Patent Application
20070065958
In general, photonics, also referred to as optoelectronics, deals with technologies that generate, modulate, guide, amplify, or detect light. The worldwide utilization of photonics devices is growing and adapting at a rapid pace as more and more applications use optoelectronic devices to enhance performance, reduce size, or reduce cost. For example, fiber-optic cables provide much higher bandwidth than conventional copper wires and thus support a broader range of commercial applications, including real-time multimedia applications.
In the area of microelectronics, “packaging” refers to the encapsulation of microelectronic components into a form that can easily be connected into a circuit, i.e., attaching an electronic circuit, e.g., an integrated circuit (“IC”), onto a printed-circuit board (“PCB”), substrate, carrier, or lead-frame resulting in an encapsulated package. In the area of photonics, packaging may also include providing an optical connection, e.g., using an optical filter that is highly directional in nature and requires extremely precise control of positional tolerances between the electronic and the photonics components.
Manufacturing costs of photonics devices have been a drawback to the more widespread use of these devices. Therefore, there is a need to reduce the costs to fabricate photonics components so as make them more viable in commercial applications. A portion of the market for photonics devices deals with high-performance components manufactured in low volume, primarily for military applications, where costs are relatively unimportant. However, there is also a need to develop efficient, high-volume manufacturing processes for commercial applications, such as devices connecting a consumer's electronic equipment to an optical network. It has been estimated that packaging, which includes methods for aligning optical elements and integrating photonics and electronics components, currently accounts for 60 to 80 percent of the manufacturing cost of photonics components.
As an example,
In the next step 108, singulation, the many individual devices of the encapsulated package produced in step 105 are physically separated into individual encapsulated packages 110 for subsequent packaging with a photonics component. This may be accomplished by sawing, stamping, or laser singulation. It is appreciated by those skilled in the art that these first four steps may be conventional processes originally developed in the semiconductor industry.
The encapsulation process with an optical device starts in step 110, with the application of an adhesive to a single encapsulated package. The adhesive may be a glue, an epoxy resin, a light-curable adhesive, which may include an ultraviolet (“UV”) curable composition, and other attachment means. In step 114, an optical device may be aligned and attached to the encapsulated package utilizing the adhesive applied in step 110. The optical device may be an optical filter that may be fabricated on a large glass substrate. One type of optical filter is an interference filter, where the finished filter may include multiple substrates laminated together to produce a specifically-desired resolution patterning. These filters may be fabricated in the form of a large glass wafer of varying dimensions that may be diced into smaller components in either a circular, square, or rectangular configuration. Once the optical device is attached, the entire package is then cured in step 116, resulting in a completed encapsulated package in step 118.
In
Additional steps, e.g., curing, baking, sealing, testing, marking, etc., are utilized to produce the finished product. However, it is appreciated that the main steps of the assembly process are shown in
Therefore, there is a need for an improved method of manufacturing photonics devices that is more efficient and reduces the costs of fabrication associated with the previous methods of manufacture.
In general, this invention is a method for attaching an optical device to an encapsulated electronic package prior to singulation in order to reduce misalignment problems, thereby increasing the efficiency of the manufacturing process and reducing the costs of manufacturing. As an example, the method may include applying an adhesive to the encapsulated electronic package in the form of a single component having multiple dies, aligning the optical device relative to the single component, and then attaching the optical device to the single component using the adhesive. The method may also include curing the single component with the attached optical device and then singulating the single component into a plurality of separate encapsulated packages, each with a portion of the optical device attached. By singulating the single component together with the optical device attached, the process cycle time is reduced significantly, and at the same time, problems related to misalignment of the optical filters with a singulated electronic package are also reduced.
As another example of a method for attaching an optical device to an encapsulated electronic package prior to singulation, the method may include dicing an unsingulated optical device having multiple optical devices into a plurality of separated optical devices, applying an adhesive to the single component, aligning each of the separated optical devices relative to the single component, and attaching each of the separated optical devices to the single component using the adhesive. The method may also include curing the single component with the attached plurality of separated optical devices and then singulating the single component with the attached plurality of separated optical devices into a plurality of separate encapsulated packages, each separate encapsulated package with a separated optical device attached to a single die of the encapsulated electronic package. This method also reduces the process cycle time significantly, as well as misalignment and handling-damage problems.
Other systems, methods and features of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.
The invention can be better understood with reference to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
In the following descriptions of example embodiments, reference is made to the accompanying drawings that form a part hereof, and which show, by way of illustration, a specific embodiment in which the invention may be practiced. Other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
In general, the invention is a method of attaching an optical device to an encapsulated electronic package prior to singulation in order to reduce misalignment problems, thereby increasing the efficiency of the manufacturing process and reducing the costs of manufacturing.
In
In step 310, a single large optical device is aligned and attached to the encapsulated package. As an example, the optical device may be an optical filter fabricated on a large glass substrate and may include multiple substrates laminated together. Optical filters may also include interference filters, which are filters having multiple layers (thin coatings) of dielectric materials on a substrate where the selection of the materials and the thickness of the layers are chosen to provide specifically-customized resolution patterning, i.e., reflection or transmission of light at a desired wavelength. This large glass wafer may be fabricated to the desired specification and then diced into smaller components of varying configurations. In this example, the glass wafer may be designed to completely cover the encapsulated package, as shown in
In step 312, the encapsulated package with the attached optical device is cured. Curing may involve the application of heat or illumination by short-wavelength light depending on the type of adhesive used.
After curing, the encapsulated package is singulated in step 314. It is appreciated by those skilled in the art that there are various methods of singulation, e.g., laser scribing and diamond wheel sawing. As an example, sawing may be utilized to either partially cut or scribe the surface of the encapsulated package, with the encapsulated package then broken along the saw lines, or to completely cut through the encapsulated package. Another example is dry process dicing, where a diamond scribe tool creates a stress line on the encapsulated package and a breaking mechanism fractures the encapsulated package along the stress line. The advantages of this process are narrower dicing cuts and less residual stress in the sides of the encapsulated package.
The process ends in step 316 with multiple photonics components obtained from the singulation of the encapsulated package. Each of these photonics components may require additional processing to obtain the final product, e.g., testing, marking, etc. Marking may include placing corporate and product identification on a photonics component using ink or laser marking.
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In step 510, a single large optical device is singulated into a plurality of separate smaller optical devices. As an example, the optical device may be an optical filter fabricated on a large glass substrate and may include multiple substrates laminated together, and the smaller optical devices may be in either a circular, square, or rectangular configuration.
The process then proceeds to step 512, where the smaller optical devices produced in step 510 are individually aligned and attached to encapsulated package produced in step 506. In step 512, as an example, the smaller optical devices may be positioned equidistant along the X and Y axes of the encapsulated package 500 so as to allow optimal singulation; that is, the smaller optical devices may be positioned on the encapsulated package so as to maximize the number of components produced per each encapsulated package or to minimize the number of sawing cuts required to singulate the encapsulated package.
In step 514, the encapsulated package with the attached optical device is cured. Curing may involve the application of heat or illumination by short-wavelength light depending on the type of adhesive used. After curing, the encapsulated package is singulated in step 516. It is appreciated by those skilled in the art that there are various methods of singulation, e.g., laser scribing and diamond wheel sawing. As an example, sawing may be utilized to either partially cut or scribe the surface of the encapsulated package, with the encapsulated package then broken along the saw lines, or to completely cut through the encapsulated package.
The process ends in step 518 with multiple photonics components obtained from the singulation of the encapsulated package. Each of these photonics components may require additional processing to obtain the final product, e.g., testing, marking, etc. Marking may include placing corporate and product identification on a photonics component using ink or laser marking.
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It will be understood that the foregoing description of numerous implementations has been presented for purposes of illustration and description. It is not exhaustive and does not limit the claimed inventions to the precise form disclosed. Modifications and variations are possible in light of the above description or may be acquired from practicing the invention. The claims and their equivalents define the scope of the invention.
