Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-09-21
2001-09-18
Arbes, Carl J. (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S825000, C156S922000, C156S922000, C156S922000, C324S754090, C324S765010
Reexamination Certificate
active
06289583
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a process for manufacturing a card with multiple tips, designed in particular for testing semiconductor chips or integrated circuits before encapsulation thereof and comprising a substrate one of the surfaces of which is provided with conducting strips connected to contacts in the form of tips.
2. Description of Related Art
Cards with tips are used for checking chips or integrated circuits after manufacturing and prior to encapsulation. Cards known up to now generally use different types of technologies, i.e. soldered blade tip cards, epoxy ring cards, and membrane cards, as described in the documents EP-A-0475050, WO 9409374 and EP-0646800. Placing of the tips on these known cards is nevertheless limited to a given number of tips, which is no longer in keeping with the constant progress as far as integration of semiconductor chips is concerned.
The document WO 96/36884 describes a manufacturing process of a card subjected to prior cutting to obtain a system of flexible scales. The connection strips are not mono-layer and do not make use of anisotropic etching of a monolithic substrate.
SUMMARY OF THE INVENTION
A first object of the invention is to define a process for manufacturing cards with multiple tips enabling the precision and density of implantation of the contacts to be increased.
The manufacturing process is characterized by the following stages:
a thin metal layer is deposited by vapour deposition in a vacuum or by cathode sputtering on one of the insulated surfaces of the monolithic substrate, anisotropic etching of the silicon substrate being performed before the conducting strips are obtained, said etching being non-emergent to constitute an electrical contact connection point,
the conducting strips are obtained by direct etching,
a UV photolithography operation is then performed consisting in depositing a thick layer of photosensitive resin on the thin etched layer, the resin then being revealed with the drawing of the tips,
the tips are manufactured by electroforming by means of a metal ion bath enabling electroformed pads corresponding to the shape of the drawings to be obtained,
and the remaining layer of resin is finally dissolved in a solvent bath to obtain the final implantation of the tips on the monolithic substrate.
Anisotropic etching is advantageously achieved by immersion of the silicon substrate in potassium hydroxide KOH.
According to one feature of the process, anisotropic etching of the substrate takes place after a first UV photolithography consisting in producing through a mask a local insulation of a layer of photosensitive resin previously deposited on one of the surfaces of the substrate.
The thin metal layer can be formed for example by a nickel-, gold- or aluminium-based material. Any other metallic conducting material can naturally be used.
A second object of the invention also consists in achieving a multiple-tip card, in which the pitch between the different tips is reduced to the minimum, so as to achieve a high contact density.
The tips obtained by a thick UV photolithography and electroforming are formed by metal pads with a diameter of 10 to 100 microns and a thickness of ten to a few tens of microns. The cross sections of the pads can also be square or polygonal cross sections.
Each tip is deposited on the thin conducting layer with or without securing in the substrate. The substrate can be equipped with a damping material arranged under the thin conducting layer opposite the corresponding tip.
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patent: 4924589 (1990-05-01), Leedy
patent: 4952272 (1990-08-01), Okino et al.
patent: 5103557 (1992-04-01), Leedy
patent: 5177438 (1993-01-01), Littlebury et al.
patent: 5177439 (1993-01-01), Liu et al.
patent: 5323035 (1994-06-01), Leedy
patent: 5419807 (1995-05-01), Akram et al.
patent: 5475318 (1995-12-01), Marcus et al.
patent: 5483741 (1996-01-01), Akram et al.
patent: 0 475 050 A3 (1991-07-01), None
patent: 0 646 800 A1 (1994-09-01), None
patent: WO 89/11659 (1989-11-01), None
patent: WO 94/09374 (1994-04-01), None
patent: WO 96/36884 (1996-11-01), None
Leung, Justin et al., “Active Substrate Membrane Probe Card,” XP 000624791, 1995, pp. 29.2.1-29.2.4.
Belmont Andre
Daniau William
Reynaud Vincent
Arbes Carl J.
Mesatronic
Oliff & Berridg,e PLC
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