JPH04137035U - Etching jig for semiconductor substrates - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a jig that improves the efficiency and reliability of wet etching work on semiconductor substrates. [Structure] The pedestal 4 has a concave surface a that is larger than the shape of the target semiconductor substrate 9 by a predetermined amount. It also has an inner groove c and an outer groove d provided at a predetermined interval around the concave surface.
Furthermore, there are intake holes e passing through the inner groove and the outer groove at a predetermined interval. An inner O-ring 6a is arranged in the inner groove c, and an outer O-ring 7a is arranged in the outer groove d. This pedestal 4 is attached to a pedestal having an intake groove f communicating with the intake hole e and an intake pipe 3 connected to the intake groove f. The suction pipe 3 is connected to a vacuum pump. In this way, the substrate can be easily set on the pedestal 4, and the back side is completely sealed.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is applied to wet etching of semiconductor substrates. Regarding the jigs.

0002

[Conventional technology]

A high-performance sensor that integrates a sensing section and a signal processing circuit section into one chip using a semiconductor substrate. Development and production of sensors and composite sensors that integrate several types of sensors on one chip. In the process, we are working on microfabrication of the sensing mechanism and integration of electronic circuits for signal processing. A microprocessor that applies semiconductor IC process technology and the same technology to both the front and back sides of semiconductor substrates. In many cases, it is formed using chroma-machining technology.

0003 For example, in the case of a pressure sensor chip, a cross-sectional view of the chip is shown in Figure 5, but the semiconductor A diffused resistance type strain gauge 91 is placed in the center of the upper surface of the plate 9, and electronics for signal processing are placed around it. Form the circuit 92 and etch the diaphragm 93 from the bottom surface of the strain gauge 91 It is formed by processing. In these forming processes, diaphragm processing Etching processes are indispensable for forming thin film patterns such as electronic circuits and integrated electronic circuits. Especially when forming a diaphragm by etching a semiconductor substrate, the diaphragm part It is necessary to make the thickness as thin as possible in order to increase the detection sensitivity of the pressure sensor. For this purpose, the etching thickness becomes as large as 300 to 400 μm. Etching The etching technology includes wet etching using a solution and dry etching using gas. There is a Google method. Generally, the former has better material selectivity and processing capacity in terms of etching speed. The equipment is simple and inexpensive, and it is easy to process fine patterns up to about 3 μm. Therefore, unless it is a highly integrated device such as an LSI and requires high-precision etching, An etching method is used.

0004 However, in the high-performance sensors and composite sensors mentioned above, both sides of the semiconductor substrate are Semiconductor substrates are used to form sensing mechanisms and electronic circuits for signal processing units. 9 will be wet-etched separately. In that case forms a protective film to protect areas other than the surface to be etched from the etching solution. It is necessary to do so. Therefore, the treatment process increases in number of steps, becomes more complicated, and takes more time. Not only does it take a lot of time, but it also depends on the type of sensing element and the components of the electronic circuit. Processes include forming a protective film, etching, cleaning, drying, and removing the protective film. Repeated steps may cause changes in material and characteristics, which may adversely affect sensing characteristics. This causes a significant decrease in performance, property stability, and yield.

[0005] For this reason, wet etching is only possible on one side of the semiconductor substrate. A jig is used that completely seals the surface other than the surface to be etched using a seal container etc. There is.

[0006] FIG. 3 shows a conventional wet etching jig for semiconductor substrates. using this method Place the semiconductor substrate 9 on the positioning base 13 of the fixing base 12, and then tighten the tightening cap. Tighten with a pair of screws 14 provided on the inner and outer periphery of each of the fixing base 11 and the fixing base 12. Screw the cap 11 onto the fixing base 12 and press and fix the semiconductor substrate 9 onto the fixing base 12. . O-rings 6 and 7 are attached concentrically to the upper inner surface of the tightening cap 11. each As each O-ring screws in the tightening cap 11, the outer periphery of the upper surface of the fixing base 12 and Press the outer peripheral part of the upper surface of the semiconductor substrate 9 on the positioning pedestal 13, and The outer circumference of the upper surface and the outer circumference of the upper surface of the positioning pedestal 13 are connected to the O-ring 6, the tightening cap 11, The O-ring 7 and the positioning pedestal 13 hermetically seal the bottom surface of the semiconductor substrate 9. be.

[0007] FIG. 4 shows a wet etching experiment using a conventional wet etching jig 30. The application device is shown. Etching the wet etching jig 30 incorporating the semiconductor substrate 9 The entire body is immersed in a Teflon container 21 containing a cleaning solution 22 and placed on a hot plate 24. Etching is performed while controlling the temperature of the etching solution at a constant temperature.

[0008]

[Problem that the idea aims to solve] In the above-mentioned conventional wet etching jig, the semiconductor is placed on the fixed table 12. The body board 9 is rotated and screwed into the fixing base 12 using the screw of the tightening cap 11. , are crimped and held via O-rings 6 and 7. In this way, the outside of the top surface of the semiconductor substrate 9 is Since the periphery and the outer periphery of the upper surface of the fixed base 12 are sealed, the following problems occur. there were. (1) The semiconductor substrate 9 is held and sealed by the tightening cap 1 via the O-rings 6 and 7. Since it is a screw-in type, the O-rings 6 and 7 can be used to optimally adjust the sealing surface. If it is tightened too much, the semiconductor board may crack, and if it is not tightened enough, it may cause a seal failure and cause an edge. The etching solution penetrates into the back surface and etches parts that are not designated for etching, resulting in defects. This can lead to generation and a decrease in yield rate. (2) It is not easy to replace the semiconductor substrate 9. (3) If the tightening cap 11 covers the semiconductor substrate 9 while holding the semiconductor substrate 9 under pressure, The area around the etching solution will be rough and the etching will be uneven and uneven. This occurs easily and the effective area becomes smaller.

[0009]

[Means to solve the problem]

The present invention takes the following measures to solve the above problems. In other words, for semiconductor substrates As an etching jig, it is possible to have a concave surface that is a predetermined amount larger than the shape of the target semiconductor substrate. Both have an inner groove and an outer groove provided at a predetermined interval around the same concave surface. a pedestal having a plurality of intake holes penetrating between the inner groove and the outer groove; An inner O-ring whose lower half is inserted into the inner groove, and an inner O-ring whose lower half is inserted into the outer groove. and means for sucking air from the intake hole.

0010

[Effect]

By the above means, the target semiconductor is placed on the inner and outer O-rings on the concave surface of the pedestal. A body substrate is placed on it. At this time, the stepped portion of the concave surface serves as a guide. Next, the suction means When it is activated and air is sucked from the intake hole, the same side of the semiconductor substrate is sucked and held. At the same time, the back side is sealed. The semiconductor is then immersed in an etching solution. Uniform etching of only the upper surface of the substrate can be easily and efficiently performed.

[0011] In this way, the semiconductor substrate can be easily placed on the concave surface without being subjected to excessive force. Since it is set and held with the back side sealed, there is no damage to the semiconductor substrate. Work efficiency is improved and reliability is also improved.

0012

【Example】

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. In addition, the parts explained in the conventional example will be given the same number and the explanation will be omitted, and the explanation will mainly focus on the parts related to this invention.

[0013] In FIG. 1, a disk-shaped pedestal 4 is provided with a concentric circular concave surface a on its surface. This concave The diameter of the surface a is larger than the diameter of the target semiconductor substrate 9 by a predetermined amount. Also, the stepped part of the concave surface a The corners of are chamfered and serve as positioning guides b. In addition, there are places around the concave surface. An inner groove c and an outer groove d are provided concentrically at a certain interval. Also, these grooves c , d are provided with intake holes e penetrating the back surface at predetermined intervals.

[0014] The back surface of the pedestal 4 has a convex portion corresponding to the concave surface a. Furthermore, this A pedestal 1 having a surface that fits with the back surface is provided.

[0015] An intake groove f of a predetermined width is provided along the stepped portion of the recessed surface of the pedestal 1, and air is taken in from the side wall. Pipe 3 is inserted. The suction pipe 3 is a suction tube 23 as shown in FIG. is connected to the vacuum pump 26 via the pressure gauge 27, trap 25, and pressure regulator 28. I can escape. These are the means of suction.

[0016] The inner groove c and the outer groove d of the pedestal 4 are provided with an inner O-ring 6a and an outer O-ring, respectively. The lower half of 7a is inserted. Also, the back of the pedestal 4 is fitted onto the pedestal and bonded with adhesive g. be done.

[0017] In the above, the target semiconductor substrate 9 is placed on the concave surface a, that is, on the O-rings 6 and 7. be placed on top. At this time, it is easily guided by the position guide b. Next, the vacuum port When the air is sucked by the pump 26, the air between the O-rings 6a and 7a is sucked from the intake hole e. , the back surface of the semiconductor substrate 9 is sealed and held at the outer periphery. received in this way A jig 20 with a substrate 9 set on a table 4 is placed on a hot plate 24. It is also immersed in a Teflon container 21 containing an etching solution.

[0018] In this way, only the upper surface of the semiconductor substrate 9 is etched with the etching solution. In addition, a special etching protective film is applied to the bottom surface formed in the previous process. It is easily protected from the etching solution without forming a groove. However, the components of the jig are The condition for all of these is to select materials that are not attacked by the etching solution.

[0019] In this example, the etching solution contains caustic soda, isopropylene alcohol, Since a mixed solution of pure water is used, the pedestal 1, pedestal 4, and O-rings 6a and 7a are , Teflon material is applied to the pedestal 1 and pedestal 4 with O-ring to prevent them from being corroded by the etching solution. Chloroprene rubber was used for the cleaning. In addition, fluorine-based adhesive was used.

[0020] As described above, place the semiconductor substrate 9 in line with the positioning guide of the pedestal 4 of the jig. Simply connect the suction tube 23 and vacuum pump 26 to the suction pipe 3 and suction. It can be easily and easily adsorbed and held, and it can be placed in a container containing etching solution as it is. Etching can be done quickly on one side only. In addition, the following The effect on the etching process is remarkable, and the etching process in both sides of the semiconductor substrate 9 is improved. In the cutting process, it is possible to greatly simplify the process and improve quality and yield. (1) Since the semiconductor substrate 9 is held by vacuum suction, the holding force can be controlled by the pressure regulating valve 28. This can be easily done using a No cracking or the like of the semiconductor substrate 9 occurs at all. (2) Since the bottom surface of the semiconductor substrate 9 is attracted, the entire top surface can be etched. Therefore, there is no cause for non-uniform etching. (3) Even if a seal failure occurs in the O-ring part, vacuum suction will ensure that the O-rings 6 and 7 are closed. Because the pressure is negative, the etching solution 22 leaks between the two O-rings. The etching axillary that remains and leaks is sucked into the intake groove 2 through the intake hole 5, and the semiconductor substrate is There is no risk of leakage to the entire back surface of the plate 9, and an etching protective film is formed on the back surface. There is no need for a protective film removal process after etching. (4) Therefore, in the protective film formation and removal process, ready-made electronic circuits and There is absolutely no negative impact on the sensing element, such as deterioration or deterioration of materials or properties. There is no need to worry, and processing can be performed efficiently and with high reliability.

[0021]

[Effect of the idea]

As explained above, according to the present invention, the target semiconductor substrate is placed on the concave surface of the pedestal. It is easily set, the back side is sealed with an O-ring, and it is held by suction between the O-rings. Ru. Therefore, since no excessive force is applied, the semiconductor substrate does not crack. Also The back side is double sealed by the inner and outer O-rings, so only the front side is etched uniformly. There is no risk of leakage to the back side. In this way, reliable and efficient You will be able to get good etching work.

[Brief explanation of drawings]

FIG. 1 is a perspective sectional view of an embodiment of the present invention.

FIG. 2 is an overall configuration system diagram of the same embodiment.

FIG. 3 is a perspective sectional view of a conventional example.

FIG. 4 is an overall configuration diagram of the conventional example.

FIG. 5 is an explanatory diagram of the operation of the conventional example.

[Explanation of symbols]

1 Pedestal 2 Intake groove 3 Intake pipe 4 Pedestal 5 Intake holes 6, 6a Inner O-rings 7, 7a Outer O-ring 8 Adhesive 9 Semiconductor substrate 9 ₁ Diffusion strain gauge 9 ₂ Electronic circuit 9 ₃ Diaphragm 11 Tightening cap 12 Fixation Base 13 Positioning base 14 Screw 21 Teflon container 22 Etching liquid 23 Suction tube 24 Hot plate 25 Trap 26 Vacuum pump 27 Pressure gauge 28 Pressure adjustment valve

Claims (1)

[Scope of utility model registration request] Claim 1: A recessed surface having a predetermined amount larger than the shape of the target semiconductor substrate, and an inner groove and an outer groove provided around the recessed surface at a predetermined interval, and the inner groove and the outer groove. a pedestal having a plurality of intake holes penetrating between side grooves; an inner O-ring having a lower half inserted into the inner groove; and an outer O-ring having a lower half inserted into the outer groove;
An etching jig for a semiconductor substrate, comprising means for sucking air from the intake hole.