What is claimed is:
1. A touchpad for providing data input to a computer system and which includes a flexible touch-sensitive surface that conforms to arcuate surfaces, said touchpad comprising:
at least two flexible and non-conductive sheets having touchpad sensing electrodes disposed thereon, wherein the at least two flexible and non-conductive sheets overlap such that the touchpad sensing electrodes form at least a grid which defines a touch-sensitive area of the touchpad, and wherein the at least two flexible and non-conductive sheets can bend to thereby conform to an arcuate surface;
a printed circuit board; and
touchpad control circuitry which is mounted on the printed circuit board, wherein the touchpad control circuitry is electrically coupled to the touchpad sensing electrodes so as to receive sensing information therefrom, and wherein the touchpad control circuitry generates a plurality of signals that correspond to data input from the touchpad.
2. The touchpad as defined in claim 1 wherein the at least two flexible and non-conductive sheets are selected from the group of flexible and non-conductive sheets including plastic and mylar.
3. The touchpad as defined in claim 2 wherein the touchpad sensing electrodes are formed from conductive ink.
4. The touchpad as defined in claim 3 wherein the touchpad further comprises a connection system between the at least two flexible and non-conductive sheets and the touchpad circuitry on the printed circuit board, said connection system comprising:
at least two rows of solder bumps disposed on the printed circuit board, wherein the at least two rows of solder bumps are spaced apart to form a gap therebetween; and
a portion of the at least two flexible and non-conductive sheets disposed so as to cover the at least two rows of solder bumps, wherein the portion of the at least two flexible and non-conductive sheets that is disposed over the gap is secured to the printed circuit board so as to fill the gap, wherein the gap between the at least two solder bumps is sufficient to create tension on the portion of the at least two flexible and non-conductive sheets that is secured thereto.
5. The touchpad as defined in claim 4 wherein the touchpad further comprises an adhesive that is used to secure the portion of the at least two flexible and non-conductive sheets to the printed circuit board.
6. The touchpad as defined in claim 5 wherein the touchpad further comprises providing the at least two flexible and non-conductive sheets which have stiffness sufficient to create pressure to maintain electrical contact between touchpad sensing electrodes on the at least two flexible and non-conductive sheets, and the at least two rows of solder bumps.
7. The touchpad as defined in claim 6 wherein the touchpad further comprises staggering solder bumps within the at least two rows of solder bumps, such that a first row of solder bumps is offset from a second row of solder bumps, relative to the portion of the at least two flexible and non-conductive sheets.
8. The touchpad as defined in claim 3 wherein the touchpad further comprises a connection system between the at least two flexible and non-conductive sheets and the touchpad circuitry on the printed circuit board, said connection system comprising:
a first non-conductive sheet secured to the printed circuit board;
a second non-conductive sheet partially secured to the printed circuit board, parallel to the first non-conductive sheet, and spaced apart therefrom to form a gap therebetween, wherein the second non-conductive sheet is not secured along the gap; and
a row of solder bumps disposed underneath the second non-conductive sheet where it is not secured to the printed circuit board, parallel to and near an edge of the gap, wherein the portion of the at least two flexible and non-conductive sheets is disposed between the second non-conductive sheet and the row of solder bumps, and wherein touchpad sensing electrodes are in contact with the row of solder bumps.
9. A method for providing a touchpad having a flexible touch-sensitive surface that is coupled to arcuate surfaces, said method comprising the steps of:
(1) providing a flexible touch-sensitive surface that conforms to arcuate surfaces formed from at least two flexible and non-conductive sheets coupled together and having touchpad sensing electrodes disposed thereon, a printed circuit board, and touchpad control circuitry which is mounted on the printed circuit board, wherein the touchpad control circuitry is electrically coupled to the touchpad sensing electrodes so as to receive sensing information therefrom, and wherein the touchpad control circuitry generates a plurality of signals that correspond to data input from the touchpad;
(2) disposing the flexible touch-sensitive surface against a mounting surface, wherein the mounting surface is sufficiently thin to thereby enable the flexible touch-sensitive surface to detect a pointing object on an opposite side thereof; and
(3) detecting and tracking the pointing object that touches and moves along the opposite side of the mounting surface.
10. The method as defined in claim 9 wherein the method further comprises the step of securing the flexible touch-sensitive surface against the mounting surface using a non-conductive adhesive.
11. The method as defined in claim 10 wherein the method further comprises the step of selecting the at least two flexible and non-conductive sheets from the group of flexible and non-conductive sheets including plastic and mylar.
12. The method as defined in claim 11 wherein the method further comprises the step of forming the touchpad sensing electrodes from conductive ink.
13. The method as defined in claim 12 wherein the method further comprises the step of providing a connection system between the at least two flexible and non-conductive sheets and the touchpad circuitry on the printed circuit board that does not rely upon a pressure connector.
14. The method as defined in claim 13 wherein the method further comprises the steps of:
(1) providing at least two rows of solder bumps on the printed circuit board, wherein the at least two rows of solder bumps are spaced apart to form a gap therebetween, and
(2) securing a portion of the at least two flexible and non-conductive sheets so as to cover the at least two rows of solder bumps, wherein the portion of the at least two flexible and non-conductive sheets that is disposed over the gap is secured to the printed circuit board so as to fill the gap.
15. The method as defined in claim 13 wherein the method further comprises the step of utilizing a non-conductive adhesive to secure the portion of the at least two flexible and non-conductive sheets to the printed circuit board.
16. The method as defined in claim 15 wherein the method further comprises the step of staggering solder bumps within the at least two rows of solder bumps, such that a first row of solder bumps is offset from a second row of solder bumps, relative to the portion of the at least two flexible and non-conductive sheets.
17. The method as defined in claim 12 wherein the method further comprises the steps of
(1) securing a first non-conductive sheet to the printed circuit board;
(2) partially securing a second non-conductive sheet to the printed circuit board, parallel to the first non-conductive sheet, and spaced apart therefrom to form a gap therebetween, wherein the second non-conductive sheet is not secured along the gap; and
(3) providing a row of solder bumps underneath the second non-conductive sheet where it is not secured to the printed circuit board, parallel to and near an edge of the gap, wherein the portion of the at least two flexible and non-conductive sheets is disposed between the second non-conductive sheet and the row of solder bumps, and wherein touchpad sensing electrodes are in contact with the row of solder bumps.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for forming narrow trenches in a silicon substrate comprising the steps of:
etching the substrate to form first trenches separated by first silicon ribs;
performing a thermal oxidation of the substrate to form a silicon oxide layer developing inside and outside of the silicon, whereby second trenches narrower than the first trenches and second silicon ribs narrower than the first silicon ribs are obtained;
filling the second trenches with fingers of an etchable material;
etching the silicon oxide down to the upper surface of the second ribs while keeping silicon oxide portions between said etchable material fingers and the second ribs;
etching away the second silicon ribs and said etchable material fingers;
etching the silicon oxide for a duration sufficient to expose the substrate at the bottom of the silicon oxide portions, while leaving in place silicon oxide fingers; and
anisotropically etching the substrate between the oxide fingers to form narrow trenches in the substrate.
2. The method of claim 1, wherein the filling step includes the two following steps:
depositing a layer of an etchable material totally filling the second trenches and covering the silicon oxide layer, and
etching said layer of an etchable material for a duration sufficient to leave in place only fingers in the second trenches.
3. The method of claim 1, wherein an additional step of etching back of said silicon oxide fingers is provided.
4. The method of claim 3, further comprising the steps of:
depositing a filling layer formed of a material selectively etchable with respect to the substrate, the filling layer totally filling the narrow trenches and covering the substrate ribs separating the narrow trenches;
etching the filling layer to expose the substrate ribs, while keeping the material present between ribs;
performing a chemical-mechanical polishing of the upper portion of the ribs; and
etching back the material remaining between the ribs.
5. The method of claim 1, wherein the width and the spacing of the first trenches are identical and the duration of the thermal oxidation of the substrate is provided to obtain substantially identical narrow trenches.
6. The method of claim 1, wherein the etchable material used to fill the second trenches is polysilicon.
7. The method of claim 1, wherein the second silicon ribs and the etchable material fingers are etched simultaneously.
8. A method of forming trenches in a substrate, comprising:
forming first trenches in the substrate, the first trenches having a first width and being defined by first projections from the substrate having a second width;
forming second trenches within the first trenches, the second trenches having a third width narrower than the first width;
reducing the width of the first projections to form second projections having a fourth width that is less than the second width;
forming fingers of removable material within the second trenches;
exposing the fingers and the second projections;
selectively removing the second projections to expose respective individual regions of the substrate;
selectively removing the fingers of removable material from the second trenches;
removing a bottom of the second trenches to expose respective individual regions of the substrate for each second trench; and
removing portions of the substrate from the exposed individual regions to form third trenches in the substrate, the third trenches having the third and fourth widths of the second trenches and second projections, respectively.
9. The method of claim 8 wherein the substrate comprises a silicon substrate.
10. The method of claim 8 wherein the operation of reducing occurs during the operation of forming the second trenches.
11. The method of claim 8 wherein the first and second widths are approximately equal and wherein the third and fourth widths are approximately equal.
12. The method of claim 8 wherein forming second trenches within the first trenches and reducing the width of the projections to a fourth width that is less than the second width comprises thermally oxidizing the substrate to form an oxidized layer in the first trenches and on the projections having the second width.
13. The method of claim 12 wherein forming a removable material within the second trenches comprises forming a removable material within the second trenches and on the oxidized layer.
14. The method of claim 8 wherein selectively removing the second projections and selectively removing the fingers occur simultaneously.