JP5014619B2 - Semiconductor device and manufacturing method of semiconductor device - Google Patents

Description

The present invention relates to a semiconductor device such as a wafer level CSP (Chip size / scale Package) that does not use a wiring board (interposer), and a method for manufacturing the semiconductor device .

Conventionally, in semiconductor packages, peripheral terminal arrangements, such as dual inline packages and quad flat packages, where metal leads are arranged on the side and periphery of resin packages have been the mainstream. It was.
On the other hand, a chip size / scale package (CSP) capable of high-density mounting has been proposed and put into practical use.
The CSP is an application of so-called ball grid array (BGA) technology, and is a leadless semiconductor package having a structure (BGA structure) in which a plurality of electrodes are arranged in a square shape or a lattice shape on the surface of the package. In the CSP having such a structure, even if the number of electrode lattices is the same, the area occupied by the package can be reduced.

In recent years, a wafer level (WL) CSP has been proposed as a semiconductor package in which the CSP is further developed in order to achieve higher density mounting. (For example, patent document 1).
An outline of a conventional wafer level CSP will be briefly described with reference to FIG. FIG. 8 is a cross-sectional view in the thickness direction.
The semiconductor device 100 includes a semiconductor substrate 101 on which an electrode 102 and a passivation film 103 are formed, an insulating resin layer 111 provided on the semiconductor substrate 101, and a region of the insulating resin layer 111 that matches the electrode 102. An opening 111a formed in the substrate, a wiring layer 115 connected to the electrode 2 through the opening 111a, and a sealing resin for sealing the semiconductor substrate 101, the insulating resin layer 111, and the wiring layer 115. And a post 118 having a solder bump 117 formed on the upper surface thereof.
JP 2002-270720 A

  In such a conventional semiconductor device, since an opaque resin is used for the insulating resin (insulating resin layer and / or sealing resin layer), an X-ray device, an ultrasonic device or the like must be used after sealing. The inside of the resin and the inside of the element could not be inspected, and it was difficult to adapt to an optical device equipped with an image sensor, an infrared sensor, and the like.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a semiconductor device that facilitates inspection inside a resin or inside an element, and that can be applied to an optical device of a wafer level CSP. To do.

According to a first aspect of the present invention, there is provided a semiconductor device including an electrode and an optical element on at least one surface, and a part of the one surface side of the substrate that covers the optical element together with the substrate and overlaps the electrode. An insulating resin layer provided with an opening in the region, a conductive layer provided on the insulating resin layer and having one end electrically connected to the electrode through the opening, the insulating resin layer and the conductive layer A semiconductor device including a sealing resin layer covering the layer and a solder bump formed on the other end of the conductive layer, wherein the optical element is covered with the insulating resin layer, and the insulating resin In the layer and the sealing resin layer, at least a portion overlapping with the optical element is made of a material having transparency in a wavelength region used by the optical element.
According to a second aspect of the present invention, in the semiconductor device according to the first aspect, in the insulating resin layer and / or the sealing resin layer, a portion overlapping with the optical element is thinner than other portions. .
The semiconductor device according to claim 3 of the present invention, in claim 1, before Kifu sealing resin layer is characterized by having an opening in a portion corresponding to the optical element.
According to a fourth aspect of the present invention, in the semiconductor device according to the third aspect, the side surface of the opening is inclined with respect to the surface of the insulating resin layer and / or the sealing resin layer.
A semiconductor device according to a fifth aspect of the present invention is the semiconductor device according to the fourth aspect, characterized in that the slope is tapered when viewed from the cross-sectional direction.
A semiconductor device according to a sixth aspect of the present invention is the semiconductor device according to the fourth aspect, characterized in that the slope has an arc shape when viewed from the cross-sectional direction.
The semiconductor device according to a seventh aspect of the present invention is the semiconductor device according to the fourth aspect, characterized in that the slope has an uneven shape when viewed from the cross-sectional direction.
According to an eighth aspect of the present invention, there is provided a semiconductor device manufacturing method comprising: forming an electrode and an optical element on one surface of a substrate; and covering the optical element together with the substrate on one surface side of the substrate; An opening is provided in the overlapping region, and an insulating resin layer made of a material that is transparent to the optical element is formed, and one end of the insulating resin layer is connected to the electrode through the opening on the insulating resin layer. A step of forming a conductive layer, a step of covering the conductive layer and the insulating resin layer with a sealing resin layer made of a material having transparency in a wavelength region used by the optical element, and a second end of the conductive layer. And a step of forming solder bumps.

  In the present invention, in the insulating resin layer and / or the sealing resin layer, at least a portion that overlaps with the optical element is made of a material that is transparent to the optical element, and therefore an X-ray device or an ultrasonic device is used. In addition, the inside of the resin and the inside of the element can be inspected. Further, according to the present invention, the wafer level CSP can be applied to the optical device.

  Hereinafter, an embodiment of a semiconductor device according to the present invention will be described with reference to the drawings.

<First embodiment>
FIG. 1 is a cross-sectional view showing an example of a semiconductor device of the present invention.
In this semiconductor device 10, an integrated circuit electrode 2 and a passivation film 3 are formed on the surface of a semiconductor substrate 1 on which an integrated circuit (IC, not shown) and optical elements are formed.
The optical element may be a light receiving element or a light emitting element. The semiconductor device 10 includes a photosensor 4 as an optical element.

Further, this semiconductor device includes an insulating resin layer 11 provided on the passivation film 3 of the semiconductor substrate 1, an opening 11a formed in a region matching the electrode 2 of the insulating resin layer 11, and the opening 11a. A conductive layer 12 connected to the electrode 2 through the semiconductor substrate 1, a sealing resin layer 13 covering the semiconductor substrate 1, the insulating resin layer 11 and the conductive layer 12, and penetrating the sealing resin layer 13 on the upper surface. The solder bumps 14 are formed. As shown in FIG. 1, the photosensor 4 is covered with an insulating resin layer 11, and the conductive layer 12 disposed on the insulating resin layer 11 is covered with a sealing resin layer 13. That is, the photosensor 4 is covered with two layers of the insulating resin layer 11 and the sealing resin layer 13, and the conductive layer 12 has a structure covered only with the sealing resin layer 13.

The semiconductor substrate 1 is provided with, for example, an Al pad as an electrode 2 on at least one surface of a base material 1a whose surface layer forms an insulating portion (not shown), and further a passivation film 3 (passivation) such as SiN or SiO ₂ on the surface. Insulating film) is formed. The passivation film 3 is provided with an opening 3a at a position aligned with the electrode 2 and an opening 3b at a position aligned with the photosensor 4, and the electrode 2 and the photosensor 4 are exposed through the openings 3a and 3b. Has been. The passivation film 3 can be formed by, for example, the LP-CVD method, and the film thickness is, for example, 0.1 to 0.5 μm.

  The conductive layer 12 is a rewiring layer (underpass) that electrically connects the electrode 2 and the solder bump 14. One end of the conductive layer 12 penetrates the insulating resin layer 11 through the opening 11 a and is electrically connected to the electrode 2. The other end portion of the conductive layer 12 extends to a position where it is aligned with the solder bump 14.

In the semiconductor device of the present invention, at least a portion of the insulating resin layer 11 and the sealing resin layer 13 that overlaps with the photosensor 4 is made of a material that is transparent to the photosensor 4.
Here, having transparency means having transparency for the wavelength range in which the photosensor 4 is used.
Specifically, for example, it is preferable to have a transmittance of 50% or more in a wavelength region of 700 to 1100 nm.
Examples of such a resin having transparency include polyimide, polyphenylene oxide (PPO), and polybenzoxazole.

In the semiconductor device 10, since the insulating resin layer 11 and the sealing resin layer 13 are made of a permeable material, the inside of the resin and the inside of the element can be inspected without using an X-ray device or an ultrasonic device. it can. As a result, the inspection can be simplified. In addition, the sensitivity of the photosensor 4 is improved, and the optical characteristics of the semiconductor device 10 can be improved.
Further, in a semiconductor device including an optical element, by using a material having transparency in a portion overlapping with the optical element, it is possible to adapt to an optical device of a wafer level CSP. Thereby, a process can be simplified compared with the past, and the freedom degree of design improves.

  The semiconductor substrate 1 may be a semiconductor wafer such as a silicon wafer, or may be a semiconductor chip obtained by cutting (dicing) the semiconductor wafer into chip dimensions. When the semiconductor substrate 1 is a semiconductor chip, first, a plurality of semiconductor elements, ICs, induction elements, etc. are formed on a semiconductor wafer and then cut into chip dimensions to obtain a plurality of semiconductor chips. Can do.

The insulating resin layer 11 has an opening 11 a formed at a position aligned with the electrode 2. The insulating resin layer 11 is made of a material that is transparent to the photosensor 4 as described above, at least a portion that overlaps the photosensor 4, and has a thickness of, for example, 5 to 50 μm.
The insulating resin layer 11 can be formed by, for example, a spin coating method, a printing method, a laminating method, or the like. The opening 11a can be formed, for example, by patterning using a photolithography technique.

The conductive layer 12 is composed of a laminate composed of a seed film (not shown) and a conductive film (not shown) disposed thereon.
As the material of the conductive layer 12, for example, copper is used, and the thickness thereof is, for example, 1 to 20 μm. Thereby, sufficient electrical conductivity is obtained. The conductive layer 12 can be formed by, for example, a plating method such as an electrolytic copper plating method, a sputtering method, a vapor deposition method, or a combination of two or more methods.

  The sealing resin layer 13 is made of a material having transparency for the photosensor 4 as described above, at least a portion overlapping with the photosensor 4, and has a thickness of, for example, 5 to 150 μm. The sealing resin layer 13 is provided with openings 13 a for mounting the solder bumps 14.

The solder bump 14 can be formed through a reflow process in which a solder material is placed on the opening 13a formed in the sealing resin layer 13 and heated to a temperature equal to or higher than the solder melting temperature, for example.
Although only a portion corresponding to one element on the semiconductor substrate is illustrated in FIG. 1, the present invention can also be applied to a semiconductor device including a plurality of elements.

Next, a method for manufacturing the semiconductor device shown in FIG. 1 will be described.
First, as shown in FIG. 2A, a semiconductor substrate 1 having an integrated circuit (not shown), a photosensor 4, an electrode 2, and a passivation film 3 is prepared. As described above, the semiconductor substrate 1 has the electrode 2, the photosensor 4, and the passivation film 3 formed on one surface of the substrate 1 a, and the passivation film 3 has an opening at a position aligned with the electrode 2. 3a, a semiconductor wafer in which an opening 3b is provided at a position aligned with the photosensor 4.

Next, as shown in FIG. 2B, an insulating resin layer 11 having an opening 11 a is formed on the passivation film 3 of the semiconductor substrate 1.
Such an insulating resin layer 11 is formed by, for example, forming a film made of the above resin on the entire surface of the passivation film 3 by, for example, a spin coating method, a printing method, or a laminating method, and then performing patterning using, for example, a photolithography technique. It can be formed by forming the opening 11a at a position aligned with the electrode 2.

Next, as illustrated in FIG. 2C, the conductive layer 12 is formed on the insulating resin layer 11.
Here, an example of a suitable method for forming the conductive layer 12 will be described.
First, a thin seed film (not shown) for electrolytic plating is formed on the entire surface of the insulating resin layer 11 or a necessary region by sputtering or the like. The seed film is, for example, a laminated body made of a Cu layer and a Cr layer formed by a sputtering method, or a laminated body made of a Cu layer and a Ti layer. Further, it may be an electroless Cu plating layer, a metal thin film layer formed by a vapor deposition method, a coating method, a chemical vapor deposition method (CVD), or the like, or a combination of the above metal layer forming methods. Good.

Next, a resist film (not shown) for electrolytic plating is formed on the seed film. The resist film is provided with an opening in a region where the conductive layer 12 is to be formed, and the seed film is exposed in the opening. The resist film can be formed by, for example, patterning using a photolithography technique, a method of laminating a film resist, a method of spin-coating a liquid resist, or the like.
Then, a conductive film made of Cu or the like is formed on the exposed seed film using the resist film as a mask by an electrolytic plating method or the like. In this way, the conductive layer 12 is formed in a desired region. Thereafter, unnecessary resist film and seed film are removed by etching so that the insulating resin layer 11 is exposed in a portion other than the region where the conductive layer 12 is formed.

Thereafter, as shown in FIG. 2D, the sealing resin layer 13 is formed so as to cover the conductive layer 12 and to have an opening 13a in a portion on which the solder bump 14 is placed. Its thickness is about 5 to 150 μm.
Such a sealing resin layer 13 can form the sealing resin layer 13 having the opening 13a at a desired position by patterning a photosensitive resin such as a photosensitive polyimide resin by a photolithography technique, for example. it can. In addition, the formation method of the sealing resin layer 13 is not limited to this method, For example, the pattern application | coating by a printing method may be sufficient.

Next, as shown in FIG. 2 (e), solder bumps 14 are formed on the openings 13 a formed in the sealing resin layer 13. For the solder bump 14, eutectic type or lead-free type solder can be used.
Examples of the method of forming the solder bumps 14 include a solder ball mounting method, a solder paste printing method, a metal jet method, a solder paste dispensing method and then a reflow, or an electrolytic solder plating method and a solder vapor deposition method. It is done.
After the solder bumps 14 are formed, a semiconductor chip in which the conductive layer 12 is packaged can be obtained by dicing a semiconductor wafer on which various structures such as the conductive layer 12 are formed into predetermined dimensions.

In this semiconductor device 10, since the insulating resin layer 11 and the sealing resin layer 13 are made of a permeable material, the inside of the resin and the inside of the element can be inspected without using an X-ray device or an ultrasonic device. Can do. Furthermore, the inspection can be simplified by configuring the entire surface of the insulating resin layer 11 and / or the sealing resin layer 13 from a material having transparency. In addition, the sensitivity of the photosensor 4 is improved, and the optical characteristics of the semiconductor device 10 can be improved.
In addition, in a semiconductor device including an optical element, by using a material having transparency in a portion having sensitivity to light, that is, a portion overlapping with the optical element, it is possible to adapt to a wafer level CSP optical device. Thereby, a process can be simplified compared with the past, and the freedom degree of design improves.
<Second Embodiment>

    Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a cross-sectional view showing an example of the semiconductor device of this embodiment.
In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description of common portions is omitted.
The semiconductor device 20 includes an insulating resin layer 21 provided on the semiconductor substrate 1, an opening 21a formed in a region matching the electrode 2 of the insulating resin layer 21, and the electrode through the opening 21a. 2, a conductive resin layer 22 covering the semiconductor substrate 1, the insulating resin layer 21, and the conductive layer 22, and solder bumps 24 penetrating the sealing resin layer 23 and formed on the upper surface. And have. As shown in FIG. 3, the photosensor 4 is covered with an insulating resin layer 21, and the conductive layer 22 disposed on the insulating resin layer 21 is covered with a sealing resin layer 23. That is, the photosensor 4 is covered with two layers of the insulating resin layer 21 and the sealing resin layer 23, and the conductive layer 22 has a structure covered only with the sealing resin layer 23.

In the semiconductor device 20, a portion of the insulating resin layer 21 and / or the sealing resin layer 23 that overlaps with the photosensor 4 is thinner than other portions. FIG. 3 shows an example in which the portion 23 a overlapping the photosensor 4 in the sealing resin layer 23 is thin.
By thinning the portion that overlaps the photosensor 4, the transparency of the insulating resin layer 21 and / or the sealing resin layer 23 at the portion that overlaps the photosensor is improved. Thereby, the inside of the element can be inspected without using an X-ray apparatus or an ultrasonic apparatus. In addition, the sensitivity of the photosensor 4 is improved, and the optical characteristics of the semiconductor device 20 can be improved.

In the above description, the case where the portion overlapping the photosensor 4 in the sealing resin layer 23 is thinned is described as an example. However, even when the portion overlapping the photosensor 4 in the insulating resin layer 21 is thinned, Similar effects can be obtained.
<Third embodiment>

    Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a cross-sectional view showing an example of the semiconductor device of this embodiment.
In FIG. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description of common parts is omitted.
The semiconductor device 30 includes an insulating resin layer 31 provided on the semiconductor substrate 1, an opening 31a formed in a region matching the electrode 2 of the insulating resin layer 31, and the electrode through the opening 31a. 2, a conductive resin layer 32 covering the semiconductor substrate 1, the insulating resin layer 31, and the conductive layer 32, and solder bumps 34 penetrating the sealing resin layer 33 and formed on the upper surface. And have. As shown in FIG. 4, the photosensor 4 is covered with an insulating resin layer 31, and the conductive layer 32 disposed on the insulating resin layer 31 is covered with a sealing resin layer 33. That is, the photosensor 4 is covered with two layers of the insulating resin layer 31 and the sealing resin layer 33, and the conductive layer 32 has a structure covered only with the sealing resin layer 33.

The semiconductor device 30 has an opening in a portion corresponding to the photosensor 4 of the insulating resin layer 31 and / or the sealing resin layer 33. In FIG. 4, the case where the opening 33a is formed in the sealing resin layer 33 is shown as an example.
In the insulating resin layer 31 and / or the sealing resin layer 33, by forming an opening in a portion corresponding to the photosensor 4, the transparency of the portion can be improved. Thereby, the inside of the element can be inspected without using an X-ray apparatus or an ultrasonic apparatus. In addition, the sensitivity of the photosensor 4 is improved, and the optical characteristics of the semiconductor device 30 can be improved.

It is preferable that the side surface of the opening 33 a is inclined with respect to the surface of the insulating resin layer 31 and / or the sealing resin layer 33. Since the side surface of the opening is inclined, the optical axis of light reception / emission of the photosensor 4 can be changed in a direction other than vertical. Thereby, the width of the optical path can be widened, and a semiconductor device suitable for the application can be provided.
Various optical functions can be given to the semiconductor device 30 by changing the shape of the inclination.

For example, as shown in FIG. 4, the slope 33b can be tapered (trapezoidal) when viewed from the cross-sectional direction.
By making the inclination tapered and adjusting the inclination angle, the optical path of the light incident / exiting the photosensor 4 can be controlled. Thereby, the semiconductor device according to a use can be provided.

Further, as shown in FIG. 5, the slope 33b can be formed in an arc shape when viewed from the cross-sectional direction. The arc shape may be convex or concave.
By making the inclination arc-shaped, it is possible to impart a lens function to the inclination. Thereby, the optical path of the light incident / exited to the photosensor 4 can be controlled, and a semiconductor device suitable for the application can be provided.

In addition, as shown in FIG. 6, the slope 33b can be formed to have an uneven shape when viewed from the cross-sectional direction. The unevenness is, for example, stepped or sawtooth. The unevenness may be formed randomly or in a stripe shape.
By making the inclination uneven, a special lens function can be imparted to the inclination. Thereby, the optical path of the light incident / exited to the photosensor 4 can be controlled, and a semiconductor device suitable for the application can be provided.

  In the above description, the case where the opening is formed in the sealing resin layer 33 is described as an example, but the same effect can be obtained even when the opening is formed in the insulating resin layer 31. .

Such an opening can be formed, for example, by irradiating the insulating resin layer and / or the sealing resin layer by moving the laser beam under program control. Thereby, the side surface of the resin layer remaining as a result of etching can be inclined with respect to the surface. Further, batch processing may be performed using a metal mask.
As the laser, for example, an excimer laser, a CO ₂ laser, a UV-YAG laser, or the like can be used. This etching is not limited to laser etching, and may be anisotropic plasma etching using CF ₄ plasma, for example.
Furthermore, the insulating resin layer and / or the sealing resin layer may be formed from a photosensitive resin, and the opening may be formed in the insulating resin layer and / or the sealing resin layer by photolithography. In addition, the formation method of an opening part is not limited to these methods.

  The semiconductor device and the method for manufacturing the same according to the present invention have been described above. However, the present invention is not limited to this, and can be appropriately changed without departing from the spirit of the present invention.

A semiconductor device as shown in FIG. 1 was manufactured using a resin having transparency for the insulating resin layer and the sealing resin layer.
FIG. 7 shows the transmittance of the used resin in the visible to near-ultraviolet region. It can be seen that there is a region with a transmittance of 1% or more in a region where the wavelength of light is 400 nm or more.
This semiconductor device was able to inspect all foreign substances and wiring shapes in the resin by using a relatively inexpensive appearance inspection apparatus using a visible light region.
Moreover, it was confirmed that this semiconductor device has sensitivity to near infrared rays having a wavelength of 900 nm.

  The present invention is applicable to various semiconductor devices incorporating various optical elements such as photosensors.

It is sectional drawing which shows an example of the semiconductor device of this invention. FIG. 2 is a cross-sectional view showing an example of a method for manufacturing the semiconductor device shown in FIG. It is sectional drawing which shows an example of the semiconductor device of this invention. It is sectional drawing which shows an example of the semiconductor device of this invention. It is sectional drawing which shows an example of the semiconductor device of this invention. It is sectional drawing which shows an example of the semiconductor device of this invention. It is a figure which shows the transmittance | permeability of resin used in the Example. It is sectional drawing which shows an example of the conventional semiconductor device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate (board | substrate), 2 electrodes, 3 Passivation film | membrane, 4 Photosensor (optical element) 10, 20, 30 Semiconductor device, 11 Insulating resin layer, 12 Conductive layer, 13 Sealing resin layer, 14 Solder bump.

Claims (8)

A substrate having electrodes and optical elements on at least one surface;
An insulating resin layer that covers the optical element together with the substrate on one surface side of the substrate, and has an opening provided in a partial region overlapping the electrode;
A conductive layer provided on the insulating resin layer and having one end electrically connected to the electrode through the opening;
A semiconductor device comprising: a sealing resin layer covering the insulating resin layer and the conductive layer; and a solder bump formed on the other end of the conductive layer,
The optical element is covered with the insulating resin layer,
In the insulating resin layer and the sealing resin layer, at least a portion overlapping with the optical element is made of a material having transparency in a wavelength region used by the optical element.   2. The semiconductor device according to claim 1, wherein in the insulating resin layer and / or the sealing resin layer, a portion overlapping with the optical element is thinner than other portions. Before Kifu sealing resin layer, the semiconductor device according to claim 1, characterized in that has an opening in a portion corresponding to the optical element.   The semiconductor device according to claim 3, wherein a side surface of the opening is inclined with respect to a surface of the insulating resin layer and / or the sealing resin layer.   The semiconductor device according to claim 4, wherein the inclination is tapered when viewed from a cross-sectional direction.   The semiconductor device according to claim 4, wherein the inclination has an arc shape when viewed from a cross-sectional direction.   The semiconductor device according to claim 4, wherein the inclination is uneven when viewed from a cross-sectional direction. Forming an electrode and an optical element on one surface of the substrate;
Forming an insulating resin layer made of a material that covers the optical element together with the substrate on the one surface side of the substrate and is provided with an opening in a region overlapping the electrode, the material having transparency to the optical element; ,
Forming a conductive layer having one end connected to the electrode through the opening on the insulating resin layer;
Covering the conductive layer and the insulating resin layer with a sealing resin layer made of a material having transparency in a wavelength region used by the optical element; forming a solder bump on the other end of the conductive layer; A method for manufacturing a semiconductor device, comprising:

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