SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME
According to one embodiment, a semiconductor device includes first, second, and third molded bodies. The first molded body covers a first light emitting element, a part of a lead electrically connected to the first light emitting element, a first light receiving element configured to detect a light emitted from the first light emitting element, and a part of a lead electrically connected to the first light receiving element with a first resin. The second molded body covers a second light emitting element, a part of a lead electrically connected to the second light emitting element, a second light receiving element configured to detect a light emitted from the second light emitting element, and a part of a lead electrically connected to the second light receiving element with the first resin. The third molded body molds the first and the second molded bodies as one body using a second resin.
Latest Kabushiki Kaisha Toshiba Patents:
This application is based upon and claims the benefit of priority from Japanese Patent Application No.2011-224285, filed on Oct. 11, 2011; the entire contents of which are incorporated herein by reference.
FIELDEmbodiments described herein relate generally to a semiconductor device and a method for manufacturing the same.
BACKGROUNDA photocoupler, for example, which is a semiconductor device, includes a light emitting element and a light receiving element built-in and transmits a signal by an optical coupling. Therefore, the photocoupler is used for an isolation circuit that electrically insulates the primary side and the secondary side. Although the photocoupler has various uses, high insulating properties between the light emitting element on the primary side and the light receiving element on the secondary side are required in common. In addition, in a dual type product that includes two sets of a light emitting element and a light receiving element and has two transmission channels, it is necessary to suppress a crosstalk between channels.
For example, in a product in which the light receiving element side is connected to one frame, fabrication becomes easier by employing a method in which two sets of a light emitting element and a light receiving element are encapped by a one-body resin, but the crosstalk between channels cannot be suppressed. There is also a method in which two sets of a light emitting element and a light receiving element are individually encapped and are molded by a light blocking resin. The crosstalk can be suppressed by this method. However, a gap may be formed at the interface between the encap and the mold resin, and the dielectric breakdown voltage may be decreased. Thus, a semiconductor device in which the crosstalk between channels can be suppressed and the dielectric breakdown voltage can be increased and a method for manufacturing the same are required.
According to one embodiment, a semiconductor device including: a first molded body, a second molded body, and a third molded body. The first molded body covers a first light emitting element, a part of a primary lead electrically connected to the first light emitting element, a first light receiving element configured to detect a light emitted from the first light emitting element, and a part of a secondary lead electrically connected to the first light receiving element with a first resin. The second molded body covers a second light emitting element, a part of a primary lead electrically connected to the second light emitting element, a second light receiving element configured to detect a light emitted from the second light emitting element, and a part of a secondary lead electrically connected to the second light receiving element with the first resin. The third molded body molds the first molded body and the second molded body as one body using a second resin. One of the primary lead and the secondary lead is disposed to extend over the first molded body and the second molded body, and a surface of a portion extending between the first molded body and the second molded body is covered with a thin film made of the first resin.
Various embodiments will be described hereinafter with reference to the accompanying drawings. Identical components in the drawings are marked with the same reference numerals, and a detailed description thereof is omitted as appropriate and different components are described.
The semiconductor device 100 is, for example, a photocoupler, and includes a light emitting element and a light receiving element built-in. As shown in
As shown in
The resin package 10 includes an internal mold 9 enclosing the light emitting element 7 and the light receiving element 13 and an external mold 3 covering the exterior of the internal mold 9. The internal mold 9 is made of, for example, a transparent resin; and transmits the light that the light emitting element 7 emits and causes the light to be incident on the light receiving surface of the light receiving element 13. On the other hand, the external mold 3 is made of a resin that blocks the external light; and suppresses a dark current of the light receiving element 13 and reduces the noise level.
The transparent resin used for the internal mold 9 preferably transmits 100% of the light emitted from the light emitting element 7, but may absorb part of it. For example, an epoxy resin may be used.
A resin having the same main component as the internal mold 9 is preferably used for the external mold 3. Thereby, the adhesion between the internal mold 9 and the external mold 3 can be improved. In the resin forming the external mold 3, members that absorb the external light are scattered. For example, what is called a black resin in which carbon is scattered in an epoxy resin may be used. Furthermore, what is called a white resin in which members that reflect the external light are scattered may be used. For example, an epoxy resin in which a fine powder of titanium oxide is scattered may be used. Here, the external light refers to the background light excluding the light that the light emitting element 7 emits, for example, refers to light in a wavelength range in which the light receiving element 13 has sensitivity.
As shown in
On the other hand, the light emitting element 7 is fixed to leads 5a and 5b (see
Thus, in the semiconductor device 100, the leads 5a, 5b, 6a, and 6b that supply a drive current to the light emitting element 7 are provided as leads on the primary side. On the other hand, the leads 15, 17a, 17b, and 19 are provided on the secondary side where a signal is outputted from the light receiving element 13.
As shown in
The light receiving element 13a fixed to the mount portion 15a and the light emitting element 7a fixed to the lead 5a are enclosed in an internal mold 9a that is a first molded body using a first resin. The light receiving element 13b fixed to the mount portion 15b and the light emitting element 7b fixed to the lead 5b are enclosed in an internal mold 9b that is a second molded body using the first resin. The first resin is the transparent resin described above.
The internal molds 9a and 9b are covered with the external mold 3 that is a third molded body. The external mold 3 is molded by a second resin having light blocking properties. A shield portion 3a is provided between the internal mold 9a and the internal mold 9b. The shield portion 3a blocks the light of the light emitting element 7a propagated toward the light receiving element 13b, and blocks the light of the light emitting element 7b propagated toward the light receiving element 13a. Thereby, the crosstalk between channels is suppressed.
A connection portion 15c that is part of the lead 15 and connects the mount portion 15b and the mount portion 15a is covered with a thin film 9c made of the same first resin as that of the internal molds 9a and 9b. In the embodiment, the internal molds 9a and 9b are made of the same resin connected via the thin film 9c, and are in a state of enclosing the lead 15 therein. Also the leads 5a and 5b to which the light emitting elements 7a and 7b, respectively, are fixed are enclosed in the same resin.
Furthermore, as shown in
Thereby, the dielectric breakdown voltage between the leads 5a, 5b, 6a, and 6b provided on the primary side and the leads 15, 17a, 17b, and 19 provided on the secondary side can be increased.
As shown in
In contrast, in the case where, for example, the thin film 9c covering the connection portion 15c does not exist, the connection portion 15c is in a state of extending from the internal mold 9a to the external mold 3 across the interface and further being inserted from the external mold 3 into the internal mold 9b across the interface. Hence, for example, as shown in
The distance between the lead 5a and the connection portion 15c in the leak path B, what is called the creeping distance, is shorter than the creeping distance of the path A1 or A2. Therefore, the insulation resistance of the path B is smaller than the insulation resistance of the path A1 or A2. Consequently, in the case where the thin film 9c covering the connection portion 15c of the lead 15 is not provided, the dielectric breakdown voltage between the lead 6a and the lead 5a on the primary side and the lead 15 on the secondary side is decreased.
Thus, by covering the connection portions 15c and 19a of the leads provided to extend over the internal mold 9a and the internal mold 9b with the thin film 9c, the path B with a short creeping distance can be eliminated, and the creeping distance between leads can be extended. Thereby, the dielectric breakdown voltage of the semiconductor device 100 can be increased.
Next, the manufacturing processes for the semiconductor device 100 are described with reference to
In the lead frame 20 shown in
The light emitting elements 7a and 7b are, for example, fixed to the mount portions 5c and 5d, respectively, via a conductive silver (Ag) paste. The wires 21a and 21b are, for example, gold (Au) wires, and are bonded between the electrodes of the light emitting elements 7a and 7b and the ends 6c and 6d of the leads 6a and 6b, respectively.
In the lead frame 30 shown in
The mount portions 15a and 15b are provided at the end of the lead 15 that is the fifth lead. The light receiving element 13a is fixed to the mount portion 15a, and the light receiving element 13b is fixed to the mount portion 15b. The light receiving elements 13a and 13b may be fixed via, for example, an adhesive resin or an Ag paste. In the case where the light receiving elements 13a and 13b are silicon devices, they may be fixed via a silicide layer between the surface of the lead 15 and the back surfaces of the light receiving elements 13a and 13b.
The light receiving elements 13a and 13b each include a light receiving surface 13c, a power supply terminal 13e, a signal terminal 13f, and a ground terminal 13g. The power supply terminal 13e is connected to the lead 19 via wires 23a and 23b. The signal terminal 13f of the light receiving element 13a is connected to the lead 17a that is the sixth lead via a third wire 22a. The signal terminal 13f of the light receiving element 13b is connected to the lead 17b that is the seventh lead via a fourth wire 22b. Furthermore, the ground terminal 13g is connected to the lead 15 via wires 24a and 24b. The wires 22 to 24 are, for example, Au wires.
Next, the internal molds 9a and 9b are formed by the molding processes shown in
As shown in
Subsequently, the upper die 41 and the lower die 42 are mold-clamped together to form a first cavity 43 and a second cavity 45. The cavity 43 houses a portion of the lead 5a to which the light emitting element 7a is fixed, a portion of the lead 6a to which the wire 21a is bonded, the wire 21a, the mount portion 15a to which the light receiving element 13a is fixed, a portion of the lead 17a to which the wire 22a is bonded, the wire 22a, a portion of the lead 19 to which the wire 23a is bonded, the wire 23a, a portion to which the wire 24a of the mount portion 15a is bonded, and the wire 24a.
The cavity 45 houses a portion of the lead 5b to which the light emitting element 7b is fixed, a portion of the lead 6b to which the wire 21b is bonded, the wire 21b, the mount portion 15b to which the light receiving element 13b is fixed, a portion of the lead 17b to which the wire 22b is bonded, the wire 22b, a portion of the lead 19 to which the wire 23b is bonded, the wire 23b, a portion to which the wire 24b of the mount portion 15b is bonded, and the wire 24b.
Furthermore, the connection portion 15c that is part of the lead 15 between the mount portion 15a and the mount portion 15b is housed in a gap 47 running from the cavity 43 to the cavity 45.
Next, the first resin molten is injected into the cavity 45 via a runner 49a communicating with the cavity 45. Furthermore, in the embodiment, a through gate 49b running from the cavity 45 to the cavity 43 is provided. Thereby, the first resin injected into the cavity 45 moves to the cavity 43, and is put in both of the cavities 43 and 45. The first resin is put also in the gap 47 that houses the connection portion 15c.
At this time, it is also possible to move the molten resin from the cavity 45 to the cavity 43 via the gap 47. However, in the case where the spacing of the gap 47 is made narrow and a thin-film-like resin is molded around the connection portion 15c in order to suppress the crosstalk between channels, the resin may not smoothly move from the cavity 45 to the cavity 43. Therefore, it is preferable to separately provide the through gate 49b for injecting the resin from the cavity 45 to the cavity 43. Furthermore, the runner 49a for injecting the molten resin into the cavity 45 and the through gate 49b are preferably provided at the same height from the bottom surfaces of the cavities 43 and 45. The runner 49a and the through gate 49b are preferably provided so as to be aligned in a straight line in the injection direction of the molten resin.
Subsequently, the resin put in the cavities 43 and 45 is cured to mold the internal molds 9a and 9b. The internal mold 9a is molded in the cavity 43, and the internal mold 9b is molded in the cavity 45. The thin film 9c is formed on the surface of the connection portion 15c.
In the molding processes mentioned above, the connection portion 15c between the mount portion 15a and the mount portion 15b and the connection portion 19a of the lead 19 are housed in the gap 47, and are therefore not caught and pressed between the upper die 41 and the lower die 42. Thereby, the deformation of the lead 15 is suppressed, and the light receiving elements 13a and 13b can be molded in the respective prescribed positions in the internal molds 9a and 9b.
The embodiment illustrates an example in which the internal molds 9a and 9b are molded using dies of what is called a through gate type whereby the molten resin moves from the cavity 43 to the cavity 45 via the through gate 49b. The system of injection molding is not limited thereto, and the arrangement of the runner and the gate may be altered in accordance with the system of the lead frame, for example.
As shown in
Next, the first resin formed around and between the internal molds 9a and 9b is removed. For example, the runner portion resin 49c and the through gate portion resin 49d formed in the portions of the runner 49a and the through gate 49b, respectively, a burr formed during molding, etc. are removed by punching processing using a punching blade matched with the external shapes of the inner molds 9a and 9b. Thereby, between the internal mold 9a and the internal mold 9b, the thin film 9c covering the connection portions 15c and 19a can be left and the surplus resin can be removed.
Next, by the molding processes shown in
As shown in
Next, the second resin molten is injected via a runner 65 communicating with the cavity 63. Then, the resin put in the cavity 63 is cured to mold the external mold 3 covering the internal molds 9a and 9b and the thin film 9c. Subsequently, the lead frames 20 and 30 with the external mold 3 molded therearound are taken out of the dies, and the common frames 31 and 33 are cut to produce individually separated semiconductor devices 100.
In the manufacturing processes mentioned above, a hard epoxy resin, for example, may be used as the first resin; thereby, the strength of the connection portions 15c and 19a covered with the thin film 9c can be increased. Thereby, the deformation of the lead frames 20 and 30 with the internal molds 9a and 9b molded thereon can be suppressed, and the quality and manufacturing yield of the semiconductor device 100 can be improved.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.
Claims
1. A semiconductor device comprising:
- a first molded body covering a first light emitting element, a part of a primary lead electrically connected to the first light emitting element, a first light receiving element configured to detect a light emitted from the first light emitting element, and a part of a secondary lead electrically connected to the first light receiving element with a first resin;
- a second molded body covering a second light emitting element, a part of a primary lead electrically connected to the second light emitting element, a second light receiving element configured to detect a light emitted from the second light emitting element, and a part of a secondary lead electrically connected to the second light receiving element with the first resin; and
- a third molded body molding the first molded body and the second molded body as one body using a second resin,
- one of the primary lead and the secondary lead being disposed to extend over the first molded body and the second molded body, and a surface of a portion extending between the first molded body and the second molded body being covered with a thin film made of the first resin.
2. The device according to claim 1, wherein
- a light emitting surface of the first light emitting element is disposed opposed to a light receiving surface of the first light receiving element and
- a light emitting surface of the second light emitting element is disposed opposed to a light receiving surface of the second light receiving element.
3. The device according to claim 1, wherein a main component of the first resin is same as a main component of the second resin.
4. The device according to claim 1, wherein the thin film is provided continuously between the first molded body and the second molded body and covered with the second resin.
5. The device according to claim 1, wherein
- the first resin transmits light emitted from the first light emitting element and the second light emitting element and
- the second resin blocks external light.
6. The device according to claim 1, wherein the third molded body includes a shield portion blocking light of the second light emitting element propagated toward the first light receiving element and blocking light of the first light emitting element propagated toward the second light receiving element.
7. The device according to claim 1, wherein the one of the primary lead and the secondary lead disposed to extend over the first molded body and the second molded body includes a first mount portion having the first light receiving element mounted, a second mount portion having the second light receiving element mounted, and a connection portion connecting the first mount portion to the second mount portion, and the connection portion is provided between the first molded body and the second molded body.
8. The device according to claim 1, wherein
- each of the first light receiving element and the second light receiving element includes a light receiving surface, a power supply terminal, a signal terminal, and a ground terminal and
- the device includes a secondary lead configured to supply an electric power to the power supply terminal and a secondary lead configured to output a signal from the signal terminal.
9. The device according to claim 8, wherein the secondary lead configured to supply the electric power to the power supply terminal is disposed to extend over the first molded body and the second molded body and includes a portion covered with the thin film.
10. The device according to claim 1, wherein each of the primary lead and the secondary lead includes a portion extending from the third molded body.
11. The device according to claim 10, wherein
- the primary lead connected to the first light emitting element and the primary lead connected to the second light emitting element extend from one side surface of the third molded body and
- the secondary lead connected to the first light receiving element and the secondary lead connected to the second light receiving element extend from another side surface on an opposite side to the one side surface.
12. A semiconductor device comprising:
- a first lead;
- a first light emitting element fixed to the first lead;
- a second lead disposed away from the first lead and electrically connected to the first light emitting element via a first wire;
- a third lead disposed away from the first lead and the second lead;
- a second light emitting element fixed to the third lead;
- a fourth lead disposed away from the first lead, the second lead, and the third lead and electrically connected to the second light emitting element via a second wire;
- a fifth lead disposed away from the first lead, the second lead, the third lead, and the fourth lead and including a first mount portion and a second mount portion;
- a first light receiving element fixed to the first mount portion and configured to detect a light emitted from the first light emitting element;
- a second light receiving element fixed to the second mount portion and configured to detect a light emitted from the second light emitting element;
- a sixth lead disposed away from the first lead, the second lead, the third lead, the fourth lead, and the fifth lead and electrically connected to the first light receiving element via a third wire;
- a seventh lead disposed away from the first lead, the second lead, the third lead, the fourth lead, the fifth lead, and the sixth lead and electrically connected to the second light receiving element via a fourth wire;
- a first molded body covering a portion of the first lead with the first light emitting element fixed, the first wire, a portion of the second lead with the first wire bonded, the first mount portion with the first light receiving element fixed, the third wire, and a portion of the sixth lead with the third wire bonded;
- a second molded body covering a portion of the third lead with the second light emitting element fixed, the second wire, a portion of the fourth lead with the second wire bonded, the second mount portion with the second light receiving element fixed, the fourth wire, and a portion of the seventh lead with the fourth wire bonded; and
- a third molded body molding the first molded body, the second molded body, and a portion of the fifth lead between the first mount portion and the second mount portion as one body, the portion of the fifth lead extending between the first molded body and the second molded body,
- a part of the fifth lead being covered with a thin film made of a first resin contained in the first molded body and the second molded body, a second resin contained in the third molded body covering the thin film.
13. The device according to claim 12, wherein
- the first molded body and the second molded body transmit the light emitted from the first light emitting element and the second light emitting element and
- the third molded body blocks external light.
14. The device according to claim 12, wherein the third molded body includes a shield portion blocking the light of the second light emitting element propagated toward the first light receiving element and blocking the light of the first light emitting element propagated toward the second light receiving element.
15. The device according to claim 12, wherein
- each of the first lead, the second lead, the third lead, and the fourth lead includes a portion extending from one side surface of the third molded body and
- each of the fifth lead, the sixth lead, and the seventh lead includes a portion extending from another side surface on an opposite side to the one side surface.
16. A method for manufacturing a semiconductor device comprising:
- preparing a first frame including a first lead with a first light emitting element fixed, a second lead electrically connected to the first light emitting element via a first wire, a third lead with a second light emitting element fixed, and a fourth lead electrically connected to the second light emitting element via a second wire and a second frame including a fifth lead with a first light receiving element fixed to a first mount portion and with a second light receiving element fixed to a second mount portion, a sixth lead electrically connected to the first light receiving element via a third wire, and a seventh lead electrically connected to the second light receiving element via a fourth wire;
- setting a combination of the first frame and the second frame in a die and performing molding including: housing a portion of the first lead with the first light emitting element fixed, a portion of the second lead with the first wire bonded, the first mount portion with the first light receiving element fixed, and a portion of the sixth lead with the third wire bonded in a first cavity of the die in a state of a light emitting surface of the first light emitting element and a light receiving surface of the first light receiving element being faced each other; housing a portion of the third lead with the second light emitting element fixed, a portion of the fourth lead with the second wire bonded, the second mount portion with the second light receiving element fixed, and a portion of the seventh lead with the fourth wire bonded in a second cavity of the die in a state of a light emitting surface of the second light emitting element and a light receiving surface of the second light receiving element being faced each other; housing part of the fifth lead between the first mount portion and the second mount portion in a gap communicating the first cavity with the second cavity; and filling the first cavity, the second cavity, and the gap with a first resin; and
- forming a third molded body made of a second resin and covering a first molded body molded in the first cavity, a second molded body molded in the second cavity, and part of the fifth lead covered with a thin film made of the first resin.
17. The method according to claim 16, wherein the die includes a through gate communicating the first cavity with the second cavity.
18. The method according to claim 16, wherein a main component of the first resin is same as a main component of the second resin.
19. The method according to claim 16, wherein
- the first resin transmits a light emitted from the first light emitting element and the second light emitting element and
- the second resin contains a member absorbing external light.
20. The method according to claim 16, wherein
- the first resin transmits a light emitted from the first light emitting element and the second light emitting element and
- the second resin contains a member reflecting external light.
Type: Application
Filed: Mar 20, 2012
Publication Date: Apr 11, 2013
Applicant: Kabushiki Kaisha Toshiba (Tokyo)
Inventors: Atsushi TAKESHITA (Fukuoka-ken), Hidetomo Tanaka (Fukuoka-ken)
Application Number: 13/425,232
International Classification: H01L 31/16 (20060101); H01L 31/18 (20060101);