Etching circuit boards

J ¢5 S O.

<img file="AU3664584A_D0001.tif" />

<img file="AU3664584A_D0002.tif" />

<img file="AU3664584A_D0003.tif" />

<img file="AU3664584A_D0004.tif" />

<img file="AU3664584A_D0005.tif" />

<img file="AU3664584A_D0006.tif" />

<img file="AU3664584A_D0007.tif" />

” - W · O'- ·

SSfiLEN/T OFFICE patent office z¢// ’c* (J·

PATENTS ACT 1952 hereby apply s

PATENT OF

<img file="AU3664584A_D0008.tif" />

s*

COMMONWEALTH OF AUSTRALIA

APPLICATION FOR A PATENT

I, WALTER HOLZER of Drosteweg 19, D-7758, Meersburg, West Germany, for the grant of a patent for an invention entitled:

ETCHING CIRCUIT BOARDS which is described in the accompanying Complete Specification.

This application is a Convention Application and is based on the application for a patent or similar protection made in West _ Germain/ on December 13, 1983) numbered P 33 45 050.1, by the said WALTER HOLZER.

O C «' O &amp; ?

t&gt; e&gt;

Φ &lt;·» V b

My address for service is care of:B. W. NORMAN &amp; ASSOCIATES, Suite 3615, Australia Square, Sydney, Australia, Patent Attorneys. ^r· · · - &lt; . .

DATED this 13th day of December, 1984.

WALTER HOLZER f E»SS» fe VU'C J m .. '4c • r««c&lt;r.„

Fellow, Institute of Patent Attorneys of Australis of B. W. NORMAN &amp; ASSOCIATES

FEE: $225

TO: The Commissioner of Patents,

Canberra, A.C.T.

o

.. 1 i - V'

Name (s) of _ϋ Applicant(s) . Title

Name (s) and address(e&amp;l of person(s) «&gt; smaking . Country,filing : » m date and name © ft itS ’ . &lt;,a» «_of Applicant (s) ; _e*₀°%for the or ° “^'each basic &amp;pp 1 i c 8. ΐΰ Q Γ» •dG er . &amp; C fc

-Λ.

&gt;* to &amp;

«.·» ^&amp;S'**2Naine(s) and 4^· address (es) of the or each actual inventor

See reverse side of this form for guidance in corrtpleting this part

Australia Patent Declaration worm

Forms 7 and 8

AUSTRALIA

Patents Act 1952

DECLARATION IN SUPPORT OF A CONVENTION OR NON-CONVENTION APPLICATION FOR A PATENT OR PATENT OB' ADDITION

In support of the application marie by ΗΆΤ.τκρ HOLZER, for a patent for an . invention entitled.

_-----------------------, —.,, ..... ... —

—...........-____________ etohtng QTPCiTT-p ηοΑΡη.ς·'______._____________

I /-We .WALTER HOLZER of DROSTEWEG 19, D-7758 MEERSBURG, -jaESHL-GERMANY...............:

do

2.

3.

4.

5.

solemnly and sincerely declare as follows:I am/w®~art© the applicant4»·) for the patent, -&amp;&amp;

-the—abovemsRbi-SR&amp;d—appi-icRR-t fee—raake-^teh'ls.......dee4r&amp;jeabieR—i-feo—be-ha-M.

The basic application (e·) as defined by Section 141 of the Act was/wese made in the following country ©¥—on the following date(-&amp;4 by the following applicant's-) namely:by THE SAID WALTER HOLZER in_______________________ on £E£1EMBER L1 „19_

The said basic application (-&amp;) was/wete the first application^ made in a Convention country in respect of the invention the subject of the application.

The actual inventor (-β·)* of the said invention is/«R&amp;

.THE SAID WALTER HOLZER

The facts upon which the applicant(s) is/are entitled to make this application are as follows :-

<img file="AU3664584A_D0009.tif" />

<img file="AU3664584A_D0010.tif" />

g (11) AU-A-366A5/8A

ETCHING CIRCUIT GOAR&amp;S

WALTER HOLZER

36645/84

3345050

20.6.85

H05K 3/07 ;wo

Claim (22) 13*12.84 (32) 13.12.83 (33) DE (24) 13.12.83

A method of etching circuit boards or the . imwtersion in a tank of etching solution, characterised the etching solution is supplied with kinetic energy swirling action of a circulation pump.

S'

2.

immersion in solution is said board is characterised „ etching tank, that said originating electrolyte \ weight' of .

*73/1 like by in that by the like by method of etching circuit boards or the etching solution, characterised in that the etching regenerated and that corroded copper derived from precipitated in ah electrolytic cell.

method of etching of circuit boards of the like, ί in that an electrolytic cell is connected to an manner of communicating tanks, in such a way maintained by the thermodynamic current cell and by the gas bubbles rising in the in the cell is in the and additionally by the diminution of the specific the electrolyte following depletion of the copper

.../2

17 kJ

<img file="AU3664584A_D0011.tif" />

<img file="AU3664584A_D0012.tif" />

<img file="AU3664584A_D0013.tif" />

<img file="AU3664584A_D0014.tif" />

<img file="AU3664584A_D0015.tif" />

-36645/84

<img file="AU3664584A_D0016.tif" />

cwponent of said board; whereby a flow circuit of the electrolyte arises, which is regulated in such a way that it draws electrolyte from the electrolytic cell out of the etching tank through an aperture and the electrolyte flows back into the etching tank through a reflux aperture.

<img file="AU3664584A_D0017.tif" />

IL . &gt;

•C

FEE: $225 TO;

WALTER HOLZER

<img file="AU3664584A_D0018.tif" />

I * ί iwifc ' . _ ... I ’« ' · »

Fellow, Institute of Patent Attorneys' of Australia of B. W. NORMAN &amp; ASSOCIATES

The Commissioner of Patents, Canberra# A. C.T.

<img file="AU3664584A_D0019.tif" />

FORM 10

COMMONWEALTH OF AUSTRALIA

PATENTS ACT 1952^

COMPLETE SPECIFICATION (ORIGINAL)

FOR OFFICE USE:

'A

Application

Class

Int. Class

Number:

Lodged:

Q

Q « « a ♦

** ♦ 0^ »» w « «ί»® : ,’Priority:

oa Ό

V. « * e »

Related « &lt;

O « »

j^mplete

Specification Lodged: Accepted: Published:

, _/ »#«* i·· urar gtmmmmiyMMi « »S

‘.«Name of Applicant

WALTER HOLZER ·**'.&lt;

® ♦ * * «♦ ·;·«Actress of Applicant

DROSTEWEG 19, D-7758 MEERSBURG, WEST GERMANY «I · « « &amp; 4 »

Actual inventor.

»«*««·s ·

WALTER HOLZER

Address for Service: B. W. Norman and Associates, Suite 3615, Australia Square, Sydney

ETCHING CIRCUIT BOARDS

Complete Specification for the Invention entitled:

The following statement is a full description of this invention, Including the best method of performing it known to me/w:— ^v

Vx_,) guidance. in completing this part 'Ί

-·ίίχ··

DECLARED at MEERSBURG this day of 6&lt;

<img file="AU3664584A_D0020.tif" />

This invention concerns a method and apparatus for the etching of circuit boards

Previous methods using spray etching were expensive and not suitable for small installations.

An object of the invention is to develop a method wi\th corresponding device for operation which etches reliably and ensures.

by trouble-free regeneration, that environmental problems arising, from the dumping of etching solution are avoided.

A particular interest of the invention is developing a method and operating' device in such a way that small installations can be established, where ecological regeneration of the etching solution is made possible by precipitation of the etched copper. A further object of the invention is to develop a method and operating device in such a way that a dependable and ecological immersion process is made available to the n © « ® &amp; c. ft ·» o ©oft ft ft V non-technician, which removal of all moving guarantees trouble-free operating parts and where ecological benefit achieved with the exclusive use of closed circuits.

Methods and devices of this type can be offered to non-technfoian in electronics shops, where amateur handymen by is the can ft ft * ό

O * ft ft ft &amp; ft V ft ft ft » have their circuit boards etched there and then, according to their own design and circuit.

exercise example solution

According comprises to the by the swirling in a dip tank.

the invention the solution to this introduction of kinetic energy, for of a circulating pump, to the etching

<img file="AU3664584A_D0021.tif" />

[).

t] id (· t,.

apparatus for the

So comparable to as to achieve greater that of spray etching, intensity with dip etching, kinetic energy is fed to the ig were expensive etching solution so that it strikes agains the circuit board to ?lop hes a method with reliably and at environmental

Lng solution are )n is developing a way that small [ical regeneration acipitation of the on is to develop a a dependable and 'ailable to the ee operating by •gica.l benefit is its.

C CiO cs ο ο o

O to ¢) © « be offered to the teur handymen can ao aen, according to o e# solution to this ;tic energy, for &gt;, to the etching —I create a rapid but thorough etching.

It is desirable that the etching solution is recyclable and that the corroded copper electrolytic cell, to avoid any means of ’ waste material, etching solution requires during electrolysis, both off from the electrolytic

Since oxygen is precipitated in on the environment and ammonia, of thebe resulting an by of an ammonia cal which accumulates gases are drained cell over the liquid level and fed to the etching solution by a water jet pump or injector, whereby the

'.J internal mixing of the gases with the etching medium effects an accelerated regeneration in the water jet pump.

For continuous use of the etching installation it is important that electrolytic cell etching tank, in the copper precipitation capacity is higher than order to avoid medium with copper. More copper what is fed to the etching medium of the the corrosion capacity over-enriching of the of the etching ought to be precipitated than in the etching tank.

So as to avoid a severe depletion of the copper content, it is important that when copper content per litre of etching electrolytic another value

In a pre-selectable minimal solution is reached the cell is switched off and switched on again is shown.

one embodiment of the invention this when is

SO /, fl « c· v ft

I

r

645/84 t

accomplished monitors the electrolytic . .. , ' x? x τ . ; x/ .

simply, in that a float designed as a sensor density of the etching solution, the etching solution reaches a cell is switched off by a contact so that when low limit, connected to the the the float.. The provision of a stabilizing zone in the etching circulation, not achieved by the intensive through-flow etching ifledium, is suggested as much for the measuring density as for the regular supply of etching solution electrolytic cell.

Another aspect of the invention embodies a medium of of to the the the method, which is independent from the type where copper is corroded from the circuit electrolyte cell without board,, whereby a continuous measured supply of or etching medium a pump or by other particular simple is effected by the electrolytic measuring embodiment of constructing an etching tank with communicating containers.

'1

The solution according to means.

of the method consists electrolytic cells this embodiment of as the invention is a common etching chamber and an tank, divided electrolytic by a cell;

partition into an this partition assume other functions also. The partition can be formed by may the required anode plate of the electrolytic cell, which has corresponding connecting apertures. In the lower part of the partition or anode plate are openings which allow the flow of etching medium into the electrolytic cell. In the upper parf of the partition or anode plate, but still below the liquid leVel,

<img file="AU3664584A_D0022.tif" />

Ϊ

I are other openings which enable the reflux of the etching medium out of the electrolytic cell into the etching tank

This arrangement leads to a circulation of the etching medium through the where the copper is deposited on the cathode.

continuous, slow electrolytic cell,

The flow arises on the one hand through the gas bubbles, formmed by the chemical reaction (ff'or example, oxygen and ammonia) and on the other hand through the thermo-electric flow, since the current necessary for precipitation of the copper and which is fed to the electrolytic cell is of considerable intensity. The current is supported by diminution of the copper content.by depositing on the cathode and the resulting diminution of the specific weight of the electrolyte. This arrangement is not only exeptionally simple and effective, but also despenses with the use of electrolyte pumps or other circulation apparatus.

Should the anode plate be formed as an insertable v 5 e c e

O ¢1.

Q ««

O V ft « Φ P partition, it is possible to match the intensity of the flow to the optimum conditions by size and arrangement of the connecting v ΰ ο o ft

V dis O ft ft holes and even to match the through-flow of the electrolytic cell optimally to the plant with holes of varying size.

conditions by replacing the anode plate

Since similar points of view apply to washing of the

Λ V © O' &amp; b a * r* ft o ft «« Oft

- « » ft ft © a corroded circuit boards as to etching itself, namely an intensive .··/ effect of the rinsing liquid on the surface of the circuit boards, it· is suggested to supply kinetic energy also in the rins ing tank bymeans of a rotary pump.

It xs also necessary for the rinsing cycle to be a closed system, to avoid external discharge of contaminated rinsing liquid.

The invention suggests the provision of one of more ionic exchangers in the rinsing cycle, which combine copper residue or ammonia drawn from the rinsing liquid. In this case, as it is a? closed system, a constant depletion of the drawn off contaminating substances is sufficient; it is also suggested to have the ionic exchangers situated

Q ¢. ft ft ft ft ftft ύ G &amp;

the rinsing agent to appropriately formed as rinsing tank, whereby the pump.

cassettes,

The ionic exchangers set into the chambers in circulate freely through the cassettes, goes directly to are the to the reflux .to the pump. Fixing or sealing of the ionic exchangers chambers of the rinsing tank proves unnecessary.

the in o ft ft ft

V ft ft ft ft ft ©0 aft ft

C SO the

The invention also suggests that tfye liquid level ..•'ί, .

i.take aperture rinsing agent is kept constant over the of the ionic exchangers. This prevents exchanger resins when the plant is not further improvement is switched off a way that drying in use o^ out of the ionic l! :

J:

that w^en the pump is the liquid level in the rinsing tank settles in such constaq/61y covered by fl - ^: actual rinsing tank is the ionic exchanger resin is liquid. When the pump is switched on the rinsing liquid is pumped out of the chamber filled and surrounding the ionic exchanger. As the rinsing liquid enters the top of the ionic exchanger there is a change in the level.

v 'fr &lt;

4.

promoting a flow through the ionic exchanger.

exchanger are made of

The invention further recommends cassettes are at least partly transparent and that they a material which undergoes a colour change when that the ionic saturated.

in the interests of a convenient, cost-saving device it is further suggested that all components are housed in one tank; these include etching chamber, electrolytic cell, rinsing chamber with ionic exchanger and pumps and power supply for the electrolytic cell.

Figure shows an embodiment of the invention.

to/'

Furthel optional features of the invention follow from the

<img file="AU3664584A_D0023.tif" />

illustration represents a terminates in and specification.

q-irculation pump 1, an injector 14 and a

Figure the lower side jet 9. The jet in the etching tank or the immersion tank 5;

is then forced circuit board 2 schematically of which is located the etching liquid through this jet 9 against in such, a way that the entire the surface of etching process is supported by a connection from certain kinetic energy. The injector 14 has its suction side 15 by a suction pipe 16 to suction aperture 17 which above the liquid level 4.

and ammonia of the etching terminates in an electrolytic cell

When regenerated the liberated oxygen solution is fed through well mixed, so is forced against the surface of the that the etching solution circuit board 2 w.j,th optimally regenerated effect with kinetic © ©» c © φ ©-bo a

OS’* β ΰ&gt;

vϋ ©

Ο Φ ΟΦο© ο , © _ο © » β ο *

ΰ «·¢, ©«5

¢.η * φ ' © φ « © φ

<img file="AU3664584A_D0024.tif" />

energy. In the electrolytic cell 3 the anode 8 is located (shown

I

Ό ck

Λ .

A

<img file="AU3664584A_D0025.tif" />

ί&gt; .. φ &lt;

• C Φ ft to e? to &amp;

β-b® B &amp;

® to to a w '© &lt; o « o 6&gt;5βο

P 9 o a &amp; t5 3(t

5&gt; g « « ·

O £ Φ 5t 9 &lt;.

&lt;s as the, partition between etching tank 5 and electrolytic cell 3) as is the cathode 31, which serves in a known fashion as precipitation of the' corroded copper. The cathode 31 is removable in the arrow direction 32 so as co prevent corrosion of the already precipitated copper during extended non-use of the unit, or to draw off the precipitated copper. ' ·- To corrode the circuit board 2 in the mount 30, .it suffices to insert it through the slot 25 and switch on one of the time switches 28.

11^' Following the etching process the mount 30 with circuit board 2 is introduced into the rinsing chamber 12 through the slot 27. Here, too, a circulation pump 29 provides a turbulent through-flow of the rinsing chamber with its pressure pipe 35 and jets 9. The reflux of the rinsing liquid results from both chambers 11 with their pressureless return flows 36 to the pump 29.

Ionic exchanger· cassettes 37 can be inserted in the chambers,, 11 and the circulating rinsing liquid flows back through them. The rinsing liquid enters the ionic exchanger cassettes 37 2q via, the supply aperture 38, flows through the ionic exchanger material 39 and returns to the pump 29 by the outlet 33, The ionic exchanger cassettes 37 are easily removable from the chambers 11/ so as to allow regeneration of the ionic exchanger material 39 following its saturation.

' During rinsing also an environmentally acceptable closed circuit is produced, from which no damaging waste products

<img file="AU3664584A_D0026.tif" />

pressure results ^s 36 to in the through ttes 37 changer

2m the :hanger ptable oducts through &gt;vides _a

The

<img file="AU3664584A_D0027.tif" />

Figure 1 shows how simply all necessary components of the a this lid 20.

by a excha:

tank

The switch box both and this contains all switch circulation pump a way also contains switch box cassei rectifiers supplying the

Standi annode 8 is on plus and the cathode 31 on minus.

When the value.

the v is designed as a of the

This which m turn is float intak the value following reaches low electrolyte density balar and in tt its th rot the direc &amp; * © © w L ex chi at a

W « t, ci· is u ·- 4 W &lt;

U 4 &lt; VV 4

X.⁴ fl?

ove,‘f /7' 1 ionic electrolyte.

as the soon the float transformers sensor e a «j c the copper from that including electrical component the contact 19 opens sinks

<td colspan="2"> ~ cell 3)</td>

<td> shi on</td><td> as</td>

<td> s 31</td><td> is</td>

<td> Tosion</td><td> of</td>

<td> e of</td><td> the</td>

<td> t 3®,</td><td> it</td>

n one aredumped externally.

type of etching unit the « are housed in one tank 40, closed off may also be housed in the same time switches 28 for the timed switching of the and the circulation pump 29.

corresponding electrolytic cell with current.

the precipitation of electrolyte or the etching solution does not sink below a minimum provides automatic regulation of the density

In Figure 1 the sensor 18 which directly activates the contact 19, designed appropriately as © CX XXX t clt x OB;

interrupts the power supply to magnetic switch.

the electrolytic cell.

It is important that the float is not disturbed m function by the turbulent flow in the etching tank 5.

working example this is achieved in that the suction aperture of the pipe 34, through which the electrolyte flows back to the pump is located not in the floor but above it

A stabilizing zone is set up around the pipe 34 and this also helps to stabilize t

Λ &lt;,· t

Γ'&gt;

electrolyte flow through the electrolytic cell and through : Λ/ the ts of d off the aperture 7.

For trouble-free, improved functioning of the ionic : tank exchanger cassettes the invention suggests that, when the unit is both at a stand-still, that is when the circulation pump 29 is ί pump switched off, the stabilizing level 44 should be selected in such itains a way that the ionic exchanger material 3 9 ip, the ionic exchanger the cassettes 37 remains covered by liquid. Figure 2 shows this nd the stand-still condition.

1-0

Figure 3 shows the state of the rinsing chamber 12 &gt;m the dnimum when the pump 29 is switched on. In this case the level rises to

V. » · oV)®yflow 42 and the rinsing level pours into the intake 3 8 of the density id as a turn is as the llowing *ns and ionic exchangercassettes 37.

Through the pressureless reflux 36 the water in

This results intake 38 the ionic balance of to the in the chambers 11 a change in now sinks to the reflux level 43.

pressure from the height of the reflux level 43, which determines the flow exchanger cassettes. The partitions 41 prevent liquid between the overflow level 42 and the level of in the chambers 11.

in its

Excess rinsing liquid can, insofar as it does not flow

In the ture of he pump wo t

O ft 0 o itu

V ft ft U V * ft Q&gt;

ng zone :abilize through thd' ionic directly into the exchanger cassettes exchanger cassettes, exit by the intake space between the chambers 11 and the ionic

37i

<img file="AU3664584A_D0028.tif" />