JP2005207880A - Electron beam device which modifies property of sample and method for manufacturing device by using such electron beam device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron beam device which can irradiate a sample with a low-energy electron beam in an electron beam device for irradiating a low-permittivity material with an electron beam to anneal or harden it and a method for manufacturing a device by using the electron beam device. <P>SOLUTION: In the electron beam device where the sample 3 is irradiated with an electron beam emitted from an electron gun 11 to modify a material property 2 on the surface of the sample 3, the electron gun 11 is located in a position which cannot be seen directly from the sample 3 and the electron beam emitted from the electron gun 11 is deflected by a deflection means 13 and is incident on the surface of the sample 3. The electron gun 11 is located so as to form a prescribed angle between its optical axis and the normal 4 of the sample 3, and deflection means 16 and 17 deflect the electron beam so as to irradiate the surface of the sample 3 with the electron beam of a uniform irradiation dose. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electron beam apparatus for performing annealing or curing by irradiating a low dielectric constant material with an electron beam and a device manufacturing method using the electron beam apparatus.

  In order to anneal an organic low dielectric constant material, conventionally, a method using heating, a method using ultraviolet irradiation, or a method using an electron beam irradiation apparatus with a window has been used. However, heating requires a long time to process one wafer, and even if ultraviolet irradiation is performed, there is a problem that a long time is required to process one wafer because the output of the irradiation apparatus is small. . In addition, when using an electron beam apparatus with a window, it is necessary to use a high energy beam so that the electron beam can pass through the window. However, when the electron beam has a high energy, most of it passes through the material. There was a problem that it was inefficient.

  The present invention has been proposed to solve the above-described problems. The present invention relates to an electron beam apparatus that can be annealed or cured by irradiating a low energy electron beam in a vacuum, and the electron beam. An object of the present invention is to provide a device manufacturing method using the apparatus.

In order to achieve the above object, the invention of claim 1
In an electron beam apparatus that irradiates a sample with an electron beam emitted from an electron gun and changes the material of the surface of the sample,
The electron gun is disposed at a position where it cannot be directly viewed from the sample;
An electron beam apparatus comprising deflection means for deflecting an electron beam emitted from the electron gun so as to enter the surface of the sample;
I will provide a.

  According to a second aspect of the present invention, the electron gun is arranged so that an optical axis of the electron gun and a normal line of the sample form a predetermined angle, and the deflecting unit moves the electron beam along the optical axis. It is characterized by operating to deflect in a direction along the normal from the direction.

The invention of claim 3 is characterized in that the deflecting means further includes a deflector for deflecting the electron beam so as to uniformly irradiate the surface of the sample.
The invention of claim 4 further includes an aperture plate disposed in the vicinity of the deflector and having a small aperture for allowing the electron beam to pass therethrough.

The invention of claim 5 includes (1) a step of applying a dielectric material to a substrate, (2) a step of loading the substrate coated with the dielectric material into a sample chamber, and (3) claims 1-4. Irradiating the dielectric material with an electron beam using the electron beam apparatus according to any one of
A device manufacturing method is provided.

FIG. 1 is a diagram schematically showing a configuration in one embodiment of an electron beam apparatus according to the present invention. In the figure, a wafer 3 having a surface coated with a low dielectric constant layer 2 having a dielectric constant in the range of 1.5 to 3 is placed on a stage (not shown) provided at the bottom of the sample chamber 1. Is placed. The material of the wafer 3 is, for example, Si. The low dielectric constant layer 2 on the surface of the wafer 3 is irradiated with an electron beam traveling in the direction of the normal 4 of the wafer 3. The energy of this electron beam is 2 to 10 keV. For this purpose, the sample chamber 1 is mounted with a cylindrical body 5 having a cylindrical portion 51 and a truncated cone portion 52 which is continuous with the cylindrical portion 51 and whose diameter decreases toward the upper end. The inside of the cylinder 5 is kept in a vacuum. An electron gun chamber 6 is provided in the upper part of the truncated cone part 52 of the cylindrical body 5. A cathode 7 made of LaB ₆ , a carbon heater 8 for heating the cathode, a Wehnelt electrode 9 and an anode electrode 10 are contained therein. An electron gun 11 is provided. The inside of the electron gun chamber 6 is evacuated by an ion pump and kept at a high vacuum. Thereby, the cathode 7 made of LaB ₆ can be maintained in a long life.

  The electron gun 11 is provided such that its optical axis 12 is inclined at a predetermined angle, for example, 15 degrees with respect to the normal 4 of the wafer 3. In order to irradiate the wafer 3 with the electron beam emitted from the electron gun 11, an electromagnetic deflector 13 is disposed in front of the electron gun 11, and the electron beam emitted from the electron gun 11 is transmitted by the electromagnetic deflector 13. The traveling direction is deflected by a predetermined angle and proceeds parallel to the normal 4. The electromagnetic deflector 13 includes, for example, a permanent magnet and a coil for adjusting the deflection amount. The angle formed between the optical axis 12 and the normal 4 of the wafer 3 may be any value within the range of 5 degrees to 45 degrees.

  An opening plate 14 is disposed at a position connecting the electron gun chamber 6 and the truncated cone portion 52, and the opening plate 15 has a small opening 15 at the center thereof. Therefore, the electron beam whose traveling direction is changed by the electromagnetic deflector 13 passes through the small opening 15 of the aperture plate 14, enters the truncated cone portion 52, and travels toward the wafer 3. The aperture plate 14 is provided in order to prevent unnecessary substances such as gas emitted from the wafer 3 from entering the electron gun chamber 6. For example, most of the positive ions emitted from the wafer 3 by the irradiation of the electron beam. Is blocked by the aperture plate 14 and cannot enter the electron gun chamber 6. Even if it enters, the positive ions are not bent by the electromagnetic deflector 13, so that the cathode 7 is not damaged and the cathode 7 is deteriorated. Can be prevented.

  The first deflector 16 is disposed outside the upper end of the truncated cone portion 52 so as to surround the aperture plate 14, and a portion of the truncated cone portion 52 surrounded by the first deflector 16 and the vicinity thereof are thin made of Ti. Made of walls. As a result, the first deflector 16 can form a high-frequency deflection magnetic field in the vicinity of the inside of the upper end of the truncated cone portion 52. The second deflector 17 is disposed outside the lower portion of the cylindrical portion 51 at the upper position of the wafer 3, and the portion surrounded by the second deflector 17 of the cylindrical portion 51 and the vicinity thereof are also thin walls made of Ti. Made. Thus, the second deflector 17 can form a high-frequency deflection magnetic field inside the cylindrical portion 51. As a result, the electron beam that has passed through the aperture plate 14 draws a spiral with a constant width and a constant scanning speed by the cooperative action of the first deflector 16 and the second deflector 17. The wafer 3 is irradiated with a uniform dose within the range indicated by the alternate long and short dash line, and the wafer 3 is irradiated with a uniform and appropriate dose on the low dielectric constant layer 2 covering the surface of the wafer 3. Thus, since the low dielectric constant layer 2 is irradiated with an electron beam having a uniform and appropriate intensity, the low dielectric constant layer 2 can be annealed or cured.

  Further, when a ferromagnetic core 53 and an excitation coil 54 that constitute an electromagnetic lens are provided outside the apparatus so as to surround the truncated cone portion 52, and the beam diameter on the wafer 3 is controlled to a predetermined value, the wafer It is convenient to irradiate the surface with a uniform dose.

The electron beam apparatus according to the present invention described above with reference to FIG. 1 is applied in the annealing step in the semiconductor device manufacturing method shown in FIGS.
FIG. 2 is a flowchart showing an example of a semiconductor device manufacturing method. This manufacturing method includes the following main steps.
(1) Wafer manufacturing process for manufacturing a wafer (or wafer preparation process for preparing a wafer) S1
(2) Mask manufacturing process for manufacturing a mask used for exposure (or mask preparation process for preparing a mask) S2
(3) Wafer processing step S3 for performing necessary processing on the wafer
(4) Chip assembly process S4 for cutting out chips formed on the wafer one by one and making them operable.
(5) Inspection step S5 for inspecting the completed chip.
Each of the above main processes further comprises several sub-processes.

Among these main processes, the wafer processing process S3 of (3) has a decisive influence on the performance of the semiconductor device. In this process, designed circuit patterns are sequentially stacked on a wafer to form a large number of chips that operate as memories and MPUs. This wafer processing process includes the following processes.
(1) A thin film forming process for forming a dielectric thin film to be an insulating layer, a wiring part, or a metal thin film for forming an electrode part (using CVD, sputtering, etc.)
(2) Oxidation process for oxidizing the thin film layer and the wafer substrate (3) Lithography process for forming a resist pattern using a mask (reticle) to selectively process the thin film layer and the wafer substrate (4) Etching process that processes thin film layers and substrates according to patterns (eg using dry etching technology)
(5) Ion / impurity implantation diffusion step (6) Resist stripping step (7) A step of inspecting the processed wafer.
The wafer processing process is repeated for as many layers as necessary to produce a semiconductor device that operates as designed.

FIG. 3 is a flowchart showing a lithography process that forms the core of the wafer processing process of FIG. The lithography process includes the following processes.
(1) Resist coating step S11 for coating a resist on the wafer on which the circuit pattern is formed in the previous step.
(2) Step S12 for exposing the resist
(3) Development step S13 of developing the exposed resist to obtain a resist pattern
(4) A post-baking step S14 for stabilizing the developed resist pattern.

  The above semiconductor device manufacturing method, wafer processing step, and lithography step are well known and will not be described here. Further, in order to perform multilayer wiring, (1) dielectric coating process, (2) annealing process, (3) via formation process, (4) conductor plating process, and (5) etching process are performed by the number of layers of the multilayer wiring. repeat. When the electron beam apparatus according to the present invention is used in the annealing step (2), the dielectric layer can be formed with low throughput with good throughput, the high frequency characteristics of the product are improved, and the mechanical strength of the chip is increased. improves.

  Although one embodiment of the electron beam apparatus according to the present invention has been described in detail above, the present invention is not limited to such an embodiment. For example, in the above description, the low dielectric constant layer covering the surface of the wafer is irradiated with the electron beam, but any other sample can be used instead of the wafer. In addition, the angle between the normal line of the sample and the optical axis of the electron gun is not limited to 15 degrees, and can be set to any angle within the range of 5 degrees to 45 degrees depending on the characteristics of the electromagnetic deflector. It is.

As will be understood from the fact that one embodiment of the electron beam apparatus according to the present invention has the above-described configuration, the present invention
(1) Since the sample can be irradiated with a low energy electron beam of 2 to 10 keV, the low dielectric constant material on the sample surface can be annealed or cured.
(2) Since it is possible to reduce the intrusion of unnecessary substances such as positive ions produced by ionizing the gas released from the sample by electron beam irradiation into the electron gun chamber, the deterioration of the cathode of the electron gun can be reduced. Can prevent,
(3) Materials such as La, B, and C evaporated from the electron gun cathode and carbon heater are not added to the low dielectric constant material.
There are exceptional effects such as.

1 is a diagram schematically showing one embodiment of an electron beam apparatus according to the present invention. It is a flowchart which shows the procedure of the device manufacturing method which can use the electron beam apparatus which concerns on this invention. It is a flowchart which shows the procedure of the lithography process in FIG.

Explanation of symbols

1: sample chamber, 2: low dielectric constant material, 3: wafer, 4: normal,
5: cylinder, 6: electron gun chamber, 7: cathode, 8: carbon heater, 9: Wehnelt electrode, 10: anode electrode, 11: electron gun, 12: optical axis of electron beam,
13: Electromagnetic deflector, 14: Aperture plate, 15: Small aperture, 16:17: Deflector,
51: Cylindrical part 52: Frustum part 53, 54: Electromagnetic lens

Claims (5)

In an electron beam apparatus that irradiates a sample with an electron beam emitted from an electron gun and changes the material of the surface of the sample,
The electron gun is disposed at a position where it cannot be directly viewed from the sample;
An electron beam apparatus, comprising: a deflecting unit that deflects an electron beam emitted from the electron gun so as to enter the surface of the sample. The electron gun is arranged so that an optical axis of the electron gun and a normal line of the sample form a predetermined angle,
The deflecting means operates to deflect the electron beam from a direction along the optical axis in a direction along the normal;
The electron beam apparatus according to claim 1, wherein:   2. The electron beam apparatus according to claim 1, wherein the deflecting unit further includes a deflector for deflecting the electron beam so as to uniformly irradiate the surface of the sample.   The electron beam apparatus according to claim 3, further comprising an aperture plate disposed in the vicinity of the deflector and having a small aperture for allowing the electron beam to pass therethrough. (1) applying a dielectric material to the substrate;
(2) loading a substrate coated with the dielectric material into a sample chamber;
(3) Using the electron beam apparatus according to any one of claims 1 to 4, irradiating the dielectric material with an electron beam;
A device manufacturing method comprising:

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