JP2000049260A - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a PBGA which is a semiconductor package,
The α-rays generated from the radioactive substance contained in the filler in the transfer mold cause malfunction of the semiconductor chip. According to the present invention, a protective film or a resin film having a thickness equal to or greater than a range in an α-ray substance generated from a radioactive substance contained in a filler in a transfer mold is formed on a semiconductor chip. In addition, malfunction of the semiconductor chip due to α rays can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a semiconductor chip mounted on a wiring board and sealing the semiconductor chip with a resin, and more particularly to a semiconductor device with solder bumps and a method of manufacturing the same. .

[0002]

2. Description of the Related Art In recent years, semiconductor devices having a large number of electrode terminals have been developed as electronic circuits become more sophisticated. A typical example is a plastic ball grid array (Pl) which is a surface mount type multi-terminal package.
asic Ball GridArray)
Described as PBGA. ).

[0003] A conventional technique will be described below with reference to the drawings. FIG. 5 is a cross-sectional view showing a conventional PBGA. FIG.
As described in the above, a connection electrode 3 for wire bonding with the semiconductor chip 1 is provided on the upper surface side, a pad electrode 4 for providing a solder bump 6 on the lower surface side, and a wiring 15 at the center of the resin substrate 2 is provided. Thermal via holes 16 for connecting the semiconductor chip 1 to the pad electrodes 4 to dissipate heat, through holes 14 for connecting the connection electrodes 3 and the pad electrodes 4, and resists 5 for protecting the wiring 15. , A semiconductor chip 1 fixed to a central portion of the wiring substrate 18 with a die bonding agent 7, a protective film 12 for protecting circuit elements on the semiconductor chip 1, electrodes of the semiconductor chip 1, and wiring Substrate 18
A structure including bonding wires 8 for connecting the connection electrodes 3 to each other, transfer molds 9 for sealing the semiconductor chips 1 and the bonding wires 8, and solder bumps 6 on the pad electrodes 4 of the wiring board 18. Has become.

Next, a method of manufacturing a PBGA will be described. 6 to 9 are cross-sectional views showing a manufacturing process of a conventional PBGA.

As shown in FIG. 6, a resin substrate 2 is made of a glass epoxy resin having a rectangular shape and a thickness of about 0.2 mm, and a copper foil 17 having a thickness of about 18 μm is provided on both upper and lower surfaces thereof. The resin substrate 2 is provided with thermal via holes 16 for heat radiation between the plurality of through holes 14 and the semiconductor chip 1 by cutting drilling. After cleaning the substrate surface including the wall surfaces of the through hole 14 and the thermal via hole 16, an electroless copper plating layer is provided on the entire surface of the resin substrate 2. The copper plating layer is
And the thermal via hole 16 is formed.

Next, a photosensitive dry film is adhered to the upper and lower surfaces of the resin substrate 2 and exposed and developed to form an etching resist film. Thereafter, an etching solution is sprayed on the upper and lower surfaces of the resin substrate 2 to remove exposed copper without an etching resist film. After this etching, the remaining etching resist film is removed. As shown in FIG. 7, the connection electrodes 3 for wire bonding are formed on the upper surface of the resin substrate 2 and the solder bumps 6 are formed on the lower surface.
And a wiring 15 on both sides. The process of forming the connection electrode is called a patterning process. The wiring 15 at the center of the resin substrate 2 and the pad electrode 4 are connected via a thermal via hole 16, and the connection electrode 3 corresponding to the opening of the resist and the pad electrode 4 are connected via a through hole 14.

Further, as shown in FIG. 8, a resist is laminated on both surfaces of the resin substrate 2 and exposed and developed to provide a resist 5, and a portion corresponding to the connection electrode 3 and the pad electrode 4 has an opening in the resist 5. Is provided. This step is called a resist forming step.

Next, a nickel plating layer having a thickness of about 2 to 5 μm is provided on the surfaces of the copper plating layers of the exposed electrodes on the upper and lower surfaces of the resin substrate 2. Further, on the surface of the nickel plating layer, there is provided a flash gold plating layer having a thickness of about 0.05 μm, which contains impurities such as cobalt and is apt to bite the nickel plating layer. Although not shown, the steps up to the copper plating layer, the nickel plating layer, and the flash gold plating layer are the base plating steps for providing the base plating layer.

[0009] Next, on the base plating layer, a conductive material having excellent conductivity with the bonding wire 8 having a thickness of 0.3 μm to 0.1 μm is formed.
A gold plating layer of about 7 μm is provided. Although not shown,
This step is a gold plating step for forming a gold plating layer.
Thus, the wiring board 18 is completed.

Next, as shown in FIG.
A die bonding agent 7 is applied on a central portion on the upper surface side of the semiconductor chip 1, the semiconductor chip 1 is placed thereon, and the semiconductor chip 1 is dried until the die bonding agent 7 is cured. Thereafter, a wire bonding process is performed to electrically connect the electrodes of the semiconductor chip 1 and the connection electrodes 3 on the wiring board 18 with the bonding wires 8. Next, the semiconductor chip 1 and the bonding wires 8 are subjected to a transfer molding process of sealing with a transfer mold 9.

At this time, a protective film 12 for protecting circuit elements is formed on the semiconductor chip 1, and an electrode portion to be connected by wire bonding is opened by exposing and developing the protective film 12.

Next, solder balls having a diameter of 0.6 mm to 0.8 mm are supplied to the pad electrode 4 on the lower surface side of the wiring board 18 and heated by using a heating furnace, so that the solder bumps 6 are provided. This completes the PBGA.

[0013]

In a PBGA which is a semiconductor package, a sealing resin 9 used contains a filler 6 for the purpose of lowering the coefficient of thermal expansion. As the filler 6, SiO2, calcium carbonate, alumina or the like is used, and radioactive substances such as uranium and thorium are contained therein.

The α-rays generated from the radioactive substance may rewrite the contents of the recording circuit element incorporated in the semiconductor chip 1 and reduce the amount of the radioactive substance contained in the filler 6 in the sealing resin 9. Need to reduce.

However, reducing the amount of the radioactive substance in the filler 6 requires steps, time and cost, so that the price is about 3 to 10 times that of the unrefined one.

An object of the present invention is to provide a semiconductor package, PBGA, which is not affected by α-rays generated from a radioactive material even if a sealing resin using an inexpensive filler containing a radioactive material is used. An object of the present invention is to provide a mounting structure and a mounting method of a semiconductor device.

[0017]

In order to achieve the above object, a semiconductor device and a method of manufacturing the same according to the present invention employ the following configurations and manufacturing methods.

A semiconductor device according to the present invention has a wiring board provided with electrodes for wire bonding to a semiconductor chip on an upper surface side, a semiconductor chip fixed on the wiring board, and a circuit element on the semiconductor chip for protecting circuit elements. A protective film having a thickness greater than or equal to the range in the α-ray material, a bonding wire for connecting an electrode of the semiconductor chip to a connection electrode of the wiring board, and a semiconductor chip and a bonding wire.
And a transfer mold for sealing.

A semiconductor device according to the present invention has a wiring board provided with electrodes for wire bonding with a semiconductor chip on an upper surface side, a semiconductor chip fixed on the wiring board, and a circuit element on the semiconductor chip for protecting circuit elements. A protective film, a resin film having a thickness greater than or equal to the range in the α-ray material, mainly only on the recording circuit element on the semiconductor chip, and for connecting the electrode of the semiconductor chip and the connection electrode of the wiring board. , And a transfer mold for sealing the semiconductor chip and the bonding wire.

According to the method of manufacturing a semiconductor device of the present invention, a patterning step for forming electrodes of a semiconductor chip and connection electrodes connected by bonding wires is performed on the upper surface side of a resin substrate, and a resist is formed on the resin substrate. A resist forming step of arranging and forming a resist opening in the connection electrode; and a protective film forming step of arranging a protective film having a thickness equal to or more than the range in the α-ray material on the semiconductor chip and opening the electrode portion. And a die bonding step of fixing a semiconductor chip on a wiring board;
A wire bonding step of connecting the fixed semiconductor chip electrode and the connection electrode of the wiring board with a bonding wire, and a bonding step of connecting the semiconductor chip fixed on the wiring board with the connection electrode on the wiring board; And a transfer molding step of sealing the wire with a resin.

According to the method of manufacturing a semiconductor device of the present invention, a patterning step for forming electrodes of a semiconductor chip and connection electrodes connected by bonding wires is performed on the upper surface side of a resin substrate, and a resist is formed on the resin substrate. A resist forming step of arranging and forming a resist opening in the connection electrode; a protective film forming step of arranging a protective film on the semiconductor chip and opening the electrode portion; A resin film forming step of forming a resin film having a thickness greater than or equal to the range in the material of the wire, a die bonding step of fixing a semiconductor chip on the wiring board, and a connection electrode of the fixed semiconductor chip and a connection electrode of the wiring board. A wire bonding step of connecting with a bonding wire, and bonding for connecting the semiconductor chip fixed on the wiring board and the connection electrode on the wiring board It is characterized by having a transfer molding step of sealing the ear with a resin.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION In order to examine the range of an α-ray generated from a radioactive substance contained in a sealing resin in an organic substance, the α-ray dose was measured using the following samples.

The measurement sample was 100 parts by weight of bisphenol F type epoxy as a main ingredient, 98 parts by weight of methyltetrahydrophthalic anhydride as a curing agent, and 1 part by weight as a curing accelerator.
An adhesive containing 90 parts by weight of a filler to which 1 part by weight of cyanoethyl-2-ethyl-4-methylimidazole was added, and a layer having a thickness of 40 μm formed by applying and heat-treating, and protecting a semiconductor chip thereon; Polyimide to be a film was formed by coating and heat treatment at intervals of 10 μm from 0 to 40 μm, and the α dose at that time was measured.

The amount of radioactive material contained in the filler 6 used at this time is 50 ng / g for uranium and 170 g for thorium.
ng / g was used.

As a result of measuring the α dose, the results shown in Table 1 were obtained. Α-rays were not detected as the thickness of the protective film provided on the layer in which the filler was present increased, and if the thickness of the adhesive used was 30 μm or more, α-rays could not be detected.

[0026]

[Table 1]

From this, the semiconductor package P
In BGA, a transfer film is formed on a semiconductor chip by forming a protective film or a resin film having a thickness greater than or equal to the range in an α-ray material generated from a radioactive material contained in a filler in a transfer mold. The effect on the semiconductor chip due to the α-rays generated from the radioactive material contained in the filler in the mold is eliminated, and no malfunction occurs.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a PBG according to a first embodiment of the present invention.
It is sectional drawing which shows A. As shown in FIG. 1, a connection electrode 3 for wire bonding with the semiconductor chip 1 is provided on the upper surface side, a pad electrode 4 for providing solder bumps 6 on the lower surface side, and a central portion of the resin substrate 2 is further provided. The semiconductor chip 1 is connected by connecting the wiring 15 and the pad electrode 4.
Thermal via holes 16 for dissipating the heat of
A wiring board 18 having a through hole 14 for connecting the connection electrode 3 and the pad electrode 4, a resist 5 for protecting the wiring 15, and a semiconductor fixed on a central portion of the wiring board 18 with a die bonding agent 7 Α generated from radioactive material contained in the filler in the transfer mold 9 for protecting the chip 1 and the circuit elements on the semiconductor chip 1
A protective film 12 having a thickness greater than or equal to the range of the wire material, a bonding wire 8 for connecting the electrode of the semiconductor chip 1 to the connection electrode 3 of the wiring board 18, and an insulating resin 10 mainly covering the bonding wire. A transfer mold 9 for sealing the semiconductor chip 1 and the bonding wires 8, and a solder bump 6 on the pad electrode 4 of the wiring board 18.
And a structure having:

Next, a method of manufacturing the semiconductor device according to the first embodiment will be described. The wiring board can be manufactured by a conventional method. As shown in FIG. 2, a die bonding agent 7 is applied on a central portion on the upper surface side of the wiring board 18 formed by the method described above, and the semiconductor chip 1 is placed thereon, and the die bonding agent 7 is cured. Then, after the die bonding step of fixing the semiconductor chip 1 on the wiring board 18, a wire bonding step of electrically connecting the electrodes of the semiconductor chip 1 and the connection electrodes 3 on the wiring board 18 with the bonding wires 8 is performed.

After that, the semiconductor chip 1 and the bonding wires 8 are subjected to a transfer molding process of sealing with a transfer mold 9. At this time, the semiconductor chip 1 to be mounted has a protective film 12 for protecting circuit elements formed through a protective film forming process, as shown in FIG. Protective film 1 of the terminal portion which is longer than the range of α-rays generated from the contained radioactive material and which is connected by wire bonding
2 is opened by exposure and development.

Next, solder balls having a diameter of 0.6 mm to 0.8 mm are supplied to the pad electrode 4 on the lower surface side of the wiring board 18 and the solder bumps 6 are provided by heating using a heating furnace. Thus, the semiconductor device of the present invention is completed.

FIG. 3 shows a PBG according to a second embodiment of the present invention.
It is sectional drawing which shows A. As shown in FIG. 3, a connection electrode 3 for wire bonding with the semiconductor chip 1 is provided on the upper surface side, a pad electrode 4 for providing solder bumps 6 on the lower surface side, and a central portion of the resin substrate 2 is further provided. The semiconductor chip 1 is connected by connecting the wiring 15 and the pad electrode 4.
Thermal via holes 16 for dissipating the heat of
A wiring board 18 having a through hole 14 for connecting the connection electrode 3 and the pad electrode 4, a resist 5 for protecting the wiring 15, and a semiconductor fixed on a central portion of the wiring board 18 by a die bonding agent 7 A chip 1; a protective film 12 for protecting circuit elements on the semiconductor chip 1; and a resin having a thickness greater than or equal to the range in an α-ray substance mainly disposed on the recording circuit element 20 on the semiconductor chip. A film 19, a bonding wire 8 for connecting the electrode of the semiconductor chip 1 to the connection electrode 3 of the wiring board 18, an insulating resin 10 mainly covering the bonding wire, and a sealing for the semiconductor chip 1 and the bonding wire 8; Transfer mold 9
And a solder bump 6 on the pad electrode 4 of the wiring board 18.

Next, a method of manufacturing a semiconductor device according to the second embodiment will be described. The wiring board can be manufactured by a conventional method.

As shown in FIG. 4, a die bonding agent 7 is applied on the central portion on the upper surface side of the wiring board 18 formed by the method described above, and the semiconductor chip 1 is placed thereon, and the die bonding agent 7 Is dried until the semiconductor chip 1 is hardened, and after the die bonding step of fixing the semiconductor chip 1 on the wiring board 18,
The electrodes of the semiconductor chip 1 and the connection electrodes 3 on the wiring board 18
Is electrically connected by a bonding wire 8.

Thereafter, the semiconductor chip 1 and the bonding wires 8 are subjected to a transfer molding step of sealing with a transfer mold 9. At this time, as shown in FIG. 4, the semiconductor chip 1 to be mounted has a protective film 12 for protecting circuit elements formed in a protective film forming step, and the protective film 12 at a terminal portion connected by wire bonding is exposed. An opening is formed by development, and a thickness not less than the range in the α-ray substance generated from the radiation substance contained in the filler in the transfer mold 9 is mainly formed on the recording circuit element 20 in the protective film 12 on the protective film 12. The resin film 19 is formed through a resin film forming process by exposure and development.

Next, a solder ball having a diameter of 0.6 mm to 0.8 mm is supplied to the pad electrode 4 on the lower surface side of the wiring board 18, and the solder bump 6 is provided by heating using a heating furnace. Thus, the semiconductor device of the present invention is completed.

[0038]

As is clear from the above description, in the semiconductor device and the method of manufacturing the same according to the present invention, the semiconductor device is provided with a semiconductor chip and an α-ray material generated from a radioactive material contained in the filler in the transfer mold. Since a protective film or a resin film having a thickness greater than the range is formed, malfunction of the semiconductor chip due to α-rays does not occur. In addition, inexpensive fillers containing radioactive substances can be used,
Cost reduction becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a sectional view illustrating a manufacturing method for forming a semiconductor device according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a semiconductor device according to a second embodiment of the present invention.

FIG. 4 is a sectional view illustrating a manufacturing method for forming a semiconductor device according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a semiconductor device in a conventional example.

FIG. 6 is a sectional view showing a manufacturing method for forming a semiconductor device in a conventional example.

FIG. 7 is a cross-sectional view illustrating a manufacturing method for forming a semiconductor device in a conventional example.

FIG. 8 is a cross-sectional view illustrating a manufacturing method for forming a semiconductor device in a conventional example.

FIG. 9 is a cross-sectional view illustrating a manufacturing method for forming a semiconductor device in a conventional example.

[Explanation of symbols]

 Reference Signs List 1 semiconductor chip 2 resin substrate 3 connection electrode 4 pad electrode 5 resist 6 solder bump 7 die bonding agent 8 bonding wire 9 transfer mold 12 protective film 14 through hole 15 wiring 16 thermal via hole 17 copper foil 18 wiring substrate 19 resin film 20 recording circuit element

Claims (4)

[Claims] 1. A wiring board provided with an electrode for wire bonding with a semiconductor chip on an upper surface side, a semiconductor chip fixed on the wiring board, and a thickness on the semiconductor chip which is equal to or greater than a range of an α ray in a substance. A semiconductor device comprising: a protective film having: a bonding wire for connecting an electrode of a semiconductor chip to a connection electrode of a wiring board; and a transfer mold for sealing the semiconductor chip and the bonding wire. . 2. A wiring board having electrodes for wire bonding with a semiconductor chip on an upper surface side, a semiconductor chip fixed on the wiring board, a protective film on the semiconductor chip, and a recording mainly on the semiconductor chip. A resin film having a thickness greater than or equal to the range of the α-ray material only on the circuit element, a bonding wire for connecting the electrode of the semiconductor chip to the connection electrode of the wiring board, and the semiconductor chip and the bonding wire are sealed. And a transfer mold for stopping the transfer. 3. A method of forming a protective film having a thickness greater than or equal to the range of an α-ray in a semiconductor chip on a semiconductor chip, forming a protective film for opening an electrode portion, and fixing the semiconductor chip on a wiring substrate. Bonding process for connecting the electrode of the semiconductor chip and the connection electrode of the wiring board with a bonding wire, and bonding for connecting the semiconductor chip fixed on the wiring board and the connection electrode on the wiring board A method of manufacturing a semiconductor device, comprising: a transfer molding step of sealing a wire with a resin. 4. A protective film forming step of arranging a protective film on a semiconductor chip and opening an electrode portion, and a resin having a thickness greater than or equal to a range in an α-ray material mainly in a recording circuit element on the semiconductor chip. A resin film forming step of forming a film, a semiconductor chip fixed on the wiring board, and a wire bonding step of connecting electrodes of the fixed semiconductor chip and connection electrodes of the wiring board with bonding wires; And a transfer molding step of sealing a bonding wire connecting the semiconductor chip and a connection electrode on a wiring board with a resin.