Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2002-06-20
2004-08-10
Osele, Mark A. (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S345420, C156S529000, C156S583200, C083S177000, C438S458000
Reexamination Certificate
active
06773534
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sample processing apparatus and method and, more particularly, to a processing apparatus and method suitable for processing a sample having a separation layer.
2. Description of the Related Art
A substrate (SOI substrate) having an SOI (Silicon On Insulator) structure is known as a substrate having a single-crystal Si layer on an insulating layer. A device using this SOI substrate has many advantages that cannot be achieved by ordinary Si substrates. Examples of the advantages are as follows.
(1) The integration degree can be increased because dielectric isolation is easy.
(2) The radiation resistance can be increased.
(3) The operating speed of the device can be increased because the stray capacitance is small.
(4) No well step is necessary.
(5) Latch-up can be prevented.
(6) A completely depleted field-effect transistor can be formed by thin film formation.
Since an SOI structure has the above various advantages, researches have been made on its formation method for several decades.
As one SOI technology, the SOS (Silicon On Sapphire) technology by which Si is heteroepitaxially grown on a single-crystal sapphire substrate by CVD (Chemical Vapor Deposition) has been known for a long time. This SOS technology once earned a reputation as the most matured SOI technology. However, the SOS technology has not been put into practical use to date because, e.g., a large amount of crystal defects are produced by lattice mismatch in the interface between the Si layer and the underlying sapphire substrate, aluminum that forms the sapphire substrate mixes in the Si layer, the substrate is expensive, and it is difficult to obtain a large area.
The SIMOX (Separation by Ion iMplanted OXygen) technology has appeared next to the SOS technology. For this SIMOX technology, various methods have been examined to reduce crystal defects or manufacturing cost. The methods include a method of ion-implanting oxygen into a substrate to form a buried oxide layer, a method of bonding two wafers via an oxide film and polishing or etching one wafer to leave a thin single-crystal Si layer on the oxide film, and amethod of ion-implanting hydrogen to a predetermined depth from the surface of an Si substrate having an oxide film, bonding the substrate to another substrate, leaving a thin single-crystal Si layer on the oxide film by heating or the like, and peeling one (the other substrate) of the bonded substrates.
The present applicant has disclosed a new SOI technology in Japanese Patent Laid-Open No. 5-21338. In this technology, a first substrate prepared by forming a non-porous single-crystal layer (including a single-crystal Si layer) on a single-crystal semiconductor substrate having a porous layer is bonded to a second substrate via an insulating layer. After this, the substrates are separated at the porous layer, thereby transferring the non-porous single-crystal layer to the second substrate. This technique is advantageous because the film thickness uniformity of the SOI layer is good, the crystal defect density in the SOI layer can be decreased, the surface planarity of the SOI layer is good, no expensive manufacturing apparatus with special specifications is required, and SOI substrates having about several hundred angstrom to 10-&mgr;m thick SOI films can be manufactured by a single manufacturing apparatus.
The present applicant has also disclosed, in Japanese Patent Laid-Open No. 7-302889, a technique of bonding first and second substrates, separating the first substrate from the second substrate without destroying the first substrate, smoothing the surface of the separated first substrate, forming a porous layer again, and reusing the porous layer. Since the first substrate is not wasted, this technique is advantageous in greatly reducing the manufacturing cost and simplifying the manufacturing process.
In the above techniques, when a substrate (to be referred to as a bonded substrate stack hereinafter) obtained by bonding two substrates is separated at the porous layer, they must be separated with high reproducibility and without inflicting any damage on them.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above situation, and has as its object to provide an apparatus and method suitable for preventing any damage in separating a sample such as a substrate having a separation layer.
When a sample such as a substrate having a separation layer is to be separated, a partial region is left as an unseparated region in the first process, and then, a force is applied to the unseparated region from a predetermined direction to completely separate the sample in the second process, thereby preventing defects in separating the sample.
An apparatus and method according to the first and second aspects of the present invention are suitable for the first process. Separation conditions in the second process are uniformed by the apparatus and method according to the first and second aspects to facilitate control of the second process, thereby preventing defects in separating the sample.
According to the first aspect of the present invention, there is provided a processing apparatus for processing a sample having a separation layer, characterized by comprising a separation mechanism for partially separating the sample at the separation layer while leaving a predetermined region of the separation layer as an unseparated region.
In the processing apparatus according to the first aspect, preferably, for example, the separation mechanism has an ejection portion for ejecting a fluid to the separation layer and partially separates the sample using the fluid.
In the processing apparatus according to the first aspect, for example, the sample preferably comprises a plate member having a layer with a fragile structure as the separation layer.
In the processing apparatus according to the first aspect, for example, the separation mechanism preferably partially separates the sample while leaving a substantially circular region as the unseparated region.
In the processing apparatus according to the first aspect, for example, the separation mechanism preferably partially separates the sample while leaving a substantially circular region at a substantially central portion of the separation layer as the unseparated region.
In the processing apparatus according to the first aspect, preferably, for example, the separation mechanism comprises a driving mechanism for rotating the sample about an axis perpendicular to the separation layer, and the ejection portion for ejecting a fluid to the separation layer, and the sample is partially separated while rotating the sample by the driving mechanism.
In the processing apparatus according to the first aspect, preferably, for example, the driving mechanism rotates the sample at a low speed at an initial stage of partial separation processing of the sample and then rotates the sample at a high speed.
In the processing apparatus according to the first aspect, for example, the driving mechanism preferably increases a rotational speed of the sample gradually or stepwise in partially separating the sample.
In the processing apparatus according to the first aspect, for example, the driving mechanism preferably changes a rotational speed of the sample in partially separating the sample.
In the processing apparatus according to the first aspect, preferably, for example, the ejection portion ejects a fluid with a high pressure at an initial stage of partial separation processing of the sample and then reduces the pressure of the fluid.
In the processing apparatus according to the first aspect, for example, the ejection portion preferably reduces a pressure of the fluid to be ejected gradually or stepwise in partially separating the sample.
In the processing apparatus according to the first aspect, for example, the ejection portion preferably changes a pressure of the fluid to be ejected in partially separating the sample.
In the processing apparatus according to the first as
Omi Kazuaki
Sakaguchi Kiyofumi
Yanagita Kazutaka
Yonehara Takao
Morgan & Finnegan
Osele Mark A.
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