Process for manufacturing nonvolatile memory cells with dimensional control of the floating gate regions
First Claim
1. A process for manufacturing electronic devices having floating gate nonvolatile memory cells, comprising:
- defining an active area in a substrate of semiconductor material;
forming a first insulating region on top of said active area;
depositing a first dielectric material layer on top of said substrate;
said first dielectric material layer comprising a tunnel area;
forming a floating gate region on top of said first dielectric material layer and on top of said first insulating region, said forming the floating gate region comprising depositing a first semiconductor material layer on top of said dielectric material layer and of said first insulating region and selectively removing said first semiconductor material layer using a floating gate mask having an outer delimiting side, an opening with an internal delimiting side facing said outer delimiting side at a preset distance, in that said step of selectively removing comprises the step of removing said first semiconductor material layer at the side of said external delimiting side and below said opening, forming a hole in said floating gate region, and filling said hole with an electrically insulating material;
forming a second insulating region surrounding said floating gate region;
forming a control gate region on top of said floating gate region; and
forming conductive regions in said active area.
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Accused Products
Abstract
A manufacturing process including: forming a first insulating region on top of an active area; forming a tunnel region at the side of the first insulating region; depositing and defining a semiconductor material layer using a floating gate mask to form a floating gate region. The floating gate mask has an opening with an internal delimiting side extending at a preset distant from a corresponding outer delimiting side of the mask, so that the floating gate region forms inner a hole, and the tunnel region is defined, as regards its length, by the floating gate ask alone. The hole is filled with a dielectric material layer. The surface of the floating gate region is planarized, and an insulating region of dielectric material is made. A control gate region and conductive regions in the active area are then formed.
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Citations
16 Claims
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1. A process for manufacturing electronic devices having floating gate nonvolatile memory cells, comprising:
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defining an active area in a substrate of semiconductor material;
forming a first insulating region on top of said active area;
depositing a first dielectric material layer on top of said substrate;
said first dielectric material layer comprising a tunnel area;
forming a floating gate region on top of said first dielectric material layer and on top of said first insulating region, said forming the floating gate region comprising depositing a first semiconductor material layer on top of said dielectric material layer and of said first insulating region and selectively removing said first semiconductor material layer using a floating gate mask having an outer delimiting side, an opening with an internal delimiting side facing said outer delimiting side at a preset distance, in that said step of selectively removing comprises the step of removing said first semiconductor material layer at the side of said external delimiting side and below said opening, forming a hole in said floating gate region, and filling said hole with an electrically insulating material;
forming a second insulating region surrounding said floating gate region;
forming a control gate region on top of said floating gate region; and
forming conductive regions in said active area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A manufacturing process, comprising:
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forming a first insulating region on top of an active area in a substrate of semiconductor material;
forming a tunnel region at the side of the first insulating region;
depositing a layer of semiconductor material; and
defining the layer of semiconductor material using a floating gate mask to form a floating gate region, the floating gate mask having an opening with an internal delimiting side extending at a preset distance from a corresponding outer delimiting side of the mask to form a hole in the floating gate region by the floating gate mask. - View Dependent Claims (11, 12, 13, 14)
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15. A process for manufacturing nonvolatile memory cells with dimensional control of floating gate regions, the method comprising:
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forming a floating gate mask having an opening over a first polycrystalline silicon layer on a substrate of semiconductor material;
etching the first polycrystalline silicon layer to form a floating gate region having a hole formed under the opening in the floating gate mask;
depositing a layer of dielectric material to fill the hole in the floating gate region and to define a tunnel area under the floating gate region;
depositing a layer of dielectric material to fill the hole in the floating gate region; and
planarizing the surface above the floating gate region to remove the dielectric material from the surface above the floating gate region and to leave the dielectric material at the sides of the floating gate region and in the hole of the floating gate region. - View Dependent Claims (16)
forming an interpoly dielectric layer to seal the floating gate region on the top and at least a portion of the sides thereof;
growing a high-voltage oxide; and
depositing and shaping a second polycrystalline silicon layer to form a control gate region.
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Specification