JPH0685397B2 - Electrode structure for cutting and grooving - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode structure for cutting and grooving in a strain-free precision cutting device utilizing a radical reaction, and more particularly to a silicon and germanium single crystal or gallium-arsenic for semiconductor manufacturing. The present invention relates to an electrode structure for cutting and grooving used for manufacturing a wafer by cutting a compound or the like.

[0002]

2. Description of the Related Art A conventional dicing method using a diamond wheel has been used to cut a silicon single crystal or the like. Since this processing principle utilizes brittle fracture due to fine cracks, there is no crystallographic controllability of the processed surface, and it probabilistically causes extremely deep damage exceeding the finishing processed layer. When a semiconductor element is manufactured using a cut wafer, the yield is low and the electrical performance thereof is deteriorated, which is one of the factors that limit the limit of the degree of integration.

Therefore, the applicant of the present invention, as disclosed in JP-A-1-125829, arranges a workpiece and a wire electrode in an atmosphere gas containing a reaction gas and applies a high frequency voltage to the wire electrode. Then, a radical based on a reaction gas is generated between the workpiece and the electrode, and the volatile substance generated by the radical reaction between the radical and the atom or molecule constituting the workpiece is vaporized, removed, and cut. Proposed.

However, when an expensive silicon single crystal or the like is cut to manufacture a wafer, it is required to make the cutting width as narrow as possible in order to use the material efficiently, and for that purpose, it is as thin as possible. Although the wire electrode must be used, there is a problem in the strength of the wire electrode. That is, a highly corrosive fluorine-based, chlorine-based, or the like is used as the reaction gas, but the wire electrode itself is also consumed by the highly reactive radicals generated around the wire electrode, and if it is a polycrystalline particle There is a problem that the field strength is lowered, the tensile strength of the wire electrode is lowered, and the electrode is cut.

Therefore, the applicants have proposed to use a blade-shaped electrode as an electrode of a strain-free precision cutting device utilizing a radical reaction. If this blade-shaped electrode is used, the cutting width can be narrowed, and even when a corrosive reaction gas is used, the problems of corrosion and strength deterioration of the electrode due to the reaction gas can be solved,
New problems arise such that the holding structure becomes complicated when a large number of blade-shaped electrodes are arranged side by side, and a means for supplying a reaction gas into the narrow working groove is required.

[0006]

SUMMARY OF THE INVENTION In view of the above situation, the present invention aims to solve the problem of the cutting width by using a plurality of blade-shaped electrodes arranged in parallel as electrodes. As a result, the newly created holding structure for a plurality of blade-shaped electrodes is simplified and integrated, enabling mass production of electrodes, and supplying the reaction gas into the machining groove by using a member other than the electrode in the machining groove. The purpose is to be able to do without inserting into.

[0007]

In order to solve the above-mentioned problems, the present invention applies a direct current voltage or an alternating current voltage to an electrode, generates a neutral radical based on a reaction gas by the electric field, and generates the neutral radical. Electrode structure for cutting and grooving in a strain-free precision machining device by vaporizing and removing volatile substances generated by radical reaction between atoms and molecules constituting the machining surface of a workpiece In, the electrode structure for cutting and grooving, in which a plurality of slits are juxtaposed while leaving the surrounding frame body in a flat plate electrode substrate made of a conductive material having corrosion resistance to a reaction gas, and the slits serve as blade electrodes. Made up the body.

Further, a plurality of slits are provided in parallel on the flat plate electrode base made of an insulating material having a corrosion resistance against the reaction gas, leaving the surrounding frame, and the slits serve as a blade-shaped electrode base. A guide groove is formed at the tip of each blade-like electrode base body, the widthwise central portion of the blade-like electrode base, and a frame body continuous with the center portion, and a conductive wire electrode is run along the guide groove to form a blade-like electrode. It is also preferable that

Further, it is preferable that the opening edge of the gas supply chamber is airtightly bonded to the back surface side of the frame body, or a gas supply hole communicating with each slit is formed in the frame body.

[0010]

With the electrode structure for cutting and grooving of the present invention having the above-mentioned contents, when a high-frequency voltage is applied to the flat plate electrode base by a high-frequency power source, an electric field is applied to the edges of the plurality of blade-shaped electrodes integrally formed. Are concentrated and a plasma of an atmospheric gas containing a reaction gas is generated only in the vicinity of this edge, whereby neutral radicals based on the reaction gas are generated only in the vicinity of this edge, and the blade is attached to the workpiece. -Shaped electrodes are made to approach each other in parallel and vaporized to remove volatile substances generated by radical reaction between neutral radicals and atoms or molecules constituting the processed part of the workpiece to be removed from the processed part. Is formed, and the blade-shaped electrode is advanced in accordance with the retreat of the processed portion to cut or groove the workpiece. Further, since the blade-like electrode is formed by arranging a plurality of slits in parallel on the flat plate electrode base, it becomes integral with the surrounding frame body, and the frame body acts as a reinforcing material, The effect is to keep the interval of constant.

Further, a conductive wire electrode is made to run along a guide groove formed at the tip edge of the blade-like electrode base body made of an insulating material, so that the blade-like electrode base body and the wire electrode are formed. The electrode can always be processed by a new and good electrode surface, and is particularly effective when an electrode material highly corrosive to the reaction gas is used.

Further, when the opening edge of the gas supply chamber is airtightly joined to the back surface side of the frame body, the atmosphere gas containing the reaction gas is supplied into the gas supply chamber or the frame body When a gas supply hole communicating with the slit is formed, by supplying an atmosphere gas containing a reaction gas from this gas supply hole, the reaction gas is discharged from the slit between the blade-shaped electrodes during the cutting or grooving process. Etc. can be supplied to the reaction space between the blade-shaped electrode and the processed portion of the workpiece.

[0013]

The present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 shows a typical embodiment of an electrode structure E of the present invention, and FIG. 2 shows a state in which a workpiece W is cut or grooved using the same.

According to the processing principle of the present invention, a DC voltage or an AC voltage is applied to the electrode to form a high electric field between the electrode and the processed portion of the workpiece W, and the reaction gas and the inert gas are supplied to this reaction region. By supplying the atmosphere gas containing the gas, the inert gas is first ionized or excited to be activated, and then inelastically collides with the reaction gas to generate a neutral radical based on the inert gas. The volatile substance generated by the radical reaction with the atoms or molecules that make up the machined surface of the workpiece is vaporized and removed to proceed with the machining.Because cutting or grooving is performed depending on the machining depth. is there.

In the electrode structure E of the present invention, a plurality of slits 3, ... Are arranged side by side in a horizontal direction on a flat plate electrode substrate 1 made of a conductive material having corrosion resistance against a reaction gas, while leaving a surrounding frame body 2. The strip-shaped blade-shaped electrode 4 is provided between the slits 3 and 3. The electrode structure E is manufactured by a precision casting method suitable for mass production. Although it is very expensive, it can be manufactured by electrical discharge machining or the like.

Here, the cross-sectional shape of the blade-shaped electrode 4 is set such that the width in the vertical direction, that is, the depth of the slit 3 is set sufficiently wider than the thickness in the horizontal direction, for example, three times or more. It is also preferable to chamfer the tip end edge of the blade-shaped electrode 4 in an arc shape so that the electric field is not excessively concentrated on the edge portion.

According to the present invention, as shown in FIG. 2, an atmosphere gas containing a reaction gas of 1 atm or more is supplied between the blade electrode 4 and the processing portion 5 of the workpiece W, and the workpiece W is rotated. At the same time, the blade-shaped electrode 4 is approached in parallel with a plane orthogonal to the rotation axis, and a high-frequency voltage is applied to the blade-shaped electrode 4 from a high-frequency power source (not shown). In reality, a voltage is applied to the frame body 2. Then, a neutral radical based on the reaction gas is generated between the blade-shaped electrode 4 and the processing portion 5, and the volatile substance generated by the radical reaction between the neutral radical and the atoms or molecules forming the processing portion 5 is vaporized. , The annular processed groove 6 is removed, and the electrode structure E is further advanced in accordance with the receding of the processed portion 5, and the processed groove 6 is continuously cut in due course, and the workpiece W becomes a silicon single crystal or the like. , The plurality of wafers 7 ... Are cut out at the same time.
Of course, it is also possible to cut the workpiece W without rotating it, and it is also possible to perform grooving similarly to the cutting.

The atmosphere gas facilitates the generation and maintenance of a reaction gas that is a source of neutral radicals and high-pressure plasma.
It is a mixed gas of an inert gas that is activated by colliding with the reaction gas. The combination and mixing ratio of the reaction gas and the inert gas are optimally determined according to the material of the workpiece W and the processing conditions. Here, in order to cut a semiconductor material such as a silicon single crystal, fluorine-based SF ₆ or CF ₄ is used as a reaction gas, and its electrode material is aluminum (Al) which is excellent in corrosion resistance against this reaction gas. ) Is used. He, Ne, Ar or the like is used as the inert gas, and one or a mixture of two or more thereof is used, and an inert gas suitable for the reaction gas (SF ₆ ) used when cutting the silicon single crystal is used. He is used as the active gas. In this case, the volatile substance generated by the radical reaction is SiF ₄ which has the property of sublimation and high vapor pressure. In order to vaporize this volatile substance and proceed with the processing, it is necessary to appropriately heat the components other than those that vaporize at room temperature or lower to increase the vapor pressure and accelerate the vaporization, but the heating temperature is the workpiece W. It is a temperature that does not impair the physical properties of.

Also, chlorine-based Cl ₂ or the like is used as a reaction gas depending on the material of the workpiece W. Therefore, a material having a high corrosion resistance other than Al should be used as an electrode material depending on the reaction gas used. is there. Further, the electrode structure E
Moreover, it is also preferable to coat a material having excellent corrosion resistance against the reaction gas. For example, even when a material that is corrosive to SF ₆ is used, the corrosion problem can be solved by coating and dipping a material having corrosion resistance such as Al ₂ O ₃ or MgF _{2 on the} surface.

The workpiece W to be processed according to the present invention is
A silicon ingot, a germanium single crystal, a gallium-arsenic compound, or other ingot for semiconductor production is mainly used, and a cylindrical ingot is cut into a thin disk shape with a thickness of about 0.5 mm to produce a wafer. When applied in this case, the effect becomes particularly remarkable, but the present invention is not limited to the ingot, but can be widely applied to cutting and grooving difficult-to-process brittle materials such as ceramic materials.

The blade-shaped electrode 4 of the present invention has a thickness of 20.
Since the width of the processed groove 6 formed in the work W is as narrow as about 200 μm, it is set to be very thin, up to 100 μm. It is not possible to supply a necessary amount of atmospheric gas to the processing portion 5 at the bottom through the narrow processing groove 6 only by filling the atmospheric gas. Therefore, in the present invention, gas supply means capable of supplying a required amount of atmospheric gas is provided integrally with the electrode structure E as described below.

In the structure shown in FIG. 3, the open end of a substantially box-shaped gas supply chamber 8 having one side opening on the back side of the flat plate electrode base body 1 is airtightly joined, and The electrode structure E is shown in which a gas supply pipe 9 is connected to an appropriate place of the gas supply chamber 8, for example, the back surface, to integrally provide a gas supply means. Then, the atmospheric gas containing the reaction gas is pressurized and supplied to the gas supply chamber 8 through the gas supply pipe 9,
Atmospheric gas is jetted from the slits 3, ..., For example, the processing groove 6 of the workpiece W is processed even during the processing shown in FIG.
It is possible to supply a necessary amount of reaction gas or the like to the processing section 5 through the. Moreover, since the atmospheric gas temporarily stays in the gas supply chamber 8, it can be uniformly supplied to each processing unit 5. The gas supply chamber 8 is made of a conductive material, and a voltage is applied to the blade electrode 4 by connecting a high voltage power source to the gas supply chamber 8.

Further, what is shown in FIG. 4 is the frame bodies 2 and 2 of the plate electrode base body 1 facing each other, which communicate with the frame bodies 2 corresponding to both ends of each slit 3, respectively. The electrode structure E in which the gas supply holes 10, ... Are formed is shown. In this case, although not shown, a channel-shaped member having a U-shaped cross section or the like is attached in an airtight state to the outer surface of the frame body 2 in which the gas supply holes 10 are formed, or a flexible tube for gas supply is provided in each gas supply hole 10. Shall be connected. Then, the atmospheric gas containing the reaction gas supplied through this member is supplied into the slits 3, ... Through the gas supply holes 10, ..., Thus, a necessary amount of the reaction gas or the like is supplied to the processing section 5.

Further, in the structure shown in FIGS. 5 and 6, a plurality of slits are left on the plate electrode base 1 made of an insulating material such as ceramics having a corrosion resistance against the reaction gas, leaving the surrounding frame 2 in the same manner as described above. 3, ... are arranged side by side in the lateral direction to form a strip-shaped blade-shaped electrode base 11 between the slits 3, 3 and the tip end edge of the blade-shaped electrode base 11 is continuous with the central portion of its width. 2 shows an electrode structure E in which a guide groove 12 is formed in the frame bodies 2 and 2 and a conductive wire electrode 13 is made to travel along the guide groove 12. That is, the blade-shaped electrode substrate 11 and the wire electrode 13
And constitute a blade-shaped electrode 4 similar to the above.
Here, the wire electrodes 13 are supplied by guide pulleys 15 and 16 of a feeding device 14 having a supply drum and a winding drum, respectively, so that a new electrode surface is always located at the tip of the blade-shaped electrode base 11. To be done. The structure shown here has the same structure as the gas supply chamber 8 or the gas supply hole 1 described above.
Of course, it is also possible to construct the electrode structure E in which the gas supply means are integrally provided by arranging 0s in parallel.

FIG. 7 shows a modification of the electrode structure E having the gas supply holes 10, ... Shown in FIG. 4, in which the tip of the blade electrode 4 is retracted from the frame 2, that is, The width of the blade-shaped electrode 4 is set narrower than the width of the frame body 2,
Then, on the opposite side surfaces of the frame body 2 closer to the processed portion 5 than the tip edge of the blade-shaped electrode 4, and not on the frame body 2 portion reaching the end of the slit 3, the vicinity of both end edges of the blade-shaped electrode 4 is the same as above. The gas supply holes 10, ... Are formed.
It should be noted that, similarly to the above, a channel-shaped member (not shown) is attached in an airtight state or a flexible tube is connected to the outer surface of the frame body 2. In this case, the reaction gas or the like can be supplied from a position closer to the processing unit 5 than that shown in FIG.

[0026]

The cutting and grooving electrode structure of the present invention as described above has the following effects. First, according to claim 1, the blade-shaped electrode is integrated with the frame body around the blade-shaped electrode, and the frame body serves as a reinforcing member to facilitate the handling of the thin blade-shaped electrode. The interval can be kept constant.
Further, the electrode structure having this structure can be mass-produced by the precision casting method and can be supplied at a low cost. Furthermore,
Since there is a frame around the blade-shaped electrode, by supplying an atmosphere gas containing a reaction gas into this frame, diffusion to the outside can be suppressed and the reaction gas etc. can be efficiently supplied to the processed part of the workpiece. Can supply well.

Further, according to the second aspect, the durability of the electrode structure can be improved, and the processing can be always advanced by the electrode surface in a new and good state. Particularly, a highly corrosive reaction gas can be generated. It is effective when used.

Further, according to the third aspect, the reaction gas and the like can be sufficiently supplied to the processing portion at the bottom of the narrow processing groove of the workpiece even while the cutting processing is in progress.
Since the reaction gas etc. is temporarily retained in the gas supply chamber,
The amount of gas supplied from each slit is uniform.

Further, according to the fourth aspect, the reaction gas or the like can be sufficiently supplied to the processing portion at the bottom of the narrow processing groove of the workpiece even while the cutting processing is in progress, and the gas supply is compact. It can be a means.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing a first embodiment of an electrode structure of the present invention.

FIG. 2 is a sectional view of an essential part showing a state of similarly cutting or grooving a workpiece using the electrode structure.

FIG. 3 is a perspective view of essential parts showing a second embodiment of the electrode structure according to the present invention.

FIG. 4 is a partially omitted perspective view showing a third embodiment of the electrode structure of the present invention.

FIG. 5 is a sectional view of an essential part showing a fourth embodiment of the electrode structure of the present invention.

FIG. 6 is an overall perspective view of the electrode structure of the fourth embodiment with a part omitted.

FIG. 7 is a partially omitted perspective view showing a modified example of the electrode structure shown in FIG.

[Explanation of symbols]

 E Electrode Structure W Workpiece 1 Flat plate electrode base 2 Frame 3 Slit 4 Blade electrode 5 Machining part 6 Processing groove 7 Wafer 8 Gas supply chamber 9 Gas supply pipe 10 Gas supply hole 11 Blade electrode base 12 Guide groove 13 Wire electrode 14 Feeder 15 Guide pulley 16 Guide pulley

Claims (4)

[Claims] 1. A direct current voltage or an alternating current voltage is applied to an electrode, a neutral radical based on a reaction gas is generated by the electric field, and the neutral radical is a radical with an atom or a molecule constituting a processing surface of a workpiece. A plate electrode made of a conductive material having corrosion resistance to a reaction gas in an electrode structure for cutting and grooving in a strain-free precision machining device in which a volatile substance generated by a reaction is vaporized and removed to proceed with machining. An electrode structure for cutting and grooving, characterized in that a plurality of slits are provided side by side on a substrate, leaving a peripheral frame body, and the slits serve as blade-shaped electrodes. 2. A flat plate electrode base made of an insulating material having a corrosion resistance to a reaction gas, and a plurality of slits are arranged in parallel with each other while leaving a surrounding frame, and the slits serve as a blade-shaped electrode base. A guide groove is formed at the tip of each blade-like electrode base body, the widthwise central portion of the blade-like electrode base, and a frame body continuous with the center portion, and a conductive wire electrode is run along the guide groove to form a blade-like electrode. An electrode structure for cutting and grooving characterized by being formed. 3. The cutting and grooving electrode structure according to claim 1, wherein an opening edge of the gas supply chamber is airtightly joined to the back surface side of the frame body. 4. The cutting and grooving electrode structure according to claim 1 or 2, wherein gas supply holes communicating with each slit are formed in the frame body.