Background technology
The perforation conducting of general traditional printed-wiring board (PWB) is still uses metallized six steps of hole wall, makes chemical copper be deposited on hole wall, reaches the purpose of whole hole conducting.These six step divisions are as follows: step 1: smoothing agent
Because glass fibre and resin in the former material substrate of printed-wiring board (PWB) have faint electric charge, can influence the absorption of activator, and cause micropore to break the phenomenon of (microvoid), therefore must use the polarity that smoothing agent is adjusted substrate, activator can evenly be adsorbed, and this step has clean surface fingerprint or smeary effect.Step 2: microetch is handled
Mainly be the microetch copper face effect that utilizes dioxysulfateization or Sodium Persulfate, so that remove the smoothing agent be adsorbed on the copper face, avoid the decortication phenomenon that causes because of smoothing agent is residual, this step has the effect that improves the sedimentary sticking power of chemical copper.Step 3: pre-activator
Activate base material in advance, in order to the absorption of activator, it is contaminated to prolong the work-ing life of activator to reduce activator.Step 4: activator
Activator is divided into colloidal palladium activator and two kinds of series of ionic palladium activator; The colloidal palladium activator is that Shipley company delivers for No. 3011920 in United States Patent (USP) in 1961, this kind colloidal palladium activator is with tin protochloride Palladous chloride to be reduced into the atom palladium, and with excessive tin protochloride and hydrochloric acid the atom palladium is surrounded and to form stabile colloid, after this kind palladium colloid is adsorbed on hole wall, utilizes accelerator to remove peripheral tin protochloride again and the palladium atom is spilt and the heavy copper reaction of catalytic chemistry copper groove.
The ionic palladium activator be Sehering in nineteen ninety United States Patent (USP) deliver for No. 4966786, this kind activator is with organic misfit agent palladium ion to be combined into the misfit body, and hole wall in basic solution, adsorbing, with reductive agent palladium ion is reduced into the palladium atom again so that the heavy copper reaction of catalytic chemistry copper groove.Step 5: accelerator and reductive agent
Mainly, the palladium atom is exposed with catalytic chemistry copper react at the palladium ion of peripheral tin protochloride that divests the acidoid palladium or reduction alkalescence palladium misfit body.Step 6: chemical copper deposition
Mainly be to make hole wall produce the copper deposition and the purpose that reaches conduction; The main component of general chemical copper is that copper has copper sulfate, cupric chloride from the source; Reductive agent is formaldehyde, dimethyamine borane; The misfit agent is Seignette salt, ethylenediamine tetraacetic acid (EDTA); It is sodium hydroxide, potassium hydroxide that pH value is adjusted agent; And specific additive.
The multiple-plate manufacturing of traditional printed wiring, need before beginning, above-mentioned steps add the de-smear processing procedure, this be since when boring because of high speed rotating produce high temperature with the resin melt coating on internal layer copper, these resins that are coated on the internal layer copper must be removed with bulk, oxidation step, and remove residual oxygenant with reduction step, in order to avoid influence the perforation conducting processing procedure of back.
Traditional perforation conducting processing procedure, because of adjusting the effect of substrate polar, activator can be adsorbed on the hole wall, as strengthening smoothing agent by smoothing agent, then the absorption of activator can be strengthened and is more even, but can make its more difficult washing because of strengthening smoothing agent, promptly have the danger that the residual plate face of smoothing agent causes having heavy copper decortication, as weaken smoothing agent, then there is activator to adsorb very little or uneven worry, therefore, the selection of smoothing agent and control become tradition perforation conducting processing procedure, promptly metallized one puzzlement greatly.
Summary of the invention
The purpose of this invention is to provide the metallized method of a kind of nonmetallic surface, this method is the smoothing agent step of removing in the traditional method, uses the puzzlement that smoothing agent was produced to solve; This method also is applied to colloidal palladium activator and ionic palladium activator in the treatment step simultaneously, utilizes both to have the heavy copper response characteristic of catalytic chemistry copper groove, and makes heavy copper more even, and this method is controlled easily, reliability is good, and this method may further comprise the steps:
1, microetch is handled
2, the pre-activation treatment of colloidal palladium
3, colloidal palladium activation treatment
4, the pre-activation treatment of ionic palladium
5, ionic palladium activation treatment
6, reduction is handled
7, chemical copper depositing treatment
With the heavy copper of the resulting Nonconductor surface of the present invention's method, cover evenly, backlight good.
Concrete steps of the present invention are as follows in regular turn:
1, microetch is handled
The microetch treatment step comprises and will have the wiring board of copper or copper alloy surface, sulfuric acid and hydrogen peroxide or Sodium Persulfate and the processing of the vitriolic aqueous solution with effective dose, make the copper surface sting erosion 20~50 microinchs, under 25~45 ℃ temperature, carried out 0.5~2.0 minute usually; Wiring board after the microetch usually must be through the washing of twice adverse current to remove the micro-etching agent that the surface is had;
2, the pre-activation treatment of colloidal palladium
The pre-activation treatment of colloidal palladium is to be made into tank liquor with colloidal palladium activator preparation salt, and this tank liquor only contains preparation salt and do not contain colloidal palladium, and the wiring board after microetch is handled at room temperature soaked 0.5~1.0 minute in this tank liquor;
3, colloidal palladium activation treatment
Wiring board must not washed after pre-activation treatment, directly immerses in the colloidal palladium activator, under 40~50 ℃ temperature, soaks after 4~6 minutes, activates tank liquor through the washing of twice adverse current to remove the surperficial colloidal palladium that is had;
4, the pre-activation treatment of ionic palladium
Be made into tank liquor with ionic palladium activator preparation salt, only contain preparation salt in the tank liquor, do not contain ionic palladium, the wiring board after the colloidal palladium activation treatment at room temperature soaked in this tank liquor 0.5~1.0 minute;
5, ionic palladium activation treatment
Wiring board must not washed after the pre-activation treatment of ionic palladium, directly immerses the ionic palladium activator, under 40~50 ℃ temperature, soaks after 4~6 minutes, activates tank liquor through the washing of twice adverse current to remove the surperficial ionic palladium that is had;
6, reduction is handled
Wiring board after the ionic palladium activation treatment immerses the reductive agent groove of dimethyamine borane and sodium hydroxide, under 30~40 ℃ temperature, carry out 4~6 minutes reduction reaction, make ionic palladium be reduced into the palladium atom after, through twice adverse current washing to remove the reductive agent tank liquor of surperficial contained band;
7, chemical copper depositing treatment
The chemical copper depositing treatment adopts general general chemical copper, and its copper ion source is copper sulfate, cupric chloride; Reductive agent is formaldehyde, dimethyamine borane; The misfit agent is Seignette salt, ethylenediamine tetraacetic acid (EDTA); It is sodium hydroxide, potassium hydroxide that pH value is adjusted agent; And specific additive; Wiring board after reduction is handled immerses the chemical copper groove, under 25~35 ℃ temperature, till heavy copper to the hole wall that carried out 10~20 minutes is covered by heavy copper fully.
One of advantage of the present invention is not contain the smoothing agent step, has exempted and has used the puzzlement that smoothing agent brought; Another advantage of the present invention is to adopt colloidal palladium and ionic palladium activator simultaneously, utilizes its heavy copper response characteristic with catalytic chemistry copper groove, can operate low containing under the palladium concentration, and get the heavy copper of uniform hole wall.
If the space is limited or be subject to existing machinery equipment, pre-activation treatment two steps of colloidal palladium activation treatment in the method for the present invention and ionic palladium, one of them can be omitted as one sees fit or two steps all can be omitted, also can obtain identical heavy copper effect, but, the work-ing life of colloidal palladium and ionic palladium activator groove, because of not implementing pre-activation treatment step, and can so shorten, now its relevant processing procedure of simplifying is described below: one, the step of the processing procedure of the Nonconductor surface metallization of the pre-activation treatment of omission colloidal palladium:
1. microetch is handled
Same as described above, do not repeat to give unnecessary details so omit;
2. colloidal palladium activation treatment
Wiring board directly immerses in the colloidal palladium activator after microetch processing and the washing of twice adverse current,
Under 40~50 ℃ temperature, soak after 4~6 minutes, wash through the twice adverse current
To remove the colloidal palladium activation tank liquor that the surface is had;
3. the pre-activation treatment of ionic palladium
4. ionic palladium activation treatment
5. reduction is handled
6. chemical copper depositing treatment
3rd, 4,5,6 steps are identical with the aforementioned processing program, do not repeat to give unnecessary details so omit.Two, the step of the processing procedure of the Nonconductor surface metallization of the pre-activation treatment of omission ionic palladium:
1. microetch is handled
2. the pre-activation treatment of colloidal palladium
3. colloidal palladium activation treatment
1st, 2,3 steps are identical with the aforementioned processing program, do not repeat to give unnecessary details so omit;
4. ionic palladium activation treatment
Wiring board directly immerses ionic palladium and lives after colloidal palladium activation treatment and the washing of twice adverse current
Change agent, under 40~50 ℃ temperature, soaked 4~6 minutes, through the twice adverse current
The ionic palladium activation tank liquor that washing is had to remove the surface;
5. reduction is handled
6. chemical copper depositing treatment
5th, 6 steps are identical with the aforementioned processing program, do not repeat to give unnecessary details so omit.Three, the step of the processing procedure of the Nonconductor surface metallization of omission colloidal palladium, the pre-activation treatment of ionic palladium:
1. microetch is handled
This step is identical with the aforementioned processing program, does not repeat to give unnecessary details so omit;
2. colloidal palladium activation treatment
Wiring board directly immerses in the colloidal palladium activator after microetch processing and the washing of twice adverse current,
Under 40~50 ℃ temperature, soak after 4~6 minutes, wash through the twice adverse current
To remove the colloidal palladium activation tank liquor that the surface is had;
3. ionic palladium activation treatment
Wiring board directly immerses ionic palladium and lives after colloidal palladium activation treatment and the washing of twice adverse current
Change agent, under 40~50 ℃ temperature, soak after 4~6 minutes, contrary through twice
Flowing water is washed to remove the ionic palladium activation tank liquor that the surface is had;
4. reduction is handled
5. chemical copper depositing treatment
4th, 5 steps are identical with the aforementioned processing program, do not repeat to give unnecessary details so omit.
Be specific embodiments of the invention below, this embodiment for explanation, is not to be used for limiting the scope of the invention only, in following each embodiment, test piece is the wiring boards that are drilled with different big apertures, through brushing and with the slag fabrication process mistake of generally removing photoresist, again it is cut off into 5cm * 5cm and makes.
Embodiment one:
Get the above-mentioned wiring board test piece of a slice, handle through the following step in regular turn: step 1: immerse and contain in the Sodium Persulfate and the vitriolic aqueous solution, under 30 ℃, soak 1.5
After minute, take out fully washing.Step 2: immerse and contain in the aqueous solution of pre-activator, promptly contain the aqueous solution of the acid-salt of chlorion
In, under 24 ℃, soak after 1 minute, take out.Step 3: immerse and contain in the aqueous solution of colloidal palladium activator, promptly contain tin protochloride and palladium colloidal
In the aqueous solution, under 45 ℃, soak after 5 minutes, take out fully washing.Step 4: immerse and contain in the aqueous solution of pre-preserved material, promptly contain in the alkaline aqueous solution of sodium hydroxide,
After soaking 1 minute under 24 ℃, take out.Step 5: immerse and contain in the aqueous solution of ionic palladium activator, promptly contain the water of palladium ion and misfit thing
In the solution, under 45 ℃, soak after 5 minutes, take out fully washing.Step 6: immerse and to contain in the aqueous solution of reductive agent, promptly contain sodium hydroxide and dimethyamine borane
In the aqueous solution, under 35 ℃, soak after 5 minutes, take out fully washing.Step 7: immerse and to contain in the solution of chemical copper, promptly contain copper sulfate, Seignette salt, formaldehyde and
In the aqueous solution of sodium hydroxide, under 30 ℃, soak after 10~20 minutes, get
Go out abundant washing and drying.
The test piece of handling through above-mentioned steps in regular turn, the chemical copper uniform deposition is on copper face and hole wall, and good tack arranged, one row's aperture transversal (Microsection), and wear into that 1.5cm is long, 0.3cm is wide and 0.6cm is high, contain the slice of half hole wall, place microscopically to check that with 50 times of magnifications its hole wall sinks the copper situation, and measure its heavy copper integrity with printing opacity, and be complete black after measured, hole wall is fully by heavy copper covering.
Embodiment two
Repeat other six steps of one li all except step 2 of embodiment.The gained test piece is through looking into, and the chemical copper deposition is also even, tack is good; Through its transparence of cut sections for microscopic examination, be determined as complete deceiving, hole wall is covered by heavy copper fully.
Embodiment three
Repeat other six steps of one li all except step 4 of embodiment.The gained test piece is through looking into, and the chemical copper deposition is even, tack is good; Through its transparence of cut sections for microscopic examination, be determined as complete deceiving, hole wall is covered by heavy copper fully.
Embodiment four
Repeat other five steps of one li all except step 2 and step 4 of embodiment.The gained test piece is through looking into, and the chemical copper deposition is even, tack is good; Through its transparence of cut sections for microscopic examination, be determined as complete deceiving, hole wall is covered by heavy copper fully.