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Title:
METHOD AND APPARATUS FOR DEPOSITING NANOMATERIALS
Document Type and Number:
WIPO Patent Application WO/2012/161561
Kind Code:
A1
Abstract:
There is disclosed an apparatus for depositing nanomaterials; said apparatus comprising: at least one heating element; at least one sample holder (14) formed with a recess (14a) etched therethrough, said recess (14a) sized to fit a sample (10) and holding the sample (10) thereon; wherein one surface of the sample (10) is exposed to the heating element; at least one spacing member (16, 17) for holding the sample holder (14) in predetermined distance from that of the heating element; said spacing member (16, 17) is adjustably secured to the sample holder (14); at least one hole to channel in gases to be in contact with the sample (10); and at least one high temperature substrate (12). With the recess (14a) formed on the holder (14) of the present invention, only one surface of the sample is directly exposed for heating.

Inventors:
SHIH TEH AUN (MY)
SHENG DANIEL BIEN CHIA (MY)
SIN TAN KAI (MY)
Application Number:
PCT/MY2012/000105
Publication Date:
November 29, 2012
Filing Date:
May 22, 2012
Export Citation:
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Assignee:
MIMOS BERHAD (MY)
SHIH TEH AUN (MY)
SHENG DANIEL BIEN CHIA (MY)
SIN TAN KAI (MY)
International Classes:
H01L21/687; H01L21/67
Foreign References:
US20080066684A12008-03-20
US6161499A2000-12-19
Attorney, Agent or Firm:
MAHALINGAM, Maniam (No. 7-M Biz Avenue, Neo Cyber,Lingkaran Cyber Point Barat, Cyberjaya, Selangor Darul Ehsan, MY)
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Claims:
CLAIMS

1. An apparatus for depositing nanomaterials; said apparatus comprising: at least one heating element; at least one sample holder (14) formed with a recess (14a) etched therethrough, said recess (14a) sized to fit a sample (10) and holding the sample (10) thereon; wherein one surface of the sample (10) is exposed to the heating element; at least one spacing member (16, 17) for holding the sample holder (14) in predetermined distance from that of the heating element; said spacing member (16, 17) is adjustably secured to the sample holder (14); at least one hole to channel in gases to be in contact with the sample (10); at least one high temperature substrate (12).

2. The apparatus as claimed in Claim 1 wherein the sample (10) is positioned in an inverted manner within the recess (14a) such that only the top surface of the sample is exposed to heat.

3. The apparatus as claimed in Claim 1 wherein the substrate is formed based on either silicon, ceramics and refractory materials, or a combination of materials thereof.

4. The apparatus as claimed in Claim 1 wherein the spacing member is formed based on either silicon, ceramics and refractory materials, or a combination of materials thereof.

5. The apparatus as claimed in Claim 1 , wherein the apparatus further comprises a section for the placement of a thermocouple.

6. The apparatus as claimed in Claim 1 wherein there is a plurality of spacing members.

7. The apparatus as claimed in Claim 1 wherein there is a plurality of holes for channeling in gases.

8. The apparatus as claimed in Claim 1 wherein it is used for chemical vapour deposition methods and atomic layer deposition systems of thin films and nanomaterial

9. A method for depositing nanomaterials comprising the steps of:

providing a heating element;

providing a holder for a sample,

etching a recess on said sample, said recess sized to fit and hold the sample; positioning the sample within the recess in a manner such that only one surface is exposed to the heating element;

holding the holder of the sample in position with respect to the heating element;

adjusting the position of the sample with respect to the heating element.

Description:
METHOD AND APPARATUS FOR DEPOSITING NANOMATERIALS

FIELD OF THE INVENTION Embodiments of the present invention are directed generally to an apparatus and method for use in depositing nanomaterials, and in particular, a wafer heating apparatus and method thereof with generally improved and defined heating features.

BACKGROUND OF THE INVENTION

Applications involving the use of nanomaterials have gained great momentum and much has been written about them. In view of advancements, nanotechnology research has contributed to novel material characteristics discovery that could further enhance current applications and even possibly generate new ones. One of the major interests and perhaps also a challenge to researchers in providing improved characteristics lies in incorporating nanomaterials onto current electrical and electronic platforms or products.

Currently in nanomaterial synthesis, chemical vapour deposition has become a valuable and common tool for enabling the fabrication of electrical and electronic devices. Chemical vapour deposition (CVD) has been used to deposit various nanomaterials, including nanoparticles, nanotubes and nanowires, and has also been widely used in thin film depositions. With CVD, the strength of this method lies in its ability to deposit nanomaterials directly at predetermined sites on a substrate using patterned catalysts. In addition, process temperatures for depositing nanomaterials are typically lower with CVD. For example, with carbon nanotubes (CNTs) CVD temperatures range between 450-900'C while with methods such as arc discharge and laser ablation process temperatures are much higher ranging from 1200-3000 * 0. From the above, although CVD offers lower in temperature, generally, CVD temperatures still exceed 450°C which is a primary disadvantage in terms of the compatibility with CMOS process industry as any processing above 400-450 may disrupt previous diffusion treatments.

Currently, there exists various heating apparatus and methods gradually developed to accommodate the apparent shortcomings of CVD and methods of the likes. An example of such methods is as disclosed in United States Patent No. 616, 1499, D Carnahan et al. There is disclosed a method and apparatus for nucleation and growth of diamond by hot- filament DC plasma deposition. It is mentioned that the apparatus uses a resistively heated filament array for dissociating hydrogen in the reactant gas. Generally, this nucleation method simplifies the growth process and provides a convenient and economical means for heteroepitaxial growth of diamond nuclei on single crystal substrates like Si. However there is no explicit disclosure on the use of a sample support or heating elements.

Recognizing the shortcomings of the existing heating methods as discussed above, there is dire need to provide an improved method and apparatus to be used in the deposition of nanomaterials which can effectively address the glaring issues.

It is therefore a primary object of the present invention to provide an apparatus and method thereof for use in deposition of nanomaterials, said apparatus wafer apparatus facilitates localised surface heating thus resulting in a reduction of heat exposure to the layers beneath the top surface.

It is yet an object of the present invention to provide an apparatus and method thereof for use in deposition of nanomaterials, which opens up the possibility of utilizing a variety of materials and substrates which are not suitable at high temperatures such as polymers, glass and metals.

Still other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein embodiments of the invention are described by way of illustration. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modifications in various respects, all without departing from the spirit and the scope of the present invention.

SUMMARY OF THE INVENTION

There is disclosed an apparatus for depositing nanomaterials; said apparatus comprising: at least one heating element; at least one sample holder (14) formed with a recess (14a) etched therethrough, said recess (14a) sized to fit a sample (10) and holding the sample (10) thereon; wherein one surface of the sample (10) is exposed to the heating element; at least one spacing member (16, 17) for holding the sample holder (14) in predetermined distance from that of the heating element; said spacing member (16, 17) is adjustably secured to the sample holder (14); at least one hole to channel in gases to be in contact with the sample (10); at least one high temperature substrate (12).

In another aspect of the present invention, there is provided a method for depositing nanomaterials comprising the steps of: providing a heating element; providing a holder for a sample, etching a recess on said sample, said recess sized to fit and hold the sample; positioning the sample within the recess in a manner such that only one surface is exposed to the heating element; holding the holder of the sample in position with respect to the heating element; adjusting the position of the sample with respect to the heating element. BRIEF DESCRIPTION OF THE DRAWINGS Features of the invention will be apparent from the following description when read with reference to the accompanying drawings:

FIG 1 shows a conventional method of depositing nanomaterials; FIG 2 shows a block diagram of the apparatus in accordance with a preferred embodiment of the present invention;

FIG 3 shows a view of the apparatus in accordance with the preferred embodiment of the present invention in effect;

FIG 4 shows an example of a component in accordance with the preferred embodiment of the present invention in effect;

FIG 5 shows an example of a component of the present invention;

DETAILED DESCRIPTION

In the following description, reference is made to the accompanying drawings where, by way of illustration, specific embodiments of the invention are shown. It is to be understood that other embodiments may be used as structural and other changes may be made without departing from the scope of the present invention. Also, the various embodiments and aspects from each of the various embodiments may be used in any suitable combinations. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

FIG 2 shows the conventional method of fabricating nanomaterials. In contrast to that of the present invention, whereby a thin layer of catalyst of 0.1-15.0 nm thickness is deposited onto an underlayer or support layer which is 5-50nm in thickness on a substrate (thickness >150 m). The substrate/sample is then annealed to form nucleation sites and growth of the nanomaterial is initiated by introducing the process gasses as the feedstock. Nanomaterial growth depends on pressures, gas flows, catalysts preparation and most importantly the deposition temperature. Based on the conventional methods, the nanomaterial growth typically occurs at the utmost top layer, thereby only the top surface needs to be heated to the right surface energies for growing the material.

Referring now to the figures, FIG. 2 is a block diagram showing the apparatus in accordance to a preferred embodiment of the present invention, whereby the main components of the apparatus comprise of at least one sample (10) to be placed in contact with a substrate (12), a holder (14), which is adapted to hold the sample in a manner that heat is applied to a specific surface, at least one inlet or hole ( 5) adapted to channel in gases formed thereon; and at least one spacing element (16, 17) for holding the sample (10) and substrate (12) in position.

As discussed briefly earlier, nanomaterial growth typically occurs at the utmost top layer, thereby typically only the top surface needs to be heated to the right surface energies. In accordance to a preferred embodiment of the present invention and as shown in FIG 2, the apparatus is assembled in a manner such that it inverts the samples/substrates so that the sample surface is directly exposed to the heat emanating from the heating element during deposition. Still referring to FIG 2, the substrate being adapted as the sample holder (14) may be formed from a suitable material that has high tolerance to heat, or absorbs heat. In one arrangement of a preferred embodiment of the present invention, the sample (10) is placed in a manner such that it is suitably held by the spacing members (16, 17). On at least one surface of the sample holder (14), there is formed a through opening or recess (14a) etched therethrough, sized in a manner such that it can fit the sample (10) and at the same time holding the sample (10) thereon. In order to achieve this, there may be provided a pair of tongue or protrusions (14b, 14c) formed at the peripheral area of the recess (14a) to act as support protrusions for the sample ( 0). It is preferred that when fitted into the recess (14a), at least one surface of the sample (10) is exposed. There may be provided at least one inlet/hole (15) formed on said sample holder (14) for allowing gas flow when heating is performed. The spacing element (16, 17) may be formed from a suitable material that is also highly tolerant to heat and preferably of robust feature. The spacing element (16, 17) is generally formed resembling a bolt, wherein at least one section is formed to larger than the other, thus forming the head section. There may be provided a plurality of spacing elements in order to achieve the result as intended in accordance to the present invention.

The apparatus is assembled in a manner such that at least one surface of the sample (10) is exposed to heat treatment, during fabrication of wafer apparatus, as shown in FIG 3. Still referring to FIG 2, the sample (10) is placed to fit the recess (14a) formed on the sample/substrate holder (14) and held therein, while exposing the selected surface for heating. The spacing members (16, 17) are then positioned spaced apart at a predetermined distance from each other and arranged such that they provide a clamping effect for the sample holder (14). In this arrangement, the sample holder (14) is positioned in between the spacing members (16, 17). According to the preferred embodiment of the present invention, the position of the spacing members (16, 17) can be adjusted, or adjustably secured to the sample holder (14). Conceivably, with such feature, direct exposure of sample surface to heating element can be controlled. By controlling the surface heating, heat exposure to the bottom layers and substrate is reduced. The exposed surface of the sample (10) is preferably the top surface which is directed towards the heating element or heating stage (70). Inlets (15) are sized to allow gas flow into the heating area during operation and thus to be in contact with the heated area or surface of the sample (10). The gases are supplied as the feedstock for producing the respective nanomaterial. The sample can be kept in position during deposition within the recess formed on the sample holder (14). There may be further provided a thermocouple (60) to monitor the temperature of the heating operation.

In accordance with the preferred embodiment of the present invention, by using this apparatus to facilitate local surface heating, the under layers and substrate is less exposed to heat treatment.

Further in accordance with the preferred embodiment of the present invention, the recess (14a) may be tailored for any sample shapes and sizes. FIG 4 and FIG 5 depict examples of the sample holder (14) adapted for holding multiple dies of similar size and shape and a holder for holding wafers. It should be mentioned that instead of etching, machining can be used to fashion a holder, with the criteria that the substrate is made of a high temperature material exceeding the required CVD deposition temperature. With this apparatus described in accordance with the preferred embodiments of the present invention, the choice of utilising materials and substrates for nanomaterial growth which are usually not suitable at high temperatures such as polymers, glass and metals is made possible due to the reduced heat exposure to the substrate during the deposition process. Other benefits of the apparatus above are that it is reconfigurable and reusable.

While the invention has been particularly shown and described with reference to the illustrated embodiments, those skilled in the art will understand that changes in form and detail may be made without departing from the scope of the invention.