JPH01215068A - Photosensor built-in semiconductor device - Google Patents

Abstract

PURPOSE:To prevent lowering of sensitivity by a method wherein a light transmitting substance is arranged before the light receiving surface of a photosensor, resin molding is given so as to wrap the periphery of this light transmitting substance, the central part of the light transmitting substance is made to be exposed to the surface of a package so as to make the photosensor to take in the light from this exposed surface. CONSTITUTION:A semiconductor chip 10 is fixed on a die pad 21 on a lead frame by sticking with a conductive epoxy adhesive 13 or by soldering, while connecting a connecting pad 12 to the tip of a lead 22. Next, a light transmitting substance 40 such as a glass plate is fixed on the upper surface of a semiconductor chip 10 with a transparent acrylic adhesive or epoxy resin 41 so as to cover a photosensor 11. Next, a small piece of a film of polyethylene or Teflon is stuck on the light transmitting substance 40 as a spacer 42 for opening a window to a resin molding 50. Next, when both metal molds 61 and 62 are closed together while holding a lead frame between the molds 61 and 62, a molding cavity is formed of the recesses 61a and 62a of both metal molds, while a bringing beam 26 of a lead frame 20 is kept on the underside of the upper metal mold 62 by a projection 61b of a lower metal mold 61 to close the cavity. Thereby, sensitivity and detection capacity of a photosensor is prevented from lowering.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device in which an optical sensor or an optical sensor array is embedded and housed in a resin mold package.

[Conventional technology]

The above-mentioned optical sensor embedded semiconductor device is widely used as a single sensor or as an optical sensor array or image sensor in which multiple optical sensors are arranged.More recently, optical sensor arrays have been integrated for automatic focusing cameras, for example. It has also come to be used in the form of being integrated with a circuit.In either case, since it is a semiconductor device, it must be used after being housed in some kind of package, and when it was first developed, it had to be used with a window. It was housed in a hand-held puff cage and received light from a window.However, with a can-shaped puff cage, the dimensions are inevitably large, making it inconvenient to incorporate into the intended use, and as production volume increases, it becomes difficult to reduce costs. Therefore, resin molded puff cages have come to be used. Fig. 4 shows this conventional example.

In the example shown in FIG. 4, an optical sensor 11 is incorporated in a semiconductor chip 10 for an integrated circuit in the form of an optical sensor array, and as shown in the figure, it is housed in a DIP type resin molded package. The semiconductor chip 10 is mounted on the die pad 21 of the lead frame by adhesive 13 or the like, and the connection pad 12 is attached to the lead 22 of the lead frame.
is connected to one end of the bonding wire 30 via a bonding wire 30.

Since it is necessary for the optical sensor 11 on the top surface of the semiconductor chip 10 to receive light, transparent epoxy resin or acrylic resin is used as the material for the resin mold body 50 for the package, and the mold is molded by transfer molding or injection molding. molded. As is well known, after this molding step, the leads 22 are separated from the lead frame by removing excess portions from the lead frame and folded, for example, as shown.

Problems that d1 gate aims to solve] The above-mentioned transparent resin mold type semiconductor device with built-in photosensor can be manufactured at low cost without requiring much effort in assembly or molding work, but there are no problems in terms of performance. One of the problems is that the light transmittance gradually decreases due to deterioration or discoloration of the resin, and the sensitivity of the optical sensor decreases during use.

As is well known, transparent resins that do not contain fillers have the disadvantage that they deteriorate relatively quickly. Another problem is that the hardness of the molding resin is not very high, so the resin surface directly above the optical sensor is easily scratched, and the incident light is scattered or reflected in a specific direction. In some cases, the sensitivity of the optical sensor also decreases. Yet another drawback is that it is susceptible to the influence of stray light Ls as shown in the figure, and the light that enters the resin package from various directions is internally reflected on its surface and becomes stray light L3, which is transmitted to the optical sensor 11. If the optical sensor is an optical sensor array, a pattern different from the image pattern received by the optical sensor may be detected, or the original contrast of the pattern may be reduced, making it difficult to detect the pattern. There will be inconveniences that will make it difficult.

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems and provide a semiconductor device incorporating an optical sensor in which the sensitivity and detection ability of the optical sensor do not deteriorate during use.

[Means to solve the problem]

The above-mentioned problem is that a semiconductor device with a built-in photosensor is made of a semiconductor chip with a built-in photosensor and a light-transmitting material placed on the semiconductor chip so as to cover at least the surface of the part of the semiconductor chip in which the photosensor is installed. A plate-shaped transparent body, a plurality of leads each connected to a semiconductor chip, a peripheral portion of the transparent body, a semiconductor chip, and a connection portion between the leads and the semiconductor chip, and the leads are wrapped outward. This problem can be solved by constructing a resin molded body made of a light-shielding resin so as to protrude from the resin molded body, and exposing the central surface of the light-transmitting body from the resin molded body.

As the light-transmitting body, it is preferable to use a thin glass plate with high hardness, and black ink.A filter or the like for adjusting the sensitive wavelength band of the optical sensor can be used in combination with this.

[Effect]

As can be seen from the above structure, the present invention arranges a light-transmitting body in front of the light-receiving part of an optical sensor of a semiconductor chip, and applies a resin mold so as to wrap around the peripheral edge of the light-transmitting body. By exposing the center part to the surface of the package and allowing light to penetrate into the optical sensor from this exposed surface, even if the mold resin 6 deteriorates, it will not affect the sensitivity of the optical sensor, and it will not transmit light. By making the exposed surface recessed from the surface of the molded resin at the periphery of the body less susceptible to scratches from the outside, and by using a light-shielding material in the molded resin to surround the sides of the transparent body and the semiconductor chip/nob. , the above-mentioned 11 problems are solved by preventing stray light from entering the optical sensor.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.
The figure is a cross-sectional view of a completed first embodiment of the present invention.

FIG. 2i is a top view showing it in a state before being resin molded. FIG. 3 shows the state of each main manufacturing process in cross section.

In FIG. 1, a semiconductor chip 10 in this embodiment is shown.
is the same as the case in Figure 4 (for integrated circuits, a photosensor array 11 is built into the center of the top surface, and connection pads 12 are arranged in the front and back direction of the figure on the left and right peripheries. It is attached by gluing or soldering the bottom surface onto the connection pad 12 of the frame. Although not shown, the top surface of the semiconductor chip 1O other than the connection pad portion is covered with a very thin protective film such as a silicon nitride film. The transparent body 40 is, for example, a thin glass plate about 0.5 mm thick, and is attached or placed on the upper surface of the semiconductor chip 10 by means of adhesive or the like so as to cover the optical sensor 11 and its surrounding area.Semiconductor Connection pad 12 of chip 10
The connection between the lead frame glue 22 and the lead frame glue 22 is made by a bonding wire 30, which is shown in detail in FIG.

The lead frame 20 is commonly provided for a plurality of semiconductor devices punched out of a thin metal plate as usual, and the area between the pair of vertical dash-dotted lines in the figure is the repetition unit 2.
It is now 0m. In the figure, one frame is formed by a pair of upper and lower horizontal beams 23 and a pair of left and right vertical beams 24,
A guide pad 21 to which a semiconductor chip 10 is attached at the center thereof is supported by a crossbeam 23 via a pair of supports 25. ? jI Several leads 22 are arranged so that their tips surround the guide band 21, their bases are supported by longitudinal beams 24, and the middle parts are interconnected by connecting beams 26 and also communicated with the horizontal beams 23. . The connection using the bonding wires 30 described above is made by connecting each of the connection pads 12 arranged on the left and right edges of the semiconductor chip.
This is done as shown between the slightly spread tips of 2. The connection between the semiconductor chip lO and the lead 22 by this bonding wire and the semiconductor balance 1 of the transparent body 40 described above.
After completing the arrangement on the 0, a resin mold is applied to the area surrounded by the pair of cross beams 23 and the pair of connecting beams 26 and shown with partial hunting in the figure.

This resin mold, as shown by the resin mold body 50 in FIG. On the other hand, it is applied so as to cover the peripheral edge and side surfaces of the upper surface except for the center part. As the resin for this, it is desirable to use a black light-shielding or light-absorbing resin, for example.Specific means will be described later, but
jj: 50a is opened in the upper part of the light-transmitting body 40 of the light-shielding resin molded body 50, and the central part of the light-transmitting body 40 is exposed at the bottom of this window, and the light incident thereon is transparent. As can be seen from Figure 0, the light that passes through the light body 40 and is applied to the optical sensor 11 is only that which enters the optical sensor 11 through the window 50a in front of it, and stray light mixes in from the side. There is virtually no room left. Since the transparent body 40 is sunk below the upper surface of the resin molded body 50, there is much less risk of scratches caused by objects hitting its surface even if it is handled a little roughly. Of course, even if the resin for the resin mold body 50 deteriorates during use, there is no fear that the amount of light received by the optical sensor will be affected.

Note that after molding the resin mold body 50, the transverse beams 23. of the lead frame 20 are assembled as usual. By cutting off all the longitudinal girders 24 and connecting girders 26 by punching or the like, separating the leads 22 from each other, and bending them appropriately, the first
It is put into the state shown in the figure.

FIG. 3 shows the main manufacturing steps of a semiconductor device incorporating an optical sensor according to the present invention. The same figure (in Tsukasa's process, the semiconductor chip 1G is attached to the lead frame's lead frame pad 21 by bonding or soldering with a conductive epoxy adhesive 13 containing AT powder, etc.)
A bonding wire 30, usually a gold wire, interconnects the contact pad 12' of the semiconductor chip and the tip of the lead 22. In the process shown in Fig. 1), a light transmitting body 40 such as a glass plate is attached to the upper surface of the semiconductor chip 10 with a transparent acrylic adhesive or epoxy resin 41 so as to cover the optical sensor 11. At this time, it is convenient to use an ultraviolet curing type adhesive 41 by utilizing the light transmittance of the transparent body 40.

The same figure (0) shows the state at the time of resin molding. Therefore,
The lead frame 20 to which the semiconductor chip and the transparent body are attached is inserted into the mold 61, 62, but before that, a spacer 42 of a predetermined thickness is used as a kind of spacer 42 to open the window 50a mentioned above in the resin mold body 50. A small piece of film such as polyethylene or Teflon is pasted onto the transparent body 40. It is convenient to use a slightly thicker so-called adhesive tape as this film. When both molds 61 and 62 are closed together as shown in the figure with the lead frame in between, the recesses 61a in both molds.

62a forms a molding cavity, and as shown in the figure, the connecting beam 26 of the lead frame 20 connects to the protrusion 6 of the lower mold 61.
1b is pressed against the lower surface of the upper mold 62, and the cavity is completely closed. As the molding resin, it is preferable to use an epoxy resin containing a black filler, and molding can be completed within a short time by the usual transfer molding method or injection molding method.

The same figure (cl) shows different aspects of the resin molding process,
In this example, the lead frame 20 is inserted between the molds 63 and 64 upside down from the previous example, and a window protrusion 63c is provided in the center of the recess 63a of the lower mold 63. As before, a molding cavity is formed by the recesses 63a and 64a of the mold, and the connecting beam 26 of the lead frame is held down by the protrusion 63b of the lower mold to close the cavity. This figure also shows a resin passage 64b provided in the upper mold 64 and a gate 64c through which resin is injected into the molding cavity, and its shape is similar to that of the lower crossbeam 23 in the previous figure 2. As can be seen from Figure 0 indicated by the thin line above, when the resin is injected into the cavity from the gate 64c, the lead frame 20 is compressed by the molding pressure.
is pushed downward, and the lower surface of the transparent body 40 in this figure is pressed against the protrusion 63c of the lower mold 63, thereby creating a window in the resin molded body.

The semiconductor device manufactured as described above is used after cleaning the surface of the transparent body with a solvent such as alcohol. It has been demonstrated that there is almost no decrease in sensitivity or pattern detection ability of the optical sensor array.

In addition to the embodiments described above, the present invention can be implemented in various embodiments. For example, the light-transmitting body is a single glass plate, but it can also be implemented as a light sensor or a light sensor built into a semiconductor chip. Since the array has high sensitivity in the region near the infrared, a filter that cuts other wavelength regions is sometimes used, and a transparent material is used to have a filtering effect on this.
The eyelid arm 1 can combine a transparent body with a filter.

〔Effect of the invention〕

As described above, in the present invention, a semiconductor device incorporating an optical sensor includes a semiconductor chip incorporating an optical sensor, and a light transmitting device disposed on the semiconductor chip so as to cover at least the surface of the portion of the semiconductor chip in which the optical sensor is incorporated. A plate-shaped light-transmitting body made of a transparent material, a plurality of leads each connected to a semiconductor chip, a peripheral portion of the light-transmitting body, a semiconductor chip, and a connection portion between the leads and the semiconductor chip are wrapped, and the leads are wrapped outward. A resin molded body made of light-shielding resin is molded to protrude from the resin molded body, and the central surface of the light-transmitting body is exposed from the resin molded body, so that the molded resin as a package does not deteriorate. The sensitivity and detection ability of the optical sensor will not decrease even when the surface of the light-transmitting body is slightly submerged from the package, so there is less risk of it being scratched by collisions with foreign objects, and the optical sensor is protected from light from the front. When implementing the present invention, it is sufficient to place a very small light-transmitting body on the surface of the semiconductor chip and then apply resin molding, so the manufacturing cost is lower than that of the conventional method. Almost unchanged,
The above effects can be obtained at the lowest cost.

The present invention is particularly useful for a semiconductor device that integrates an integrated circuit and a photosensor array for an autofocus camera, and by implementing the present invention, it is possible to maintain the ability to detect image patterns of a subject at a constant level over a long period of time. You can get the most effective results.

[Brief explanation of the drawing]

1 to 3 relate to the present invention, and FIG. 1 is a sectional view of an embodiment of a semiconductor device incorporating a photosensor according to the present invention;
FIG. 2 is a top view showing the state before resin molding, and FIG. 3 is a sectional view showing the state at each of its main manufacturing steps. FIG. 4 is a cross-sectional view of a semiconductor device incorporating an optical sensor according to the prior art, in which 10: semiconductor chip, 11: optical sensor or optical sensor array, 12: connection band, 11 adhesive layer, 20: lead frame, 20a: Unit of lead frame, 21; Die pad, 22: Lead, 23: Cross beam 23.24: Vertical beam, 25; Die pad support, 26: Connection beam, 30: Bonding line, 40: Transparent body, 41: Adhesive layer, 42 varnish spacer, 50: Resin mold body, 50a: Window, 61: Lower mold, 61a: Recess, 61b + protrusion, 62: Upper mold, 6
2a: recess, 63: lower mold, 63a: recess, 63b: projection, 63c: window forming projection, 64: upper mold, 64a: recess, 64b: resin passage, 64c: resin injection gate, L
:Light, L3:Figure 1Figure 2

Claims (1)

[Claims] A semiconductor chip with a built-in optical sensor; a plate-shaped transparent body made of a light-transmitting material disposed on the semiconductor chip so as to cover at least the surface of a portion of the semiconductor chip in which the optical sensor is incorporated; and a semiconductor chip. It consists of a light-shielding resin molded to wrap around a plurality of leads each connected to the transparent body, the peripheral part of the transparent body, the semiconductor chip, and the connection part between the leads and the semiconductor chip, and to cause the leads to protrude outward. What is claimed is: 1. A semiconductor device incorporating a photosensor, comprising: a resin molded body, and a central surface of the transparent body is exposed from the resin molded body.