Abstract:
A ROM device with an array of cells and a method of manufacturing comprises: forming closely spaced conductors in the surface of a semiconductor substrate having a second type of background impurity. Insulation is formed on the substrate. Closely spaced, parallel, conductors on the insulation are arranged orthogonally to the line regions. Glass insulation is formed over the conductors. Reflowing the glass insulation, forming contacts and forming a metal layer on the glass insulation follow. A resist is formed, exposed forming a resist metal pattern, then etching through the resist to pattern metal and removing the resist. Depositing a resist onto the patterned metal, and exposing the second resist with a custom code pattern, developing the resist into a mask follow. Impurity ions are implanted into the substrate adjacent to the conductors through the openings in a second resist layer. The device is passivated followed by activating the implanted impurity ions by annealing the device at a temperature less than or equal to about 520.degree. C. in a forming gas or N.sub.2 atmosphere.
Abstract:
An interposer for a semiconductor package structure includes a base substrate, a plurality of passive devices formed on the base substrate, and an identification (ID) code. The base substrate includes a first surface and an opposite second surface. The ID code is formed on the first surface or the second surface of the base substrate.
Abstract:
A bonding pad structure of semiconductor device having improved bondability is disclosed. The bonding pad structure uses at least one level comprising conductive islands and conductive plugs used as fasteners to prevent the bonding pad layer from peeling and cracking during the bonding process.
Abstract:
A semiconductor read-only memory (ROM) and a method of fabricating the same are provided. The ROM device is structured in such a manner that allows the fabrication to include a fewer number of mask processes. This makes it more cost effective and allows a cycle time that is shorter than that of the prior art. Moreover, the particular structure of the ROM device makes punchthrough less likely to occur between any neighboring pairs of the buried bit lines when the ROM device is further scaled down. The ROM device is constructed on a semiconductor substrate which is partitioned into a peripheral region and a cell region. A plurality of STI structures are formed at predefined locations in both the peripheral region and the cell region. Immediately after this, a first ion-implantation process can be performed on the cell region to form a plurality of buried bit lines. Subsequently, the dielectric isolation layers in all of the STI structures in the cell region are removed, leaving a plurality of empty trenches behind. A conformal insulating layer and a conductive layer are then successively formed over the wafer, and the conductive layer is further selectively removed to form a word line in the cell region and a gate in the peripheral region. In the code implantation process, selected channel regions between the buried bit lines are doped with impurities for code implantation of data into the ROM device.
Abstract:
A method of manufacturing a code pattern on a semiconductor substrate with an array of substantially parallel buried bit lines integral therewith and with word lines above the buried bit lines, includes: forming a titanium nitride layer above the word lines, forming and patterning a code mask above the titanium nitride layer, implanting impurities into the substrate through openings in the code mask to form the code pattern, and performing rapid thermal annealing of the implant. The step height of the titanium nitride layer is employed to form the code identification on the substrate.
Abstract:
A device under test (DUT) array provides defect information rapidly and systematically. The DUT array includes a plurality of test units arranged in a matrix, a plurality of bit lines and a plurality of word lines. Each test unit has a first terminal and a second terminal. Each second terminal of the test unit is electrically connected to a ground point. The first terminals of the test units are electrically connected to the bit lines. The word lines are coupled to the test units. Defects in the each test unit can be identified by providing voltages to the bit lines and the word lines. Accordingly, defects in various devices of an integrated circuit can be detected rapidly and systematically by applying signals to the DUT array.
Abstract:
A mask ROM stores information by selecting the work function of the gates of each FET in an array of FETs. The polysilicon gates of some of the FETs are doped N-type and the gates of the other FETs are doped P-type to form gates having different work functions, thereby forming FETs having different threshold voltages. The ROM consists of a parallel array of buried N+ bit lines formed in the substrate, a gate oxide layer deposited over the bit lines and a layer of polysilicon deposited on the gate oxide. The polysilicon is blanket doped P-type and then an encoding mask is formed, with openings in the encoding mask exposing regions of the polysilicon to be formed into gates of FETs with low threshold voltages. Either arsenic or phosphorus is doped into the polysilicon through the mask openings. The mask is removed, a layer of conductive material such as tungsten silicide is deposited and the polysilicon and the conductive material are formed into word lines for the ROM. The word lines of the ROM serve as gates for the FETs and the bit lines serve as sources and drains for the FETs.
Abstract:
A mask ROM stores information by selecting the work function of the gates of each FET in an array of FETs at a late stage in the manufacture of the ROM. The polysilicon gates of some of the FETs are doped N-type and the gates of the other FETs are doped P-type to form gates having different work functions, thereby forming FETs having different threshold voltages. The ROM consists of a parallel array of buried N.sup.+ bit lines formed in the substrate, a gate oxide layer deposited over the bit lines and a layer of polysilicon deposited on the gate oxide. The polysilicon is blanket doped N-type, gate electrodes are defined by photolithography, and then self-aligned silicide layers are formed on the gate electrodes. An insulating layer is then formed over the gate electrodes. Programming of the ROM is accomplished by forming a mask on the insulating layer and then implanting ions through openings in the mask, through the insulating layer and the silicide layer, and into the polysilicon layer. The implantation converts individual gate electrodes from N-type to P-type to alter the threshold voltage of the selected transistors. Relatively few additional processing steps are needed after the programming to complete the ROM.
Abstract:
A process for fabricating high-voltage MOSFET devices on a semiconductor substrate is disclosed. The substrate has heavily-doped impurities of a first conductivity type, and constitutes the drain region for the MOSFET. The process of fabrication comprises the steps of subsequently forming on the substrate a first doped layer, a second doped layer, a third doped layer and a shielding layer. All of these doped layers are of the first conductivity type. The second doped layer has an impurity concentration and a thickness smaller and larger than the impurity concentration and thickness respectively of the first doped layer, and larger and smaller than the impurity concentration and thickness respectively of the third doped layer. The impurity concentration of the first doped layer is smaller than the impurity concentration of the substrate. An opening in the shielding layer is formed, and then the source region of the MOSFET is formed in the area exposed by the opening. Afterwards, thermal oxidation is performed to form a field oxide layer over the surface of the source region. Next, an etching process is performed to remove the third doped layer, thereby revealing the surface of said second doped layer to form a source protruding body. Sidewalls of the source protruding body is then covered by an insulating layer. Finally, the field oxide layer and the insulating layer are then utilized as masking for implanting impurities of a second conductivity type into the second doped layer, thereby forming the gate region for the MOSFET.
Abstract:
An improved structure and process of fabricating a metal oxide field effect (MOSFET) which has a high resistance to electro-static discharge. The device has pre-gate heavily doped source and drain regions which overlap the gate electrode and the source and drain regions. This improved MOSFET device with overlapping pre-gate source and drain regions is incorporated into an electro-static discharge (ESD) circuit to form a memory device which has a high resistance to electro-static discharge (ESD).The MOSFET device with pre-gate heavily doped source and drain regions can be formed as follows. Spaced pre-gate source and drain regions of a second conductivity type are formed in the substrate with a background doping of a first conductivity type. A gate oxide and a gate is formed in the regions between the pre-gate source and drain regions. The gate at least partially overhangs the pre-gate source and drain regions. Subsequently, spacers are formed on the vertical sidewalls of the gate. Source and drain regions in the substrate are formed on either side of the spacers. Next, using conventional processes, insulating and metal layers are added to connect the circuit elements and form a memory device. The device is connected to form the input and input/output ESD circuits. The combination of the device of the invention and the ESD protection circuit forms an ESD resistant circuit using a minimum number of manufacturing steps.