CA1046648A - Method of structuring thin layers - Google Patents
Method of structuring thin layersInfo
- Publication number
- CA1046648A CA1046648A CA232,152A CA232152A CA1046648A CA 1046648 A CA1046648 A CA 1046648A CA 232152 A CA232152 A CA 232152A CA 1046648 A CA1046648 A CA 1046648A
- Authority
- CA
- Canada
- Prior art keywords
- layer
- structured
- photolacquer
- substrate
- mask
- 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
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/04—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed mechanically, e.g. by punching
- H05K3/046—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed mechanically, e.g. by punching by selective transfer or selective detachment of a conductive layer
- H05K3/048—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed mechanically, e.g. by punching by selective transfer or selective detachment of a conductive layer using a lift-off resist pattern or a release layer pattern
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
- G03F7/11—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having cover layers or intermediate layers, e.g. subbing layers
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/26—Processing photosensitive materials; Apparatus therefor
- G03F7/40—Treatment after imagewise removal, e.g. baking
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/26—Processing photosensitive materials; Apparatus therefor
- G03F7/42—Stripping or agents therefor
- G03F7/428—Stripping or agents therefor using ultrasonic means only
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
- H01L23/29—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the material, e.g. carbon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
Abstract
ABSTRACT:
A method of structuring oxide layers, nitride layers or magnetic layers in such manner that a photo-lacquer mask is manufactured on a substrate and the layer to be structured is provided by means of cathode sputter-ing both on the photolacquer mask and on the surfaces of the substrate not covered with lacquer. The substrate is then treated with a solvent attacking the lacquar mask; the mask swells up and the parts of the layer to be structured present thereon are chipped off. In order to stimulate this latter process, a layer is provided below the photolacquer mask on the substrate relative to which photolacquer has a small adhesive capacity and, after providing the layer to be structured, an increase in volume of the lacquer mask is produced by thermal treat-ment. After the complete removal of the photolacquer mask and the parts of the layer to be structured present thereon, the structured thin layer remains on the sub-strate as a negative of the pattern of the photolacquer mask.
A method of structuring oxide layers, nitride layers or magnetic layers in such manner that a photo-lacquer mask is manufactured on a substrate and the layer to be structured is provided by means of cathode sputter-ing both on the photolacquer mask and on the surfaces of the substrate not covered with lacquer. The substrate is then treated with a solvent attacking the lacquar mask; the mask swells up and the parts of the layer to be structured present thereon are chipped off. In order to stimulate this latter process, a layer is provided below the photolacquer mask on the substrate relative to which photolacquer has a small adhesive capacity and, after providing the layer to be structured, an increase in volume of the lacquer mask is produced by thermal treat-ment. After the complete removal of the photolacquer mask and the parts of the layer to be structured present thereon, the structured thin layer remains on the sub-strate as a negative of the pattern of the photolacquer mask.
Description
-PHD. 74-130.
104~6~ff The invention relates to a method of structur-ing thin layers in which the layer to be structured is - . .
provided on a substrate masked locally by a layer of photolacquer and is removed again partly by removing the layer of photolacquer.
Such methods are already known and are used in thin-layer-technology, for example, in manufacturing maska for integrated circuits.
It is already known to manufacture SiO2 masks on a semiconductor substrate in such manner that a photolacquer mask is formed on the substrate by means of photolithographic processes and a layer of silicon oxide or silicon nitride is provided by means of cathode sputtering in a gas discharge both on the photolacquer ma~k and on the surfaces of the semiconductor substrate not covered with lacquer. The substrate is then treated w1th a solvent which attacks the lacquer mask; the photolacquer mask swells up and the parts of the layer of silicon oxide or silicon nitride present thereon are removed by chipping off. After removing the photo-lacquer mask, the desired silicon oxide or silicon nitride mask remains on the semiconductor substrate a~ a negative ~l of the pattern of the photolacquer mask.
It has been found that this known method ex-:
~, . '' . 1~
. ~ , .
."
''~
~ ,.. , . .. ~, ,, , . . , .. . :
PHD. 74.130~ ~
~046~4t3 hibits drawbacks in the cases in which very finely struc-tured layers having layer thicknesses of more than 1 are to be formed on a substrate. According to the kncwn method, structured layers of this type cannot be manu-factured with the desired reproducibility. In other w~rds:
the yield of fully, accurately proportioned and perfectly structured layers on a substrate in ccmparison wi$h the pattern of the mask is not high enough. "Full" structuring is to be understoad to mean that all the surfaces on the substrate to be exposed are exposed indeed in a repro-ducible manner, while the "perfect" structuring relates in particular to the quality of the edges of the profile formed in the layer to be structured. It is of importance ; especially with a view to series pr~duction to be able to manufacture layers of the said kind with always the same quality and with a great precision. Inaccuracies in the profile, for example, have a particularly disadvan-tageous effect in forming structured m~lt;l~yers.
The invention is based on the reoognition that the reproducibility and the yield, respectively, depend on the quality of the surface on which the layer of photo-I laoquer is provided and on which the layer to be struk-! tured is provided in the places not covered with laoquer:
' this surface should be such that the photolacquer has only a small adhesive capacity with respect to that.
The invention is furthermDre based on the re-cDgnitiQn tbat the chipping off Erocess of the parts of : ~ ;
.
`', :, . , .. . . ~ , ~ . .. .
PHD. 74.130.
104~8 the layer to be structured present on the photolacquer can be stimulated by vDlume variations of the layer o~
photolaoquer which can be obtained, for example, by temr perature influen oes.
It is thus an cbject of the invention to pro-vide an Lmprov3d method of Qbtaining very fine structures in thin layers of different materials.
The methcd of the kind mentioned in the prea~ble is therefore characteri æd acoDrding to the invention in - -that a layer is provid~d directly on the substrate (1) as a supporting layer (2) for the layer of photolaoquer ~3) and for the layer (4) to be structured with respect to which photolaoquer, in the subs~quent thermal treat- ~ -ment, has only a small adheslve capacity and that the substrate, after providing the layer to be structured, is heated in ~uch a temperature range that the chemical I reaction capacity of the phstolaoquer is just not yet '''1 ::
detr$mentally influew ed and the photolaoquer is remaved.
e advantages resulting fram the use of the iDvEntion consist in particular in that fully, accurately ¦ proportioned, structured layers having a good profile qu~lity with respect to the mas;k can be abtained in a :.
readily reproducible yield~ The layer thicknesses of the ;~ layers to be structured are preferably in the rang fr~m .,.~ I .
~ 25 approxlmately 1 to 3 /um; however, they may also be larger.
, .
e layer thicknesses of the layers to be structured are Iimdted m the first instance by the possibility of .,,. ~ .
,~
~: .
,~
~ :. ~
i~, ~
.,.
; ~ i 4 ~"
1`
PHD. 74.130.
~046~;~8 pmviding correspondingly thick photolacquer layers.
m e invention will now be described in greater detail with reference to an enbodlment and the accompa- -~ying drawings, in which:
figs. la - lc are cmss-sectional vie~s of a substrate in various stages of the method, fig. 2 is a graph showing the yield of perfectly and fully struotured layers as a function of the quality of the surface of the substrate and of the duration of the thermal treatment.
Figs. 3a - 3f are cross-sectional views of a substrate having multi-layers in various stages of the method, and Fig. 4 shows the yield of perfectly and fully structured layers and the angle of inclination of the edges of the layer of photolaoquer as a function of the baking temperature of the laoquer mask.
, For the exa~ple below is described the manu-facture of a structured aluminium layer which may be used, for example, as a layer of oonductor tracks on a substrate, sald aluminium tracks being 5 /um wide and approximately !
20 mm long and being present at a distance of 5 /um fr~m j each other. The thickness of the aluminium tracks should ~ be approximately 1 ~ m. In the same m2nner, layers of a i~ 25 different quality can also be structured, for example, titanlun L3ysrs, magnetic layers for mass m2m~ries or thlr~ yn~ti~ h~bd~ or Layers of oxides and nitrides _ which are used as diffusion masks, oxidation masks, dif-fusion sources, d;electr;cs or passivating layers ;n planar semiconductor technology.
On a substrate 1 (Fig. l_) a supporting layer 5 2 is provided to which photolacquer does not readily adhere. SiO2 and aluminium have proved to be particularly suitable as a material for such layers. In the case of a silicon substrate, an SiO2 layer can be formed by thermal oxidation; however, the layers may equally readily be -l~ formed, for example, by cathode sputtering in the gaseous phase or by vapour deposition. On the substrate l having the supporting layer 2 a masking photolacquer layer 3 having steep edges is then provided by means of the known photolithographic methods, the photolacquer mask being the negat~ve of the structured layer to be formed. Both a positive and a negative lacquer may be used for the ~I manufacture of the photolacquer layer 3. For the present ;l embodiment was used the positive photolacquer of Messrs.
1 Shipley (AZ* 135 OH) in a thickness of approximately 3 /um.
! 20 At any rate the th;ckness of the photolacquer layer must be larger than the thickness of the layer to be structured.
The photolacquer layer 3 after providing and developing, . ~
may no longer be heated so as not to influence the steep-ness of the edges dlsadvantageously. After providing the photolacquer layer, a 1 /um thick layer 4 of aluminium is provided on the cooled substrate l having the support-ng layer 2 and the photolacquer layer 3 by means of high A registered trade mark.
.
:
.~' : ~ '" " ~ ' PHD. 74.130.
~o4~;4~3 :
frequency cathode sputtering in a gas discharge tprefe-rably in Argon) (Fig. lb). The substrate is then heated for 30 minutes at 130C. ~-The practical results have demonstrated that ~' such a temperature treatment considerably stimulates the chipping off process of the p æts of the layer to be structured present on the photolacquer layer. Ihis may be a result of the fact that due to expansion of the photolacquer, as a result of thermal expansion or by giving off of solvent residues still present in the ; lacquer, the cracking or at least the formation of cracks in the layer to be structured i5 stimulated. The tempe-rature should be as high as possible and be at any rate above the flow limit d the photolaoquer but on the other hand may not be so high that as a result of this a fur-, .. .
ther "cross linking" of the photolaoquer is produced and hence the solubility thereof in an associated solvent is reduced.
Bow great the importance of the quality of the surface of the substrate on which the photolaoquer layer and the layer to be structured as provided is for I the yield of perfectly and fully structured layers, ''1 appears fron the following table and from Fig. 2. The ~ ' surface of the substrate should have such a quality that the phDtoiacquer'layer'does'not readily adhere to it. ' When'an SiO2 layer'was formed on a silicon substrate '~
-1 by thermQl oxidation, the yield was much better than .::. ,~ .
~ 7 '~ ' :
: ;
-.. ,, . , , - - ~ ~ . . : . ,. - ,. , ... . . . .: ... . ~.
PHD. 74.130.
10466~8 whRn, for example , a chrcmiunrnickel layer was provided on the substrate as a supporting layer for the photo-lacquer layer and the layer to be structured. -The fav~urable effects when using an SiO2 layer as a supporting layer also beoome apparent from the Example in which a chromium~nickel layer on the substrate was covered with a further SiO2 layer which in turn then farmEd the supportin~ layer for the photolaoquer layer and the layer to be structured. -~
Surface of the substrate Yield (%) silioon substrate having SiO2 supp~rting layer 98 silioon substrate having chromiumr ;I nickel supporting layer (0.1 /um) 45 silicon substrate having a chrcmiumr nickel intermediate layer (0.1 ~ ) and an SiO2 supporting layer (0.1 ~ ) 96.
¦ After the temperature treatment of the substrate 1 having the photolaoquer layer 3 and the layer 4 to be , ~ .
~;j 20 structured, the substrate is dipped in a solvent which dis-, } solve~ the photolaoquer. Su~h a solvent may be, for example, acetone. As a result of diffusion through the layer 4 to be structured, the solvent dissolves the phctD-lacquer present below the layer and causes it to ~well up.
The treatment can be acaelerated by ultrasanic effects.
e swelling phL~olacquer 3 causes the parts of the ~ `~
~; - 8 -. ; ' ' .~' ~ . .
~. 74.130. '~ -~04664t3 the layer 4 to be structured present thereon to be re~
maved, the renaining parts of the layer 4 to be struc*ured '' remaining on the substrate l having the supporting layer 2 after the ccmplete re val of the photolacquer (Fig. lc).
According to the principle described, multi-layers can also be structured which are built up from layers of different materials, for example, an insulating material and a material for oanductor trac~s. Such multi-layers are of importance, for exa~ple, for the oonstruc-' 10 tion of integrated magnetic mem~ries.
Fig. 3a is a cross-sectional view of a sub-strate 1 having a supporting layer 2, in this case in the fonm of a magnetic layer of FeSi, a photolacquer layer 3 covering the supporting layer 2 partly, an SiO2 ~ ' layer 4 provided by cathode sputtering and an alumLnium '~ layer S provided on said SiO2 layer 4 by cathode sputter-ing. After removing the photolaoquer layer 3, the sub- ;~
~ strate l covered with a double layer having the sueport-;1 ing layer 2, the SiO2 layer'4 and the aluminium layer 5 is obtained as is shown in Fig. 3b. These suocessive ' layers shown in Fig. 3b can now be provided again with an insulating layer and a layer'of conductor tradks; the stage shcwn in Fig. 3c is then'obtained, in which on the'substrate l with the first layer structure 4 and 5 25' a further pb~tolacqyer layer 33 is provided and a further SiO2 layer'44 and a ~urthe~'aluminium layer 55 are pro, vided by cathode sFuttering. After removing the photo~
j~.~ . ~ . .
, 1~ .
PHD. 74.130.
~0466~8 laoquer layer 33 the substrate 1 with the supporting layer 2 and the double layer structures 4,5 and 44, 55 is obtained as is shcwn in Fig. 3d. A third SiO2-layer 444 as an insulating layer (Fig. 3e) may be pr~vided on said m~ltiple-structured successive layers in a further process step by cathode sputtering, which insulating layer may then be provided, for exa~ple by electroless plating, with a magnetic c wering layer, for example, of nickel-iron (Fig. 3f). The magnetic coupling between the magnetic supporting layer 2 and the magnetic covering layer 6 is not shcwn in the fig~res.
The steepness of the edges of the structured photolacquer layer is of great importance in the me*hDd described; in addition the photolaoquer layer should show sides w~ich are rounded off as little as possible. For `1 example, a thermal treat~.ent of a photolaoquer layer .
prior to providing the layer to be structured results in flattening of the angle of inclination of the edges and in rounding of the sides.
I 20 Fig. 4 shows the yield of perfectly and fully structured thin layers, (solid line) and the angle of I the edges as a function of the baking temperature of .~ the lacquer mask (broken line).
,1 ' .
, : ' 1': .. :
- 10 - ' ' 1 ' ;
:.1 i
104~6~ff The invention relates to a method of structur-ing thin layers in which the layer to be structured is - . .
provided on a substrate masked locally by a layer of photolacquer and is removed again partly by removing the layer of photolacquer.
Such methods are already known and are used in thin-layer-technology, for example, in manufacturing maska for integrated circuits.
It is already known to manufacture SiO2 masks on a semiconductor substrate in such manner that a photolacquer mask is formed on the substrate by means of photolithographic processes and a layer of silicon oxide or silicon nitride is provided by means of cathode sputtering in a gas discharge both on the photolacquer ma~k and on the surfaces of the semiconductor substrate not covered with lacquer. The substrate is then treated w1th a solvent which attacks the lacquer mask; the photolacquer mask swells up and the parts of the layer of silicon oxide or silicon nitride present thereon are removed by chipping off. After removing the photo-lacquer mask, the desired silicon oxide or silicon nitride mask remains on the semiconductor substrate a~ a negative ~l of the pattern of the photolacquer mask.
It has been found that this known method ex-:
~, . '' . 1~
. ~ , .
."
''~
~ ,.. , . .. ~, ,, , . . , .. . :
PHD. 74.130~ ~
~046~4t3 hibits drawbacks in the cases in which very finely struc-tured layers having layer thicknesses of more than 1 are to be formed on a substrate. According to the kncwn method, structured layers of this type cannot be manu-factured with the desired reproducibility. In other w~rds:
the yield of fully, accurately proportioned and perfectly structured layers on a substrate in ccmparison wi$h the pattern of the mask is not high enough. "Full" structuring is to be understoad to mean that all the surfaces on the substrate to be exposed are exposed indeed in a repro-ducible manner, while the "perfect" structuring relates in particular to the quality of the edges of the profile formed in the layer to be structured. It is of importance ; especially with a view to series pr~duction to be able to manufacture layers of the said kind with always the same quality and with a great precision. Inaccuracies in the profile, for example, have a particularly disadvan-tageous effect in forming structured m~lt;l~yers.
The invention is based on the reoognition that the reproducibility and the yield, respectively, depend on the quality of the surface on which the layer of photo-I laoquer is provided and on which the layer to be struk-! tured is provided in the places not covered with laoquer:
' this surface should be such that the photolacquer has only a small adhesive capacity with respect to that.
The invention is furthermDre based on the re-cDgnitiQn tbat the chipping off Erocess of the parts of : ~ ;
.
`', :, . , .. . . ~ , ~ . .. .
PHD. 74.130.
104~8 the layer to be structured present on the photolacquer can be stimulated by vDlume variations of the layer o~
photolaoquer which can be obtained, for example, by temr perature influen oes.
It is thus an cbject of the invention to pro-vide an Lmprov3d method of Qbtaining very fine structures in thin layers of different materials.
The methcd of the kind mentioned in the prea~ble is therefore characteri æd acoDrding to the invention in - -that a layer is provid~d directly on the substrate (1) as a supporting layer (2) for the layer of photolaoquer ~3) and for the layer (4) to be structured with respect to which photolaoquer, in the subs~quent thermal treat- ~ -ment, has only a small adheslve capacity and that the substrate, after providing the layer to be structured, is heated in ~uch a temperature range that the chemical I reaction capacity of the phstolaoquer is just not yet '''1 ::
detr$mentally influew ed and the photolaoquer is remaved.
e advantages resulting fram the use of the iDvEntion consist in particular in that fully, accurately ¦ proportioned, structured layers having a good profile qu~lity with respect to the mas;k can be abtained in a :.
readily reproducible yield~ The layer thicknesses of the ;~ layers to be structured are preferably in the rang fr~m .,.~ I .
~ 25 approxlmately 1 to 3 /um; however, they may also be larger.
, .
e layer thicknesses of the layers to be structured are Iimdted m the first instance by the possibility of .,,. ~ .
,~
~: .
,~
~ :. ~
i~, ~
.,.
; ~ i 4 ~"
1`
PHD. 74.130.
~046~;~8 pmviding correspondingly thick photolacquer layers.
m e invention will now be described in greater detail with reference to an enbodlment and the accompa- -~ying drawings, in which:
figs. la - lc are cmss-sectional vie~s of a substrate in various stages of the method, fig. 2 is a graph showing the yield of perfectly and fully struotured layers as a function of the quality of the surface of the substrate and of the duration of the thermal treatment.
Figs. 3a - 3f are cross-sectional views of a substrate having multi-layers in various stages of the method, and Fig. 4 shows the yield of perfectly and fully structured layers and the angle of inclination of the edges of the layer of photolaoquer as a function of the baking temperature of the laoquer mask.
, For the exa~ple below is described the manu-facture of a structured aluminium layer which may be used, for example, as a layer of oonductor tracks on a substrate, sald aluminium tracks being 5 /um wide and approximately !
20 mm long and being present at a distance of 5 /um fr~m j each other. The thickness of the aluminium tracks should ~ be approximately 1 ~ m. In the same m2nner, layers of a i~ 25 different quality can also be structured, for example, titanlun L3ysrs, magnetic layers for mass m2m~ries or thlr~ yn~ti~ h~bd~ or Layers of oxides and nitrides _ which are used as diffusion masks, oxidation masks, dif-fusion sources, d;electr;cs or passivating layers ;n planar semiconductor technology.
On a substrate 1 (Fig. l_) a supporting layer 5 2 is provided to which photolacquer does not readily adhere. SiO2 and aluminium have proved to be particularly suitable as a material for such layers. In the case of a silicon substrate, an SiO2 layer can be formed by thermal oxidation; however, the layers may equally readily be -l~ formed, for example, by cathode sputtering in the gaseous phase or by vapour deposition. On the substrate l having the supporting layer 2 a masking photolacquer layer 3 having steep edges is then provided by means of the known photolithographic methods, the photolacquer mask being the negat~ve of the structured layer to be formed. Both a positive and a negative lacquer may be used for the ~I manufacture of the photolacquer layer 3. For the present ;l embodiment was used the positive photolacquer of Messrs.
1 Shipley (AZ* 135 OH) in a thickness of approximately 3 /um.
! 20 At any rate the th;ckness of the photolacquer layer must be larger than the thickness of the layer to be structured.
The photolacquer layer 3 after providing and developing, . ~
may no longer be heated so as not to influence the steep-ness of the edges dlsadvantageously. After providing the photolacquer layer, a 1 /um thick layer 4 of aluminium is provided on the cooled substrate l having the support-ng layer 2 and the photolacquer layer 3 by means of high A registered trade mark.
.
:
.~' : ~ '" " ~ ' PHD. 74.130.
~o4~;4~3 :
frequency cathode sputtering in a gas discharge tprefe-rably in Argon) (Fig. lb). The substrate is then heated for 30 minutes at 130C. ~-The practical results have demonstrated that ~' such a temperature treatment considerably stimulates the chipping off process of the p æts of the layer to be structured present on the photolacquer layer. Ihis may be a result of the fact that due to expansion of the photolacquer, as a result of thermal expansion or by giving off of solvent residues still present in the ; lacquer, the cracking or at least the formation of cracks in the layer to be structured i5 stimulated. The tempe-rature should be as high as possible and be at any rate above the flow limit d the photolaoquer but on the other hand may not be so high that as a result of this a fur-, .. .
ther "cross linking" of the photolaoquer is produced and hence the solubility thereof in an associated solvent is reduced.
Bow great the importance of the quality of the surface of the substrate on which the photolaoquer layer and the layer to be structured as provided is for I the yield of perfectly and fully structured layers, ''1 appears fron the following table and from Fig. 2. The ~ ' surface of the substrate should have such a quality that the phDtoiacquer'layer'does'not readily adhere to it. ' When'an SiO2 layer'was formed on a silicon substrate '~
-1 by thermQl oxidation, the yield was much better than .::. ,~ .
~ 7 '~ ' :
: ;
-.. ,, . , , - - ~ ~ . . : . ,. - ,. , ... . . . .: ... . ~.
PHD. 74.130.
10466~8 whRn, for example , a chrcmiunrnickel layer was provided on the substrate as a supporting layer for the photo-lacquer layer and the layer to be structured. -The fav~urable effects when using an SiO2 layer as a supporting layer also beoome apparent from the Example in which a chromium~nickel layer on the substrate was covered with a further SiO2 layer which in turn then farmEd the supportin~ layer for the photolaoquer layer and the layer to be structured. -~
Surface of the substrate Yield (%) silioon substrate having SiO2 supp~rting layer 98 silioon substrate having chromiumr ;I nickel supporting layer (0.1 /um) 45 silicon substrate having a chrcmiumr nickel intermediate layer (0.1 ~ ) and an SiO2 supporting layer (0.1 ~ ) 96.
¦ After the temperature treatment of the substrate 1 having the photolaoquer layer 3 and the layer 4 to be , ~ .
~;j 20 structured, the substrate is dipped in a solvent which dis-, } solve~ the photolaoquer. Su~h a solvent may be, for example, acetone. As a result of diffusion through the layer 4 to be structured, the solvent dissolves the phctD-lacquer present below the layer and causes it to ~well up.
The treatment can be acaelerated by ultrasanic effects.
e swelling phL~olacquer 3 causes the parts of the ~ `~
~; - 8 -. ; ' ' .~' ~ . .
~. 74.130. '~ -~04664t3 the layer 4 to be structured present thereon to be re~
maved, the renaining parts of the layer 4 to be struc*ured '' remaining on the substrate l having the supporting layer 2 after the ccmplete re val of the photolacquer (Fig. lc).
According to the principle described, multi-layers can also be structured which are built up from layers of different materials, for example, an insulating material and a material for oanductor trac~s. Such multi-layers are of importance, for exa~ple, for the oonstruc-' 10 tion of integrated magnetic mem~ries.
Fig. 3a is a cross-sectional view of a sub-strate 1 having a supporting layer 2, in this case in the fonm of a magnetic layer of FeSi, a photolacquer layer 3 covering the supporting layer 2 partly, an SiO2 ~ ' layer 4 provided by cathode sputtering and an alumLnium '~ layer S provided on said SiO2 layer 4 by cathode sputter-ing. After removing the photolaoquer layer 3, the sub- ;~
~ strate l covered with a double layer having the sueport-;1 ing layer 2, the SiO2 layer'4 and the aluminium layer 5 is obtained as is shown in Fig. 3b. These suocessive ' layers shown in Fig. 3b can now be provided again with an insulating layer and a layer'of conductor tradks; the stage shcwn in Fig. 3c is then'obtained, in which on the'substrate l with the first layer structure 4 and 5 25' a further pb~tolacqyer layer 33 is provided and a further SiO2 layer'44 and a ~urthe~'aluminium layer 55 are pro, vided by cathode sFuttering. After removing the photo~
j~.~ . ~ . .
, 1~ .
PHD. 74.130.
~0466~8 laoquer layer 33 the substrate 1 with the supporting layer 2 and the double layer structures 4,5 and 44, 55 is obtained as is shcwn in Fig. 3d. A third SiO2-layer 444 as an insulating layer (Fig. 3e) may be pr~vided on said m~ltiple-structured successive layers in a further process step by cathode sputtering, which insulating layer may then be provided, for exa~ple by electroless plating, with a magnetic c wering layer, for example, of nickel-iron (Fig. 3f). The magnetic coupling between the magnetic supporting layer 2 and the magnetic covering layer 6 is not shcwn in the fig~res.
The steepness of the edges of the structured photolacquer layer is of great importance in the me*hDd described; in addition the photolaoquer layer should show sides w~ich are rounded off as little as possible. For `1 example, a thermal treat~.ent of a photolaoquer layer .
prior to providing the layer to be structured results in flattening of the angle of inclination of the edges and in rounding of the sides.
I 20 Fig. 4 shows the yield of perfectly and fully structured thin layers, (solid line) and the angle of I the edges as a function of the baking temperature of .~ the lacquer mask (broken line).
,1 ' .
, : ' 1': .. :
- 10 - ' ' 1 ' ;
:.1 i
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of structuring thin layers in which the layer to be structured is provided on a substrate masked locally by a photolacquer layer and is removed again partly by removing the photolacquer layer, characterized in that a layer is provided directly on the substrate as a supporting layer for the photolacquer layer and for the thin layer to be structured, with respect to which support-ing layer the photolacquer, in the subsequent thermal treatment, has only a small adhesive capacity and that the substrate, after being provided with the thin layer to be structured, is heated in a temperature range such that the chemical reaction capacity of the photolacquer is just not yet detrimentally influenced and that the photolacquer layer is removed.
2. A method as claimed in Claim 1, characterized in that SiO2 is used as a material for the supporting layer.
3. A method as claimed in Claim 1, characterized in that aluminium is used as a material for the supporting layer.
4. A method as claimed in Claim 1, characterized in that a magnetic material is used as a material for the supporting layer.
5. A method as claimed in Claim 1, characterized in that the heating is carried out in a temperature range of 100 - 200°C.
6. A method as claimed in Claim 1, characterized in that the layer to be structured is provided in a thickness of 1 - 3 µm.
7. A method as claimed in Claim 6, characterized in that the layer to be structured is provided on the sub-strate by cathode sputtering.
8. A method as claimed in Claim 6, characterized in that the layer to be structured is provided on the sub-strate by vapour deposition.
9. A method as claimed in Claim 1, characterized in that the layer to be structured is provided as a multi-layer.
10. A method as claimed in Claim 1, 2 or 3, charac-terized in that the photolacquer layer is provided in a thickness which exceeds the thickness of the layer to be structured.
11. A method as claimed in Claim 1, characterized in that the photolacquer layer locally masking the substrate is designed with steep edges.
12. A method as claimed in Claim 1, characterized in that a metal or an alloy is used for the layer to be structured.
13. A method as claimed in Claim 1, characterized in that an oxide is used for the layer to be structured.
14. A method as claimed in Claim 1, characterized in that a nitride is used for the layer to be structured.
15. A method as claimed in Claim 1, characterized in that a magnetic material is used for the layer to be structured.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742436568 DE2436568C3 (en) | 1974-07-30 | Process for structuring thin layers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1046648A true CA1046648A (en) | 1979-01-16 |
Family
ID=5921886
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA232,152A Expired CA1046648A (en) | 1974-07-30 | 1975-07-24 | Method of structuring thin layers |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5140770A (en) |
| CA (1) | CA1046648A (en) |
| FR (1) | FR2280717A1 (en) |
| GB (1) | GB1512029A (en) |
| NL (1) | NL7508955A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52107199U (en) * | 1977-02-17 | 1977-08-15 | ||
| JPH0459523A (en) * | 1990-06-29 | 1992-02-26 | Toa Tsushin Kogyo Kk | Vertical feeding conduit for lamination piece |
| DE102004034418B4 (en) * | 2004-07-15 | 2009-06-25 | Schott Ag | Process for producing structured optical filter layers on substrates |
-
1975
- 1975-07-24 CA CA232,152A patent/CA1046648A/en not_active Expired
- 1975-07-25 GB GB3118575A patent/GB1512029A/en not_active Expired
- 1975-07-26 JP JP9072875A patent/JPS5140770A/en active Pending
- 1975-07-28 NL NL7508955A patent/NL7508955A/en not_active Application Discontinuation
- 1975-07-29 FR FR7523629A patent/FR2280717A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5140770A (en) | 1976-04-05 |
| DE2436568B2 (en) | 1977-07-07 |
| NL7508955A (en) | 1976-02-03 |
| DE2436568A1 (en) | 1976-02-12 |
| GB1512029A (en) | 1978-05-24 |
| FR2280717B1 (en) | 1980-06-27 |
| FR2280717A1 (en) | 1976-02-27 |
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