Semiconductor Components Industries, LLC

Nathan Wayne Chapman

Swarnal Borthakur

Marc Allen Sulfridge

Brian A Vaartstra

Ulrich C Boettiger

Amanda Thuy Trang Vu

An imaging device may include a plurality of single-photon avalanche diode (SPAD) pixels. The SPAD pixels may be overlapped by microlenses to direct light incident on the pixels onto photosensitive regions of the pixels and a containment grid with openings that surround each of the microlenses. During formation of the microlenses, the containment grid may prevent microlens material for adjacent SPAD pixels from merging. To ensure separation between the microlenses, the containment grid may be formed from material phobic to microlens material, or phobic material may be added over the containment grid material. Additionally, the containment grid may be formed from material that can absorb stray or off-angle light so that it does not reach the associated SPAD pixel, thereby reducing crosstalk during operation of the SPAD pixels.

Microlens structures for semiconductor device with single-photon avalanche diode pixels

An image sensor with uniform, well-controlled air gaps is provided. A structure that is at least partially filled with organic material may be formed on the image sensor. A hybrid organic/inorganic film layer may be formed over the organic material. The image sensor may then be exposed to energy, which causes the organic material to sublimate through the hybrid film layer, which itself may become a gas permeable layer when exposed to energy. After sublimation, the regions where the organic material was previously filled become air gaps with a low index of refraction. Air gaps formed in this way can be configured over photodiodes as light guides or focusing structures, as concave/convex microlenses, in between photodiodes as isolation structures, in between color filter elements to reduce crosstalk, and/or over microlenses to enhancing focusing power.

Methods for using a gas permeable layer to form air gaps in an image sensor

An image sensor may include high dynamic range imaging pixels having an inner sub-pixel surrounded by an outer sub-pixel. To steer light away from the inner sub-pixel and towards the outer sub-pixel, the high dynamic range imaging pixels may be covered by a toroidal microlens. To mitigate cross-talk caused by high-angled incident light, various microlens arrangements may be used. A toroidal microlens may have planar portions on its outer perimeter. A toroidal microlens may be covered by four additional microlenses, each additional microlens positioned in a respective corner of the pixel. Each pixel may be covered by four microlenses in a 2&#xd7;2 arrangement, with an opening formed by the space between the four microlenses overlapping the inner sub-pixel.

Microlenses for high dynamic range imaging pixels

An image sensor may include an array of pixels having a color filter layer. The color filter layer may include colored elements and clear elements. The clear elements may be formed from transparent dielectric material. The color filter layer may include a grid of light-blocking material that forms color filter container structures having an array of openings in which the colored elements and the clear elements are formed. The color filter container structures may be formed from the same transparent dielectric material that forms the clear elements. The color filter container structures may be formed from opaque materials or transparent materials that form structures such as planarization layers, microlenses, or antireflection coatings for the array of pixels. The material used to form the color filter container structures may have a refractive index that is sufficiently high to prevent light from passing between adjacent elements in the color filter layer.

Structures and methods of creating clear pixels

Global shutter imaging pixels may include a charge storage region that receives charge from a respective photodiode. Global shutter imaging pixels may be formed as frontside illuminated imaging pixels or backside illuminated imaging pixels. Shielding charge storage regions from incident light may be important for image sensor performance. To shield charge storage regions in backside illuminated global shutter imaging pixels, shielding structures may be included over the charge storage region. The shielding structures may include backside trench isolation structures, a metal layer formed in a backside trench between backside trench isolation structures, and frontside deep trench isolation structures. The metal layer may have angled portions that reflect light towards the photodiodes.

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Middleton, ID, United States of America

Nathan Wayne Chapman