GB1559595A - Method for selective etching of titanium dioxide - Google Patents
Method for selective etching of titanium dioxide Download PDFInfo
- Publication number
- GB1559595A GB1559595A GB50734/76A GB5073476A GB1559595A GB 1559595 A GB1559595 A GB 1559595A GB 50734/76 A GB50734/76 A GB 50734/76A GB 5073476 A GB5073476 A GB 5073476A GB 1559595 A GB1559595 A GB 1559595A
- Authority
- GB
- United Kingdom
- Prior art keywords
- titanium dioxide
- layer
- solution
- ammonia
- hydrogen peroxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims description 56
- 239000004408 titanium dioxide Substances 0.000 title claims description 27
- 238000000034 method Methods 0.000 title claims description 17
- 238000005530 etching Methods 0.000 title claims description 13
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 18
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 16
- 239000000243 solution Substances 0.000 claims description 16
- 229910021529 ammonia Inorganic materials 0.000 claims description 9
- 230000003647 oxidation Effects 0.000 claims description 8
- 238000007254 oxidation reaction Methods 0.000 claims description 8
- 239000004065 semiconductor Substances 0.000 claims description 6
- 230000004807 localization Effects 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 4
- 230000005484 gravity Effects 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 13
- 239000004411 aluminium Substances 0.000 description 12
- 229910052782 aluminium Inorganic materials 0.000 description 12
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 12
- 239000004922 lacquer Substances 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 238000001259 photo etching Methods 0.000 description 3
- 238000011282 treatment Methods 0.000 description 3
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 229910004078 HF-NH4F Inorganic materials 0.000 description 1
- 229910003810 HF—NH4F Inorganic materials 0.000 description 1
- 229910018594 Si-Cu Inorganic materials 0.000 description 1
- 229910008465 Si—Cu Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 230000003190 augmentative effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012777 electrically insulating material Substances 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31105—Etching inorganic layers
- H01L21/31111—Etching inorganic layers by chemical means
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
- H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
- H01L21/0223—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate
- H01L21/02244—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of a metallic layer
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
- H01L21/32139—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer using masks
Landscapes
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Weting (AREA)
- ing And Chemical Polishing (AREA)
- Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
Description
(54) METHOD FOR SELECTIVE ETCHING OF TITANIUM DIOXIDE (71) We, PHILIPS ELECTRONIC AND As
SOCIATED INDUSTRIES LIMITED of Abacus
House, 33 Gutter Lane, London, EC2V 8AH a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
The present invention relates to a method of selectively etching a layer of titanium oxide used as a mask for the localisation of the anodic oxidation of an oxidizable metal layer. It is already known to use the anodic oxidation of a metal layer, in particular aluminium, to effect the passivation of a semiconductor surface or the realization of localized contacts on said surface.
In order to obtain said anodic oxidation which thus is generally localise, a screen or mask is used which, for example, does not cover the parts to be oxidozed and which protects the parts which must not be treated.
An electrically insulating material, either a layer of impervious alumina, or a photosensitive lacquer or a layer of silicon dioxide is generally used as a mask. All the various methods using these masks present drawbacks: defects in the localisation are found in the case of alumina, bubbles may be present in the mask or the mask does not adhere adequately in the case of photosensitive lacquers, and protruberances may be present in silicon dioxide masks, the deposition of the latter necessitating temperatures which are unacceptably high.
Taking into account these numerous difficulties, it is more convenient to form the mask starting from a layer of titanium dioxide. Titanium dioxide can be deposited at a low temperature and in a thin layer which is free from bubbles. Moreover, titanium dioxide has the property of resisting corrosion and avoiding the formation of bubbles in the underlying layers.
It is for this latter reason that the etching and/or the removal of the titanium dioxide layer are very difficult. It has been found that titanium dioxide can withstand a great number of cold dilute acid solutions currently used in photoetching. It has meanwhile been found that titanium dioxide is sensitive to a hydrofluoric acid and ammonium fluoride solution but this solution also etches the metals generally disposed below the titanium dioxide layer and in particular aluminium, so that it becomes useless in these conditions for the photoetching or anodic oxidation treatments. In order to mitigate this drawback, it has been suggested to interpose an alumina layer between the titanium dioxide layer and the underlying metal layer, the alumina presenting the property of being more resistant to the action of the HF-NH4F the above etching solution than aluminium.
In these conditions, however, said alumina layer must then be removed by means of an etching solution usually comprising acetic acid and ammonium fluoride. Consequently, by this supplementary operation, the risks of deterioration of active elements adjacent to the said aluminium layer are increased either as a result of the actual chemical treatment, or due to the manipulations necessitated by said treatment, and the costs of the resulting device are also augmented. Moreover, it may be found that the result obtained is not always that which was anticipated.
It is the object of the present invention to mitigate said drawbacks and to make it possible to selectively etch a titanium dioxide layer without damaging adjacent materials and to simplify an etching method or an anodic oxidation method using a titanium dioxide mask.
The present invention provides a method of selectively etching a titanium dioxide layer used as a mask for the localisation of the anodic oxidation of an oxidisable metal layer, using an etchant consisting of a solution comprising hydrogen peroxide and ammonia.
This solution may be used for etching the titanium dioxide layer so as to give it the configuration of a mask, as well as for removing the remainder of the said layer after it has been used as a mask, and it uses commerically available materials, notably 30% by weight of H201 in water and an aqueous solution of ammonia having a specific gravity of 0-90.
Moreover, this solution also presents the advantage of not attacking the materials generally present below the titanium dioxide layer, and in particular the said solution attacks neither aluminium nor alumina.
Advantageously, the ratio of the volume of ammonia with respect to the volume of hydrogen peroxide to form the solution according to the invention is equivalent to that obtained by adding between 0-10 and 0'50 unit volumes of an aqueous solution of ammonia having a specific gravity of 0. 90 to one unit volume of 30% by weight hydrogen
peroxide in water.
In this range of proportions, the etching
rate of titanium dioxide by the solution is practically constant and it is rapid. For comparison it has been the etching rate of titanium dioxide decreases progressively when an etchant found that containing more than 0-50 unit volumes of the ammonia solution
per unit volume of 30 Ó by weight hydrogen peroxide is used.
The present invention also relates to the
manufacture of a semi-conductor device of which the apertures in a metallic layer which
are necessary for making contacts have been provided by the method according to the invention, which manufacture is character
ized in that a titanium dioxide film is deposited on a metallic layer (notably of aluminium) present on the surface of a
semiconductor crystal, and in that a portion
of the said titanium dioxide film is selectively etched by a method according to the invention.
An embodiment of the invention will now
be described with reference to the accompanying drawing in which Figures 1 to 3 are
schematic cross-sections of part of a semi
conductor device at different stages in the
performance of a method according to the
invention.
It is to noted that the dimensions in the
Figures are considerably exaggerated and are
not drawn to scale for the sake of clarity.
Referring now to Figures I to 3, on the
surface of a semiconductor material I in which active and/or passive islands (not
shown) have been formed, an aluminium
layer 2 has been deposited which can be
oxidised anodically and in which it is desired,
for example, to form porous oxide islands.
The layer 2 could, for example consist of an aluminium-based alloy (A l-Si, Al-CuX or
Al-Si-Cu). The masking is destined for the
localisation of islands to be formed generally
consisting of porous alumina.
A layer 3 of titanium dioxide is deposited
on said layer 2 by known means, said deposit
having the advantageous particularity that it
can be effected at low temperature (150 C).
The next operation consists of photoetching said titanium dioxide layer 3: in order to do this a known method is used by depositing a photosensitive lacquer layer 4, locally irradiating and polymerising the lacquer layer-4 so that after development aperture 5 is formed in the lacquer layer 4 opposite to an area of the aluminium layer 2 which must be maintained conductive (Figure ')..., With the aid of the mask formed by the lacquer layer 4, an aperture 6 (Figure 2) is then etched in the titanium dioxide layer 3, said aperture being disposed opposite to the aperture 5 provided in the lacquer layer 4.
The aperture 6 was etched using a solution consisting of 50 cm3 of a solution of 30% by weight of H202 in water and 10 cTn'of an aqueous solution of ammonia having a specific gravity of 0-90.
Said aperture 6 exposes an area 7 of the surface of the underlying aluminium layer 2.
Said exposed area 7 is then transformed into an impervious aluminium oxide film, for example by a known anodic oxidation method. The structure shown in Figure 2 is then obtained.
By means of the same solution of hydrogen peroxide and ammonia used to etch the aperture 6, the remainder of the titanium dioxide layer 3 is removed and the portion 2a of the aluminium layer 3 which is not protected by the aluminium oxide film 7 can then easily be transformed into oxide which is generally porous. The aluminium portion 2b protected by the film 7 preserves its original nature and consequently remains conductive (Figure 3) and may be used for various applications, notably as a contact.
Claims (4)
- WHAT WE CLAIM IS :- 1. A method of selectively etching a titanium dioxide film used as a mask for the localisation of the anodic oxidation of an oxidisable metallic layer, using an etchant consisting of a solution comprising hydrogen peroxide and ammonia.
- 2. A method as claimed in Claim 1, characterized in that the quantities of ammonia and hydrogen peroxide in the said solution are equivalent to those obtained by adding between O'tO and 0-50 unit volumes of an aqueous solution of ammonia having a specific gravity of 0-90 to one unit volume of 30 Ó by weight of hydrogen peroxide in water.
- 3. A method of selectively etching a titanium dioxide film, substantially as herein described with reference to the accompanying drawings.
- 4. A method of manufacturing a semiconductor device, characterized in that during the formation of contacts an oxidisable metallic layer is deposited on the surface of the device a titanium dioxide film is formed on said metallic layer, and in that a part of the said titanium dioxide film is removed by the method as claimed in any of Claims 1 to 3.'"'""''''-'...''-"''''.-'.'''.''. < ''h-'..'.'''': < .\r--/...-. < ..' < . < '.i;;-;-''.'.'H.: < -,,'t/f <
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7537658A FR2334770A1 (en) | 1975-12-09 | 1975-12-09 | METHOD OF ATTACKING AN OXIDIZABLE METAL LAYER SERVING AS A PHOTOGRAVURE MASK |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1559595A true GB1559595A (en) | 1980-01-23 |
Family
ID=9163509
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB50734/76A Expired GB1559595A (en) | 1975-12-09 | 1976-12-06 | Method for selective etching of titanium dioxide |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5271984A (en) |
| CA (1) | CA1091139A (en) |
| DE (1) | DE2653710A1 (en) |
| FR (1) | FR2334770A1 (en) |
| GB (1) | GB1559595A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102007025136A1 (en) * | 2007-05-30 | 2008-12-11 | Helmholtz-Zentrum Berlin Für Materialien Und Energie Gmbh | Process for the wet-chemical etching of TiO 2 thin films and TiO 2 particles and etchants |
-
1975
- 1975-12-09 FR FR7537658A patent/FR2334770A1/en active Granted
-
1976
- 1976-11-26 DE DE19762653710 patent/DE2653710A1/en not_active Withdrawn
- 1976-12-06 GB GB50734/76A patent/GB1559595A/en not_active Expired
- 1976-12-06 JP JP51145713A patent/JPS5271984A/en active Granted
- 1976-12-07 CA CA267,352A patent/CA1091139A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2653710A1 (en) | 1977-06-16 |
| CA1091139A (en) | 1980-12-09 |
| JPS5546055B2 (en) | 1980-11-21 |
| FR2334770A1 (en) | 1977-07-08 |
| JPS5271984A (en) | 1977-06-15 |
| FR2334770B1 (en) | 1978-05-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |