Use of barrier refractive or anti-reflective layer to improve laser trim characteristics of thin film resistors
AssigneeIntersil Corporation
InventorMichael J. Morrison
Life of this patent
Estimating the term…
Abstract
A precision resistor of NiCr or SiCr has a refractive and thermal barrier layer beneath the resistor. The refractive barrier is a layer of refractory metal. The refractory metal prevents the incident laser beam of a laser trimmer penetrating lower layers of the device. Unwanted reflections and refractions caused by lower layers are avoided. The reflective barrier layer is a material selected from the group consisting of tungsten, titanium, molybdenum, TiSi2l3,14, CoSi215, MoSi2, TaSi2 and WSi2.
Claims7
An integrated circuit with a precision trimmable resistor comprising:
- a semiconductor device substrate;
- one or more devices or an integrated circuit formed in the substrate;
- an opaque reflective layer disposed over the substrate for reflecting a trimming laser beam;
- a trimmable resistor layer disposed over the reflective layer;
- and
- a transparent insulating layer disposed over the substrate between the reflective layer and the trimmable resistor layer.
An integrated circuit with a trimmable precision resistor layer comprising:
- a handle substrate;
- a bond oxide layer for bonding the handle wafer to a device substrate;
- a device substrate;
- a refractory, reflective barrier metal layer over the device substrate for reflecting incident laser light;
- a thermal barrier on the refractory, reflective barrier metal layer for insulating superior layers from heat generated when laser light strikes the refractory, reflective metal layer;
- a laser trimmable precision resistor layer over the thermal barrier layer;
- a planarized oxide layer over the laser trimmable precision resistor layer;
- and
- a passivation layer over the planarized oxide layer.
Dependencies are inferred from the claim text.