Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Tpo Hong Kong Holding Limited

David J McCulloch

Ian D French

Nigel David Young

John A Clarke

Stanley D Brotherton

Carl Glasse

Soo Y Yoon

A method of manufacturing an active matrix display device involves manufacturing a first substrate arrangement comprising a rigid glass substrate and an overlying plastic substrate. Pixel circuits are formed over the plastic substrate. The rigid glass substrate () is only removed from the plastic substrate after the mounting of the active and passive plates of the display into display modules (). This method enables substantially conventional substrate handling, processing and cell making to be employed, for example in standard AMLCD factories, with only minimal extra equipment needed. A more general manufacturing method is also disclosed for fabricating TFTs on a spin-on plastic layer.

Active matrix displays and other electronic devices having plastic substrates

A method of manufacturing an electronic device comprising a thin film transistor (), comprises forming a hydrogen-containing layer () over a semiconductor layer (), irradiating the hydrogen-containing layer so as to hydrogenate the semiconductor layer, and then forming electrodes () over the semiconductor layer. A short diffusion length and direct path is provided for the hydrogen thus allowing rapid hydrogenation of the semiconductor layer using relatively few, high-fluence laser pulses. The supporting substrate () is not heated significantly making the method particularly useful for TFTs on polymer substrates. Crystallisation and hydrogenation of the semiconductor layer can be executed in the same irradiation step.

Method of manufacturing an electronic device comprising a thin film transistor

In a laser system for laser crystallization of semiconductor films, a laser source produces a laser beam that is transmitted to a lens system having a plurality of lens elements adapted to divide the beam into a plurality of beamlets. At least one of the beamlets is inverted relative to the others, such that a desired intensity profile is generated at the output of the laser system.

Laser system with mixed polarity beamlets

A method of producing a top gate thin-film transistor in which an insulated gate structure ( ) is formed over an amorphous silicon layer with upper gate conductor ( ) directly over the gate insulator layers. The gate conductor is patterned to be narrower than a spacing to be provided between source and drain electrode contacts. Laser annealing of areas of the amorphous silicon layer ( ) not shielded by the gate conductor ( ) is carried out to form polysilicon portions. The gate insulator layers are formed as a gate insulator layer ( ) of first refractive index, and an overlying surface insulator layer ( ) of second, lower, refractive index. The overlying surface insulator layer has been found to reduce fluctuations in the reflectance of the structure in dependence upon the specific thicknesses of the gate insulator layers. Therefore, the tolerances for the thicknesses of the gate insulator layers can be reduced whilst maintaining control of the laser annealing process.

Top gate thin-film transistor and method of producing the same

A laser system ( ) for producing a line beam laser output ( ) comprises a laser source ( ), and a lens system ( ) for modifying the intensity profile of the incident laser input, and comprising a plurality of lens elements ( ) arranged at a predetermined lens pitch. An optical filter ( ) is provided between the laser source ( ) and the lens system ( ), the filter comprising transmissive portions ( ) and opaque portions ( ). The transmissive portions ( ) define a repeating pattern ( ) with a pitch corresponding to the lens pitch. The optical filter ( ) modifies the input to the lens system ( ) such that the output of the lens system gives rise to a desired intensity profile at the output of the laser system ( ). This desired profile can have a tapered profile at the top of the hat, which gives improved performance for laser crystallization. The invention can be implemented with minimum adaptation of an existing top hat profile laser system.

Laser system

A laser crystallization method comprises the steps of providing a film of semiconductor material on an insulating substrate, and scanning a pulsed laser beam over the film, the laser beam being shaped to define a chevron. Each pulse of the laser beam comprises at least a first pulse portion of a first energy and a second subsequent pulse portion of a second energy. The first and second pulse portions of each pulse are applied at substantially the same position over the film. This method is used to form electronic devices and enables reliable crystallization to form large single crystal areas in thin semiconductor films.

Laser crystallization of thin films

The invention provides a method of manufacturing a large-area electronic device, for example a flat panel display, comprising thin-film circuit elements, and also laser apparatus for crystallizing a portion of a semiconductor thin-film (1) with a beam (11) of set energy. The energy of the beam (11) is set in accordance with the output from a light detector (22) to regulate the crystallization of a device portion (3,4 and/or 5) of a semiconductor thin film (1) at which the beam (11) is subsequently directed with its set energy. The light detector (22) monitors the surface quality of a previously crystallized portion (2). In accordance with the present invention, the light detector (22) is located at a position outside the specular reflection path (25) of the light returned by the surface area of the crystallized portion (2) and detects a threshold increase (D) in intensity (I.sub.s) of the light (26) being scattered by the surface area of the crystallized portion. This threshold increase (D) occurs when the energy (E.sub.p) of the beam (11) is increased sufficiently to cause the onset of surface roughening.

Electronic device manufacture

In the manufacture of an electronic device comprising thin-film circuitry, a semiconductor film (1) on a polymer substrate (2) is subjected to a laser treatment, for example laser crystallisation, with a laser beam (10). The beam is reflected by the film (1). Significant non-uniformities in the laser treatment are found to occur due to a local overheating effect if the reflected laser beam 10b impinges again on the heated area of the film (1). Thus, the invention identifies a particularly acute problem which arises when the device substrate (2) is of a heat-distortable polymer material in that the substrate (2) may experience temporarily a concave distortion at an area where the semiconductor film (1) on the substrate (2) is heated by the incident laser beam (10). The beam is focused as well as reflected by the concave distortion in the substrate (2). Although the film (1) is under a window (22) of the treatment cell (20), this focused and reflected laser beam (10a) is prevented from being reflected again onto the same area of the film (1), by tilting the window (22) and/or the film/substrate (1,2) at the area of the concave distortion at an angle .theta. so as to be inclined with respect to one another along the path of the beam (10).

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Redhill, United Kingdom

David J McCulloch