DE102008035901A1 - Process for the production of optoelectronic components and optoelectronic component - Google Patents

Abstract

A method for wafer-based production of a plurality of optoelectronic components, each having at least one semiconductor body and a component housing, in which a plurality of optoelectronic semiconductor bodies each having a first electrical contact and a second electrical contact and a substrate wafer (10) having a first main surface (12) and a second main surface (12 ') are provided, at least two spaced recesses in the substrate (10) from the first main surface (12) are formed forth, electrically conductive material is introduced into the recesses, the substrate wafer is thinned such that the electrically conductive material in the region of the recesses forms electrically conductive feedthroughs through the substrate (10), the optoelectronic semiconductor bodies (30) are applied to the first main surface of the substrate wafer, electrically conductive connections between the electrical ones Contacts of the semiconductor body and each of these associated feedthroughs are formed, a plurality of at least one semiconductor body enclosing encapsulants are applied to the substrate wafer and the substrate wafer is divided between the encapsulations such that separate optoelectronic devices arise. It is specified such a manufactured device.

Description

The The present invention relates to a method for wafer-based Production of a plurality of optoelectronic components and an optoelectronic component.

Optoelectronic Due to their high efficiency, components are increasingly displacing theirs long life and its robustness in numerous applications classic incandescent and discharge lamps. It play surface mountable Executions a significant role. You can be easily integrated into a wide variety of applications.

A newer technology for producing bright surface mount LEDs is T. Murphy and J. Kuhmann, "Silicon wafer packaging for HB-LEDs", Technology White Paper, Hymite GmbH, September 2007 described. In this case, recesses for LED chips are formed in a silicon wafer and electrical vias are etched into the silicon from the back side of the wafer.

So-called High Brightness LEDs require a housing construction that ensures good heat dissipation from the LED chip. In addition, other optical components such. As lenses, on easy way into such a housing structure integrable be.

A The object of the present invention is a method for producing of an optoelectronic component which is wafer-based is and includes few, simple process steps. Furthermore, an optoelectronic component is to be provided be produced in a simple manner based on wafers.

These The object is achieved by a method having the features of the claim 1 or by a component having the features of claim 11 solved. Advantageous developments of the method and the component are in the subclaims 2 to 10 or 12 to 15 indicated.

• – Bereitstellen eines Substratwafers mit einer ersten und einer der ersten gegenüberliegenden zweiten Hauptfläche,
• – Aufbringen einer mit Öffnungen versehenen Maskenschicht auf die erste Hauptfläche,
• – Bilden von Gräben in dem Substrat im Bereich der Maskenöffnungen,
• – Entfernen der Maskenschicht
• – Ausbilden einer Passivierungsschicht, die die Gräben auskleidet,
• – Zumindest teilweises Füllen der Gräben mit metallischem Material,
• – Entfernen von Substratmaterial von der zweiten Hauptfläche her, derart, dass das metallische Material auf der von der ersten Hauptfläche abgewandten Seite des Substratwafers freigelegt wird und dadurch metallische Durchführungen durch den Substratwafer gebildet werden,
• – Aufbringen eines optoelektronischen Halbleiterkörpers auf eine der metallischen Durchführungen,
• – elektrisches Verbinden von elektrischen Kontakten des Halbleiterkörpers mit metallischen Durchführung des Substratwafers, und
• – Ausbilden einer den Halbleiterkörper umhüllenden Linse mittels eines Spritzpressverfahrens.

A method according to the invention preferably comprises the following steps:

• Providing a substrate wafer having a first and one of the first opposing second major surfaces,
• Applying an apertured mask layer to the first major surface,
• Forming trenches in the substrate in the region of the mask openings,
• - Remove the mask layer
• Forming a passivation layer lining the trenches,
• At least partially filling the trenches with metallic material,
• Removal of substrate material from the second major surface, such that the metallic material is exposed on the side of the substrate wafer remote from the first main surface, thereby forming metallic feedthroughs through the substrate wafer,
• Applying an optoelectronic semiconductor body to one of the metal bushings,
• - electrically connecting electrical contacts of the semiconductor body with metallic passage of the substrate wafer, and
• - Forming a semiconductor body enveloping the lens by means of a transfer molding process.

It become metallic feedthroughs in a substrate wafer formed on both the front, d. H. its first Main surface, as well as on its back, d. H. whose second main surface is exposed. For structuring The trenches can be a wet-chemical etching process or a dry etching process or a combination thereof Procedures are used. In this way, bushings can be made with a large cross-sectional area, in the operation of the optoelectronic device good heat dissipation from Semiconductor body out of the component housing enable.

In According to an advantageous embodiment, the substrate wafer made of an electrically conductive material, preferably made of Silicon or from a silicon-based material, and become the inner surfaces of the recesses before introducing the electric conductive material with an electrically insulating Layer provided.

The Encapsulation is preferably by means of a transfer molding process applied to the substrate wafer and preferably consists of a Silicone material. The encapsulation can be technical in this way very easy to be formed as a lens.

The Method allows the production of a flat design with a very stable connection between chip carrier and lens. A silicon substrate provides a very good surface for a subsequent application of a silicone lens by means of transfer molding at. There are only a few process steps needed, what a low cost production possible.

The Wells are advantageously by applying a Mask on the first major surface of the substrate wafer and following etching of the substrate material.

In an advantageous embodiment, the inner surfaces of the recesses are first with provided a metal layer and subsequently the wells at least partially filled with metallic material, for example by means of the generally known from thin-film technology chemical or physical vapor deposition (CVD, PVD, PECVD).

at In an advantageous embodiment, the filling takes place the recesses with metallic material by screen printing a Metal paste and subsequent sintering of the metal paste. Especially for bushings with a larger diameter the structure resolution of a screen printing process is sufficient. This embodiment has a low complexity in the litigation. It requires no additional for example, lithographic structuring of a metal layer on the substrate, making this a simple and inexpensive Production of the optoelectronic component possible is.

at Another advantageous embodiment is by means of of a galvanic deposition method metallic material in introduced the wells. The metallic material is added for example by means of a lithographically produced mask deposited only in the wells.

at an advantageous variant, the metallic material on the Side of the wells compliant, that is, the entire surface deposited on the substrate wafer and subsequently outside the wells again removed from the substrate wafer. The latter will for example, again by means of a lithographically produced Mask and an etching process or by means of a chemical-mechanical Polishing step accomplished.

at Using a silicon substrate wafer, the mask is preferred by forming a mask layer on the substrate wafer and following lithographic patterning of the mask layer such that Places where the recesses are provided, in the mask layer windows be formed, produced. A mask layer of silicon oxide can, for example, by means of thermal oxidation of the surface of the silicon substrate wafer or by CVD (Chemical Vapor Deposition) be formed. After lithographic structuring of the Mask layer - such patterning methods are out The silicon technology fundamentally known and used by therefore not explained in detail at this point - be then below in the windows of the mask the wells in the Etched silicon substrate wafer, for example by means of KOH or a similar etchant or by means of a basically known dry etching process from silicon technology. As well For example, it is possible to have the depressions in the silicon substrate wafer to form by means of a laser beam. The following are the inner surfaces the recesses provided with an electrically insulating layer, for example, by means of thermal or CVD passivation followed from the application of a seed layer for the metallic material to fill the wells. On the germ layer becomes a applied further mask layer and subsequently lithographically structured, such that over the wells window through which then the metallic material for filling the wells is introduced. In an alternative method a metal paste is pressed into the recesses by screen printing and subsequently sintered, before then reinforcing is plated with a metal layer.

photolithography is a standard technique of semiconductor manufacturing and enables advantageously a high yield in already established process control.

metals For example, by means of a sputtering process with high Efficiency applied to the surface of a semiconductor wafer. The resulting conformal coverage of the semiconductor wafer can be patterned by means of suitable resist masks to the / Remove metal / s outside the wells. Since that Pattern of the pits to that of the mask for the pits is complementary, preferably the same photomask can be used which leads to a reduction in production costs.

present suitable metals are, for example, gold, copper, palladium or any other combination of galvanic or otherwise depositable Metals with sufficiently high thermal and / or electrical Conductivity.

The Exposing the bushings to the second major surface, That is, at the back of the substrate wafer takes place at an advantageous embodiment of the method by means a chemical-mechanical polishing method.

following become opto-electronic semiconductor bodies on the substrate wafer applied, preferably in each case to one of the electrical feedthroughs, and the electrical contacts of the semiconductor body with each connected to an electrical feedthrough before then the encapsulants applied to the semiconductor body and finally the substrate wafer between the encapsulations is severed.

In a particularly advantageous embodiment of the method, a combination of a silicon substrate with a silicone lens is used as the encapsulation for the semiconductor body. Silizi and silicone adhere well to each other and therefore form an interface with high density.

One Optoelectronic component according to the invention includes a chip carrier substrate having a first major surface, wherein in the chip carrier substrate at least two electrically separate, electrically conductive bushings are provided. On the chip carrier substrate is an optoelectronic semiconductor body applied with at least two electrical contacts and the electrical Contacts are each electrically connected to one of the bushings. The chip carrier substrate is finally with a the encapsulation surrounding the semiconductor body, which is preferred is formed as a lens provided.

at overlaps an advantageous embodiment one of the electrical contacts with one of the bushings at least partially, preferably completely. Thereby is in the operation of the device on this implementation a good heat dissipation from the semiconductor chip to the back ensured the device out.

The Chip carrier substrate is preferably made of silicon or made of a silicon-based material, which is a cost-effective wafer-based production of inventive optoelectronic devices allowed.

Further advantages, advantageous embodiments and developments of the invention will become apparent from the following in connection with the 1 to 2E described embodiments. In this case, functionally equivalent elements, regions and structures are provided with the same reference numerals. Insofar as elements, regions or structures correspond in their function, their description is not repeated for each of the exemplary embodiments.

It demonstrate:

1 an embodiment of an optoelectronic semiconductor device in a schematic sectional view, and

2A to 2E An embodiment of a method for producing an optoelectronic component in schematic sectional views.

The optoelectronic component 5 according to 1 includes a chip carrier substrate 100 which preferably consists essentially of silicon or of a silicon-based material. Such substrates are collectively referred to herein as silicon substrates.

Other materials known to those skilled in the art, such as gallium arsenide or germanium, but are not excluded.

The chip carrier substrate 100 has a first major surface 120 and a second major surface opposite thereto 120 ' on. In the chip carrier substrate 100 are at least two metallic feedthroughs 24 . 25 educated. The metallic bushings 24 . 25 are through an electrically insulating layer 20 between substrate material and the electrical feedthroughs 24 . 25 , for example in the form of a passivation layer on the substrate material, electrically from the adjacent material of the chip carrier substrate 100 isolated.

An optoelectronic semiconductor body 30 with two electrical contacts 31 . 32 on opposite sides of the semiconductor body 30 For example, a LED (Light Emitting Diode) chip is connected to one of its electrical contacts 31 , For example by means of a conductive adhesive, on one of the two bushings 24 applied. The other electrical contact 32 is by means of a bonding wire 33 as an electrically conductive connection with the other of the two feedthroughs 25 electrically connected. The metallic execution 24 For example, cover the back of the LED chip, as in 1 It is also conceivable that the implementation 24 smaller than the back of the LED chip is formed.

On the first main surface 120 of the chip carrier substrate 100 is a silicone lens 40 on the optoelectronic semiconductor body 30 pressed on the semiconductor body 30 including bonding wire 33 envelops.

In the above-described optoelectronic component 5 is one of the two executions 24 as a thermal connection for the optoelectronic semiconductor body 30 provided so that through this implementation 24 heat generated during operation in the semiconductor body from inside the encapsulant 40 and the chip carrier substrate 100 formed component housing can be passed to the outside.

With reference to the 2A to 2E In the following, exemplary embodiments of a method for wafer-based production of a plurality of optoelectronic components are described 5 according to 1 described.

In 2A is the starting point of the procedure shown. It becomes a substrate wafer 10 For example, a silicon wafer having a first major surface 12 and one of these opposing second major surfaces 12 ' provided. First and second main surface are referred to as the front 12 or as the back 12 ' of the substrate wafer 10 be records.

On the front side 12 of the substrate wafer 10 becomes a mask 14 generated. As a starting point, for example, one on the front 12 produced silicon dioxide layer, for example, as a thermal oxide or via a vapor deposition method on the first major surface 12 is trained. To structure the mask is 14 , For example, a lithographic process is used in which a silicon dioxide layer by means of photomask and spin-on resist with windows 15 is provided.

Below, as also in 2A illustrated in the substrate wafer 10 in the window area 15 from the front side a plurality of spaced recesses 16 formed in the form of trenches. For this purpose, for example, an anisotropic etching process can be used, such. For example, reactive ion etching (dry etching) or wet chemical etching with potassium hydroxide (KOH). Other etching methods known to the person skilled in the art and suitable in the present case are, of course, not excluded.

After etching the trenches 16 becomes the mask 14 from the substrate wafer 10 away.

On the front side 12 including the trenches 16 of the substrate wafer 10 then becomes a passivation layer 20 trained, which are also the trenches 16 lining (see 2C ). The passivation layer 20 For example, it can be made of silicon dioxide, which is formed either by thermal oxidation of the substrate wafer material or by deposition from the gas phase.

In a first variant of the method, the trenches 16 by compliant deposition of a metal layer, that is, full-surface deposition of a metal layer filled and the metal layer outside the trenches 16 removed again. For this purpose, for example by means of a sputtering a metal layer on the front 12 including inner surfaces of the trenches 16 of the substrate wafer 10 applied, whose thickness, for example, the depth of the trenches 16 equivalent. That beside the trenches 16 on the substrate wafer 10 applied metal is subsequently removed, for example, by means of a further lithographic process section (see. 2C ).

Removing the metal layer outside the trenches 16 can also be done by means of chemical-mechanical polishing, in which the metal layer is removed to the front of the substrate wafer.

Alternatively, for example, first a so-called metallic seed layer 22 on the passivation layer 20 applied, these outside the trenches by means of a mask 14 ' provided and then the trenches 16 with metallic material 23 filled before then the mask 14 ' including metallic seed layer 22 and passivation layer 20 next to the filled trenches 16 is removed again (cf. 2 B ).

The removal of the metallic seed layer 22 and the passivation layer 20 outside the trenches 16 is carried out for example by means of chemical-mechanical polishing, in which the layers to the front 12 of the substrate wafer 10 be removed.

In a further variant of the method, the bushings 24 formed by screen printing a metal paste and subsequent sintering of the metal paste. In order to achieve a good coverage, it is conceivable, after application of the passivation layer in the trenches 16 First, a so-called metallic seed layer 22 ("seed layer") to separate.

suitable Metals for the bushings are for example Gold, copper and palladium and every other combination of galvanic or otherwise depositable metals with a sufficiently high thermal and / or electrical conductivity. Others the expert are metals or alloys of metals which are known to be suitable Of course not excluded.

In a further step, the bushings are now exposed 24 . 25 at the bottom of the trenches 16 that is from the back 12 ' of the substrate wafer 10 her (see 2D ). This is done for example by means of a chemical-mechanical polishing step.

Each on a performance 24 a related pair of executions 24 . 25 an optoelectronic component is subsequently an optoelectronic semiconductor body 30 applied, such that one of its electrical contacts on the implementation 24 rests and is electrically and thermally conductively connected thereto, for example by means of a conductive adhesive. A second electrical contact of the semiconductor body 30 is then by means of a bonding wire 33 with the other implementation 25 electrically connected, see 2E ,

Hereinafter, a plurality of lenses 40 , For example, of silicone material, each at least one of the optoelectronic semiconductor body 30 including bonding wire 32 encloses, on the substrate wafer 10 applied. This is done for example by means of a transfer molding process.

To the Separating the substrate wafer with the semiconductor bodies applied thereon and encapsulations in separate optoelectronic devices For example, the substrate wafer is sandwiched between the encapsulations severed by sawing.

at A method according to the invention are electrical and / or thermal feedthroughs in a substrate wafer formed, which are exposed on both sides of the substrate wafer. To the Making the feedthroughs are recesses in the substrate wafer formed, in the following electrically and / or thermally conductive Material is filled. The depressions become, for example by means of a wet and / or dry chemical etching process produced. It is also conceivable to use a mechanical Process, such as milling. Furthermore it is possible, the recesses in the substrate wafer by means to form a laser beam. A combination of the above methods is also conceivable. For example, by means of a laser beam a recess are formed, which subsequently with an etching process is widened.

With The method can be carried out in a technically simple manner with a sufficiently large cross-sectional area for a good heat dissipation from the semiconductor body will be realized.

One such method advantageously enables the manufacture very flat designs for optoelectronic components, especially LEDs.

The The invention is not by the description based on the embodiments limited. Rather, the invention includes every new feature as well any combination of features, especially any combination includes features in the claims, also if this feature or combination itself is not explicit specified in the patent claims or exemplary embodiments is.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - T. Murphy and J. Kuhmann, "Silicon wafer packaging for HB-LEDs", Technology White Paper, Hymite GmbH, September 2007 [0003]

Claims (15)

Method for wafer-based production of a plurality of optoelectronic components ( 5 ) each having at least one semiconductor body ( 30 ) and a component housing ( 40 . 100 ) comprising the following method steps: - providing a plurality of optoelectronic semiconductor bodies ( 30 ) each having a first electrical contact ( 31 ) and a second electrical contact ( 32 ), - providing a substrate wafer ( 10 ) with a first main surface ( 12 ) and a second main surface ( 12 ' ), - forming at least two recessed depressions ( 16 ) in the substrate wafer ( 10 ) from the first main surface ( 12 ), - introduction of electrically conductive material ( 23 ) into the depressions ( 16 ), - thinning of the substrate wafer ( 10 ), such that the electrically conductive material ( 23 ) in the area of the depressions ( 16 ) electrically conductive bushings ( 24 . 25 ) through the substrate ( 10 ), - applying the optoelectronic semiconductor body ( 30 ) on the substrate wafer ( 10 ), - forming electrically conductive connections between the electrical contacts ( 31 . 32 ) the semiconductor body ( 30 ) and their associated feedthroughs ( 24 . 25 ), - applying a plurality of in each case at least one semiconductor body ( 30 ) enclosing encapsulations ( 40 ) on the substrate wafer ( 10 ), and - dividing the substrate wafer ( 10 ) between the encapsulations ( 40 ), such that separate optoelectronic components ( 5 ) arise. The method of claim 1, wherein - the substrate wafer ( 10 ) consists of an electrically conductive material, and - the inner surfaces of the recesses ( 16 ) before introducing the electrically conductive material ( 23 ) with an electrically insulating layer ( 20 ). Method according to Claim 2, in which the substrate wafer ( 10 ) consists of silicon or of a silicon-based material. Method according to one of Claims 1 to 3, in which the encapsulations ( 40 ) are produced by means of a transfer molding process. Method according to one of Claims 1 to 4, in which the encapsulations ( 40 ) are shaped as lenses. Method according to one of Claims 1 to 5, in which the encapsulations ( 40 ) are made of a silicone material. Method according to one of Claims 1 to 6, in which the depressions ( 16 ) by applying a mask ( 14 ) on the first main surface ( 12 ) of the substrate wafer ( 10 ) and subsequent etching of the substrate material. Method according to one of claims 1 to 7, wherein when introducing electrically conductive material ( 23 ) into the depressions ( 16 ) the inner surfaces of the depressions ( 16 ) first with a metal layer ( 22 ) and then the wells ( 16 ) at least partially with metallic material ( 23 ) are filled. Method according to one of claims 1 to 8, wherein when introducing electrically conductive material ( 23 ) into the depressions ( 16 ), These are at least partially filled with metal paste by screen printing and then the metal paste is sintered. Method according to one of claims 1 to 8, wherein when introducing electrically conductive material ( 23 ) in the recesses, these by means of a galvanic deposition at least partially with metallic material ( 23 ) are filled. An optoelectronic component comprising a chip carrier substrate ( 100 ) with a first main surface ( 120 ), wherein in the chip carrier substrate ( 100 ) at least two electrically isolated from each other, electrically conductive bushings ( 24 . 25 ), an optoelectronic semiconductor body ( 30 ) with at least two electrical contacts ( 31 . 32 ) on the chip carrier substrate ( 100 ), the electrical contacts ( 31 . 32 ) each with one of the bushings ( 24 . 25 ) are electrically connected and the chip carrier substrate ( 100 ) with a semiconductor body ( 30 ) surrounding encapsulation ( 40 ) is provided. Optoelectronic component according to Claim 11, in which one of the electrical contacts ( 31 ) at least partially overlapped with one of the bushings. Optoelectronic component according to one of Claims 11 and 12, in which the chip carrier substrate ( 100 ) consists of silicon or of a silicon-based material. Optoelectronic component according to one of Claims 11 to 13, in which the encapsulation ( 40 ) is formed as a lens. Optoelectronic component according to one of Claims 11 to 14, in which at least one of the feedthroughs ( 24 ) as Wärmeleitanschluss for dissipating the thermal energy from the semiconductor body ( 30 ) is provided.