Method for joining a silicon plate to a second plate

• US 20040082145A1
• Filed: 11/13/2003
• Published: 04/29/2004
• Est. Priority Date: 10/05/2001
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Lutz, Markus, Fischer, Frank, Reichenbach, Frank, Haag, Frieder, Hausner, Ralf, Graf, Eckhard
• Granted Patent: US 6,955,975 B2
• Time in Patent Office: Days
• US Class Current: 438/455
• CPC Class Codes: B29C 65/1612 Infrared [IR] radiation, e.g. by infrared lasers
• CPC Class Codes: B29C 65/1635 at least passing through one of the parts to be joined, i.e. laser transmission welding
• CPC Class Codes: B29C 65/1683 coated on the article
• CPC Class Codes: B29C 65/608 the integral rivets being pushed in blind holes
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/12421 Teardrop-like, waterdrop-like or mushroom-like interlocking undercuts
• CPC Class Codes: B29C 66/472 said single elements being substantially flat
• CPC Class Codes: B29C 66/53461 joining substantially flat covers and/or substantially flat bottoms to open ends of container bodies
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/712 the composition of one of the parts to be joined being different from the composition of the other part
• CPC Class Codes: B29C 66/7392 characterised by the material of at least one of the parts being a thermoplastic
• CPC Class Codes: B29K 2083/00 Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material
• CPC Class Codes: B29L 2031/756 Microarticles, nanoarticles
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 1/00357 involving bonding one or several substrates on a non-temporary support, e.g. another substrate
• CPC Class Codes: B81C 2201/019 Bonding or gluing multiple substrate layers
• CPC Class Codes: B81C 2203/019 characterised by the material or arrangement of seals between parts
• CPC Class Codes: H01L 21/2007 Bonding of semiconductor wafers to insulating substrates or to semiconducting substrates using an intermediate insulating layer H01L21/2011 takes precedence; bonding of semiconductor wafers to semiconductor wafers for junction formation H01L21/187
• CPC Class Codes: H01L 21/76251 using bonding techniques
• CPC Class Codes: H01L 2224/80224 using a laser
• CPC Class Codes: H01L 2224/80365 : Shape, e.g. interlocking features
• CPC Class Codes: H01L 2224/80379 : Material material of the bonding area prior to the connecting process H01L2224/05099 and H01L2224/05599
• CPC Class Codes: H01L 2224/804 : with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/80488 : Glasses, e.g. amorphous oxides, nitrides or fluorides
• CPC Class Codes: H01L 2224/83224 : using a laser
• CPC Class Codes: H01L 2224/834 : with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/83424 : Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/83447 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/83466 : Titanium [Ti] as principal constituent
• CPC Class Codes: H01L 2224/83471 : Chromium [Cr] as principal constituent
• CPC Class Codes: H01L 2224/83487 : Ceramics, e.g. crystalline carbides, nitrides or oxides glass ceramics H01L2224/83488
• CPC Class Codes: H01L 2224/8349 : with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/83801 : Soldering or alloying
• CPC Class Codes: H01L 24/83 : using a layer connector
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/12042 : LASER

Abstract

A method is proposed for joining a silicon plate (1) to a second plate (2), a laser beam being directed through the silicon plate (1) at the second plate (2). In the process, the wavelength of the laser beam is selected in such a way that only a negligibly small amount of energy is absorbed in the silicon plate (1). A strongly absorbent material is hotmelted by the laser beam'"'"'s energy and then produces a bond between the silicon plate (1) and the second plate (2).

Claims

1. A method for joining a silicon plate (1) to a second plate (2), the silicon plate (1) and the second plate (2) being place one upon the other for purposes of joining the two plates,

wherein a laser beam (3) is directed through the silicon plate (1) at the second plate;

the wavelength of the laser beam being selected in such a way that only a small amount of energy is absorbed in the silicon plate (1);

on a surface of the silicon plate (1) facing the second plate (2), strongly absorbent material is provided, which almost completely absorbs the energy of the laser beam and is hotmelted by the energy introduced by the laser beam (3);

the melted material is cooled again, and a bond is produced between the silicon plate (1) and the second plate (2).

2. The method as recited in claim 1,

wherein a layer (20) of the strongly absorbent material is situated in the area of a bonding site between the silicon plate (1) and the second plate (2).

3. The method as recited in claim 1,

wherein the second plate (2) is completely formed from the strongly absorbent material.

4. The method as recited in one of the preceding claims,

wherein silicon, metal, glass, plastic, metal, germanium or silicon germanium are selected as material for the second plate (2).

5. The method as recited in one of the preceding claims,

wherein metal, germanium, silicon germanium, heavily doped polysilicon or a plastic is used as strongly absorbent material.

6. The method as recited in one of the preceding claims,

wherein the hotmelted, strongly absorbent material produces a hotmelt-adhesive connection, a soldered connection, a positive-engagement connection, or a welded connection between the silicon plate (1) and the second plate (2).

7. The method as recited in one of the preceding claims,

wherein the bond is formed using a circumferential seam which completely surrounds an area of the surface of the silicon plate;

an electrical feed-through lead (52, 54) being provided within the circumferential seam in the silicon plate (1) or the second plate (2), through which an electrical contact to an interior space (23) is established which is situated between the silicon plate (1) and the second plate (2).

8. The method as recited in one of the preceding claims,

wherein a multiplicity of structures is provided on the silicon plate (1) and the second plate (2);

the structures are adjusted relatively to one another; and

the adjustment is accomplished by directing infrared light through the silicon plate (1).

9. The method as recited in claim 8,

wherein following the adjustment, spot-type connections are formed between the silicon plate (1) and the second plate (2), through which the adjusted position of the silicon plate (1) is retained relatively to the second plate (2) in the subsequent bonding process.