JP2003031819A - Method for manufacturing semiconductor part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve production yield by protecting normal semiconductor parts, when semiconductor parts are partially damaged in etching a silicone wafer. SOLUTION: The bending detection elements and wiring parts of respective pressure sensors are formed on the side of the front surface of a silicone wafer 11, and a recess groove for a diaphragm part is formed by etching. Then, when etching is given to the recess groove, a seal material 12 consisting of resin material, etc., is placed on the side of the front surface of the silicon wafer 11, and the seal material 12 is pressed toward the silicon wafer 11 by using compression air. In this state where the side of the front surface is sealed with a seal ring 14, etc., etching reagent is made into contact with the side of a rear surface. Thus, even when the diaphragms of the pressure sensors are partially damaged, it is possible to prevent the other normal pressure sensors prevented from being damaged by the etching reagent infiltrating to the side of the front surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a pressure sensor by etching a silicon wafer.
The present invention relates to a semiconductor component manufacturing method suitable for manufacturing semiconductor components such as a flow rate / flow velocity sensor.

[0002]

2. Description of the Related Art Generally, when manufacturing semiconductor parts such as a pressure sensor and a flow rate / flow velocity sensor, a method of manufacturing a plurality of semiconductor parts by etching a single silicon wafer is used.

A pressure sensor manufactured by using this type of conventional technique has a substrate made of a part of a silicon wafer, a thin diaphragm portion provided on the front surface side of the substrate, and a thin-walled diaphragm portion located on the diaphragm portion. And a deflection detecting element such as a piezoresistor provided on the front surface side of the substrate.

Here, the diaphragm portion is formed by etching the back surface of the substrate to form a groove.
The surface layer portion of the substrate is located on the bottom surface side of the groove. In addition, a wiring portion made of a metal film such as aluminum is provided on the front surface side of the substrate, and one end side of this wiring portion is connected to the bending detection element and the other end side serves as an electrode pad for external connection. There is.

In the pressure sensor, when the diaphragm portion is flexibly deformed by applying a pressure difference such as air pressure or hydraulic pressure to both sides of the diaphragm portion, a detection signal corresponding to the flexural deformation amount is output from the flexure detecting element to the wiring portion. Is output to the outside via.

[0006] In manufacturing the pressure sensor, for example, 3
A method is used in which a large number of pressure sensors of about 00 to 400 are formed on a single silicon wafer and then the silicon wafer is separated into individual pressure sensors.

At the time of forming each pressure sensor, for example, by using a method such as an ion implantation method, a sputtering method, a CVD method or an etching process, the deflection detecting element and the wiring portion of each pressure sensor are first formed on the front surface side of the silicon wafer. To form.

Next, the front side of the silicon wafer is hermetically sealed by using, for example, a jig for etching, and the back side of the silicon wafer is dipped in an etching solution such as KOH or hydrazine in this state so that only the back side is formed. Etching is performed to form the concave groove (diaphragm portion) of each pressure sensor.

In this case, there is also used a method in which a single coating member or the like for covering the entire surface of the silicon wafer is formed in advance during the etching process, and the front surface side is sealed from the etching solution by the coating member.

[0010]

By the way, in manufacturing the pressure sensor according to the above-mentioned prior art, the front surface side of the silicon wafer is sealed and only the back surface side is dipped in the etching solution, so that the deflection detecting element on the front surface side is formed. The wiring part and the wiring part are protected from the etching solution, and the concave groove is etched on the back surface side.

However, the diaphragm portion of the pressure sensor is
For example, since it is often a thin portion having a thickness of about 10 to 100 μm, during the etching processing of the concave groove, for example, cracks or the like may occur in the diaphragm portion of some pressure sensors due to poor quality of the silicon wafer or dimensional variation of groove depth. May be damaged.

When the etching process is continued in this state, the etching solution permeates from the back surface side of the silicon wafer to the front surface side through cracks in the diaphragm, etc., and the etching solution is applied between the front surface of the silicon wafer and the coating member. It may spread to the surroundings through a slight gap formed in the.

Therefore, in the prior art, when a large number of pressure sensors are manufactured using a silicon wafer, it is assumed that
Even if only one diaphragm part is damaged, the bending detection elements of other normal pressure sensors located around it and the electrode pads of the wiring part are eroded by the etching solution, and many pressure sensors cannot be used. Therefore, there is a problem that the yield is reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to efficiently form a plurality of semiconductor components on a silicon wafer, and temporarily store some semiconductor components during manufacturing. Another object of the present invention is to provide a semiconductor component manufacturing method capable of protecting other semiconductor components even when they are damaged and improving the yield.

[0015]

In order to solve the above-mentioned problems, the present invention provides a plurality of circuit elements on the front surface side of a silicon wafer, and performs etching processing on the back surface side of the silicon wafer to form each circuit element. It is applied to a method of manufacturing a semiconductor component in which a groove is formed at a corresponding position.

A feature of the method adopted by the invention of claim 1 is that a protective film for covering substantially the entire surface of the silicon wafer is provided in advance, and the silicon is applied in a state where the protective film is pressed toward the silicon wafer. The groove is formed on the back surface of the wafer by etching.

According to this structure, even if the surface side portion of the silicon wafer located on the bottom side of the groove is damaged at the position of some circuit elements during the etching process of the groove, By pressing the protective film toward the silicon wafer, the silicon wafer and the protective film can be adhered to each other without a gap. Therefore, the protective film can prevent the etching solution or the like from entering the surface side of the silicon wafer from the damaged portion, and the other normal circuit elements can be protected from the etching solution or the like by the protective film provided on each circuit element. can do.

According to a second aspect of the present invention, the surface side of the silicon wafer is filled with a pressurized gas to press the protective film.

As a result, for example, in a state where the silicon wafer is housed in a closed container, the surface side of the silicon wafer is filled with a pressurized gas to keep the surface side of the protective film in a positive pressure state and the protective film. Can be pressed against the silicon wafer.

According to the third aspect of the present invention, the surface of the silicon wafer is filled with a pressurized liquid or fluid to press the protective film.

Thus, for example, while the silicon wafer is housed in the closed container, the surface side of the silicon wafer is filled with the pressurized liquid or fluid to keep the surface side of the protective film in a positive pressure state. The protective film can be pressed against the silicon wafer.

According to a fourth aspect of the invention, the protective film is formed of a sealing material made of a resin material, and the sealing material is pressed and fixed on the front surface side of the silicon wafer.

With this, by reducing the pressure applied to the sealing material after forming the groove, the sealing material can be easily separated from the silicon wafer.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a case where a diaphragm type pressure sensor is manufactured using a method for manufacturing a semiconductor component according to an embodiment of the present invention will be described as an example with reference to the accompanying drawings.

Reference numeral 1 denotes a pressure sensor as a semiconductor component manufactured by using a silicon wafer 11 described later. The pressure sensor 1 is a silicon wafer 1 as shown in FIGS.
Square silicon substrate 2 formed by a part of 1
A thin-walled diaphragm portion 3 provided at the center of the front surface side of the silicon substrate 2 and a circuit provided on the front surface side of the silicon substrate 2 and formed on the diaphragm portion 3 by a piezoresistor or the like. The deflection detecting element 4 as an element and a wiring portion 5 formed of a metal material such as aluminum and provided on the front surface side of the silicon substrate 2 are included.

Here, the substrate 2 is formed as a base material portion 2A formed as a p-type silicon material by adding boron or the like and an n-type silicon layer by adding phosphorus or the like, It is composed of an element processing portion 2B provided on the front surface side of the base material portion 2A. The diaphragm portion 3 is etched from the back surface side of the silicon substrate 2 to form a substantially pyramidal groove 6 in the base material portion 2A.
By forming a part of the element processing portion 2B, the bending detection element 4 is embedded in the element processing portion 2B at this position.

The wiring portion 5 is made of, for example, silicon oxide,
It is formed on the front surface side of the silicon substrate 2 through an insulating film 7 made of silicon nitride or the like, and one end side thereof is connected to the deflection detecting element 4 through a through hole 7A provided in the insulating film 7 and the other end side thereof is formed. Is provided with an electrode pad 5A connected to the outside by means such as wire bonding.

Further, on the surface side of the silicon substrate 2, a protective insulating film 8 for covering the deflection detecting element 4 and the wiring portion 5 is provided on the entire surface by using, for example, silicon oxide, silicon nitride, etc. The film 8 has an electrode pad 5 of each wiring portion 5.
Electrode extraction holes 8A, 8A for exposing A to the outside are formed. Further, another insulating film 9 having an opening 9A for etching is also formed on the back surface side of the silicon substrate 2.

The pressure sensor 1 used in the present embodiment is constructed in this way. However, in the pressure sensor 1, when a pressure difference occurs on both sides of the silicon substrate 2 due to, for example, air pressure, hydraulic pressure, etc. It is flexibly deformed, and a detection signal corresponding to the flexural deformation amount is output from the flexure detection element 4 to each wiring portion 5.
Is output to the outside via.

Next, the pressure sensor 1 used in this embodiment.
The manufacturing method will be described with reference to FIGS.

Here, 11 is a silicon wafer prepared in advance for manufacturing a large number of pressure sensors 1, and the silicon wafer 11 is formed of, for example, a single crystal silicon material in a substantially disc shape. Also, the silicon wafer 1
1 is a base material portion 11A made of, for example, p-type silicon material
And an element processing portion 11B provided on the front surface side of the base material portion 11A and formed of an n-type silicon layer,
For example, each silicon substrate 2 is formed by cutting along the imaginary line shown in FIG.

In the element forming step shown in FIG. 5, a mask (not shown) such as a resist film or an insulating film is used, and a predetermined portion corresponding to each pressure sensor 1 of the element processing portion 11B of the silicon wafer 11 is used. Ion implantation of boron or the like is performed on the region of (1) to form a plurality of bending detection elements 4 made of a piezoresistor in the element processing portion 11B.

As a result, a large number of, for example, about 300 to 400 deflection detecting elements 4 are formed on the silicon wafer 11 at predetermined positions, so that means such as a thermal oxidation method or a CVD method is provided on the surface side. The insulating film 7 is formed by using this, and the insulating film 9 is also formed on the back surface side. Further, the insulating film 7 is subjected to etching processing to form a through hole 7A.

Next, in the electrode forming step shown in FIG. 6, a metal film of aluminum or the like is formed on the insulating film 7 by using, for example, a sputtering method, a CVD method or the like, and the metal film is subjected to etching processing. The wiring portion 5 of each pressure sensor 1 is formed. Then, after forming the insulating film 8 that covers the deflection detecting element 4 and the wiring portion 5 of each pressure sensor 1 by using a method such as the CVD method, the insulating film 8 is etched to form the electrode extraction hole 8A. Then, the electrode pads 5A of each wiring part 5 are exposed.

Next, in the protective film mounting step shown in FIG. 7, the sealing material 12 as a thin protective film is mounted on the surface side of the silicon wafer 11. Here, the sealing material 12 is formed of a resin material such as tetrafluoride resin into a thin film sheet having a thickness of about 0.40 mm so that it can be adhered to the surface of the silicon wafer 11. In addition to having elasticity, it does not permeate gas such as air and has resistance to etching liquid. Also,
The sealing material 12 is detachably mounted on the front surface side of the silicon wafer 11 without using an adhesive or the like.

Next, in the pressing step shown in FIG. 8, for example, the silicon wafer 11 and the sealing material 12 are placed in a box-shaped jig 13.
Are housed together and the surface side of the silicon wafer 11 is filled with pressurized air.

In this case, first, the insulating film 9 on the back surface side is etched to form openings 9A (see FIG. 9) at predetermined positions corresponding to the respective pressure sensors 1. Then, the silicon wafer 11 is housed in the jig 13, and the front side of the silicon wafer 11 is hermetically sealed using the seal rings 14, 14 and the like provided in the jig 13. In this state, for example, 0.012 MPa (≈0.12 kgf / cm) is applied to the surface side of the silicon wafer 11 through the passage 13A of the jig 13.
² ) Fill it with air that has been pressurized to a certain degree. That is, the sealing material 1
In order to keep the surface side of 2 at the positive pressure state, pressurized air is supplied through the passage 13A in the direction of the arrow in FIG. After that, the end of the passage 13A is closed to seal the pressurized air. As a result, the sealing material 12 is pressed against the silicon wafer 11, deforms along the irregularities on the surface of the silicon wafer 11, and is fixed in a close contact state.
Note that, instead of air, another gas may be pressurized and filled.

Next, in the groove forming step shown in FIG. 9, after the sealing material 12 is brought into close contact with the silicon wafer 11 by the pressurized air, the sealing ring 14 provided in the jig 13 is
In the state where the front surface side of the silicon wafer 11 is hermetically sealed by using, for example, 14
Etching solution such as OH and hydrazine is used for silicon wafer 1
Contact only the back side of 1.

As a result, the base material portion 11A of the silicon wafer 11 is anisotropically etched along the specific crystal plane of the single crystal silicon by using the insulating film 9 as a mask, and the pressure sensor 1 of each pressure sensor 1 is processed. Recessed grooves 6 are formed respectively. As a result, in the element processing part 11B of the silicon wafer 11,
A thin diaphragm portion 3 is formed at a predetermined position corresponding to each bending detection element 4 and the like.

Next, in the protective film removing step shown in FIG.
The pressurized air sealed on the front surface side of the silicon wafer 11 is released, and the silicon wafer 11 and the sealing material 12 are taken out from the jig 13. At this time, since the sealing material 12 is adhered and fixed to the surface of the silicon wafer 11 by the back pressure of air without using an adhesive or the like, it is easily peeled off and removed from the silicon wafer 11 by removing the pressurized air. can do. And finally, the silicon wafer 11
Is cut at each position indicated by the alternate long and short dash line in FIG. 10, and each pressure sensor 1 is separated for each silicon substrate 2.

Thus, in this embodiment, before the back surface side of the silicon wafer 11 is etched, the back surface side of the silicon wafer 11 is etched while the sealing material 12 is pressed against the front surface side of the silicon wafer 11. To form the diaphragm portion 3.

As a result, during the etching process on the back surface side, even if the diaphragm portion 3 of some of the pressure sensors 1 is damaged, such as cracks, the sealing material 1
Since 2 is in close contact with the silicon wafer 11 due to the back pressure, this damaged portion can be sealed with the sealing material 12,
It is possible to prevent the etching solution from penetrating from the back surface side of the silicon wafer 11 to the front surface side through the damaged portion of the diaphragm portion 3. As a result, even if one pressure sensor 1 is damaged, another normal pressure sensor 1 can be protected against the etching liquid penetrating from the damaged portion, and a large number of single silicon wafers 11 can be used. The pressure sensor 1 can be manufactured efficiently, and its damage can be minimized to improve the yield.

Further, since the sealing material 12 is pressed by filling the surface side of the silicon wafer 11 with pressurized air, the sealing is performed by supplying pressurized air to the surface side of the silicon wafer 11. The material 12 can be evenly pressed onto the silicon wafer 11 over the entire surface, and can be adhered to the silicon wafer 11 without any gap.

Further, since the sealing material 12 made of tetrafluoride resin or the like is pressed and fixed on the surface side of the silicon wafer 11, the sealing material 12 is fixed by the pressure of air without using an adhesive or the like. it can. Further, since the sealing material 12 can be easily peeled off by lowering the pressure of the pressurized air, the sealing material 12 can be compared with the case where a resist film or the like is applied on the surface side of the silicon wafer 11.
It is possible to reduce the man-hours and time required for the removal, and improve the productivity. Further, since the sealing material 12 can be used repeatedly, the cost required for sealing can be reduced.

In the above embodiment, as a method of filling the jig 13 with the pressurized air, other than the method of supplying the pressurized air by a pump or the like in advance, for example, the jig 1 is used.
A method may be used in which the jig 13 and the like are heated and air is pressurized after the air is hermetically sealed in the chamber 3.

Further, in the above-described embodiment, the sealing material 12 is pressed by filling the jig 13 with the pressurized air, but as compared with the modification shown in FIG. A fluid 15 such as a gel that is not easily deformed may be enclosed in a pressurized state to press the sealing material 12, or a pressurized liquid may be filled. In this case, since the fluid 15 and the like can be easily sealed (sealed), the pressure can be easily maintained and etching can be performed even if a crack or the like occurs in the sealing material 12 as compared with the case where a pressurized gas is used. No bubbles are generated in the liquid, it is possible to prevent defects in etching processing and improve reliability and productivity.

Further, in the above embodiment, the sealing material 12 made of a resin material is used as the protective film, but the present invention is not limited to this, and a resist may be used as the protective film. In this case, the resist is removed from the silicon wafer by using a release agent or the like after the etching process is completed.

Further, in the embodiment, the case where the pressure sensor is manufactured as the semiconductor component is described as an example, but the present invention is not limited to this, and the circuit element made of a temperature sensitive resistor such as platinum is used as the substrate. It may be applied to the case of manufacturing a flow rate / flow rate sensor which is formed on the diaphragm provided in the above and is configured to detect the flow rate or flow rate of the fluid by this circuit element.

[0049]

As described above in detail, according to the invention of claim 1, a protective film is provided in advance on the surface side of the silicon wafer to cover substantially the entire surface, and the protective film is pressed toward the silicon wafer. Since the groove is formed on the back surface side of the silicon wafer by etching, the surface side of the silicon wafer located on the bottom side of the groove at the position of some circuit elements during the etching processing of the groove. Even if the portion is damaged, the silicon wafer and the protective film can be adhered to each other without a gap by pressing the protective film toward the silicon wafer. For this reason, the protective film can prevent the etching solution and the like from invading the surface side of the silicon wafer from the damaged portion, and a large number of circuit elements can be efficiently manufactured using a single silicon wafer, and the damage can be minimized. The yield can be improved by suppressing

According to the second aspect of the present invention, since the protective film is pressed by filling the surface side of the silicon wafer with the pressurized gas, the entire surface of the protective film is pressed by the pressurized gas. It can be pressed evenly, and the protective film can be adhered to the silicon wafer without any gap.

According to the third aspect of the invention, since the protective film is pressed by filling the surface side of the silicon wafer with the pressurized liquid or fluid, compared with the case of using the pressurized gas. As a result, the pressure can be easily maintained, and even if a crack or the like occurs in the sealing material, bubbles are not generated in the etching solution, so that etching defects can be prevented and reliability and productivity can be improved.

According to the fourth aspect of the present invention, the protective film is formed of the sealing material made of the resin material, and the sealing material is pressed and fixed on the front surface side of the silicon wafer. The sealing material can be fixed to the silicon wafer without using it, and the sealing material can be easily peeled from the silicon wafer by lowering the pressure applied to the sealing material after forming the groove. Therefore, the time and man-hours required for removing the sealing material can be reduced, and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view of a pressure sensor applied to an embodiment.

FIG. 2 is a plan view of a pressure sensor applied to the embodiment.

3 is a vertical cross-sectional view of the pressure sensor as seen from the direction of arrows III-III in FIG.

FIG. 4 is a perspective view of a silicon wafer used in the manufacturing method according to the embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing a state in which a bending detection element of each pressure sensor is formed on the front surface side of a silicon wafer.

FIG. 6 is a vertical cross-sectional view showing a state in which a wiring portion of each pressure sensor is formed.

FIG. 7 is a vertical cross-sectional view showing a state in which a sealing material is placed on the front surface side of a silicon wafer.

[FIG. 8] A silicon wafer and a sealing material are housed in a jig,
It is sectional drawing which shows the state which pressed the sealing material toward the silicon wafer using pressurized air.

FIG. 9 is a vertical cross-sectional view of the silicon wafer showing an enlarged part a in FIG. 8 in a state where the back surface side of the silicon wafer is etched.

FIG. 10 is a vertical cross-sectional view of a silicon wafer showing a state in which a protective film is removed after etching processing.

FIG. 11 shows, as a modification of the present invention, a state in which a sealing material is pressed against a silicon wafer using a fluid.
It is a sectional view similar to FIG.

[Explanation of symbols]

1 Pressure sensor (semiconductor component) 4 Deflection detection element (circuit element) 6 groove 11 Silicon wafer 12 Seal material (protective film) 15 Fluid

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F055 AA39 BB20 CC02 DD05 EE13                       FF43 GG01                 4M112 AA01 BA01 CA01 CA03 CA04                       CA06 CA08 CA11 CA13 DA06                       DA10 DA11 EA03 EA06 EA07                       EA10 EA11

Claims (4)

[Claims] 1. Manufacturing of a semiconductor component in which a plurality of circuit elements are provided on the front surface side of a silicon wafer, and etching processing is performed on the back surface side of the silicon wafer to form concave grooves at positions corresponding to the respective circuit elements. In the method, a protective film covering substantially the entire surface of the silicon wafer is provided in advance, and the groove is formed on the back surface of the silicon wafer by etching while the protective film is pressed against the silicon wafer. Manufacturing method of semiconductor component. 2. The method of manufacturing a semiconductor component according to claim 1, wherein the surface side of the silicon wafer is filled with a pressurized gas to press the protective film. 3. The method of manufacturing a semiconductor component according to claim 1, wherein the surface side of the silicon wafer is filled with a pressurized liquid or fluid to press the protective film. 4. The structure according to claim 1, wherein the protective film is formed of a sealing material made of a resin material, and the sealing material is pressed and fixed on the front surface side of the silicon wafer.
Alternatively, the method for manufacturing a semiconductor component as described in 3 above.