center. Then, the semiconductor wafer 2 is inserted into the through hole 41 of the pot base 41.
0 is closed. Note that a mask is attached to the semiconductor wafer 2 in advance so as to cover the non-etched portion of the processing surface 29.

Above the pot base 41, a cylindrical body 42 is assembled as shown in FIG. The semiconductor wafer 2 is sandwiched between the body 42 and the pot base 41. At this time, a lip packing 425 as a sealing material for preventing leakage of the etching liquid 8 is interposed between the semiconductor wafer 2 and the body 42.

As shown in FIG. 1, the X-type packing 45 having an airway 450 penetrating up and down is attached to the pot base 41 and the body 42 by assembling the pot base 41 and the body 42.
And between them. Then, by depressurizing the respective groove-shaped pocket portions 416 and 426 provided in the portion where the X-type packing 45 is provided in the pot base 41 and the body portion 42 by a vacuum pump, the pot base 41 and the body portion 42 are drawn. . Thereby, the semiconductor wafer 2
The seal between the lip packing 425 and the lip packing 425 is kept good.

As shown in FIG. 1, an etching head 5 is provided above the etching pot 4. The etching head 5 is provided with a stirrer 51 as stirring means and a heater 52 as heating means downward from the main body 50. The stirrer 51 is connected to a rotation motor 511 provided above the main body 50, and is configured to appropriately rotate the stirring blades 512. The heater 5
2 is connected to an external power supply (not shown).

As shown in FIG. 1, the etching head 5 of this embodiment is provided with an electrode 53 adapted to electrochemical stop etching. The electrode 53 is electrically connected to a power supply 531 for electrochemical stop etching via a lead 532. The power supply 531 is also connected to the semiconductor wafer 2 forming the etching pot 4 via a lead wire 533.

As shown in FIG. 1, the etching head 5 has a water supply port 54 for supplying water for washing and an etching liquid supply port 5 for supplying the etching liquid 8.
5 is provided. An etching solution drain port 56 is provided opposite the water supply port 54 and the etching solution supply port 55. The water supply port 54 is connected to a water supply means 548 for controlling a water supply operation, and the etching liquid supply port 55 is connected to an etching liquid supply means 559 for controlling the etching liquid supply operation.

The etching pot 4 and the etching head 5 are placed on a base 17 as shown in FIG. The base 17 has a cavity 170 inside and an opening 171 in the upper central part. Base 17
A sensor moving device 7 for moving the thickness measuring sensor 6 to an arbitrary position in the three-dimensional direction is provided in the hollow portion 170 of the present embodiment.

The sensor moving device 7 has a transition mechanism in which a servo motor and a ball screw are combined inside.
The thickness measurement sensor 6 disposed on the upper part is configured to move in three-dimensional directions of up, down, left, and right. As shown in FIG. 1, the thickness measurement sensor 6 is disposed so as to protrude from the opening 171 of the base 17 and faces the non-processed surface 29 of the semiconductor wafer 2 above. Further, the thickness measuring sensor 6 of this embodiment is of a type that measures the thickness in a non-contact state by irradiating infrared rays.

The etching apparatus 1 has a control unit (not shown) in which a desired product shape of the semiconductor wafer 2 is stored in advance. The control unit also stores in advance a plurality of types of processing conditions corresponding to a plurality of types of product shapes. Then, at the start of the etching process, a desired etching process is automatically performed by selecting one of the processing conditions.

The processing conditions include the product shape described above,
The scanning area of the thickness measurement sensor, the thickness measurement position, and the like are stored. These conditions may be sent from a higher-level production management computer to the control unit and stored therein. In addition, the control unit calculates the processing shape of the semiconductor wafer 2 using the measurement data at the time of scanning by the thickness measurement sensor 6 and compares the processing shape with a previously stored product shape to specify a thickness measurement position. It is configured as follows. The control section is configured to control various functions provided in the etching head 5 according to the processing conditions.

Next, a procedure for etching the semiconductor wafer 2 using the present etching apparatus 1 will be described. First, a mask having a predetermined pattern is attached to the processing surface 28 of the semiconductor wafer 2. Next, as shown in FIG. 1, the semiconductor wafer 2 is placed on the pot base 41, and the etching pot 4 having the above configuration is assembled.

Next, the etching head 5 is set on the etching pot 4 and placed on the base 17. Next, the processing conditions are selected by the control unit. Thus, a predetermined etching process is automatically started according to an instruction from the control unit.

First, an etching solution 8 adjusted to a predetermined temperature and concentration is injected into the etching pot 4 from an etching solution supply port 55 of the etching head 5. During the etching process, the etching liquid 8 in the etching pot 4 is stirred by the stirrer 51 and the liquid temperature is kept constant by the heater 52. As a result, the portion of the processing surface 28 of the semiconductor wafer 2 that does not have a mask is gradually melted and removed, and the etching process proceeds.

Next, after the temperature of the etching liquid 8 is sufficiently stabilized and the etching process has progressed to some extent, scanning by the thickness measuring sensor 6 is started. For example, it starts after about 5 minutes have passed after the start of the etching process. As shown in FIGS. 2 and 3, the thickness of the semiconductor wafer 2 is measured by measuring the thickness of the non-processed surface 29 of the semiconductor wafer 2 by irradiating the infrared light.
1 and the interference of the reflected light from the surface S2 of the processing surface 28. Therefore, first, the vertical position of the thickness measurement sensor 6 is adjusted to the optimum state by the sensor moving device 7.

Next, as shown in FIGS. 2 and 3, the XY-direction driving device of the sensor moving device 7 is operated to scan the thickness measuring sensor 6 in a plane, and
Is measured. At this time, the scanning range of the thickness measurement sensor 6 is a rectangular area of 10 mm on a side as shown in FIG. Since the size of the chip to be obtained is 1.5 to 3.5 mm on a side, this is a range of four or more chips.

The processing shape (pattern) of the semiconductor wafer 1 is grasped by the control unit from the thickness data obtained by the scanning of the thickness measuring sensor 6. The control unit
The thickness measurement position is specified by comparing the current processed shape with a previously stored product shape.

Specifically, as shown in FIG. 4, when the shape of the chip 20 to be obtained has a concave portion 21 in which the entire central portion is depressed, the central portion K1 of the concave portion 21 is positioned at the thickness measurement position. To be specified. On the other hand, as shown in FIG. 5, when the shape of the chip 20 has a concave portion 21 depressed around the center leaving an island-shaped bulge 215, the thickness of the concave portion K2 near the corner of the chip is measured. Specify as a location.

After the thickness measurement position is specified, the etching process proceeds while the thickness measurement sensor 6 constantly measures the thickness at that position. In this example, a mode is provided in which the actual etching rate is calculated from the thickness change for 30 seconds from the start of the thickness measurement, and thereafter, whether or not the normal etching is performed.

Next, when the thickness of the semiconductor wafer 2 reaches a predetermined thickness, an etching stop operation is automatically started according to an instruction from the control unit. These work procedures are stored in the control unit in advance as the processing conditions.
Specifically, first, the heater 52 is stopped, and cleaning water 540 is introduced into the etching pot 4 from the water supply port 54. As a result, the etching solution 8 is diluted and cooled, and the etching reaction is stopped immediately.

The etchant 8 is overflowed and discharged as waste liquid 89 from the drain 56 by supplying the cleaning water 540. Further, the supply of the cleaning water is stopped after the cleanliness of the processing surface 28 of the semiconductor wafer 2 is increased for a certain period of time (for example, three minutes) from the time when the measured value of the thickness measurement sensor 6 becomes constant.

Next, after stopping the rotation of the stirrer 51,
A mixed solution of the cleaning water and the etching solution 8 is forcibly discharged from the etching pot 4 by a forced drainage device (not shown) such as a vacuum drainage device such as an ejector. Next, the etching pot 4 is disassembled, the semiconductor wafer 2 is taken out, and a series of etching processing is completed.

When the electrochemical stop etching is performed, the switch 536 of the power supply 531 is turned on and the semiconductor wafer 2 is energized when the heater 52 is stopped. As a result, an oxide that is hardly etched on the processing surface 28 is formed by the anodic oxidation reaction, and the etching is stopped.
The switch 536 of the power supply 531 is turned off before the forcible discharge of the etching liquid 8 described above.

As described above, the etching apparatus 1 of this embodiment
Is performed while directly measuring the thickness of the semiconductor wafer 2. Therefore, the following various effects were obtained. That is, first, the thickness variation could be reduced to 1/3 or less of the thickness accuracy of the chip manufactured by the conventional etching apparatus. In addition, in the present example, an etching operation in which the thickness measurement and the etching process were repeatedly performed in several times (two to four times) was repeated.
It could be replaced by one operation.

Further, conventionally, in order to cope with many types of products, it was necessary to change the etching conditions for each product, which required complicated process management. On the other hand, in the etching apparatus 1 of the present embodiment, the processing is automatically advanced while directly measuring the thickness of the semiconductor wafer 2 as described above, so that it is possible to appropriately cope with various processing conditions. Therefore, it is possible to cope with all kinds of products by one device, and it is possible to greatly streamline process control.

In this embodiment, the shape of the semiconductor wafer being etched can be directly grasped. Therefore, an accurate measurement position can always be maintained without being affected by a pattern shift on the front and back surfaces of the semiconductor wafer 2 and a shift of the set position. Therefore, the reliability of the etching process can be significantly improved.

In this example, since the minimum 4 chip portions are set as the scanning range of the thickness measurement sensor 6, when there is an abnormality in the chip portion being measured, for example, an abnormality in the etching rate is detected and this is detected. Can be determined automatically. Therefore, a chip which may become abnormal can be specified in advance, and quality control later can be further ensured.

[0059]

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a configuration of an etching apparatus according to an embodiment.

FIG. 2 is an explanatory diagram showing a scanning state of a thickness measurement sensor in the embodiment.

FIG. 3 is an explanatory diagram showing a scanning area of a thickness measurement sensor in the embodiment.

FIG. 4 shows a tip shape in the embodiment.
2A is a plan view, and FIG. 2B is a cross-sectional view taken along line DD.

FIG. 5 shows another chip shape in the embodiment.
2A is a plan view, and FIG. 2B is a cross-sectional view taken along line FF.

6A is a plan view and FIG. 6B is a cross-sectional view taken along line AA of a semiconductor wafer in a conventional example.

FIGS. 7A and 7B are a plan view and a cross-sectional view taken along line BB, respectively, showing a chip shape in a conventional example.

FIG. 8 shows another chip shape in a conventional example.
(A) The top view, (b) CC sectional view taken on the line.

FIG. 9 is an explanatory view showing a configuration of an etching apparatus according to a conventional example.

FIG. 10 is an explanatory diagram showing a relationship between an etching time and an etching amount in a time management method according to a conventional example.

FIG. 11 is an explanatory diagram showing a relationship between a current value and an etching time in an electrochemical stop etching method according to a conventional example.

[Explanation of Codes] . . Etching equipment, 2. . . Semiconductor wafer, 20. . . Chip, 21. . . Recess, 3. . . Mask, 4. . . 4. etching pot, . . 5. etching head, . . 6. Thickness measurement sensor, . . 7. Sensor moving device, . . Etchant,

Claims (5)

[Claims] An etching pot comprising a semiconductor wafer used as a bottom plate or a part of a side wall, a processing surface of the semiconductor wafer disposed on an inner surface, and a non-processing surface disposed on an outer surface, and an etching pot placed in the etching pot. An etching head having a liquid agitating means and a heating means, a thickness measuring sensor disposed on the non-processed surface of the semiconductor wafer, and a sensor moving device for moving the thickness measuring sensor to an arbitrary position in a three-dimensional direction. The etching of the semiconductor wafer is performed while measuring the thickness of the semiconductor wafer from the non-processed surface side of the semiconductor wafer by the thickness measurement sensor, and the thickness of the semiconductor wafer is reduced to a predetermined thickness. An etching processing apparatus for a semiconductor wafer, wherein the etching processing is stopped when the semiconductor wafer reaches the position. 2. The etching device according to claim 1, wherein the etching device scans a predetermined range on a non-processed surface of the semiconductor wafer by using the thickness measurement sensor after starting the etching process of the semiconductor wafer. A predetermined thickness measuring position, and then performing etching while measuring the thickness at the thickness measuring position. 3. The apparatus for etching a semiconductor wafer according to claim 2, wherein a scanning range of said thickness measurement sensor is a range of two or more chips among a plurality of chips obtained from said semiconductor wafer. 4. The etching processing apparatus according to claim 2, wherein the etching processing apparatus has a control unit in which a desired product shape of the semiconductor wafer is stored in advance, and the control unit includes:
It is configured to calculate the processing shape of the semiconductor wafer using the measurement data at the time of scanning of the thickness measurement sensor, and to specify the thickness measurement position by comparing the processing shape with the product shape. Characteristic semiconductor wafer etching equipment. 5. The etching processing apparatus according to claim 4, wherein a plurality of types of processing conditions are stored in the control unit in advance, and one of the processing conditions is selected at the start of the etching processing to thereby obtain a desired processing condition. An etching apparatus for a semiconductor wafer, wherein the apparatus is configured to perform an etching process automatically.