JP2006295095A - Image sensor in which glass having wiring is stuck to light receiving surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein the degradation of reliability as a product such as the degradation of connection strength is incurred since it is needed to perform connection at an extremely small part in order to attach protective glass, to expose the electrode of input/output signals, and to directly connect it with the electrode of a signal processing substrate in an image sensor in which a light receiving surface occupies a very large ratio. <P>SOLUTION: An electrode and wiring are formed on glass originally attached for the purpose of protecting the light receiving surface of the image sensor, and the signals of the electrode are transmitted and received between the image sensor and the signal processing substrate through the electrode and the wiring on the glass. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a structure for performing electrical connection between an image sensor and an electrode of a substrate in order to perform signal transmission and reception between an image sensor that is a semiconductor and a substrate that performs signal processing.

In the conventional image sensor, quartz glass is pasted as shown in FIGS. 17 and 18 as a material that transmits light in order to protect the light receiving surface from dust and external force.
And the image sensor which received light through glass connected with the electrode of the signal processing board | substrate using the wire bonding or the finger lead.

In the conventional example, it is necessary to expose the electrode of the image sensor and the electrode of the substrate for signal processing from the glass of the insulating material in order to directly connect the metal wire or the finger lead of the wiring material to perform electrical conduction. .
Furthermore, since the bonding area between the glass and the image sensor is small, it is difficult to obtain sufficient glass bonding strength with an image sensor chip having a large light receiving area relative to the chip size of the image sensor. However, it becomes difficult to apply heat and load sufficiently. As a result, there is a problem that the reliability of connection is lowered.
If the image sensor has a microlens, it is necessary to provide a space between the image sensor chip and the glass to protect the microlens. Therefore, it is necessary to provide a separate member to secure the space when bonding the glass. there were.

The glass that has been pasted for the purpose of protecting the light receiving surface of the image sensor is provided with a wiring that can be electrically connected to bridge not only the protection of the image sensor but also the electrical connection between the electrode of the image sensor and the substrate electrode. To do.
Further, in order to maintain the space between the glass and the image sensor, an insulating material with a certain thickness is formed on the glass electrode or the image sensor electrode by using a bump conductive material or a wiring material or a wiring material. Make space available.

By forming wiring on the glass surface, it is not necessary to expose the electrode of the image sensor, and it is possible to obtain the connection area necessary for reliability even if the ratio of the light receiving surface to the chip size increases. .
In addition, since the electrical connection of the image sensor electrode can be conducted to the external electrode at the same time as the application of the glass, it is not necessary to separately connect the application of the glass and the electrode in the manufacturing process, and the manufacturing process can be shortened.
In addition, the space between the glass and the image sensor can be stably produced in the connection process in the connection process by interposing the convex electrode or the conductive particles between the electrodes.
In addition, since the connecting portion can be observed through the glass, the advantage that the inspection of connectivity can be performed visually can be maintained.

An electrode is formed of an electrically conductive material at a position connected to the image sensor electrode on the glass surface and a position connected to an electrode of the signal processing substrate, and wiring is also formed between the electrodes using the conductive material.
Then, the image sensor electrode and the electrode on the glass are connected, and electrical conduction is realized up to the electrode of the signal processing substrate through the wiring formed on the glass.
As shown in FIG. 1, a wiring 30 is provided with a conductive material on the glass surface facing the light receiving side of the image sensor in accordance with the electrode arrangement of the image sensor 4. Wiring materials are conductive materials including metals such as ITO, Poly-Si, Al, Au, Cu, Ni, Wi, Sn, Cr, In, solder, CVD, vapor deposition, plating, inkjet method, printing method, etc. Wiring is created using the coating means.
The wiring shape is arranged as shown in FIG. 1 so as to extend from the electrode of the image sensor chip to the outside of the chip. The wiring structure may be made using a single material, but it may also be realized as a multi-layer structure of conductive materials in order to ensure the life and reliability of the connection.

As shown in FIG. 1, first, the image sensor chip 4 and the glass 1 provided with the conductive wiring 30 are connected using an anisotropic conductive material 6 containing an adhesive that is cured by heating.
At this time, a load and heat are applied from the back surface of the image sensor chip to cure the adhesive of the anisotropic conductive material, and the conductive particles are brought into contact between the glass electrode and the electrode of the image sensor chip. After that, the electrode 9 of the substrate 8 and the glass electrode 3 are connected to the substrate electrode and the glass electrode by applying heat and load from the substrate side with the same anisotropic conductive material 6.
As a result, the received image data can be converted into an electrical signal by the image sensor, and the image data can be transmitted as an electrical signal to the substrate side.
Methods such as plating, vapor deposition or deposition on the underlying wiring material with a metal such as Au or Al in order to ensure good conductivity when the glass is connected to the image sensor or substrate with an anisotropic conductive material An example of the glass provided by is shown in FIG.

5 and 6, when connecting the image sensor to the glass, the image sensor and the glass are used to prevent the anisotropic conductive material of the portion for measuring the electrical continuity between the substrate electrode and the glass electrode from being cured by the heat before the connection. Example 2 is shown in which the substrate and the glass are connected after the anisotropic conductive material is pasted or applied again after the connection.

FIG. 7 also shows a third embodiment in which a space is provided in order to reduce the conduction of heat used when the image sensor chip and the glass are connected before the substrate and the glass are connected.
The case where Example 3 of FIG. 7 is connected to the substrate is shown.

FIGS. 9 and 10 show a structure in which the conductive material that melts is selectively formed on the wiring when the conductive material that melts the glass, the chip electrode, and the substrate electrode is used.
As a specific example, In or Sn is provided in the melting conductive material on the image sensor side.

Further, in order to provide the molten material accurately at a predetermined position and to prevent a short circuit between the image sensor and the wiring on the substrate, an insulating material 31 is provided on the wiring on the glass to connect

In FIG. 11, a portion 19 formed of a material for preventing a short circuit of wiring or a metal or an insulating material at the time of forming a convex electrode at a height of about 10 to 300 μm at a position in contact with a portion of the image sensor other than the light receiving surface of the image sensor. It is the Example which secured the space between glass and an image sensor using.

In FIG. 12, a space is formed after the glass and the image sensor are connected, but a high-viscosity shield material 20 is applied to the periphery of the image sensor to prevent intrusion of dust and moisture. This is an embodiment that can prevent the dew condensation.
In addition to the wiring for connecting to the image sensor on the glass, a heater 21 for evaporating the condensed water can also be provided to easily eliminate the condensation.

14 and 15, the electrode on the glass and the convex electrode of the image sensor are connected by an anisotropic conductive material 6, and the substrate electrode and the glass electrode are connected and exposed by a metal that is melted using a solder ball. The image sensor of Example 8 using the wiring on the glass of this invention made into the structure covered with the insulating material 25 like solder resist so that the molten metal may not spread on wiring was shown.
In this embodiment, the solder balls are connected to the glass in advance, and then the image sensor is connected to the glass, and then the electrodes on the substrate and the solder balls are connected to the electrodes on the substrate by solder paste 26 melted by batch reflow. It is an example.
In this case, there is an advantage that an anisotropic conductive material that can be connected by heating at about 150c is used, and that the glass blocks heat of reflow, so that excessive heating to the image sensor can be prevented.

The image sensor structure of the present invention is extremely small in height and is implemented through wiring on the signal processing board and glass, so that the mounting area can be very small, and the camera of the mobile phone and the camera size must be reduced. It can be widely applied to surveillance cameras.

Plan view of an image sensor connected to the glass with wiring with anisotropic conductive material 1 is a cross-sectional view taken along AA ' Sectional view when the glass to which the image sensor shown in FIG. 1 is connected is connected to the substrate Illustration of glass structure with metal plated on wiring Glass provided only with an anisotropic conductive material that connects the electrode of the image sensor and the wiring electrode on the glass Image sensor in which an anisotropic conductive material is further attached after FIG. 5 and connected to the substrate Structure diagram of glass and image sensor with anisotropic conductive material attached separately to prevent anisotropic conductive material for substrate electrode connection from thermosetting before connection Sectional drawing which shows the state which connected the glass with which the image sensor of FIG. 7 was attached to the board | substrate Glass with a wiring structure in which different metals are formed that are melted and connected to the image sensor electrode and the substrate electrode, respectively. Sectional drawing of the Example which connected the image sensor and the board | substrate using the glass with the wiring structure of FIG. Sectional view when space between glass and image sensor is secured by wiring material The top view of the Example which attached the sealing material which covers the space between glass and an image sensor around the image sensor, and formed the heater wiring on glass Sectional view when cut along BB 'in FIG. Plan view of an embodiment in which a solder ball is attached to a connection portion with a glass substrate electrode, and an insulating material for preventing a short circuit is attached on a glass wiring Sectional view when cut along line CC 'in FIG. Structure diagram of the embodiment when the embodiment of FIG. 15 is mounted on a substrate Sectional drawing which shows the image sensor assembly state at the time of using the conventional wire bonding Sectional drawing which shows the image sensor assembly state at the time of using the conventional finger lead | read | reed

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass 2 Electrode on glass connected to electrode of image sensor 3 Electrode on glass connected to electrode on substrate 4 Image sensor 5 Electrode on image sensor 6 Anisotropic conductive material 7 Light 8 to receive light Substrate 9 On substrate The electrode wiring 10 of the metal plating 11 covering the electrode wiring on the glass 11 The anisotropic conductive material 12 for connecting the image sensor electrode 11 The anisotropic conductive material 13 attached after the anisotropic conductive material is cured 13 Clearance 14 provided to suppress anisotropic conductive material 15 that is divided and attached to suppress heat conduction Metal material 16 that melts and connects to substrate electrode Metal material that melts and connects to image sensor electrode 17 Metal material fused and connected to the substrate electrode 18 Metal material fused and connected to the image sensor electrode 19 For maintaining a space between the glass and the image sensor Wiring material 20 Shielding material 21 Heater wiring 22 on glass Heater wiring electrode 23 Water vapor escape hole 24 Solder ball 25 Insulating material 26 Metal material melted to hold solder ball 27 Solder paste 28 melted on substrate electrode Image sensor Bonding wire 29 for connecting the electrode and substrate electrode 29 Finger lead 30 Wiring 31 on glass Insulating material

Claims (4)

A substrate electrode that performs signal processing by forming a wiring and an external electrode with a conductive material on the glass to be attached to the light receiving surface of the image sensor and electrically connecting the electrode of the image sensor and the wiring on the glass surface. An image sensor having a structure characterized in that a signal is transmitted and received between the image sensor and a signal processing board by a wiring formed on glass for the purpose of protecting the light receiving surface of the image sensor. The connection between the electrode of the image sensor and the glass electrode used in claim 1 is performed by melting one metal using the image sensor or the glass electrode or both as convex electrodes in order to maintain the distance between the image sensor and the glass. An image sensor having a structure characterized in that electrical conductivity is ensured by interposing conductive particles between the electrodes or electrodes, and at the same time the distance between the glass and the light receiving surface of the image sensor is maintained. 2. A structure according to claim 1, wherein a member having no electrical continuity is formed on the glass surface and brought into contact with a portion other than the light receiving surface of the image sensor to maintain a distance between the glass and the light receiving surface of the image sensor. Image sensor with In claim 1, 2, and 3, in order to prevent dust, liquid or air containing a large amount of moisture from entering the space between the glass and the image sensor, the sealing material is prevented from being attached and the sealing material is applied in the shape. An image sensor characterized in that a hole communicating with the outside air is provided so that the moisture dew is evaporated in the space between the glass and the image sensor and escapes to the outside air.

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