Abstract:
A semiconductor device includes a first semiconductor chip that is mounted face-down on a substrate, a second semiconductor chip that is mounted face-up on the first semiconductor chip, and a dummy chip that is interposed between the first semiconductor chip and the second semiconductor chip. The dummy chip is made from a homogenous material comprising silicon or an alloy containing an atomic percentage majority of silicon.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 11/839,712 filed on Aug. 16, 2007. The disclosures of the above application is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a semiconductor device which is particularly preferably applied to a three-dimensional integrated configuration. 
     2. Related Art 
     There has been a method in which a face-up mounted semiconductor chip is stacked on a face-down mounted semiconductor chip in a semiconductor device of related art in order to achieve high density packaging of the semiconductor chip. 
     For example, disclosed in an example of related art is a method for forming a conductor film on a rear surface of a second semiconductor chip mounted on a first semiconductor chip in order to restrain interference between the stacked semiconductor chips caused by noise. 
     Japanese Patent No. 3,681,690 is the example of related art. 
     However, in a stacked structure of the semiconductor chips of related art, the interference occurs between the stacked semiconductor chips caused by noise, disadvantageously leading to reduced reliability of the semiconductor device. Further, in the method disclosed in the example of related art, the conductor film needs to be formed on the rear surface of the second semiconductor chip mounted on the first semiconductor chip, disadvantageously leading to a complicated manufacturing process of the second semiconductor chip. 
     SUMMARY 
     The invention is intended to provide a semiconductor device in which chips can be stacked while suppressing the interference between the chips caused by noise, and a method for manufacturing the same. 
     According to a first aspect of the invention, a semiconductor device includes a first semiconductor chip that is face-down mounted on a substrate, a second semiconductor chip that is face-up mounted on the first semiconductor chip, and an electromagnetic shielding plate that is interposed between the first semiconductor chip and the second semiconductor chip. 
     In this case, even if the second semiconductor chip is stacked on the first semiconductor chip, it may be possible to suppress the interference between the first and second semiconductor chips caused by noise, without the complicated manufacturing process of the first and second semiconductor chips. Therefore, the cost may be prevented from increasing and packaging density of the semiconductor chip may be improved. 
     According to a second aspect of the invention, a semiconductor device includes a first semiconductor chip that is face-down mounted on a substrate, a second semiconductor chip that is face-up mounted on the first semiconductor chip, and a dummy chip that is interposed between the first semiconductor chip and the second semiconductor chip and having a conductor film formed on an upper or lower surface if the dummy chip. 
     In this case, since the dummy chip is interposed between the first semiconductor chip and the second semiconductor chip, suppressed may be the interference between the first and second semiconductor chips caused by noise. Thus, the packaging density of the semiconductor chip may be improved without leading to the complicated manufacturing process of the first and second semiconductor chips. 
     According to a third aspect of the invention, a semiconductor device includes a first semiconductor chip that is face-down mounted on a substrate, a second semiconductor chip that is face-up mounted on the first semiconductor chip, and an electronic component that is arranged below the second semiconductor chip and mounted on the substrate. 
     In this case, even if the second semiconductor chip is stacked on the first semiconductor chip, the second semiconductor chip and the electronic component may be arranged above the substrate to as to overlap each other, restraining increase of the packaging area. 
     According to a fourth aspect of the invention, a semiconductor device includes a first semiconductor chip that is face-down mounted on a substrate, a second semiconductor chip that is face-up mounted on the first semiconductor chip, an electronic component that is arranged below the second semiconductor chip and mounted on the substrate, and a spacer that is interposed between the first semiconductor chip and the second semiconductor chip, the spacer separating the second semiconductor chip from the electronic component. 
     In this case, even if the second semiconductor chip is stacked on the first semiconductor chip, the second semiconductor chip and the electronic component may be arranged above the substrate to as to overlap each other, restraining increase of the packaging area. 
     In the semiconductor device of the aspects of the invention, the second semiconductor chip preferably be larger than the first semiconductor chip. 
     In this case, the electronic component may be arranged below the second semiconductor chip while not contacting with the first semiconductor chip disposed beneath the second semiconductor chip. Thus, the packaging area may be increased. 
     In the semiconductor device of the aspects of the invention, the first semiconductor chip may have an analog IC and the second semiconductor chip may have a digital IC. 
     In this case, even if the analog IC and the digital IC are stacked on the same substrate, it may be possible suppress the interference between the analog IC and the digital IC caused by noise. This may suppress increase of the packaging area and reduce characteristic deterioration of the analog IC and the digital IC. 
     According to a fifth aspect of the invention, a method for manufacturing a semiconductor device includes face-down mounting a first semiconductor chip on a substrate, disposing on the first semiconductor chip a dummy chip having a conductor film formed on an upper or lower surface of the dummy chip, and face-up mounting a second semiconductor chip on the dummy chip. 
     In this case, since the dummy chip is mounted between the first semiconductor chip and the second semiconductor chip, it may be possible to suppress the interference between the first and second semiconductor chips caused by noise. Thus, the cost may be prevented from increasing, improving the packaging density of the semiconductor chip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIGS. 1(A) and 1(B)  show a schematic configuration of an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, description will be given of a semiconductor device according to an embodiment of the invention with reference to the drawings. 
       FIG. 1(A)  is a plan view of a schematic configuration of the semiconductor device of the embodiment of the invention.  FIG. 1(B)  is a sectional view taken along line A-A′ in  FIG. 1(A) . 
     Referring to  FIGS. 1(A) and 1(B) , a carrier substrate  1  has a land  2  formed on a rear surface thereof. The land  2  is formed thereon with a protruding electrode  3 . The carrier substrate  1  has a surface thereof provided with a terminal electrode  4  coupled to a protruding electrode  5 , a terminal electrode  15  connected with the bonding wire  13 , and terminal electrodes  16  and  18  coupled respectively to electronic components  17  and  19 . As the carrier substrate  1 , used can be a double-sided substrate, multilayer wiring substrate, build-up substrate, tape substrate or film substrate, for example. The carrier substrate  1  uses as materials a polyamide resin, glass epoxy resin, BT resin, aramid/epoxy composites or ceramic. The protruding electrode  3  includes an Au bump, Cu bump and Ni bump coated with a solder or the like, or solder ball. 
     The protruding electrode  5  is formed on a semiconductor chip  6 . A conductor film  9  is formed on an upper surface of a dummy chip  8 . An electrode pad  12  is formed on a semiconductor chip  11 . The semiconductor chip  6  can have an analog IC mounted thereon, and the semiconductor chip  11  can have a digital IC mounted thereon. 
     The dummy chip  8  can be formed of a bare chip composed of a semiconductor such as Si. The conductor film  9  can be made of a metal film such as Al and Cu, for example. A thickness of the conductor film  9  may be around 10000 Å. At this time, the conductor film  9  and the dummy chip  8  can be made as follows. First, a wafer composed of a semiconductor such as Si is prepared. The wafer may have such a size as to form a plurality of the dummy chips  8 . Next, formed on one surface of the wafer entirely is a metal film such as Al and Cu, as the conductor film  9 , by use of a sputtering method, chemical vapor deposition (CVD) method, and plating method. Finally, the wafer on which the conductor film  9  is made is cut into individual pieces of a size used as the dummy chip  8 . Thus, the conductor film  9  and the dummy chip  8  are made. It should be noted that before the wafer is cut into individual pieces, a rear surface of the wafer (the surface of the wafer remote from that on which the conductor film  9  is formed) may be entirely provided with an adhesive layer  7  and then the wafer is cut into the individuals. 
     Alternatively, an electromagnetic shielding plate such as a metal plate or ferrite plate may be used instead of the dummy chip  8  provided with the conductor film  9 . 
     The semiconductor chip  6  is face-up mounted on the carrier substrate  1  with the protruding electrode  5  therebetween. The protruding electrode  5  is coupled to the terminal electrode  4 . In a case of coupling the protruding electrode  5  and the terminal electrode  4 , used may be, for example, a metal connection such as solder connection and alloy connection, as well as a pressure welding connection such as anisotropic conductive film (ACF) connection, nonconductive film (NCF) connection, anisotropic conductive paste (ACP) connection, and nonconductive paste (NCP) connection. 
     On the semiconductor chip  6  disposed is the dummy chip  8  having on the upper surface thereof the conductor film  9  formed with the adhesive layer  7  interposed between the semiconductor chip and the dummy chip. The adhesive layer  7  and the dummy chip  8  may have the same size when viewed from the top. In other words, a configuration may be such that side surfaces of the adhesive layer  7  and the dummy chip  8  are identical. 
     On the conductor film  9 , face-up mounted is the semiconductor chip  11  with an adhesive layer  10  therebetween. The adhesive layer  10  and the semiconductor chip  11  may have the same size when viewed from the top. In other words, a configuration may be such that side surfaces of the adhesive layer  10  and the semiconductor chip  10  are identical. 
     The semiconductor chip  11  is provided with the electrode pad  12  bonded to the terminal electrode  15  with the bonding wire  13 , and is coupled to the carrier substrate  1  via the bonding wire  13 . The electronic component  17  is mounted on the carrier substrate  1  with the terminal electrode  16  therebetween alongside the semiconductor chip  11 . The electronic component  19  is mounted on the carrier substrate  1  with the terminal electrode  18  therebetween below the semiconductor chip  11 . It should be noted that the electronic component  19  includes a resistor, capacitor, coil, and connector. The semiconductor chip  11  coupled with the bonding wire  13 , and the electronic components  17  and  19  are sealed in a sealing resin  20 . 
     With this configuration, in the case that the semiconductor chip  11  is disposed on the semiconductor chip  6 , it is possible to restrain the interference between the semiconductor chips  6  and  11  caused by noise with no conductive layer formed on the rear surfaces of the semiconductor chips  6  and  11 . As a result, the packaging density of the semiconductor chips  6  and  11  can be improved without requiring a complicated manufacturing process of the semiconductor chips  6  and  11 . 
     It is preferable the semiconductor chips  6  and  11 , and the dummy chip  8  are configured such that the sizes thereof are increased in the order of the semiconductor chip  6 , the dummy chip  8 , the semiconductor chip  11 . That is, the configuration is preferably such that the dummy chip  8  is larger than the semiconductor chip  6 , and the semiconductor chip  11  is larger than the dummy chip  8 . This enables the electronic component  19  to be arranged below the semiconductor chip  11  without contacting with the semiconductor chip  6  and the dummy chip  8  disposed beneath the semiconductor chip  11 , thus, suppressing the packaging area from increasing. A thickness of the dummy chip  8  can be set such that the electronic component  19  does not contact with the semiconductor chip  11 . Specifically, the thickness of the dummy chip  8  and the conductor film  9  may be set such that the upper surface of the conductor film  9  (the surface of the conductor film  9  opposite to the surface of the conductor film facing the dummy chip  8 ) is higher than the upper surface of the electronic component  19  (the surface of the electronic component  19  opposite to the surface of the electronic component  19  facing the carrier substrate  1 ). This enables the electronic component  19  to be prevented from contacting with the semiconductor chip  11 , and the dummy chip  8  to be used as a spacer. Therefore, the complicated manufacturing process can be suppressed and the electronic component  19  can be disposed below the semiconductor chip  11 . 
     The carrier substrate  1  mounting thereon the semiconductor chips  6  and  11  can be applied to an electronic apparatus such as a liquid crystal display, mobile phone, handheld terminal, video camera, digital camera, mini disc (MD) player, IC card, and IC tag. Therefore, the electronic apparatus can be reduced in size and weight, and improved in reliability. 
     In the above-described embodiment, the method for mounting the semiconductor chip is described as an example. However, the invention is not necessarily limited to the mounting method of the semiconductor chip, and may be applied to a method for mounting a resistor, capacitor and connector, as well as a method for mounting a ceramic element such as a surface acoustic wave (SAW) element, an optical element such as an optical modulator and optical switch, and various sensors such as a magnetic sensor and biosensor,