JP3270874B2 - Linear sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor type image sensor (image pickup device), and more particularly, to a structure of a linear sensor for converting the brightness of a single horizontal line into an electric signal.
You.

[0002]

2. Description of the Related Art Generally, a semiconductor linear sensor is used for reading a stripe pattern such as a facsimile or a bar code, or for industrial control or measurement. This linear sensor usually includes a light receiving section composed of a large number of photodiodes arranged in a row in a row on a chip composed of a semiconductor single crystal substrate, and each electric output from these photodiodes is provided. Are sequentially picked up by a shift register via a transfer gate (accumulation unit + shift gate), and the horizontal stripe pattern is converted into an electric signal and output to the outside.

This shift register has, for example, a silicon oxide film coated on a P-type silicon single crystal substrate and a number of electrodes made of an aluminum vapor-deposited film disposed thereon. By applying a pulse voltage to each electrode continuously from the drive circuit provided on the side or package side, a depletion layer is formed one after another in the single crystal substrate, and the charges from the photodiode are sequentially transferred in the longitudinal direction. You can shift.

[0004]

As shown in FIG. 4, a linear sensor of a type in which a drive circuit for a shift register is built in a chip, as shown in FIG.
Power supply wiring 4 to the shift register drive circuit 42
4 and a ground (earth) wiring 46 are wired along the longitudinal direction of the chip. The power supply to the drive circuit 42 is connected to an external power supply (not shown) at one end of these wirings 44 and 46, and 44 and 46 and the respective drive circuits 42 are connected to each other.

However, when such a power supply wiring 44 and a ground wiring 46 are integrally provided on the chip 40, the wirings 44 and 46 are usually formed by evaporating aluminum on the chip 40. chip longitudinal dimension is increased by the wiring 44 shown in,
The resistance value of the drive circuit 42 becomes large, and the voltage value applied to each drive circuit 42 becomes different, and the pulse voltage value applied to each electrode of the CCD shift register 48 becomes different, which may adversely affect its output characteristics. is there.

In addition, in the case where the power supply wiring 44 and the ground wiring 46 are juxtaposed on both sides of the chip 40, the width of the aluminum deposition film for one wiring is 10
Since the thickness exceeds 0 μm, the dimension in the width direction of the chip 40 increases accordingly, and the slice area of the silicon single crystal substrate at the time of manufacturing the chip increases, which causes a problem that the manufacturing cost increases.

[0007] The present invention has been made in view of such problems, chip
Power from a common external power supply to multiple drive circuits on the
The wiring resistance of the linear sensor caused when that, that the power supply
Difference in voltage value due to resistance of wiring and ground wiring
As well as reduce the impact on the output characteristics due to, it is an object to provide a linear sensor capable of reducing the manufacturing cost by reducing the chip area.

[0008]

According to the present invention, there is provided, in accordance with the present invention, a light receiving portion formed on a semiconductor substrate and comprising a large number of photodiodes arranged in a horizontal line, and a light receiving portion of the light receiving portion. A shift register that is provided on the side and sequentially picks up each electrical output from the photodiode and converts it into a series of electrical signals; and a shift register that is provided between the light receiving unit and the shift register. A transfer gate for transmitting an electrical output to the shift register; and a transfer gate provided on a side of the shift register.
Apply pulse voltage to each electrode of shift register in order
A chip is composed of a plurality of drive circuits
The plurality of drive circuits on the semiconductor substrate of the same chip
Power supply terminal and ground terminal of each drive circuit near
Pads are provided side by side, and
Power supply and ground are independent.
A linear sensor is provided.

In a preferred embodiment, the pad
Are arranged in a horizontal row along the longitudinal direction of the semiconductor substrate , have a package for accommodating the chip structure, and the pads are electrically connected to wiring on the package side by wire bonding. It is characterized by having.

[0010]

[Action] in the vicinity of the plurality of shift registers driving circuits on the chip of the semiconductor substrate, since so as to juxtapose the pad forming the power supply terminals and ground terminals to each drive circuit, Ji
The wiring formed on the package side for storing the chips can be electrically connected to the pads by wire bonding , and each drive circuit
Power supply and ground can be performed independently
You. The power supply wiring Chi <br/>-up of the semiconductor substrate by juxtaposing pad as described above, it is not necessary to secure an area for the ground wiring can make reduce the chip area by that amount.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a chip constituting a linear sensor of the present invention. Linear sensor chip 10
Is a light receiving portion 12 composed of a number of mini PN photodiodes arranged in a row at the center of a semiconductor single crystal substrate 11.
It has. The mini PN photodiode is configured as a kind of diode that generates a current in response to light.

On both sides in the width direction of the light receiving portion 12, transfer gates 14 for carrying the charges generated in the light receiving portion 12 are provided. , A CCD shift register 16 for converting the signals into a series of electric signals is provided.
The CCD shift register 16 is provided on the semiconductor single crystal substrate 1.
1 is a structure in which an insulating film is coated on the surface of the device 1 and a number of electrodes made of, for example, an aluminum vapor-deposited film are arranged thereon. And an output circuit 18 for outputting a continuous electric signal to the outside.

[0013] in the side of the CCD shift register 16, shea
The pulse voltage is applied in sequence to each electrode of the shift register 16, a plurality of drive circuits 20 are provided to form a depletion layer in order to put a charge on the substrate portion of the electrode below. The drive circuit 20 is configured as a kind of switching circuit that repeatedly connects and disconnects an external pulse voltage to and from one electrode, and shifts the charge from the transfer gate 14 to the output circuit 18 in order.

[0014] In the chip 10 of the formed linear sensor as described above, according to this embodiment, on the vicinity of the semiconductor single crystal substrate 11 of each of the drive circuit 20, power supply terminals and ground of each driving circuit 20 The bonding pads 22 constituting the terminals are provided in a horizontal line along the longitudinal direction of the chip 10 (the direction of arrow A). This is chip 10
In order to achieve the object of eliminating the power supply wiring and the ground wiring to each drive circuit 20, reducing the width W of the chip 10 as much as possible, and reducing the area of the entire chip 10.
It is constituted in.

Thus, the side edges of the chip 10 are arranged in a horizontal line.
When the chip 10 is incorporated into the semiconductor package 24, the bonding pads 22 arranged in parallel, as shown in FIG.
Are electrically connected to each other by, for example, wire bonding such as an Au wire 28. FIG. 3 is a partial external view of the semiconductor package 24 in which each of the bonding pads 22 is connected to each of the thick film wiring portions 26 independent of each other. In connection with the semiconductor package 24 side, in addition to the connection form shown in FIG. 3, the thick film wiring portions on the power supply side and the ground side on the package side are combined into one, and the bonding pad 22 May be wire-bonded.

As described above, according to this embodiment, two bonding pads 22 serving as a power supply terminal and a ground terminal are provided for each driving circuit 20 on the chip 10 of the linear sensor, and the semiconductor package is formed by wire bonding. for that to be connected with br /> cage 24 side power supply wiring portion, it is possible to supply power to the drive circuits 20 by only a low resistance corresponding to a partial which eliminated the power and ground lines on the chip 10 in the conventional . In addition, chip 1
Since it is not necessary to secure the power and ground wiring regions at 0 , the area of the chip 10 itself can be reduced , and the manufacturing cost can be reduced by reducing the slice area of the silicon single crystal substrate at the time of manufacturing. Can be reduced.

In the illustrated embodiment, the CCD shift registers 16 are provided on both sides of the light receiving section 12. However, the chip structure of the present invention can be similarly applied to a linear sensor having a CCD shift register on only one side. Applicable.

[0018]

As described above, according to the present invention, pads forming a power supply terminal and a ground terminal to each drive circuit are provided side by side near a plurality of shift register drive circuits on a chip . Power supply to each drive circuit
In addition, since the ground and the ground are independent, even if the chip itself is long , the electric resistance is reduced and
The constant voltage value applied to the path enables stable power supply, and the pulse voltage value applied to each electrode of the shift register
And the effect on the output characteristics is reduced, and a linear sensor with stable output characteristics can be obtained .

[0019] In addition, the installation of the pads, since it is not necessary to secure a space for the power supply wiring and ground wiring to the chip of the semiconductor substrate, can be reduced by that amount chip area, the slice area of the semiconductor single crystal substrate Reduced
As a result, the manufacturing cost can be significantly reduced .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a chip structure according to the present invention.

FIG. 2 is a sectional view in which the chip of FIG. 1 is mounted on a package side.

FIG. 3 is a partial external perspective view of FIG. 2;

FIG. 4 is a configuration diagram of a conventional chip structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Chip 11 ... Semiconductor substrate 12 ... Light receiving part (photodiode) 14 ... Transfer gate 16 ... CCD shift register 20 ... Drive circuit 22 ... Bonding pad 24 ... Semiconductor package

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 27/14

Claims (4)

(57) [Claims] 1. A formed on a semiconductor substrate, and a light receiving portion comprising a plurality of photodiodes juxtaposed in a row, the
Between a shift register for converting the series of electrical signals picked one after the other each electrical output from being provided on the side of the light receiving portion and the photodiode, and the light receiving portion and the shift register
Transmitting the electrical output to the shift register from the light receiving portion provided to be sandwiched between the transfer gate, before
The shift register is provided on the side of the shift register.
A pulse voltage is applied to each electrode of the resistor in order.
The number of drive circuits constitutes a chip,
Near the plurality of drive circuits on the semiconductor substrate
Connect the power and ground terminals of each drive circuit.
Pads are provided side by side to supply power to each of the drive circuits.
It is characterized by independent supply and ground
Linear sensor. 2. The semiconductor device according to claim 1, wherein the pads are arranged in a horizontal line along a longitudinal direction of the semiconductor substrate.
The linear sensor according to 1. 3. A package accommodating the chip structure.
The linear sensor according to claim 1, wherein
Sa. 4. The linear sensor according to claim 3, wherein the pad is electrically connected to the wiring on the package side by wire bonding.