Image sensor, method of fabricating the same, and exposure apparatus, measuring device, alignment device, and aberration measuring device using the image sensor

A back-illuminated image sensor comprising:

• a semiconductor base of a first conductive type;
• a plurality of charge accumulating units of a second conductive type different from said first conductive type, formed on a second-plane side which is the backside of a first plane of said semiconductor base, said charge accumulating units which accumulate, on a pixel-by-pixel basis, signal charges generated by an energy ray incident from the second-plane side;
• a charge transfer unit formed on the first-plane side of said semiconductor base facing said charge accumulating units, the charge transfer unit which transfers said signal charges to be read;
• a charge transport unit which transports said signal charges accumulated in said charge accumulating units to said charge transfer unit;
• and
• an invalid charge discharging unit which drives said charge transfer unit to discharge an invalid charge while said charge accumulating units accumulate said signal charges.

A back-illuminated image sensor comprising:

• a semiconductor base of a first conductive type;
• a plurality of charge accumulating units of a second conductive type different from said first conductive type, formed on a second-plane side which is the backside of a first plane of said semiconductor base, said charge accumulating units which accumulate, on a pixel-by-pixel basis, signal charges generated by an energy ray incident from the second-plane side;
• a charge transfer unit formed on the first-plane side of said semiconductor base facing said charge accumulating units, the charge transfer unit which transfers said signal charges to be read;
• a charge transport unit which transports said signal charges accumulated in said charge accumulating units to said charge transfer unit;
• and
• a dark current suppressing unit which approximates a potential of the first-plane side of said charge transfer unit to a substrate potential to suppress dark current flowing in from said first-plane side, at least during a predetermined period while said charge accumulating units accumulate said signal charges.

A back-illuminated image sensor comprising:

• a semiconductor base of a first conductive type;
• a plurality of charge accumulating units of a second conductive type different from said first conductive type, formed on a second-plane side which is the backside of a first plane of said semiconductor base, said charge accumulating units which accumulate, on a pixel-by-pixel basis, signal charges generated by an energy ray incident from the second-plane side;
• a charge transfer unit formed on the first-plane side of said semiconductor base facing said charge accumulating units, the charge transfer unit which transfers said signal charges to be read;
• a charge transport unit which transports said signal charges accumulated in said charge accumulating units to said charge transfer unit;
• and
• an excessive charge discharging unit which overflows an excessive charge into said charge transfer unit and drives said charge transfer unit to discharge said excessive charge, said excessive charge occurring due to exceeding a saturation charge amount of said charge accumulating units.

An image sensor comprising:

• a semiconductor base of a first conductive type;
• a plurality of charge accumulating units of a second conductive type different from said first conductive type, formed on a second-plane side which is the backside of a first plane of said semiconductor base, said charge accumulating units which accumulate, on a pixel-by-pixel basis, signal charges generated by an energy ray incident from the second-plane side;
• a charge transfer unit formed on the first-plane side of said semiconductor base facing said charge accumulating units, the charge transfer unit which transfers said signal charges to be read;
• and
• a charge transport unit which transports said signal charges accumulated in said charge accumulating units to said charge transfer unit, and wherein
• said charge transport unit applies a voltage to said semiconductor base to control said charge accumulating units in potential, whereby transports said signal charges in said charge accumulating units to said charge transfer unit.

A method of fabricating a back-illuminated image sensor, comprising:

• a thinning step of thinning a semiconductor base of a first conductive type;
• an accumulating unit forming step of forming, on one plane side of said semiconductor base thinned, a plurality of charge accumulating units of a second conductive type different from said first conductive type;
• and
• a layer forming step of forming, on the one plane side of said semiconductor base thinned, a depletion prevention layer of said first conductive type for preventing a surface deletion resulting from said charge accumulating units.

A back-illuminated image sensor comprising:

• a semiconductor base of a first conductive type;
• a plurality of charge accumulating units of a second conductive type different from said first conductive type, formed on a second-plane side which is the backside of a first plane of said semiconductor base, said charge accumulating units which accumulate, on a pixel-by-pixel basis, signal charges generated by an energy ray incident from the second-plane side;
• a charge transfer unit formed on the first-plane side of said semiconductor base facing said charge accumulating units, the charge transfer unit which transfers said signal charges to be read;
• a charge transport unit which transports said signal charges accumulated in said charge accumulating units to said charge transfer unit;
• and
• a barrier region provided on at least a part of transport paths of said signal charges formed between said charge accumulating units and said charge transfer unit, the barrier region which creates a peak of a potential barrier to block progress of said signal charges when no charge is to be transported and ensures full transportation of said signal charges by eliminating the peak of said potential barrier by said charge transport unit when a charge is transported.

A method of fabricating a back-illuminated image sensor having a barrier region, comprising the steps of:

• forming an epitaxial layer of a first conductive type on a first-plane side of a substrate;
• introducing impurities of said first conductive type into said epitaxial layer from said first-plane side to form a barrier region;
• introducing impurities of a second conductive type different from said first conductive type into said epitaxial layer so as to form a charge transfer unit in said first-plane side at a region located shallower than said barrier region as seen from said first-plane side;
• removing at least a part of said substrate to thin a second-plane side opposite of said first-plane side;
• and
• introducing impurities of said second conductive type from said second-plane side so as to form charge accumulating units in pixel-by-pixel arrangement.

A method of fabricating a back-illuminated image sensor having a barrier region, comprising the steps of:

• forming an epitaxial layer of a first conductive type on a first-plane side of a substrate;
• introducing impurities of said first conductive type into said epitaxial layer from said first-plane side to form a barrier region;
• introducing impurities of said first conductive type into the first-plane side of said first epitaxial layer at a region located shallower than said charge accumulating units as seen from said first-plane side, thereby forming a barrier region;
• forming a second epitaxial layer of said first conductive type on the first-plane side of said first epitaxial layer;
• introducing impurities of said second conductive type into the first-plane side of said second epitaxial layer to form a charge transfer unit;
• and
• removing at least a part of said substrate to thin a second-plane side opposite of said first-plane side.

A method of fabricating a back-illuminated image sensor having a barrier region, comprising the steps of:

• forming a first epitaxial layer of a first conductive type on a first-plane side of a substrate;
• introducing impurities of a second conductive type different from said first conductive type into said first epitaxial layer from the first-plane side so as to form charge accumulating units in pixel-by-pixel arrangement;
• forming a second epitaxial layer of said first conductive type on the first-plane side of said first epitaxial layer;
• introducing impurities of said first conductive type into the first-plane side of said second epitaxial layer so as to form a barrier region;
• introducing impurities of said second conductive type into the first-plane side of said second epitaxial layer at a region located shallower than said charge accumulating units as seen from the first-plane side, thereby forming a charge transfer unit;
• and
• removing at least a part of said substrate to thin a second-plane side opposite of said first-plane side.

A back-illuminated image sensor comprising:

• a semiconductor base of a first conductive type;
• a plurality of charge accumulating units of a second conductive type different from said first conductive type, formed on a second-plane side which is the backside of a first plane of said semiconductor base, said charge accumulating units which accumulate, on a pixel-to-pixel basis, signal charges generated by an energy ray incident from the second-plane side;
• a charge transfer channel formed on the first-plane side of said semiconductor base facing said charge accumulating units, the charge transfer channel which transfers said signal charges;
• and
• transfer electrodes which apply a transfer voltage to said charge transfer channel, and wherein
• said transfer electrodes are provided in a charge transfer direction of said charge transfer channel, in proportion of substantially two or less said transfer electrodes per one said charge accumulating unit.

An exposure apparatus comprising:

• an exposure unit which projects an exposure pattern onto a substrate to be exposed, through a projection optical system;
• an aberration measuring optical system which emits a pencil of light for aberration measurement to said projection optical system;
• a condenser lens which condenses said pencil of light to pass through said projection optical system onto an imaging plane of said image sensor;
• a position detecting unit which is electrically connected to said image sensor and detects positional information of said pencil of light condensed on said imaging plane;
• and
• an operation unit which is electrically connected to said position detecting unit and determines an aberration of said optical system to be measured, according to a detection result from said position detecting unit.

A method of fabricating a device comprising:

• a mark forming step of forming a first alignment mark on a first-plane side of a substrate;
• a base forming step of forming a base portion of a device on the first-plane side of said substrate;
• a first-plane side processing step of forming a first structure on the first-plane side of said base portion by using, as a reference, one of a projection and a depression which appears on the first-plane side of said base portion in the process of forming said base portion;
• a removing step of removing said substrate from a second-plane side of said base portion opposite to said first-plane side;
• and
• a second-plane side processing step of forming a second structure on the second-plane side of said base portion by using, as a reference, a second alignment mark which appears on the second-plane side of said base portion in the process of removing said substrate, said second structure being different from said first structure.

A method of fabricating a device comprising:

• a base forming step of forming a base portion of a device on a first-plane side of a substrate;
• a to-be removed region forming step of forming, in said base portion, a to-be-removed region which reaches said substrate and is selectively removable;
• a mark forming step of forming a first alignment mark on the first-plane side in said to-be-removed region;
• a first-plane side processing step of forming a first structure on the first-plane side of said base portion by using said first alignment mark as a reference;
• a layer forming step of forming a layer to cover at least said first alignment mark;
• a removing step of removing said substrate and said to-be-removed region from a second-plane side of said base portion which is opposite of said first-plane side;
• and
• a second-plane side processing step of forming a second structure on the second-plane side of said base portion by using, as a reference, a second alignment mark which appears on the second-plane side in the process of removing said substrate, said second structure being different from said first structure.

A method of fabricating a device comprising:

• a mark forming step of forming a first alignment mark on a first-plane side of a substrate;
• a base forming step of forming a base portion of a device on the first-plane side of said substrate;
• a step of forming a first structure on the first-plane side of said base portion by using, as a reference, one of a projection and a depression which appears on the first-plane side of said base portion in the process of forming said base portion;
• a processing step of forming a predetermined structure on the first-plane side of said base portion by using, as a reference, a second alignment mark which appears on the second-plane side of said base portion in the process of removing said substrate, said second structure being different from said first structure.

A method of fabricating a device comprising:

• a mark forming step of forming a first alignment mark being one of a projection and a depression on a first-plane side of a substrate;
• a base forming step of forming a base portion of a device on the first-plane side of said substrate;
• a removing step of removing said substrate from a second-plane side of said base portion which is opposite to the first-plane side, so that a second alignment mark appears on the second-plane side of said base portion;
• and
• a processing step of forming a predetermined structure on the second-plane side of said base portion by using said second alignment mark as a reference.

A method of fabricating a device comprising:

• a base forming step of forming a base portion of a device on a first-plane side of a substrate, where a first alignment mark is formed;
• a to-be-removed region forming step of forming a to-be-removed region in said base portion, said to-be-removed region reaching said substrate and being selectively removable;
• a layer forming step of forming a layer to cover at least said first alignment mark;
• a removing step of removing said substrate and said to-be-removed region from a second-plane side of said base portion which is opposite to the first-plane side, so that a second alignment mark appears on the second-plane side of said base portion;
• and
• a processing step of forming a predetermined structure on the second-plane side of said base portion by using said second alignment mark as a reference.

A method of fabricating a device comprising:

• a base forming step of forming a base portion of a device on a first-plane side of a substrate;
• a to-be-opened region forming step of forming a to-be-opened region in a to-be-opened area of said base portion during or after the process of forming said base portion, said to-be-opened region reaching said substrate and being selectively removable;
• and
• a removing step of removing said substrate and said to-be-opened region from a second-plane side of said base portion, which is opposite to the first-plane side, so that an opening hole (a trace of said removed to-be-opened region) appears on the second-plane side of said base portion.