Patents by Inventor Monte A. Douglas

Monte A. Douglas has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5318662
    Abstract: An etch process for etching copper layers that is useable in integrated circuit fabrication is disclosed which utilizes halides to react with copper, preferrably using photoenergizing and photodirecting assistance of high intensity ultraviolet light, to produce a product which is either volatile or easily removed in solution. The process is anisotropic.
    Type: Grant
    Filed: January 8, 1993
    Date of Patent: June 7, 1994
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 5316895
    Abstract: A method for patterning an integrated circuit workpiece comprises depositing a layer of non-photoactive material on the wafer. A reagent is deposited onto the entire surface of the material. A pattern is then created by exposing the surface with an energy source which produces a reaction within the reagent and/or between the reagent and the resin. The unreacted reagent is then removed by either physical or chemical means. Finally, the unexposed material is removed by means of an etch.
    Type: Grant
    Filed: December 16, 1992
    Date of Patent: May 31, 1994
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 5312516
    Abstract: A tantalum pentoxide substrate 34 immersed in a liquid ambient (e.g. 10% hydrofluoric acid 30) and illuminated with radiation (e.g. collimated visible/ultraviolet radiation 24) produced by a radiation source (e.g. a 200 Watt mercury xenon arc lamp 20). A window 26 which is substantially transparent to the collimated radiation 24 allows the radiated energy to reach the Ta.sub.2 O.sub.5 substrate 34. An etch mask (e.g. organic photoresist 32) may be positioned between the radiation source 20 and the substrate 34. The Ta.sub.2 O.sub.5 substrate 34 and liquid ambient 30 are maintained at a nominal temperature (e.g. 25.degree. C.). Without illumination, the Ta.sub.2 O.sub.5 is not appreciably etched by the liquid ambient. Upon illumination the etch rate is substantially increased.
    Type: Grant
    Filed: March 31, 1993
    Date of Patent: May 17, 1994
    Assignee: Texas Instruments Incorporated
    Inventors: Monte A. Douglas, Howard R. Beratan, Scott R. Summerfelt
  • Patent number: 5279702
    Abstract: A copper substrate 30 is immersed in a liquid 34 (e.g. 0.1 molar concentration hydrochloric acid) and illuminated with collimated radiation 24 (e.g. collimated visible/ultraviolet radiation) produced by a radiation source 20 (e.g. a 200 Watt mercury xenon arc lamp). A window 26 which is substantially transparent to the collimated radiation 24 allows the radiated energy to reach the copper substrate 30. An etch mask 32 may be positioned between the radiation source 20 and the substrate 30 (preferably the mask is also in the liquid). The copper substrate 30 and liquid 34 may be maintained at a nominal temperature (e.g. 25.degree. C.). Without illumination, the copper is not appreciably etched by the liquid. Upon illumination the etch rate is substantially increased. A further aspect is the addition of a passivant (e.g. iodine) to the liquid which forms a substantially insoluble passivation layer 36 on the substrate which is removed or partially removed by the radiation 24.
    Type: Grant
    Filed: September 30, 1992
    Date of Patent: January 18, 1994
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 5238529
    Abstract: A metal oxide substrate (e.g. barium strontium titanate 34) is immersed in a liquid ambient (e.g. 12 molar concentration hydrochloric acid 30) and illuminated with radiation (e.g. collimated visible/ultraviolet radiation 24) produced by a radiation source (e.g. a 200 Watt mercury zenon arc lamp 20). A window 26 which is substantially transparent to the collimated radiation 24 allows the radiated energy to reach the metal oxide substrate 34. An etch mask 32 may be positioned between the radiation source 20 and the substrate 34. The metal oxide substrate 34 and liquid ambient 30 are maintained at a nominal temperature (e.g. 25.degree. C.). Without illumination, the metal oxide is not appreciably etched by the liquid ambient. Upon illumination the etch rate is substantially increased.
    Type: Grant
    Filed: April 20, 1992
    Date of Patent: August 24, 1993
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 5238530
    Abstract: A titanate substrate (e.g. lead zirconate titanate 34) is immersed in a liquid ambient (e.g. 12 molar concentration hydrochloric acid 30) and illuminated with radiation (e.g. collimated visible/ultraviolet radiation 24) produced by a radiation source (e.g. a 200 Watt mercury xenon arc lamp 20). A window 26 which is substantially transparent to the collimated radiation 24 allows the radiated energy to reach the titanate substrate 34. An etch mask 32 may be positioned between the radiation source 20 and the substrate 34. The titanate substrate 34 and liquid ambient 30 are maintained at a nominal temperature (e.g. 25.degree. C.). Without illumination, the titanate is not appreciably etched by the liquid ambient. Upon illumination the etch rate is substantially increased.
    Type: Grant
    Filed: April 20, 1992
    Date of Patent: August 24, 1993
    Assignee: Texas Instruments Incorporated
    Inventors: Monte A. Douglas, Howard R. Beratan, Scott R. Summerfelt
  • Patent number: 5201989
    Abstract: A niobium pentoxide substrate 34 immersed in a liquid ambient (e.g. 10% hydrofluoric acid 30) and illuminated with radiation (e.g. collimated visible/ultraviolet radiation 24) produced by a radiation source (e.g. a 200 Watt mercury xenon arc lamp 20). A window 26 which is substantially transparent to the collimated radiation 24 allows the radiated energy to reach the Nb.sub.2 O.sub.5 substrate 34. An etch mask (e.g. organic photoresist 32) may be positioned between the radiation source 20 and the substrate 34. The Nb.sub.2 O.sub.5 substrate 34 and liquid ambient 30 are maintained at a nominal temperature (e.g. 25.degree. C.). Without illumination, the Nb.sub.2 O.sub.5 is not appreciably etched by the liquid ambient. Upon illumination the etch rate is substantially increased.
    Type: Grant
    Filed: April 20, 1992
    Date of Patent: April 13, 1993
    Assignee: Texas Instruments Incorporated
    Inventors: Monte A. Douglas, Howard R. Beratan, Scott R. Summerfelt
  • Patent number: 5122225
    Abstract: The invention discloses a method for selectively etching a first material at a faster rate than a second material, where both materials are incorporated on the surface of a semiconductor. The surface is disposed (step 100) in a plasma etcher. A reactant is flowed into the etcher (102). The etch agents are chosen so the chemical products created by a reaction between the etchant and the first material are volatile and the chemical products created by a reaction between the etchant and the second material are non-volatile. A reaction is then ignited (104) and the first material is etched (106). One embodiment discloses a method for forming a local interconnect.
    Type: Grant
    Filed: November 21, 1990
    Date of Patent: June 16, 1992
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 5100499
    Abstract: An etch process for etching copper layers that is useable in integrated circuit fabrication is disclosed which utilizes organic and amine radicals to react with copper, preferrable using photoenergizing and photodirecting assistance of high intensity ultraviolet light, to produce a product which is either volatile or easily removed in solution. The process is anisotropic.
    Type: Grant
    Filed: June 25, 1991
    Date of Patent: March 31, 1992
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 5041362
    Abstract: A photoresist layer (16) is selectively exposed to ultraviolet radiation (22). The exposed regions (23) are silylated with a silicon-liberating compound such as HMDS to create silylated regions (29). A plasma (32) is formed from a compound including at least one central atom and hydrogen. This plasma is used to differentially etch the non-protected regions (30) of the photoresist while forming a hard mask (42) from the silylated regions (29). Formation of filaments (38) on the developed photoresist sidewalls is avoided because of the low mass of the hydrogen ions and the volatility of any hydrides produced from materials sputtered from the substrate. Any filaments which are formed are easily cleaned up with conventional chemistry.
    Type: Grant
    Filed: July 6, 1989
    Date of Patent: August 20, 1991
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 5010378
    Abstract: A plasma dry etch process for etching deep trenches in single crystal silicon material with controlled wall profile, for trench capacitors or trench isolation structures. HCl is used as an etchant under RIE conditions with a SiO.sub.2 hard mask. The SiO.sub.2 hard mask is forward sputtered during the course of the Si etch so as to slowly deposit SiO.sub.x (x<2) on the sidewalls of the silicon trench. Since the sidewall deposit shadows etching at the bottom of the trench near the sidewall, the effect of this gradual buildup is to produce a positively sloped trench sidewall without "grooving" the bottom of the trench, and without linewidth loss. This process avoids the prior art problems of mask undercut, which generates voids during subsequent refill processing, and grooving at the bottom of the trench, which is exceedingly deleterious to thin capacitor dielectric integrity.
    Type: Grant
    Filed: February 20, 1990
    Date of Patent: April 23, 1991
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 5000820
    Abstract: A workpiece (W) is placed within a reaction chamber (12). The chamber (12) is evacuated (18) to a relatively low pressure such as 10 torr. An organic or nitrogen-based free radical precursor compound (36) is introduced into the reactor (12). A volume of the chamber (12) adjacent to the workpiece (W) is illuminated (28) with energy made up of one or more wavelengths in the range of about 200 to about 1300 nanometers such that an exposed surface (23) of the layer is illuminated (28). The free radical precursor compound is photodissociated in response to the illumination. Resulting free radicals are reacted with the exposed surface (23) of the workpiece (W) to create volatile compounds, which are removed from the chamber through a vacuum source (18).
    Type: Grant
    Filed: December 20, 1989
    Date of Patent: March 19, 1991
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 4999320
    Abstract: A method for suppressing ionization avalanches in a single wafer dry etch reactor is provided. An electron scavenging agent is mixed with helium gas in a container (32). The mixture of helium and the agent is introduced through an inlet (34) to a chamber (30) formed between a wafer (24), an O-ring (26) and a powered cathode (16). As free electrons are accelerated through a potential drop in the inlet and outlet (34 and 40), the electron scavenging agent combines with electrons to form anions. Partially due to the fact that anions are too massive to reach the energy level required to ionize helium, ionization avalanches of helium are suppressed and, thus, there is no arcing in the inlet and outlet (34 and 40).
    Type: Grant
    Filed: May 23, 1989
    Date of Patent: March 12, 1991
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 4984039
    Abstract: A plasma dry etch process for etching deep trenches in single crystal silicon material with controlled wall profile, for trench capacitors or trench isolation structures. HCl is used as an etchant under RIE conditions with a SiO.sub.2 hard mask. The SiO.sub.2 hard mask is forward sputtered during the course of the Si etch so as to slowly deposit SiO.sub.x (x<2) on the sidewalls of the silicon trench. Since the sidewall deposit shadows etching at the bottom of the trench near the sidewall, the effect of this gradual buildup is to produce a positively sloped trench sidewall without "grooving" the bottom of the trench, and without linewidth loss. This process avoids the prior art problems of mask undercut, which generates voids during subsequent refill processing, and grooving at the bottom of the trench, which is exceedingly deleterious to thin capacitor dielectric integrity.
    Type: Grant
    Filed: June 11, 1990
    Date of Patent: January 8, 1991
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 4980020
    Abstract: The disclosure relates to a method of forming a local interconnect by using a fluorine-based etchant with selectivity to cobalt and/or titanium silicide for removing unmasked portions of an electrically conductive interconnect pattern which is connected to a region of cobalt or titanium silicide.
    Type: Grant
    Filed: January 22, 1989
    Date of Patent: December 25, 1990
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 4957590
    Abstract: A method for etching titanium nitride local interconnects is disclosed. A layer of titaniun nitride is either formed as a by-product of the formation of titanium silicide by direct reaction or by deposition. The location of the interconnects is defined by patterning photoresist at the desired locations. A plasma etch using a chlorine-bearing agent such as CCl.sub.4 as the etchant etches the titanium nitride anisotropically at those locations covered by photoresist, and isotropically elsewhere, so that filaments of the titanium nitride are removed without undercutting the photoresist mask. The etch is selective relative to the underlying material, such as a refractory metal silicide, refractory metals, or silicon, due to the passivation of the underlying material by the carbon atoms of the CCl.sub.4. The selectivity, together with the selective anisotropy, even allows significant overetch of the material to remove the filaments without undercutting the masked interconnect material.
    Type: Grant
    Filed: September 5, 1989
    Date of Patent: September 18, 1990
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 4920073
    Abstract: The present invention provides a method for inhibiting the oxidation of a titanium layer during the direct reaction of the titanium with exposed silicon areas of an integrated circuit. In one embodiment of the present invention, a titanium nitride layer is formed on the surface of the titanium layer in the reactor where the titanium layer is deposited. The titanium nitride layer provides an effective barrier against oxidation. Thus, the formation of titanium dioxide is inhibited. In addition, in those areas where titanium nitride local interconnect is to be formed between diffused areas, the extra thickness provided by the top titanium nitride layer adds in the integrity of the conductive layers. By conducting the silicidation in a nitride atmosphere, diffusion of the nitride from the titanium nitride layer into the titanium layer and substitution of those lost nitrogen atoms by the atmosphere occurs thus providing a blocking layer for the formation of titanium silicide shorts.
    Type: Grant
    Filed: May 11, 1989
    Date of Patent: April 24, 1990
    Assignee: Texas Instruments, Incorporated
    Inventors: Che-Chia Wei, Thomas E. Tang, James G. Bohlman, Monte A. Douglas
  • Patent number: 4915777
    Abstract: A process wherein a thin film of tungsten is anisotropically etched under plasma bombardment conditions by using a feed gas mixture which includes an etchant and a carbon containing gas. This chemistry provides anisotropic high rate fluoro-etching with good selectivity to photoresist.
    Type: Grant
    Filed: March 2, 1989
    Date of Patent: April 10, 1990
    Assignee: Texas Instruments Incorporated
    Inventors: Rhett B. Jucha, Monte A. Douglas, Cecil J. Davis
  • Patent number: 4916511
    Abstract: A plasma dry etch process for etching deep trenches in single crystal silicon material with controlled wall profile, for trench capacitors or trench isolation structures. HCl is used as an etchant under RIE conditions with a SiO.sub.2 hard mask. The SiO.sub.2 hard mask is forward sputtered during the course of the Si etch so as to slowly deposit SiO.sub.x (x<2) on the sidewalls of the silicon trench. Since the sidewall deposit shadows etching at the bottom of the trench near the sidewall, the effect of this gradual buildup is to produce a positively sloped trench sidewall without "grooving" the bottom of the trench, and without linewidth loss. This process avoids the prior art problems of mask undercut, which generates voids during subsequent refill processing, and grooving at the bottom of the trench, which is exceedingly deleterious to thin capacitor dielectric integrity.
    Type: Grant
    Filed: January 6, 1989
    Date of Patent: April 10, 1990
    Assignee: Texas Instruments Incorporated
    Inventor: Monte A. Douglas
  • Patent number: 4891303
    Abstract: A method for patterning an integrated circuit workpiece (10) includes forming a first layer (16) of organic material on the workpiece surface to a depth sufficient to allow a substantially planar outer surface (36) thereof. A second, polysilane-based resist layer (22) is spin-deposited on the first layer (16). A third resolution layer (24) is deposited on the second layer (22). The resolution layer (24) is selectively exposed and developed using standard techniques. The pattern in the resolution layer (24) is transferred to the polysilane layer (22) by either using exposure to deep ultraviolet or by a fluorine-base RIE etch. This is followed by an oxygen-based RIE etch to transfer the pattern to the surface (18) of the workpiece (10).
    Type: Grant
    Filed: May 26, 1988
    Date of Patent: January 2, 1990
    Assignee: Texas Instruments Incorporated
    Inventors: Cesar M. Garza, Monte A. Douglas, Roland Johnson