JP2003282895A - Light receiving device mounted with high-speed light receiving element and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a light receiving apparatus having a mounted high-speed light receiving element the high-speed response characteristic and manufacturing yield of which can be maintained, and a manufacturing method thereof. <P>SOLUTION: The light receiving apparatus, having a mounted high-speed light receiving element on a high-frequency board, is provided with a high-frequency board having a formed hole for passing therethrough an incident light, and a surface projecting type high-speed light receiving element connected electrically with the high-frequency board and bonded with solder bumps to the high-frequency board by so providing its light receiving surface on the side the high-frequency board as to align its light receiving surface with the hole. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

The present invention relates to a light-receiving device having a high-speed light-receiving element mounted on a high-frequency substrate, and more particularly to a light-receiving device having a high-speed light-receiving element capable of maintaining high-speed response characteristics and yield and a method of manufacturing the same.

[0002]

2. Description of the Related Art There are various types of conventional high-speed light-receiving elements such as a front-illuminated type and an optical waveguide type, but a high-speed front-illuminated type light-receiving element is generally used.

On the other hand, in a light receiving device used for optical information communication, in order to transmit a very large amount of information in a short time, such a high speed light receiving element is used as a coplanar waveguide.
It is directly mounted on a high-frequency board that has a waveguide line such as uide).

FIG. 7 is a sectional view showing the structure of an example of such a conventional light receiving device. In FIG. 7, 1 is a high-frequency substrate such as a coplanar line, 2 is a front-illuminated high-speed light receiving element, 3
Reference numerals 4 and 4 are electrodes formed on the high-frequency substrate 3, and reference numeral 5 is an adhesive.

The high speed light receiving element 2 is fixed to the high frequency substrate 1 on the side opposite to the light receiving surface with an adhesive 5, and the electrodes of the high speed light receiving element 2 and the electrodes 3 and 4 formed on the high frequency substrate 1 are electrically connected by bonding wires or the like. Connected to.

Now, the operation of the conventional example shown in FIG. 7 will be briefly described. The incident light “PH01” in FIG. 7 is incident from the light receiving surface side of the high-speed light receiving element 2 and is incident on the light receiving area formed near the light receiving surface “AL01” in FIG. 7.

The detection signal converted into an electric signal in the light receiving area indicated by "AL01" in FIG. 7 is taken out to the high frequency substrate 1 through the bonding wire and the electrodes 3 and 4.

However, in the conventional example shown in FIG. 7, there is a step between the high-speed light receiving element 2 and the high-frequency substrate 1. Therefore, an electrical connection is obtained by a bonding wire. There is a problem in that the high-speed response characteristic is deteriorated because the wire is a factor that hinders the transmission of a high frequency electric signal which is a detection signal.

For example, even if the high-speed light receiving element 2 has a high-speed response, the high-speed response characteristic is deteriorated due to the step and the bonding wire.

Therefore, conventionally, in order to solve such a problem, a light receiving region is provided on the side of the high frequency substrate 1 and is bonded by a solder bump, thereby eliminating the above-mentioned step and the bonding wire.

FIG. 8 is a sectional view showing the structure of another example of such a conventional light receiving device. In FIG. 8, 1 is assigned the same reference numeral as in FIG. 7, 6 is a high speed light receiving element having a light receiving region provided on the high frequency substrate 1 side, and 7 is a solder bump.

The high-speed light-receiving element 6 has a light incident surface on the back surface of the structure, and the side opposite to the light-incident surface is fixed to the high-frequency substrate 1 by the solder bumps 7 and the electrodes of the high-speed light-receiving element 6 and the high-frequency substrate 1 are fixed by the solder bumps 7. And are electrically connected.

The operation of the conventional example shown in FIG. 8 will be briefly described. The incident light indicated by "PH11" in FIG. 8 is incident from the light incident surface side of the high speed light receiving element 6, and is incident on the light receiving area formed near the surface of the high frequency substrate 1 indicated by "AL11" in FIG.

Then, the detection signal converted into an electric signal in the light receiving area indicated by "AL11" in FIG. 8 is taken out to the high frequency substrate 1 through the solder bump 7.

As a result, the light receiving area indicated by "AL11" in FIG. 8 is provided on the side of the high frequency substrate 1 and is bonded by the solder bumps 7, thereby eliminating the step and the bonding wire which are problems in the conventional example shown in FIG. Therefore, it is possible to prevent deterioration of high-speed response characteristics.

[0016]

However, although the conventional example shown in FIG. 8 can prevent deterioration of the high-speed response characteristic, it is necessary to make the light incident surface of the high-speed light receiving element 6 a mirror finish.

Further, in the high speed light receiving element 6, it is necessary to form an antireflection film or the like on the light incident surface.

By subjecting the high-speed light-receiving element 6 to such various processing, the load on the high-speed light-receiving element 6 is increased, and the yield of the high-speed light-receiving element 6 is reduced. . Therefore, the problem to be solved by the present invention is to realize a light-receiving device mounted with a high-speed light-receiving element capable of maintaining high-speed response characteristics and yield, and a method of manufacturing the same.

[0019]

In order to achieve the above object, the invention according to claim 1 of the present invention is a light receiving device in which a high speed light receiving element is mounted on a high frequency substrate, and a hole through which incident light passes. And a high-frequency substrate on which the light-receiving surface is formed on the high-frequency substrate side, and the light-receiving surface is aligned with the hole and is bonded to the high-frequency substrate by solder bumps and is electrically connected to the high-frequency substrate. By providing the high-speed light-receiving element, it is possible to eliminate steps and bonding wires and maintain high-speed response characteristics, and it is not necessary to perform various processing on the high-speed light-receiving element, which makes it possible to maintain yields. .

According to a second aspect of the invention, in the light receiving device according to the first aspect of the invention, a collimating lens is provided in the hole portion on the side opposite to the mounting side of the high-speed light receiving element. The coupling efficiency of is improved.

According to a third aspect of the present invention, in the light receiving device according to the second aspect, the lens for collimating is a spherical lens, so that the light coupling efficiency is improved.

According to a fourth aspect of the present invention, in a method of manufacturing a light receiving device in which a high-speed light receiving element is mounted on a high frequency substrate, a step of forming a hole through which incident light passes through the high frequency substrate, and the formation on the high frequency substrate. A step of forming a solder bump in the vicinity of the hole, and the solder so that the light-receiving surface of the front-illuminated high-speed light-receiving element is on the high-frequency substrate side and the light-receiving surface is aligned with the hole formed in the high-frequency substrate. By including the step of bonding using bumps, steps and bonding wires can be omitted, so high-speed response characteristics can be maintained, and it is not necessary to perform various processing on the high-speed light-receiving element, so yield can be maintained. become.

According to a fifth aspect of the present invention, in a method of manufacturing a light receiving device in which a high-speed light receiving element is mounted on a high frequency substrate, a step of forming a hole through which incident light passes through the high frequency substrate, and the formation on the high frequency substrate. A step of forming a solder bump in the vicinity of the hole, and the solder so that the light-receiving surface of the front-illuminated high-speed light-receiving element is on the high-frequency substrate side and the light-receiving surface is aligned with the hole formed in the high-frequency substrate. By including a step of bonding using bumps and a step of aligning a lens for collimation with a portion of the hole on the side opposite to the mounting side of the high-speed light receiving element and fixing it to the high-frequency substrate with an adhesive, Since the bonding wire can be omitted, it is possible to maintain high-speed response characteristics,
Since it is not necessary to perform various processing on the high-speed light receiving element, the yield can be maintained. In addition, the light coupling efficiency is improved.

According to a sixth aspect of the present invention, in a method of manufacturing a light receiving device in which a high-speed light receiving element is mounted on a high frequency substrate, a step of forming a hole through which incident light passes through the high frequency substrate, and the method of forming the hole on the high frequency substrate. A step of aligning a lens for collimating with the hole and fixing it to the high-frequency substrate with an adhesive; a step of forming a solder bump in the vicinity of the hole on the side opposite to the mounting side of the lens; A step or a bonding wire is formed by using the solder bump so that the light receiving surface of the high-speed light receiving element is on the high frequency substrate side and the light receiving surface is aligned with the hole formed in the high frequency substrate. Therefore, it is possible to maintain the high-speed response characteristics, and it is not necessary to perform various processes on the high-speed light-receiving element, so that the yield can be maintained. In addition, the light coupling efficiency is improved.

According to a seventh aspect of the present invention, in the method of manufacturing a light receiving device according to the fifth aspect, after the high speed light receiving element is bonded to the high frequency substrate, incident light is incident on the lens and the high speed light receiving is performed. By positioning the lens based on the detection signal obtained from the element,
The positioning accuracy can be improved.

According to an eighth aspect of the present invention, in the method for manufacturing a light receiving device according to any one of the fifth to seventh aspects, since the collimating lens is a spherical lens, a step or Since the bonding wire can be omitted, it is possible to maintain the high-speed response characteristic, and it is not necessary to perform various processes on the high-speed light receiving element, so that the yield can be maintained. In addition, the light coupling efficiency is improved.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view showing the configuration of an embodiment of a light receiving device according to the present invention.

In FIG. 1, 8a and 8b are high-frequency substrates such as coplanar lines, 9 is a front-illuminated high-speed light receiving element,
10 and 11 are solder bumps.

The high speed light receiving element 9 has a solder bump 1 on the light receiving surface side.
0 and 11 are bonded to the high frequency substrates 8a and 8b and electrically connected. Also, in Fig. 1 "
As indicated by HL21 ″, a hole having a size sufficient for light reception and having no problem in mounting is formed on the high frequency substrate and near the light receiving surface of the high speed light receiving element 9.

The operation of the embodiment shown in FIG. 1 will be briefly described. The incident light indicated by "PH21" in Fig. 1 is "in Fig. 1".
HL21 "passes through a hole formed in the high frequency substrate and is incident on the light-receiving surface side of the high-speed light-receiving element 9, and" AL2 "in FIG.
The light is incident on the light receiving region formed in the vicinity of the light receiving surface indicated by 1 ″.

Then, the detection signal converted into an electric signal in the light receiving area indicated by "AL21" in FIG. 1 is taken out to the high frequency substrates 8a and 8b through the solder bumps 10 and 11.

The manufacturing method of the embodiment shown in FIG. 1 will be described with reference to FIGS. 2, 3 and 4. Here, FIG. 2, FIG. 3 and FIG. 4 are explanatory views for explaining the manufacturing method of the embodiment, and are denoted by the same reference numerals as those in FIG.

In the first step shown in FIG. 2, holes as shown by "HL31" in FIG. 2 are formed in the high frequency substrate. For example, YAG (yttrium aluminum garnet)
In Fig. 2 on a high frequency substrate by a processing device using a laser "
It is possible to form holes as shown in HL31 ".

In the second step shown in FIG. 3, solder bumps 10 and 11 are formed on the high frequency substrates 8a and 8b in the vicinity of the formed holes.

In the third step shown in FIG. 4, the light-receiving surface of the front-illuminated high-speed light-receiving element 9 is on the high-frequency substrate side, and the solder bumps 10 and Bonding using 11.

As a result, by aligning the light receiving surface with the hole formed in the high-frequency substrate and performing bonding by solder bumps, steps and bonding wires can be omitted, so that it is possible to maintain high-speed response characteristics and perform various processing. Since it is not necessary to apply it to the high speed light receiving element 9, the yield can be maintained.

In the embodiment shown in FIG. 1, the high-speed light receiving element 9 is bonded to the high frequency substrates 8a and 8b by two solder bumps for the sake of simplicity of description, but the number of solder bumps is limited to two. However, the high speed light receiving element 9 is mounted on the high frequency substrate 8a by using an arbitrary number of solder bumps.
And 8b may be bonded.

Further, in the embodiment shown in FIG. 1, the incident light which has passed through the hole formed in the high frequency substrate is made incident on the high speed light receiving element 9. However, even if a lens for collimating is mounted in the vicinity of this hole. I do not care.

FIG. 5 is a sectional view showing the construction of another embodiment of the light receiving device according to the present invention. 8 in FIG.
Reference numerals a, 8b, 9, 10 and 11 are the same as those in FIG. 1, 12 is a spherical lens for collimation, 13a and 13
b is an adhesive.

The high speed light receiving element 9 has a solder bump 1 on the light receiving surface side.
0 and 11 are bonded to the high frequency substrates 8a and 8b and electrically connected. Also, in Fig. 5 "
As indicated by HL41 ″, a hole having a size that is sufficient for receiving light and has no problem in mounting is formed in the vicinity of the light receiving surface of the high speed light receiving element 9 which is a high frequency substrate.

Further, a ball lens 12 is fixed by adhesives 13a and 13b to a hole formed in the high frequency substrate indicated by "HL41" in FIG. 5 and opposite to the side where the high speed light receiving element 9 is mounted. To be done.

The operation of the embodiment shown in FIG. 5 will be briefly described. The incident light indicated by “PH41” in FIG. 5 is the light that is incident on and collected by the spherical lens 12.

This parallel light passes through the hole formed in the high frequency substrate indicated by "HL41" in FIG. 5 and is incident on the light receiving surface side of the high speed light receiving element 9, and is near the light receiving surface indicated by "AL41" in FIG. It is incident on the formed light receiving region.

Then, the detection signal converted into an electric signal in the light receiving area indicated by "AL41" in FIG. 5 is taken out to the high frequency substrates 8a and 8b through the solder bumps 10 and 11.

Further, the manufacturing method of the embodiment shown in FIG.
Will be explained. Here, FIG. 6 is an explanatory view for explaining the manufacturing method of the embodiment, and the same reference numerals as those in FIG. 1 are attached.
However, the first step to the third step shown in FIGS.
Since it is the same as the embodiment shown in FIG.

After the third step shown in FIG. 4, in the fourth step shown in FIG. 6, the spherical lens 1 is inserted into the holes formed in the high frequency substrates 8a and 8b on the side opposite to the mounting side of the high speed light receiving element 9.
The two are combined and fixed to the high-frequency substrates 8a and 8b with adhesives 13a and 13b.

As a result, the incident light is collected through the collimating lens mounted in the vicinity of the hole and is incident on the high-speed light receiving element 9, whereby the light coupling efficiency is improved.

In FIG. 5, a spherical lens having a spherical shape is shown as an example of the collimating lens, but the collimating lens is not limited to the spherical lens, and any other shape can be used as long as the collected light can be emitted. It can be one.

Further, in the explanatory view shown in FIG. 6, for the sake of simplicity of explanation, the high-speed photodetector 9 is provided with the high-frequency substrates 8a and 8a.
Although the manufacturing process in which the spherical lens 12 is fixed to the high frequency substrates 8a and 8b after bonding to b is described, the fourth process and the second and third processes may be interchanged.

That is, the spherical lens 12 is connected to the high frequency substrate 8a.
And 8b, the high speed light receiving element 9 may be bonded to the high frequency substrates 8a and 8b.

Here, the light coupling efficiency largely depends on the positional accuracy between the high speed light receiving element 9 and the spherical lens 12. However, in the mounting of the high speed light receiving element using the solder bump, the accuracy of the height direction and the plane position is “within several μm”, so that the high speed light receiving element 9 and the ball lens 12 can be mounted with high accuracy. Is.

In order to improve the positioning accuracy,
After the high speed light receiving element 9 is bonded to the high frequency substrates 8a and 8b, incident light may be actually incident on the ball lens 12 and the ball lens may be positioned based on a detection signal obtained from the high speed light receiving element 9.

[0053]

As is apparent from the above description,
The present invention has the following effects. According to the first and fourth aspects of the present invention, since the light receiving surface is aligned with the hole formed in the high-frequency substrate and the solder bumps are used for bonding, steps and bonding wires can be omitted, so that high-speed response characteristics can be maintained. This makes it possible to maintain the yield because it is not necessary to perform various processes on the high-speed light receiving element.

According to the second and third aspects of the invention, the incident light is collected through the collimating lens mounted in the vicinity of the hole and is made incident on the high-speed light receiving element. The coupling efficiency of is improved.

According to the fifth, sixth and eighth aspects of the present invention, the collimating lens mounted in the vicinity of the hole while the light receiving surface is aligned with the hole formed in the high frequency substrate and solder bump bonding is performed. Since the incident light is collected as the collected light and is incident on the high-speed light-receiving element, it is not necessary to perform various processes on the high-speed light-receiving element, so that the yield can be maintained. In addition, the light coupling efficiency is improved.

Further, according to the invention of claims 7 and 8, after the high speed light receiving element is bonded to the high frequency substrate, the incident light is actually incident on the spherical lens and the sphere is detected based on the detection signal obtained from the high speed light receiving element. The positioning accuracy can be improved by positioning the lens.

[Brief description of drawings]

FIG. 1 is a configuration cross-sectional view showing an embodiment of a light receiving device according to the present invention.

FIG. 2 is an explanatory diagram illustrating a manufacturing method according to an embodiment.

FIG. 3 is an explanatory diagram illustrating a manufacturing method according to an embodiment.

FIG. 4 is an explanatory diagram illustrating a manufacturing method of an example.

FIG. 5 is a sectional view showing the configuration of another embodiment of the light receiving device according to the present invention.

FIG. 6 is an explanatory diagram illustrating the manufacturing method according to the embodiment.

FIG. 7 is a configuration cross-sectional view showing an example of a conventional light receiving device.

FIG. 8 is a sectional view showing the configuration of another example of a conventional light receiving device.

[Explanation of symbols]

1,8a, 8b High frequency substrate 2, 6, 9 High-speed light receiving element 3,4 electrodes 5,13a, 13b Adhesive 7, 10 and 11 Solder bumps. 12 ball lens

Claims (8)

[Claims] 1. A light-receiving device having a high-speed light-receiving element mounted on a high-frequency substrate, wherein the high-frequency substrate has a hole through which incident light passes, and the light-receiving surface is on the high-frequency substrate side, and the light-receiving surface is aligned with the hole. A light-receiving device comprising: a front-illuminated high-speed light-receiving element that is bonded to the high-frequency substrate by a solder bump and is electrically connected to the high-frequency substrate. 2. The light receiving device according to claim 1, wherein a collimating lens is provided in a portion of the hole on the side opposite to the mounting side of the high speed light receiving element. 3. The light receiving device according to claim 2, wherein the collimating lens is a spherical lens. 4. A method for manufacturing a light-receiving device in which a high-speed light-receiving element is mounted on a high-frequency substrate, the method comprising: forming a hole through which incident light passes through the high-frequency substrate; and soldering near the hole formed on the high-frequency substrate. Step of forming bumps, and bonding using the solder bumps so that the light-receiving surface of the front-illuminated high-speed light-receiving element is on the high-frequency substrate side and the light-receiving surface is aligned with the hole formed on the high-frequency substrate A method for manufacturing a light-receiving device, comprising: 5. A method of manufacturing a light-receiving device in which a high-speed light-receiving element is mounted on a high-frequency substrate, the method comprising: forming a hole through which incident light passes through the high-frequency substrate; and soldering near the hole formed on the high-frequency substrate. Step of forming bumps, and bonding using the solder bumps so that the light-receiving surface of the front-illuminated high-speed light-receiving element is on the high-frequency substrate side and the light-receiving surface is aligned with the hole formed on the high-frequency substrate A method of manufacturing a light-receiving device, comprising: a step of aligning a lens for collimation with a portion of the hole opposite to the mounting side of the high-speed light-receiving element, and fixing the collimating lens to the high-frequency substrate with an adhesive. 6. A method of manufacturing a light-receiving device in which a high-speed light-receiving element is mounted on a high-frequency board, the method comprising: forming a hole through which incident light passes through the high-frequency board; and collimating the hole formed in the high-frequency board. Aligning the lenses and fixing them to the high-frequency substrate with an adhesive; forming solder bumps in the vicinity of the holes on the side opposite to the mounting side of the lenses; receiving light from the front-illuminated high-speed light-receiving element And a step of bonding the solder bump so that the light-receiving surface coincides with the hole formed in the high-frequency substrate and the surface is on the high-frequency substrate side. 7. The high-speed light-receiving element is bonded to the high-frequency substrate, incident light is then incident on the lens, and the lens is positioned based on a detection signal obtained from the high-speed light-receiving element. 5. A method for manufacturing a light receiving device according to claim 5. 8. The lens according to claim 5, wherein the collimating lens is a spherical lens.
A method for manufacturing a light-receiving device according to any one of 1.