Package trays for semiconductor packages and related methods

Abstract

The invention relates to a package tray for a semiconductor package and a related method. Particular implementations of a package tray may include a base and a grid of electromagnetic radiation reflectors coupled to a largest plane side of the base; wherein sidewalls of the electromagnetic radiation reflector grid may be configured to direct electromagnetic radiation to sides of a plurality of semiconductor packages located within the grid. The electromagnetic radiation may be configured to facilitate curing components of the plurality of semiconductor packages.

Description

Background Art 1. Technical Field

[0001] Aspects of this document generally relate to semiconductor devices. More specific implementations relate to image sensor devices. 2. Background technology

[0003] Semiconductor packages have been designed for various semiconductor devices. Semiconductor packages include structures that route electrical signals from the semiconductor die to a motherboard or circuit board to which the semiconductor package is attached. Other semiconductor packages include structures for protecting the semiconductor die from electrostatic discharge, moisture, or shock and vibration forces. Summary of the invention

[0004] A specific implementation of a package tray may include a base and an electromagnetic radiation reflector grid coupled to a largest planar side of the base; wherein the sidewalls of the electromagnetic radiation reflector grid may be configured to direct electromagnetic radiation toward the sides of a plurality of semiconductor packages located within the grid. The electromagnetic radiation may be configured to assist in curing components of the plurality of semiconductor packages.

[0005] Specific implementations of packaging trays may include one, all, or any of the following:

[0006] The electromagnetic radiation may be ultraviolet light.

[0007] The electromagnetic radiation may be emitted by an electromagnetic radiation source that is directed substantially directly above the largest planar surface of the base.

[0008] The sidewalls of the grid include a triangular cross-sectional shape or a curved cross-sectional shape.

[0009] The sidewalls of the grid may be triangular, and the angles of two vertices of the triangular cross-sectional shape adjacent to the base may be substantially 45 degrees.

[0010] The sidewalls of the grid may be triangular, and wherein the angle of two vertices of the triangular cross-sectional shape adjacent to the base may be between 45 degrees and 60 degrees.

[0011] The side walls of the grid include a closed cross-sectional shape that may include at least two line segments that make approximately 45 degree angles with a plane formed by the largest planar surface of the base.

[0012] The grid may be integral with the base.

[0013] Specific implementations of a packaging tray may include a base including a maximum planar surface including an electromagnetic radiation reflector grid coupled thereto; wherein side walls of the electromagnetic radiation reflector grid may be angled with a plane formed by the maximum planar surface of the base.

[0014] Specific implementations of packaging trays may include one, all, or any of the following:

[0015] The sidewalls direct electromagnetic radiation toward the sides of the plurality of semiconductor packages located within the grid.

[0016] The electromagnetic radiation may be ultraviolet light.

[0017] The electromagnetic radiation may be emitted by an electromagnetic radiation source that is directed substantially directly above the largest planar surface of the base.

[0018] The sidewalls of the grid include a triangular cross-sectional shape.

[0019] A specific implementation of the method for curing multiple semiconductor packages included in a packaging tray includes: providing a base and an electromagnetic radiation reflector grid coupled to the largest planar side of the base; placing multiple semiconductor packages into openings in the grid against the base; using the side walls of the electromagnetic radiation reflector grid to direct electromagnetic radiation to the side of each semiconductor package in the multiple semiconductor packages located in the grid; and curing components of the multiple semiconductor packages using the electromagnetic radiation.

[0020] Specific implementations of the method of curing a plurality of semiconductor packages may include one, all, or any of the following:

[0021] The electromagnetic radiation may be ultraviolet light.

[0022] The method may further include emitting the electromagnetic radiation from an electromagnetic radiation source oriented substantially directly above the largest planar surface of the base.

[0023] The sidewalls of the grid may include a triangular cross-sectional shape.

[0024] Angles of two vertices of the triangular cross-sectional shape adjacent to the base may be substantially 45 degrees.

[0025] Angles of two vertices of the triangular cross-sectional shape adjacent to the base may be between 45 degrees and 60 degrees.

[0026] The side walls of the grid include a closed cross-sectional shape that may include at least two line segments that make approximately 45 degree angles with a plane formed by the largest planar surface of the base.

[0027] The foregoing and other aspects, features and advantages will be apparent to those skilled in the art from the detailed description and accompanying drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Specific implementations will be described below in conjunction with the accompanying drawings, in which like reference numerals represent like elements, and:

[0029] Figure 1 is a perspective partial view of an ultraviolet (UV) light curing device and a packaging tray;

[0030] Figure 2 This is another partial perspective view of the UV light curing equipment and packaging tray;

[0031] Figure 3 is a cross-sectional view of an image sensor package before overmolding;

[0032] Figure 4 is a top-down view of a package tray having a grid of electromagnetic radiation reflectors, wherein a plurality of image sensor packages are disposed within the grid;

[0033] Figure 5 is a side cross-sectional view of a portion of an electromagnetic radiation reflector grid and a base of a packaging tray embodiment; and

[0034] Figure 6 A side cross-sectional view of a portion of an electromagnetic radiation reflector grid and a base of another packaging tray embodiment. DETAILED DESCRIPTION

[0035] The present disclosure, its aspects, and implementations are not limited to the specific components, assembly processes, or method elements disclosed herein. Many additional components, assembly processes, and / or method elements known in the art that are consistent with the intended packaging tray will be readily apparent for use with specific implementations of the present disclosure. Thus, for example, although the present invention discloses specific implementations, such implementations and implementation components may include any shape, size, style, type, model, version, measurement, concentration, material, quantity, method element, step, etc. known in the art for such packaging trays and implementation components and methods that are consistent with the intended operation and method.

[0036] See also Figure 3, a cross-sectional view of a specific implementation of an image sensor package 2 is shown. As shown, the image sensor package 2 includes an image sensor die 4, which includes a pixel array 6, and an optically transmissive cover 8 is coupled to the pixel array via a glass adhesive / dam material 10. In this package, the bonding wires 12 have been formed before the glass adhesive material 10 is applied, so the image sensor package can be referred to as a lead-in-dam package design. Due to the presence of the bonding wires 12, the glass adhesive 10, and the bonding pads, additional stray light reflected from the materials of the bonding wires and bonding pads into the pixel array can cause performance degradation, including flare / glare in the image generated by the pixel array and the image sensor package. To help prevent light reflection or flare / glare, a black masking material 14 is placed under the optically transmissive cover 8 to form a band around the perimeter of the optically transmissive cover 8, which absorbs light transmitted through the bonding wires 12 and the optically transmissive cover above the pads and prevents the light from reaching these bonding wires and these pads. As shown Figure 3 As shown, the image sensor die 4 is bonded to a substrate 16 (in this case a land grid array substrate) which is used to route electrical signals from the image sensor die 4 to the circuit / motherboard to which the image sensor package 2 is ultimately attached. Figure 3 Not shown, but in various implementations, a molding compound is disposed around the bond wires, substrate 16, glass adhesive 10, and optically transmissive cover 8 to help seal the edges of the package and provide additional light blocking.

[0037] While the black mask 14 is used to reduce / eliminate reflections of stray light (flash / glare) during device operation, it also successfully prevents ultraviolet (UV) light from reaching the glass adhesive 10 during the UV curing operation of the glass adhesive 10. As a result, it has been observed that the curing achieved by the glass adhesive 10 during the UV curing operation is irregular around the perimeter of the image sensor package 2 and is irregular between a group of image sensor packages arranged in a packaging tray. Problems resulting from uneven curing of the glass adhesive 10 can lead to mechanical and chemical failures, leading to electrical failures and reliability issues. In some cases, mechanical failures have included delamination and intrusion of molding compound into the weir area. Chemical failures have included corrosion of bonding wires and / or pads caused by migration of ions through uncured / partially cured glass adhesive material during operation / testing. Over time, corrosion can lead to electrical failures as detected by reliability testing.

[0038] See also Figure 1, a perspective partial view of a specific implementation of the UV light curing device 16 is shown. For ease of illustration, only portions of the device are shown here, but those components (bulbs, electrical connectors, housings, etc.) that are included in various specific implementations to assist in the UV curing operation are not shown. A packaging tray 18 is shown within the UV light curing device 16, and a plurality of image sensor packages 20 are disposed thereon. As shown, a central UV light source 22 in the form of a bulb (not shown) that emits diffuse UV light of a desired frequency is placed between a central reflector 24, which is used to direct the UV light diffusely emitted from the bulb downwardly toward the packaging tray 18. Adjacent to the packaging tray 18 is a secondary reflector 19, which is oriented at approximately 90 degrees to the central reflector 24, and is used to guide the packaging tray 18 downwardly when the packaging tray 18 is passed through a conveyor belt or other transportation equipment (for illustration purposes, Figure 1 When a UV light curing device 16 is mounted on the packaging tray (not shown), the secondary reflector is used to focus the diffusely emitted UV light onto the width of the packaging tray. To help generate additional UV light, an array of UV light emitting diodes 26 are placed at an angle to the packaging tray to help increase the amount of UV light that can reach under the black mask material and promote the curing reaction in the glass adhesive material. Figure 2 is a view of the UV light curing device 16 with the center reflector removed to show a better angle of the array of light emitting diodes 26 relative to the packaging tray 18 .

[0039] Figure 1 The challenge presented by the configuration of the UV light source and reflector in the UV light curing apparatus 16 shown is that the actual illumination experienced by the glass adhesive material present in the sidewalls extending around the periphery of each image sensor package is a factor of the location of each image sensor package in the packaging tray due to the non-uniformity of the illumination provided by the apparatus itself and due to the blocking and shadowing of the glass adhesive material by the black mask and / or adjacent image sensor packages. Assessing the effects of these non-uniformities is a complex undertaking because it involves many different variables and the location of each image sensor package within the packaging tray. In addition, because the UV light source in this system is a diffuse light source as opposed to a coherent light source (such as a laser light source), the ability to direct each diffuse ray of UV light to a desired location is limited by time averaging effects. Although the diffuse UV light could theoretically reach every location in the glass adhesive material if the packaging tray was kept in the light for an infinite amount of time, this is not practical for high volume image sensor packaging operations.

[0040] See also Figure 4, shows a top-down view of a specific implementation of a package tray 28 having an electromagnetic radiation reflector grid 30 thereon, with a plurality of image sensor packages 32 disposed in openings 34 formed by the grid 30. As shown, the electromagnetic radiation reflector grid 30 surrounds the entire perimeter of each of the image sensor packages 32 and is used to direct diffusely emitted UV light from the UV light curing device 16 and / or light from the light emitting diodes 26 into / at the edges of each of the image sensor packages 32.

[0041] See also Figure 5 , shows a side cross-sectional view of a specific implementation of a portion of an electromagnetic radiation reflector grid 36 coupled to a base 38. Here, the cross-sectional shape of the sidewall 40 of the grid 36 is triangular - in this case, an equilateral triangle. Arrows 42 / 44 show the direction of UV light emitted diffusely from a UV light source in the device, which is incident substantially perpendicularly on the sidewall 40, reflects toward the sidewall and glass adhesive material 46, and for illustration purposes, is shown in FIG. Figure 5 , shown as opposing triangles. Thus, the use of the electromagnetic radiation reflector grid 36 is designed to help direct diffusely emitted UV light to the glass adhesive material all the way around the perimeter of each image sensor package 48. In this way, the use of the electromagnetic radiation reflector grid can be used to help counter the effect of one image sensor package being shaded by another image sensor package. The grid or electromagnetic radiation reflector can also help direct as much UV light as possible to the glass adhesive material in a given amount of time. This can reduce the time required to achieve the desired cure of the glass adhesive material 46, and / or can reduce the amount of non-uniformity of the glass adhesive material 46 that is cured around each image sensor package, regardless of its position in the grid of the packaging tray. In this way, the mechanical and electrical problems mentioned above can be minimized or eliminated.

[0042] Although Figure 5 The angles of the vertices of the triangular cross-sectional shape of the electromagnetic radiation reflector grid 30 are approximately 60 degrees (the angle of an equilateral triangle), but in other embodiments, the angles may be greater or less than 60 degrees. Figure 6, shows an implementation in which the angle 50 of two opposing vertices of the cross-sectional shape is about 45 degrees. In this implementation, arrows 52, 54 indicate that diffuse UV light rays falling substantially above the electromagnetic radiation reflector grid 56 are directed substantially parallel to the largest planar surface / side 60 of the base 58. In various implementations, the angle of the two vertices of each triangular cross-sectional shape may be between about 45 degrees and about 60 degrees. In such implementations, the sidewalls include line segments 62 that are angled at an angle to each of the two vertices, or angled to the plane formed by the largest planar surface 50 of the base 58. In other implementations, the angle of the two vertices may be less than 45 degrees or greater than 60 degrees.

[0043] Although Figures 4 to 6 The implementation shown in utilizes the sidewalls of the electromagnetic radiation reflector grid with line segments, but in other implementations, the sidewalls may be curved in a concave or convex direction, depending on the angle of incidence of the light leaving the diffusely reflected UV light source. The grid shape and reflector shape can be customized to obtain optimal UV lighting conditions on the sidewalls of the sensor package. In various implementations, by way of non-limiting example, the grid shape and / or sidewalls of the electromagnetic radiation reflector may be triangular, trapezoidal, circular, polygonal, or any other closed shape. For example, the central reflector 24 and the secondary reflector 26 are bent at a desired angle to help focus the diffusely emitted UV light at a desired focal point below the reflector. The use of curved sidewalls will similarly allow the diffusely emitted incident UV radiation to be focused at a desired position / point / area along the sidewalls of the image sensor package such as a glass adhesive material, thereby helping to concentrate the curing light into the adhesive material. In this way, problems associated with uneven curing of the glass adhesive material can be minimized or eliminated, while the total curing time can be reduced. In various sidewall implementations, the surface of the sidewall may be angled, curved, or have a structured texture, such as a light scattering or light diffusing texture, in combination with any of the other sidewall angles or shapes disclosed herein.

[0044] The material of the electromagnetic radiation reflector grid can be made of a variety of electromagnetic reflective materials, such as mirror polished aluminum, diffuse surface aluminum, aluminum, chrome, mirror glass, metal, chrome-plated mirror plastic, chrome-plated ceramic, or any other material capable of reflecting electromagnetic radiation of a desired wavelength, by way of non-limiting examples. The material of the base can be any of a variety of material types, including, by way of non-limiting examples, aluminum, steel, brass, plastic, resin, or any other material capable of maintaining a planar shape. In a particular implementation, the material of the electromagnetic radiation reflector grid can be the same as the material of the base. In such implementations, the electromagnetic radiation reflector grid can be integrated with the material of the base. In the case where the electromagnetic radiation reflector grid is integrated with the base, the sidewall surface of the electromagnetic radiation reflector grid can be additionally processed, including, by way of non-limiting examples, polishing, electropolishing, mirror reflection, chrome plating, electroplating, or chemical plating. After the processing of the sidewall is completed, the packaging tray can then be used.

[0045] In a specific implementation of the method for curing a plurality of semiconductor packages, various packaging trays can be used for implementation. The method includes providing a base and a grid of electromagnetic radiation reflectors coupled to the largest planar side of the base. These electromagnetic radiation reflectors can be of any type disclosed in this document. The base and the grid of electromagnetic radiation reflectors can be made of any material disclosed in this document, as well as in various specific implementations.

[0046] The method also includes placing a plurality of semiconductor packages into openings in the grid against the base. In various method implementations, the process of placing a plurality of semiconductor packages may occur in the initial step of package formation, wherein the substrate is initially placed in the opening in the grid, and then when the substrate is resting in the opening in the grid, subsequent packaging operations such as die attachment, wire bonding, glass adhesive application and optical transmission cover placement are performed. In these implementations, the packaging tray acts as a packaging assembly vehicle. However, in other method implementations, the operations of die attachment, wire bonding, glass adhesive and optical transmission cover placement may occur at the wafer level or panel level, and the segmentation operation is performed using a glass adhesive in a partially cured or b-stage cured state. After the segmentation operation, a pick-and-place tool or other device may be used to select the segmented package and place it individually into the opening of the electromagnetic radiation reflector grid. In other implementations, each image sensor package may be formed individually on a separate substrate by a die attachment operation, a wire bonding operation, a glass adhesive application operation and an optical transmission cover attachment operation, and then individually placed into each opening of the electromagnetic radiation reflector grid.

[0047] In the case where multiple image sensor packages are placed into the openings of the electromagnetic radiation reflector grid, the method includes using the sidewalls of the electromagnetic radiation reflector grid to direct electromagnetic radiation to the sides / sidewalls of each semiconductor package in the multiple semiconductor packages. The type of electromagnetic radiation can be any of a variety of types, including, by way of non-limiting example, UV, IR, visible light, microwaves, x-rays, or any other type of electromagnetic radiation. The shape of the sidewall of the electromagnetic radiation reflector can be any shape disclosed in this document, and it can also have any cross-sectional shape disclosed herein. In addition, the various sidewalls can also be angled at any set of angles or ranges of angles disclosed herein. The method also includes curing components of the multiple semiconductor packages using electromagnetic radiation to induce a chemical reaction in the components.

[0048] In this document, implementations have disclosed the use of UV light to cure the glass adhesive material. However, in other method and system implementations as disclosed herein, the material being cured may be different from or in addition to the glass adhesive material, including, by way of non-limiting example, molding compound, black mask material, weir material, die bonding material, microlens material, gapless material between an optically transmissive cover and a pixel array, or any other material type that can be partially or fully cured using electromagnetic radiation.

[0049] Specific implementations of the packaging tray include wherein the electromagnetic radiation is emitted by an electromagnetic radiation source that is directed substantially directly above the largest planar surface of the base.

[0050] Particular implementations of the packaging tray include wherein the electromagnetic radiation is ultraviolet light.

[0051] Specific implementations of the packaging tray include those in which the grid is integral with the base.

[0052] Specific implementations of the packaging tray include where the sidewalls of the grid are triangular, and the angles of two vertices of the triangular cross-sectional shape adjacent to the base are substantially 45 degrees.

[0053] Specific implementations of the packaging tray include wherein the sidewalls of the grid include a closed cross-sectional shape including at least two line segments that make approximately 45 degree angles with a plane formed by a largest planar surface of the base.

[0054] Where the above description relates to specific embodiments and implementation components, sub-components, methods and sub-methods of packaging trays, it should be apparent that various modifications may be made without departing from the essence thereof and that these embodiments, implementation components, sub-components, methods and sub-methods may be applied to other packaging tray types.

Claims

1. A packaging tray, comprising: Base; as well as an electromagnetic radiation reflector grid coupled to the largest planar side of the base; wherein the sidewalls of the electromagnetic radiation reflector grid are configured to direct electromagnetic radiation toward sides of a plurality of semiconductor packages located within the grid; and The electromagnetic radiation is configured to facilitate curing of components of the plurality of semiconductor packages. 2 . The packaging tray according to claim 1 , wherein the sidewalls of the grid comprise a triangular cross-sectional shape or a curved cross-sectional shape. 3 . The packaging tray of claim 2 , wherein the sidewalls of the grid are triangular, and wherein angles of two vertices of the triangular cross-sectional shape adjacent to the base are between 45 degrees and 60 degrees.

4. A packaging tray, comprising: a base, the base comprising a maximum planar surface, the maximum planar surface comprising a grid of electromagnetic radiation reflectors coupled thereto; Wherein side walls of the electromagnetic radiation reflector grid are angled with respect to a plane formed by the largest planar surface of the base. 5 . The package tray of claim 4 , wherein the sidewalls direct electromagnetic radiation toward sides of the plurality of semiconductor packages located within the grid. The packaging tray of claim 4 , wherein the side walls of the grid comprise a triangular cross-sectional shape.

7. A method for curing a plurality of semiconductor packages included in a package tray, the method comprising: providing a base and a grid of electromagnetic radiation reflectors coupled to a largest planar side of the base; placing a plurality of semiconductor packages into the openings in the grid against the base; directing electromagnetic radiation toward a side of each semiconductor package of the plurality of semiconductor packages located within the grid using sidewalls of the electromagnetic radiation reflector grid; as well as Components of the plurality of semiconductor packages are cured using the electromagnetic radiation. The method of claim 7 , wherein the sidewalls of the grid comprise a triangular cross-sectional shape.

9. The method of claim 8, wherein angles of two vertices of the triangular cross-sectional shape adjacent to the base are between 45 degrees and 60 degrees.

10. The method of claim 7, wherein the sidewalls of the grid comprise a closed cross-sectional shape comprising at least two line segments that are at approximately 45 degree angles to a plane formed by a largest planar surface of the base.

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