The present invention generally relates to a package structure and a manufacturing method thereof, and more particularly, to a semiconductor package and a manufacturing method thereof.
In recently years, electronic apparatus are more important for human's life. In order for electronic apparatus design to achieve being light, slim, short, and small, semiconductor packaging technology has kept progressing, in attempt to develop products that are smaller in volume, lighter in weight, higher in integration, and more competitive in market. Since the chip package technique is highly influenced by the development of integrated circuits, therefore, as the size of electronics has become demanding, so does the package technique. As such, miniaturizing the semiconductor package and keeping the reliability of the semiconductor package while maintaining the process simplicity has become a challenge to researchers in the field.
The disclosure provides a semiconductor package and a manufacturing method thereof, which improves the reliability of the semiconductor package and the processing yield.
The disclosure provides a semiconductor package including a semiconductor chip, a conductive element disposed adjacent to the semiconductor chip, an insulating encapsulation encapsulating a portion of the semiconductor chip and the conductive element, a redistribution structure disposed on the semiconductor chip and the conductive element, and a first buffer layer disposed between the redistribution structure and the insulating encapsulation. The semiconductor chip and the conductive element are electrically coupled to the redistribution structure. The first buffer layer encapsulates another portion of the semiconductor chip and the conductive element.
The disclosure provides a manufacturing method of a semiconductor package. The method includes at least the following steps. An insulating encapsulation is formed to partially cover a semiconductor chip and a conductive element, where a portion of the conductive element and a portion of the semiconductor chip are exposed by the insulating encapsulation. A first buffer layer is formed on the insulating encapsulation to partially cover the portion of the conductive element and the portion of the semiconductor chip. A redistribution structure is formed on the first buffer layer, wherein the redistribution structure is electrically connected to the semiconductor chip and the conductive element.
Based on the above, the semiconductor package includes the first buffer layer formed between the insulating encapsulation and the redistribution structure, so that the first buffer layer can be used to buffer the stress generated from a subsequently formed the redistribution structure. Accordingly, the reliability and quality of the semiconductor package are improved. In addition, the total thickness of the first buffer layer and the insulating encapsulation is substantially equal to the height of the conductive element or the height of the semiconductor chip, so that the entire thickness of the semiconductor package is not compromised. Moreover, the buffer layers may be formed at two opposite sides of the insulating encapsulation to form a sandwich-type of encapsulation structure for stress buffering. Furthermore, multiple semiconductor packages may be stacked upon one another to provide additional functionality to form a POP structure so as to open the possibility to various package designs.
To make the above features and advantages of the present invention more comprehensible, several embodiments accompanied with drawings are described in detail as follows.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
The conductive element 110 includes a first surface 110a and a second surface 110b opposite to the first surface 110a. The second surface 110b of the conductive element 110 may be facing toward the temporary carrier 50. A material of the conductive element 110 includes copper, nickel, gold, tin, lead, a combination thereof, or other suitable conductive materials. The conductive element 110 may have the shape of pillars. The top view shape of the conductive element 110 may be circles, rectangles, squares, polygons, or the like. In some embodiments, a plurality of the conductive elements 110 is distributed on the temporary carrier 50. The conductive elements 110 may be formed through a plating process (e.g., electro-plating, electroless-plating, immersion plating), or other suitable deposition processes. In alternative embodiments, the conductive elements 110 may be pre-formed and disposed on the temporary carrier 50 through a pick and place process. The height of the conductive elements 110 may be determined by the thickness of the subsequently placed semiconductor chip.
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Each semiconductor chip 120 has a first side 120a and a second side 120b opposite the first side 120a. The second side 120b may be facing toward the temporary carrier 50. The first side 120a of the semiconductor chip 120 may include a plurality of conductive bumps 122. Each of the conductive bumps 122 has a first surface 122a. A material of the conductive bumps 122 may be copper, tin, gold, nickel, solder, a combination thereof, or the like. In some embodiments, the semiconductor chip 120 is manufactured by the following steps. A wafer (not illustrated) having active components (e.g., transistors or the like) and, optionally, passive components (e.g., resistor, capacitor, inductor, or the like) formed therein is provided. An interconnection structure is formed over the wafer. The interconnection structure may include at least one circuit layer and at least one dielectric layer alternatingly formed. The dielectric layer of the interconnection structure may be made of a semiconductor oxide material including silicon oxide, silicon oxynitride, a combination thereof, or other suitable material. The conductive bumps 122 are formed over and are electrically connected the interconnection structure. The wafer is diced to obtain a plurality of the semiconductor chips 120.
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Next, a part of the thinned insulating material IM2 is removed to form the insulating encapsulation 130 as shown in
The second step of thinning process may be a selective etching process or other applicable process. For example, the wet etching is highly selective of insulating material (e.g., molding compound) as compared to metal (e.g., copper or copper alloy). Slight or no appreciable amount of conductive bumps 122 or conductive elements 110 is removed after the second step of thinning process. For example, a suitable chemical solution may be applied to the thinned insulating material IM2. The second thickness T2 of the thinned insulating material IM2 is reduced to a desired third thickness (e.g., T3-1 and T3-2) without damage (or with minimal removal) to the conductive bumps 122 and the conductive elements 110. In some embodiments, before the selective etching process, a mask (not shown) is formed on the conductive bumps 122 and the conductive elements 110 for protection. And, the mask is removed after the selective etching.
A selective etching process may be performed with any suitable chemical solutions capable of etching the thinned insulating material IM2. For example, chemical solutions for etching the thinned insulating material IM2 include nitric acid, sulfuric acid, a mixed acid, or the like. The etch rate can be controlled by adjusting a concentration of the employed chemical solutions. For example, the concentration may be increased if the etch rate is too low to give reasonable efficiency. The concentration may be selected based on a thickness of the thinned insulating material IM2 needed to be removed. During the second step of thinning process, the chemical solutions for etching may have a raised temperature to accelerate the chemical reaction. Before proceeding to the next process, a cleaning process may be performed onto the first surface 130S1 of the insulating encapsulation 130.
In alternative embodiments, the insulating encapsulation 130 may be formed through one step of thinning. For example, after forming the insulating material IM1, an etching process is performed to remove the insulating material IM1 until the first portions 112 of the conductive elements 110 and the upper portions 122U of the conductive bumps 122 are exposed.
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The front-side buffer layer 140 may be formed through a spin-coating process, a spray coating process, a deposition process, a combination thereof, or other applicable process. In some embodiments, a planarization process is performed to provide the front-side buffer layer 140 with the substantially planar surface 140a, thereby facilitating subsequent processes. The planarization process may be a grinding process, a CMP process, a dry polishing process, a combination thereof, or other suitable process. During a planarization process, portions of the upper portions 122U of the conductive bumps 122 and/or first portions 112 of the conductive elements 110 may be further reduced. In some embodiments, the surface 140a of the front-side buffer layer 140 is substantially coplanar with the first surfaces 110a of the conductive elements 110 and the first surfaces 122a of the conductive bumps 122.
The front-side buffer layer 140 may have a uniform thickness. In alternative embodiments, the thickness T4 of the front-side buffer layer 140 may not be uniform depending on the underlying insulating encapsulation 130; however, the surface 140a of the front-side buffer layer 140 may remain planar. In some embodiments, a ratio of the thickness T4 of the front-side buffer layer 140 laterally covering the upper portions 122U of the conductive bumps 122 and the thickness T3-2 of the insulating encapsulation 130 laterally covering the lower portions 122L of the conductive bumps 122 may be substantially equal to 1.
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The patterned dielectric layer 151 may be made of inorganic or organic semiconductor dielectric materials such as PBO, PI, BCB, or other suitable electrically insulating materials. The patterned dielectric layer 151 may be formed using a coating process, a deposition process, or other suitable process. In some embodiments, the patterned dielectric layer 151 and the front-side buffer layer 140 are of different materials. The Young's modulus of the patterned dielectric layer 151 of the redistribution structure may be greater than or substantially equal to the Young's modulus of the front-side buffer layer 140. The front-side buffer layer 140 disposed between the redistribution structure 150 and the insulating encapsulation 130 may be used as a stress buffer when forming the redistribution structure 150.
The patterned dielectric layer 151 includes a plurality of openings exposing portions of the conductive vias 140 and portions of the conductive bumps 122. Subsequently, the patterned conductive layer 152 may be formed in and over the patterned dielectric layer 151. The patterned conductive layer 152 includes conductive features such as conductive traces, contact pads, and/or contact vias. A material of the patterned conductive layer 152 includes copper, aluminum, metal alloy, or combinations thereof. In alternative embodiments, the patterned conductive layer 152 is formed prior to the patterned dielectric layer 151. The process may be performed multiple times to form a multi-layered redistribution structure as required by the circuit design.
After forming the redistribution structure 150, conductive terminals 160 may be formed on the redistribution structure 150 opposite to the conductive elements 110 for further electrical connection. The conductive terminals 160 may be electrically coupled to the semiconductor chip 120 at least through the redistribution structure 150. The top patterned dielectric layer 151T may have openings exposing at least a portion of the top patterned conductive layer 152 (e.g., under-ball metallurgy (UBM) pads). A material of the top patterned dielectric layer 151T may be different from the underlying patterned dielectric layers. The top patterned dielectric layer 151T may include solder sensitive material for protecting the patterned conductive layer 152 during a ball mounting process. The conductive terminals 160 are formed in the openings of the top patterned dielectric layer 151T to physically connect the underlying top patterned conductive layer 152. The conductive terminals 160 may include conductive balls, conductive pillars, conductive bumps, a combination thereof, or other forms and shapes formed by a ball mounting process, an electroless plating process, or other suitable process. A soldering process and a reflowing process are optionally performed for enhancement of the adhesion between the conductive terminals 160 and the redistribution structure 150.
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In some embodiments, the back-side buffer layer 240 exposes at least part of the third portions 116 of the conductive elements 110 for further electrical connection. The back-side buffer layer 240 may be substantially planar. In some embodiments, a surface 240a of the back-side buffer layer 240 is coplanar with the second surfaces 110b of the conductive elements 110 and the rear surface 124a of the semiconductor chip 120. In alternative embodiments, the back-side buffer layer 240 covers the second surfaces 110b of the conductive elements 110 and the rear surface 124a of the semiconductor chip 120 to act as the protective insulator for protecting the semiconductor chip 120 and the conductive elements 110 from being damaged. A material and a forming process of the back-side buffer layer 240 may be same as or similar with that of the front-side buffer layer 140. The intermediate encapsulation 230 may be harder than both of the front-side buffer layer 140 and the back-side buffer layer 240. In some embodiments, the Young's modulus of the intermediate encapsulation 230 may be greater than the Young's modulus of the front-side buffer layer 140 and the Young's modulus of the back-side buffer layer 240.
After forming the back-side buffer layer 240, a singulation process may be performed to form a plurality of semiconductor package 20. As shown in
The semiconductor device 30 may be electrically coupled to the semiconductor chip 120 through the conductive elements 110 and the redistribution structure 150. In alternative embodiments, a back-side redistribution structure (not shown) may be formed over the back-side buffer layer 240, and the semiconductor device 30 may be disposed on and electrically connected to the back-side redistribution structure. The semiconductor device 30 may be an IC package, a memory device, or other suitable semiconductor devices. Since the semiconductor device 30 is stacked over and is electrically connected to the semiconductor package 20, the integrated semiconductor package D1 having multiple packages stacked upon one another to provide additional functionality may be referred to as a package-on-package (POP) structure.
In some embodiments, the integrated semiconductor package D1 is disposed on a circuit substrate 40 to form an electronic device E1. The circuit substrate 40 may be a package substrate having integrated circuit (IC) therein, a printed circuit board (PCB), or other suitable electronic components. The conductive terminals 160 of the semiconductor package 20 may be utilized to establish electrical connections between the semiconductor package 20 and the circuit substrate 40, thereby providing the electronic device E1 of high quality and reliability. For example, the integrated semiconductor package D1 is placed on the circuit substrate 40, where the conductive terminals 160 of the semiconductor package 20 are in direct contact with the circuit substrate 40 so that the integrated semiconductor package D1 and the circuit substrate 40 are electrically connected. In other embodiments, the semiconductor package 10 as shown in
Based on the above, the semiconductor package includes the front-side buffer layer formed between the insulating encapsulation and the redistribution structure, so that the front-side buffer layer can be used to buffer the stress generated from a subsequently formed structures. Accordingly, the reliability and quality of the semiconductor package are improved. In addition, the total thickness of the buffer layers and the insulating encapsulation is substantially equal to the height of the conductive element or the height of the semiconductor chip, so that the entire thickness of the semiconductor package is not compromised. Moreover, the buffer layers may be formed at two opposite sides of the insulating encapsulation to form a sandwich-type of encapsulation structure for stress buffering. Furthermore, multiple semiconductor packages may be stacked upon one another to provide additional functionality to form a POP structure so as to open the possibility to various package designs.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.