Semiconductor device manufacturing: process – Bonding of plural semiconductor substrates – Subsequent separation into plural bodies
Reexamination Certificate
1997-11-13
2001-05-01
Whitehead, Jr., Carl (Department: 2822)
Semiconductor device manufacturing: process
Bonding of plural semiconductor substrates
Subsequent separation into plural bodies
C438S053000, C438S050000, C438S407000, C438S459000
Reexamination Certificate
active
06225190
ABSTRACT:
The present invention relates to a process for the separation of at least two elements of a structure, said two elements being in contact with one another along an interface and are fixed to one another by interatomic bonds at said interface. The two elements of the structure are made from solid materials, which can be of different types. They can be conductive, semiconductive or dielectric materials.
According to a first use of the invention, said process permits a complete separation of the two elements of the structure. According to a second use of the invention, said process permits a localized separation of the two elements in order to e.g. obtain micro-cushions pressurized by a gaseous phase.
The separation of the two elements bonded together by interatomic bonds is not easy to bring about, particularly in the case of elements having very small dimensions, such as occurs in the microelectronics field. This operation is even more difficult when it is desired to bring about a localized separation of two elements. Such a localized separation, when it is envisaged between two layers of a microelectronic structure, would make it possible to obtain micro-cushions pressurized by the introduction of a gas between the separated parts of the two layers.
The obtaining of such pressurized micro-cushions in microelectronic structures is particularly difficult to obtain using conventional processes. Thus, most microelectronics processes take place in atmospheric pressure or low pressure machines. Under such conditions, even if it is possible to introduce a gaseous phase at a given pressure into a micro-cavity produced in a structure by establishing a physical communication with a medium containing the corresponding gas at a desired pressure, it is difficult or even impossible to seal the micro-cavity maintaining the gaseous phase at the desired pressure.
The inventors of the present invention have discovered that it is possible to introduce a gaseous phase at the interface between two contacting layers without any need for a physical communication between said interface and the exterior. They have discovered that, by the implantation of ions of an appropriate gas, it is possible to break interatomic bonds existing between the atoms of the layers located on either side of the interface and even obtain, if the implanted ion dose is sufficiently high, the presence of a gaseous phase in the area of the interface which has been implanted. If the implanted ion dose is correctly adjusted, the gaseous phase introduced has an adequate pressure to bring about the detachment of the two layers and supply a pressurized micro-cushion. By treating the entire interface, it is possible to obtain a complete separation of the two layers.
The invention therefore has as its object a process for the separation of at least two elements of a structure, the two elements being in contact with one another along an interface and are fixed to one another by interatomic bonds at said interface, characterized in that it consists of carrying out an ion implantation in order to introduce ions into the structure with an adequate energy for them to reach said interface and with an adequate dose to break said interatomic bonds and permit a separation of the two elements.
The dose of implanted ions can be such that it brings about, at said interface, the formation of a gaseous phase having an adequate pressure to permit the separation of the two elements.
The process can be subdivided into the actual ion implantation stage, optionally followed by a heat treatment stage making it possible to concentrate the implanted ions at said interface.
For example, if the structure is a semiconductor structure of the silicon on insulator type, a silicon layer constituting one of the two elements of the structure and a silicon oxide layer constituting the other element of the structure, the implanted ions can be hydrogen ions.
Ion implantation can take place on the entire structure, so as to obtain a complete separation of the two elements of the structure.
It can also be performed on at least one area of said interface, so as to obtain a separation of the two elements of the structure in said area. In this case, ion implantation can take place at a dose making it possible to give the gaseous phase formed in said area an adequate pressure to deform at least one of the two elements of the structure. Preferably, the shape of said implanted area is such that the deformation of said element of the structure constitutes a pad or cushion. The outer face of the element deformed by the pressure of the gaseous phase can be rendered conductive (e.g. by depositing a metal coating), so that the structure can present a flexible electrical contact to an external element. The process can also involve the formation of electrodes positioned in such a way as to form at least one capacitor, where said gaseous phase serves as a dielectric.
According to the latter aspect of the invention, the process can be used for obtaining a pressure transducer by measuring the capacitance of the capacitor. It can also be used for obtaining an array of pressure transducers by measuring capacitances corresponding to the capacitors formed from such an array of implanted areas.
The process according to the present invention can also be used for obtaining a mass of SiC covered with a SiO
2
layer, said structure being constituted by a first silicon element and a second SiO
2
element obtained by thermal growth from the first element, the second element being joined to the SiC mass before bringing about the separation between the first and second elements.
REFERENCES:
patent: 4676841 (1987-06-01), Celler
patent: 5250460 (1993-10-01), Yamagata et al.
patent: 5346841 (1994-09-01), Yajima
patent: 5374564 (1994-12-01), Bruel
patent: 5494835 (1996-02-01), Bruel
patent: 5510277 (1996-04-01), Cunningham et al.
patent: 5559043 (1996-09-01), Bruel
patent: 5714395 (1998-02-01), Bruel
patent: 5863830 (1999-01-01), Bruel et al.
patent: 5863832 (1999-01-01), Doyle et al.
patent: 2 211 991 (1989-07-01), None
M. Bruel, et al., Proceedings 1995 IEEE International SOI Conference, Oct. 3-5, 1995, “Smart Cut: A Promising New SOI Material Technology”.
Bruel Michel
Di Cioccio Léa
Commissariat A l'Energie Atomique
Davis Jamie L.
Jr. Carl Whitehead
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
LandOfFree
Process for the separation of at least two elements of a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for the separation of at least two elements of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the separation of at least two elements of a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2534497