JP2007042665A - Semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device where a mounting area of a transformer component can be reduced and to provide a manufacturing method of the semiconductor device. <P>SOLUTION: The semiconductor device 10 is provided with a structure where a transformer part 13 formed of a circuit forming layer 16, a magnetic core 17 and coil bodies 18a and 18b is formed on a first semiconductor element 11. Thus, a mounting region of the transformer component becomes unnecessary with such constitution, and a wiring board can be miniaturized. Since the transformer component can be formed in a semiconductor manufacture process, the device can sufficiently correspond to miniaturization. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor device in which a semiconductor element and a magnetic coil component such as a transformer are integrally formed and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, a transformer used in an electronic device or the like has a primary coil and a secondary coil wound around a magnetic core having a closed magnetic circuit formed of a magnetic material such as ferrite or permalloy, and both ends of each of the primary and secondary coils. The aspect which pulled out the part to the exterior of a transformer and connected on the mounting board | substrate was employ | adopted. However, in this structure, the mounting height of the transformer is increased, and the thickness of the transformer is increased as compared with other component groups that are becoming thinner, so that it is impossible to reduce the thickness of the wiring board.

  Therefore, a configuration is known in which a magnetic core is directly mounted on a wiring board, and a coil is further wired from the magnetic core, thereby reducing the mounting area of the transformer component (for example, see Patent Document 1 below).

  FIG. 18 is an exploded perspective view showing a mounting form of a conventional transformer component described in Patent Document 1 on a wiring board. A plurality of wiring patterns 2 are formed on the wiring substrate 1 so as to cross the core arrangement region 3 where the ring-shaped magnetic core 6 is arranged. Terminal insertion holes 4 are respectively formed at the ends of these wiring patterns 2, so that each end of the upper wiring element 8 attached from above the magnetic core 6 is connected to these terminal insertion holes 4. It has become.

  After the magnetic core 6 is fixed on the core placement region 3 via the adhesive 7 on the wiring board 1, the terminals 8 are inserted into the predetermined wiring pattern 2 so that each wiring element 8 straddles the magnetic core 6. Connected to hole 4. The wiring pattern 2 and the wiring element 8 constitute a coil wound around the magnetic core 6 and are similarly configured not only on one side of the illustrated magnetic core 6 but also on the other side. The transformer component is mounted on the wiring board 1 as described above.

JP-A-8-203762

  However, the conventional transformer component mounting structure described above requires a transformer component mounting area separately from other electronic components such as an IC or an LSI, and therefore the size of the wiring board cannot be reduced. is there.

  In particular, in the configuration of the conventional transformer component, it is very difficult to cope with the miniaturization and narrowing of the wiring elements 8, and therefore, further miniaturization and narrowing of the wiring pattern in the transformer mounting area is desired. It is a big obstacle.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a semiconductor device capable of reducing the mounting area of a transformer component and a method for manufacturing the same.

  In order to solve the above problems, a semiconductor device of the present invention includes a semiconductor element, a magnetic core laminated on the surface of the semiconductor element, and a coil body wound around the magnetic core on the surface of the semiconductor element. ing.

  The method for manufacturing a semiconductor device of the present invention includes a step of forming a circuit forming layer having a plurality of sets of conductor lands on a surface of a semiconductor element, and a step of laminating a sheet-like magnetic core on the circuit forming layer. And bonding a bonding wire between the conductor lands so as to straddle the magnetic core.

  The semiconductor device of the present invention constructed and manufactured as described above has a structure in which transformer parts are stacked on semiconductor elements, so that a mounting area for the transformer parts is virtually unnecessary, and the wiring board Can be reduced in size. Further, since the transformer parts can be manufactured by the semiconductor manufacturing process, it is possible to sufficiently cope with downsizing.

  In addition, the structure mentioned above is applicable not only to transformer components but other magnetic coil components, such as a toroidal coil, a choke coil, an inductor element, for example.

  As described above, according to the present invention, for example, the mounting area of a single component such as a transformer can be reduced, so that the wiring board can be reduced in size and thickness. Further, it is possible to sufficiently cope with miniaturization of transformer parts.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1A and 1B schematically show a configuration of a semiconductor device 10 according to an embodiment of the present invention. A is an element plan view inside the device, and B is a side sectional view. First, the overall configuration of the semiconductor device 10 will be described.

  The semiconductor device 10 according to the present embodiment includes a first semiconductor element 11, a second semiconductor element 12 disposed on the back side of the first semiconductor element 11, and a transformer unit stacked on the surface of the first semiconductor element 11. The semiconductor module M composed of 13 is configured as a semiconductor package component sealed with a mold resin 14.

  Both the first semiconductor element 11 and the second semiconductor element 12 are constituted by semiconductor bare chips such as IC or LSI. In addition, the first and second semiconductor elements 11 and 12 are, for example, functional devices manufactured through a semiconductor manufacturing process such as SAW (surface acoustic wave) elements, MEMS (Micro Electro Mechanical System) parts, and the like. It may be. Moreover, the installation of the second semiconductor element 12 is arbitrary and can be omitted as necessary.

  A plurality of lead terminals 15 protrude from the outer periphery of the semiconductor device 10. These lead terminals 15 are connected to the first and second semiconductor elements 11 and 12 via bonding wires W1 and W2 such as gold wires, respectively, and are externally mounted on the wiring board (not shown) or mounted on the surface. Functions as a connection terminal.

  Next, the transformer unit 13 includes a magnetic core 17 and coil bodies 18 a and 18 b wound around the magnetic core 17 on the circuit forming layer 16 formed on the surface of the first semiconductor element 11. ing.

  The magnetic core 17 is formed by punching a sheet-like magnetic sheet into a ring shape. The material of the magnetic core 17 is not particularly limited as long as it is a magnetic material having soft magnetic properties. For example, an iron piece, a composite material obtained by mixing magnetic powder such as ferrite, permalloy, sendust and the like together with a binder, or an Fe-Si-B system, etc. Amorphous thin ribbons can be applied.

  The coil bodies 18a and 18b correspond to the primary coil and the secondary coil wound around the magnetic core 17, and are formed on the circuit forming layer 16 so as to cross the magnetic core 17 (19a1 and 19a2). And conductor lands 19b (19b1, 19b2) and bonding wires Wa, Wb such as gold wires respectively connected to the conductor lands 19a, 19b so as to straddle the magnetic core 17.

  Here, for each of the conductor lands 19 a and 19 b, the conductor lands 19 a 1 and 19 a 2 and the conductor lands 19 b 1 and 19 b 2 that face each other across the magnetic core 17 are electrically connected to each other in the circuit forming layer 16.

  The bonding wire Wa is connected so as to communicate between the conductor land 19a1 on one side and the conductor land 19a2 on the other side of the adjacent conductor lands 19a, 19a. Similarly, the bonding wire Wb is connected between the conductor lands 19b1 and 19b2. However, in order to reduce the number of turns on the secondary coil side compared to the primary coil side, in the illustrated example, the conductor lands 19b are skipped one row at a time. Wire Wb is connected.

  Around the surface of the circuit forming layer 16, a plurality of electrode pads 20 electrically connected to the first semiconductor element 11 are provided in addition to the above-described conductor lands 19 a and 19 b for coil connection. These electrode pads 20 are connected to corresponding lead terminals 15 via bonding wires W11. The second semiconductor element 12 and the lead terminal 15 are electrically connected by a bonding wire W2.

  A part of the electrode pad 20 is assigned to an input / output portion to each of the conductor lands 19a and 19b, and these are connected via a bonding wire Wc such as a gold wire. Instead of the bonding wire Wc, the connection may be achieved by a wiring layer formed in the circuit forming layer 16.

  The semiconductor device 10 of the present embodiment is configured as shown in a circuit block diagram shown in FIG. 2, for example. In FIG. 2, the rectification constant voltage circuit is composed of a first semiconductor element 11, and the logic circuit is composed of a second semiconductor element 12. The rectified constant voltage circuit (first semiconductor element 11) is connected to the secondary coil 18 b of the transformer unit 13, and the coil body 18 a as the primary coil is connected to the AC power supply 20.

  The transformer unit 13 transforms (transforms) the power supply voltage of the AC power supply 20 into a voltage corresponding to the turn ratio of the primary coil 18 a and the secondary coil 18 b and supplies the transformed voltage to the rectifying constant voltage circuit 11. The rectified constant voltage circuit 11 functions to rectify and constant the output voltage of the transformer unit 13 and supply it to the logic circuit 12.

  As described above, the semiconductor device 10 of the present embodiment is configured as a self-electromotive type electronic component that generates a necessary drive voltage by the transformer unit 13. As a result, it is possible to drive the required voltage from the external AC power supply. In addition, since the power supply circuit is uniquely provided, it is not necessary to mount a large capacity power supply. Therefore, when applied to an electronic device such as a mobile device, it is very advantageous in that the device can be reduced in size and weight.

  Further, it is possible to form the primary coil 18a in an antenna shape, so that it is possible to receive power supply by radio waves, and thus it is possible to achieve battery-less devices such as a wireless keyboard and a mouse. It becomes like this. The present invention is also applicable to a non-contact communication medium having an RFID (Radio Frequency Identification) function such as a non-contact IC card.

  On the other hand, according to the semiconductor device 10 of the present embodiment, since the transformer part 13 is laminated on the semiconductor element 11, there is no need to prepare transformer parts independently as in the prior art. As a result, the number of components and the mounting area can be greatly reduced, and the wiring board can be reduced in size, thickness, and weight.

  Further, since the transformer component can be manufactured on the surface of the first semiconductor element 11 through a semiconductor manufacturing process to be described later, the transformer component can be miniaturized. As a result, the wiring board can be further reduced in size and thickness. Furthermore, when the magnetic core 17 also functions as a heat dissipation layer, the heat dissipation performance of the component is improved.

  Next, an example of a method for manufacturing the semiconductor device 10 of the present embodiment configured as described above will be described with reference to FIGS.

(Preparation process of the first semiconductor element 11)
A first semiconductor element 11 is prepared. As shown in FIG. 3, the first semiconductor element 11 has a necessary element layer 22 such as a wiring or a capacitor formed on a Si substrate 21, and a predetermined wiring portion with a circuit forming layer 16 described later. Openings 23 are formed for electrical connection. In addition, the element layer 22 is comprised by the element group which has a function as a rectification constant voltage circuit as mentioned above.

(Formation process of the circuit formation layer 16)
First, a Ti / Cu layer is formed as a seed layer (feeding layer) 24 for electroplating over the entire surface of the first semiconductor element 11 by a sputtering method. The opening 23 is filled with the seed layer 24.

  Next, as shown in FIG. 4, a plating resist pattern 25 is formed in a predetermined region on the surface of the seed layer 24 by using a photolithography technique. The plating resist pattern 25 is formed in a pattern that opens a predetermined region including a region where the opening 23 is formed.

  Subsequently, as shown in FIG. 5, a Cu plating layer 26 is formed on the surface of the seed layer 24 by electroplating. Thereby, the opening area | region of the resist pattern 25 for metal plating is filled with the Cu plating layer 26, and Cu plating pattern of a predetermined shape is formed. Thereafter, as shown in FIG. 6, the plating resist 25 and the seed layer 24 thereunder are removed.

  Next, as shown in FIG. 7, photosensitive polyimide is applied to the entire surface of the element, and a polyimide layer (insulating layer) 27 having a predetermined shape is formed using a known photolithography technique. Subsequently, as shown in FIG. 8, aluminum is vapor-deposited from above the polyimide layer 27 to form an Al film 28 having a predetermined thickness.

  Next, as shown in FIG. 9, a resist is applied on the formed Al film 28, and a resist pattern 29 having a predetermined shape is formed using a photolithography technique. Then, after the Al film 28 is etched using the resist pattern 29 as a mask, the resist pattern 29 is removed.

  Thereby, as shown in FIG. 10, the conductor lands 19a and 19b and the electrode pad 20 are formed. Each of the conductor lands 19a and 19b is formed on the common Cu plating layer 26 so that the opposing conductor lands are electrically connected. Then, as shown in FIG. 11, the formation process of the circuit formation layer 16 is completed by forming the photosensitive polyimide layer 30 of a predetermined shape on the element surface.

(Manufacturing process of the transformer section 13)
Next, as shown in FIG. 12, the die pad part 34 that supports the semiconductor element 11 and the first lead frame 31 on which the lead terminals 15 are formed, and the sheet-like second lead on which the outer shape of the magnetic core 17 is formed. A frame 32 is prepared. The first and second lead frames 31 and 32 are formed with positioning holes 31a and 32a at the peripheral portions, respectively, and the first and second lead frames 31 and 32 are aligned with each other by inserting the positioning pins 33. Is done.

  The semiconductor element 11 is disposed between the first lead frame 31 and the second lead frame 32. As shown in FIG. 13, the semiconductor element 11 is mounted on the die pad portion 34 of the first lead frame 31, and between the conductor lands 19a (19a1, 19a2) on the surface and between the conductor lands 19b (19b1, 19b2). The magnetic core 17 is laminated by pressure bonding.

  At this time, the polyimide layer 30 located between the conductor lands 19 a and 19 b on the surface of the circuit forming layer 16 is formed so as to correspond to the formation width of the magnetic core 17, thereby achieving close contact with the magnetic core 17. The polyimide layer 30 is formed higher than the surfaces of the conductor lands 19a and 19b and the electrode pad 20. Thereby, the polyimide layer 30 is deformed in a reverse taper shape when the magnetic core 17 is pressure-bonded, and functions as a retaining layer for the magnetic core 17. The height of the polyimide layer 30 is set to a height that does not hinder the movement of the bonding tool (not shown) in the subsequent wire bonding step (FIG. 14).

  Subsequently, as shown in FIG. 14, the second semiconductor element 12 prepared in advance is mounted on the back side of the first semiconductor element 11. The second semiconductor element 12 is disposed opposite to the first semiconductor element 11 on the back surface with the die pad portion 34 interposed therebetween.

  Next, as shown in FIG. 15, the electrode pad 20 of the first semiconductor element 11 and the electrode pad 35 of the second semiconductor element 12 formed in the peripheral region of the circuit forming layer 16 are respectively bonded to the lead terminals 15 by bonding wires. W1 and W2 are connected.

  In this step, bonding wires Wa and Wb are connected between the conductor lands 19a1 and 19a2 on the circuit forming layer 16 and between the conductor lands 19b1 and 19b2 so as to straddle the magnetic core 17, and input / output In the conductor land portion corresponding to the portion, the bonding wire Wc is connected to the predetermined electrode pad 20. The semiconductor module M is completed at the same time as the transformer part 13 is manufactured as described above.

  As described above, by introducing the wire connecting step of the transformer unit 13 in the wire bonding step between the first and second semiconductor elements 11 and 12 and the lead terminal 15, the bonding equipment can be shared. The production efficiency can be improved. Note that the bonding wires Wa to Wc may be connected immediately after the magnetic core 17 is stacked prior to the connection step between the semiconductor elements 11 and 12 and the lead terminal 15 without being limited to the above-described example (see FIG. 14).

(Final process)
Subsequently, as shown in FIG. 16, the process of sealing the manufactured semiconductor module M with the mold resin 14, the process of removing unnecessary portions of the first and second lead frames 31 and 32, and the bending of the lead terminals 15. Through the steps, the semiconductor device 10 of the present embodiment is manufactured.

  As described above, in the method for manufacturing the semiconductor device 10 according to the present embodiment, the circuit forming layer 16 and the transformer unit 13 are formed on the first semiconductor element 11 by the semiconductor manufacturing process. It becomes possible to form the portion 13 with a fine and high precision, and the transformer parts can be easily miniaturized.

  In particular, the step of laminating the magnetic core 17 on the circuit forming layer 16 is integrated with the semiconductor element 11 in a state of being aligned with the first lead frame 31. The mounting accuracy of the magnetic core 17 can be ensured, and workability can be improved.

  In addition, each pattern of a plurality of sets of conductor lands 19a and 19b is formed in advance on the circuit forming layer 16, and only necessary portions are connected later by bonding wires Wa and Wb. It can easily handle the production of various types of parts.

  Furthermore, since the wire bonding method is adopted in the wiring process of the transformer unit 13, the operation is quicker, more accurate, and more efficient than the conventional case where the wiring elements are mounted one by one. Fine pitch can be easily achieved.

  The embodiment of the present invention has been described above. Of course, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

  For example, in the above embodiment, the multi-chip type semiconductor device 10 including the first semiconductor element 11 for the rectified constant voltage and the second semiconductor element 12 for the logic function has been described as an example. Not limited to this, as shown in FIG. 17, the second semiconductor element may be omitted, and the semiconductor device according to the present invention may be configured by only the first semiconductor element 11 and the transformer section 13 stacked thereon.

  In the above embodiment, the circuit forming layer 16 is directly formed on the first semiconductor element 11 using a semiconductor manufacturing process. However, the circuit forming layer is separately manufactured using a wiring board or the like, A structure in which the semiconductor element 11 is stacked may be employed.

  Further, the magnetic coil component integrated with the semiconductor element is not only the above-described transformer component, but also a single coil type magnetic coil component in which only the primary coil is formed on the magnetic core, for example, a choke coil, a toroidal coil, an inductor component, etc. Is equally applicable.

  Furthermore, not only a package component in which the semiconductor module M is sealed with the mold resin 14, but also a component form in which a stud bump is provided on the circuit forming layer 16 and mounted on the wiring board by a flip chip method can be employed.

1 is a diagram illustrating a configuration of a semiconductor device 10 according to an embodiment of the present invention, in which A is an element plan view inside the device, and B is a cross-sectional view of an essential part. 2 is an equivalent circuit block diagram showing a configuration of a semiconductor device 10. FIG. FIG. 2 is a diagram illustrating a method for manufacturing the semiconductor device 10 and is a cross-sectional view of a main part of a first semiconductor element 11. It is a figure explaining the manufacturing method of the semiconductor device 10, and has shown the formation process of the resist pattern 25 for plating. It is a figure explaining the manufacturing method of the semiconductor device 10, and the formation process of Cu plating layer 26 is shown. It is a figure explaining the manufacturing method of the semiconductor device 10, and has shown the removal process of the resist 25 for plating, and the seed layer 24. FIG. FIG. 4 is a diagram for explaining a method for manufacturing the semiconductor device 10 and shows a step of forming a polyimide layer 27. FIG. 4 is a diagram for explaining a method for manufacturing the semiconductor device 10 and shows a film forming process of an Al film 28; FIG. 8 is a diagram for explaining a method for manufacturing the semiconductor device 10 and shows a step of forming a resist pattern 29 for patterning the Al film 28. 4A and 4B are diagrams illustrating a method for manufacturing the semiconductor device 10 and are a plan view and a side cross-sectional view illustrating a process of patterning an Al film 28 to form conductor lands 19a and 19b and electrode pads 20. FIG. 2 is a diagram for explaining a method for manufacturing the semiconductor device 10 and shows a step of forming a polyimide layer 30. FIG. 2 is a diagram for explaining a manufacturing method of the semiconductor device 10, and is a plan view and a side sectional view showing a stacking process of first and second lead frames 31 and 32. 1 is a diagram for explaining a method for manufacturing a semiconductor device 10 and shows a state in which first and second lead frames 31 and 32 are stacked on a semiconductor element 11. FIG. 4 is a diagram for explaining a method for manufacturing the semiconductor device 10 and shows a stacking process of the second semiconductor elements 12. It is a figure explaining the manufacturing method of the semiconductor device 10, and has shown the wire bonding process of each part. It is a figure explaining the manufacturing method of the semiconductor device 10, and has shown the sealing process by mold resin. It is a sectional side view which shows the modification of the structure of the semiconductor device of embodiment of this invention. It is a perspective view explaining the mounting process of the conventional transformer component.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Semiconductor device, 11 ... 1st semiconductor element, 12 ... 2nd semiconductor element, 13 ... Transformer part, 14 ... Mold resin, 15 ... Lead terminal, 16 ... Circuit formation layer, 17 ... Magnetic core, 18 ... Coil body, 18a ... primary coil, 18b ... secondary coil, 19a, 19b ... conductor land, 20 ... electrode pad, 31 ... first lead frame, 32 ... second lead frame, 33 ... positioning pin, M ... semiconductor module, W1, W2, Wa, Wb, Wc ... Bonding wire

Claims (10)

A semiconductor element;
A magnetic core laminated on the surface of the semiconductor element;
A semiconductor device comprising: a coil body wound around the magnetic core on a surface of the semiconductor element. The magnetic core is composed of a ring-shaped sheet body,
The semiconductor device according to claim 1, wherein the coil body includes a primary coil and a secondary coil wound around the ring-shaped magnetic core. The coil body is
A circuit forming layer having a plurality of conductor lands formed on the surface of the semiconductor element;
The semiconductor device according to claim 1, further comprising a bonding wire joined between the conductor lands so as to straddle the magnetic core. The semiconductor device according to claim 1, wherein the semiconductor element is electrically connected to one surface of a lead frame, and the entire semiconductor element is covered with a mold resin. The semiconductor device according to claim 4, wherein a second semiconductor element is electrically connected to the other surface of the lead frame. Forming a circuit forming layer including a plurality of conductor lands on a surface of a semiconductor element;
Laminating a sheet-like magnetic core on the circuit forming layer;
Bonding a bonding wire between the conductor lands so as to straddle the magnetic core. A method of manufacturing a semiconductor device, comprising: A step of mounting the semiconductor element on one surface of a lead frame;
The method of manufacturing a semiconductor device according to claim 6, wherein the magnetic core is stacked on the surface of the semiconductor element after being relatively aligned with the lead frame. A step of mounting the semiconductor element on one surface of a lead frame;
The method of manufacturing a semiconductor device according to claim 6, wherein the step of bonding the bonding wire is performed simultaneously with the step of electrically bonding the semiconductor element and the lead frame. The method for manufacturing a semiconductor device according to claim 8, further comprising a step of mounting a second semiconductor element on the other surface of the lead frame. The method for manufacturing a semiconductor device according to claim 8, further comprising a step of covering the entire semiconductor element with a mold resin.

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