CN102108537A

CN102108537A - Solar battery electroplating pretreatement process

Info

Publication number: CN102108537A
Application number: CN 201110031756
Authority: CN
Inventors: 陈亮
Original assignee: Changzhou Trina Solar Energy Co Ltd
Current assignee: Changzhou Trina Solar Energy Co Ltd
Priority date: 2011-01-29
Filing date: 2011-01-29
Publication date: 2011-06-29

Abstract

The invention relates to a solar battery electroplating pretreatment process, which comprises the following steps of: preparing a battery plate to be electroplated; treating the battery plate to be electroplated in activation solution at room temperature for 30 to 300 seconds; and cleaning the activated battery plate with deionized water for a subsequent nickel plating process. The activation solution is prepared by mixing hydrofluoric acid (HF), ammonium fluoride (NH4F) and palladium chloride (PdCl2), wherein the concentration of HF is 50-200ml/L, the concentration of NH4F is 10-100g/L, and the concentration of PdCl2 is 0.1-1g/L. By a method for adding chemical treatment before electroplating, several high-activity elements can be deposited in an area to be subjected to nickel plating on the surface of a silicon wafer, the activity of the surface of the silicon wafer is improved, and the elements have the function of nucleating center, and promote better formation of nickel to form a high-quality nickel coating during nickel plating; meanwhile, through the invention, the damage caused by a laser doping process can be relieved to some extent.

Description

A kind of solar cell electroplating pretreatment process

Technical field

The present invention relates to a kind of solar cell electroplating pretreatment process.

Background technology

Electroplating technology has been applied in the electrode manufacture craft of solar cell at present, and its major advantage is graph thinning and autoregistration; Graph thinning is meant that general electroplating cell all selects adulterated technology to combine with laser, and the electrode width of its making is generally at 20-50um, and the electrode width of traditional silk-screened is at 80-150um; Electroplating technology is a kind of self aligned technology simultaneously, does not need to carry out print register, has improved the accuracy of electrode.Therefore the combination of plating and laser technology is one of developing direction of high-efficiency battery.

Electroplating technology needs to plate one deck nickel earlier as Seed Layer usually, and then deposit metal electrodes, and metal electrode can make copper or silver; Nickel layer has two purposes as Seed Layer, and the one, form nickel silicon alloy and reduce contact resistance, be exactly as the blocking layer in addition, prevent that electrode metal from entering PN junction battery performance is impacted.Therefore, forming the high-quality nickel dam of one deck is the key of electroplating technology quality.

Summary of the invention

Technical problem to be solved by this invention is: obtain high-quality nickel layer.

The technical solution adopted for the present invention to solve the technical problems is: a kind of solar cell electroplating pretreatment process, at first be ready to electroplated battery sheet, and then the battery sheet is carried out activation treatment, concrete steps are as follows:

A. activated solution is equipped with:

Adopt hydrofluoric acid (HF)+ammonium fluoride (NH ₄F)+Palladous chloride (PdCl ₂) the mixed preparing activated solution,

Wherein HF concentration is 50～200ml/L;

NH ₄F concentration is 10～100g/L;

PdCl ₂Concentration is 0.1～1g/L;

B. adopt activated solution to treat the electroplating cell sheet and carry out activation treatment:

At ambient temperature, electroplated battery sheet is placed on processing 30-300 second in the activated solution, the battery sheet after the activation treatment is rinsed the back well with deionized water just can carry out follow-up nickel plating technology.

The invention has the beneficial effects as follows: the present invention is by increasing chemically treated way together before plating, can treat some highly active elements of nickel plating area deposition at silicon chip surface, promote the activity of silicon chip surface, these elements can be when nickel plating, play the effect of nucleation centre, impel nickel better to form, obtain high-quality nickel layer; The present invention simultaneously can also carry out to a certain degree removal effect to the damage of laser doping technology.

Description of drawings

The present invention is further described below in conjunction with drawings and Examples;

Fig. 1 is the nickel plating effect that does not have activating process;

Fig. 2 is the nickel plating effect after the employing activation treatment.

Embodiment

A kind of solar cell electroplating pretreatment process comprises the steps: at first to be ready to electroplated battery sheet, and electroplated battery sheet can be made by following method: surface wool manufacturing cleans; Surface diffusion N+ layer; Go PSG, edge etching; PECVD prepares surperficial SiN antireflective film; Back electrode, the printing of back of the body electric field; Back side sintering; Laser selective mixes and forms N++.

Then the battery sheet is carried out activation treatment:

A. activated solution is equipped with:

Activated solution by the HF+ weak oxidant (as NH ₄F)+activator is (as PdCl ₂) mixing solutions form, wherein the combination of HF and weak oxidant can also be played the effect of removing the silicon chip surface affected layer;

Wherein HF concentration is 50～200ml/L;

NH ₄F concentration is 10～100g/L;

PdCl ₂Concentration is 0.1～1g/L;

The proportioning of optimizing is:

Wherein HF concentration is 80～120ml/L;

NH ₄F concentration is 20～60g/L;

PdCl ₂Concentration is 0.5～1g/L.

Embodiment:

Silicon chip adopts the P type monocrystalline of 125cm, and resistivity is 1.0ohm/cm;

Concrete processing step is as follows:

Making herbs into wool: alkali making herbs into wool single face etching extent is 7um;

Diffusion: the tubular type diffusion, diffuse source is phosphorus oxychloride, the resistance of diffusion rear is 80ohm/sq;

Remove PSG, carve the limit: the RENA wet chemical process;

PECVD: flat-plate type PECVD equipment deposition SiN, the thickness of SiN is 80nm, specific refractory power is 2.05;

Silk screen printing: back electrode, back of the body electric field adopt the preparation of traditional silk-screened method, carry out back side sintering after the printing;

Laser is selected to mix: adopt laser to carry out selective doping on the SiN surface and handle, used doped source is the mixing solutions of phosphoric acid;

Activation treatment: adopt HF (100ml/L), NH4F (40g/L), the mixing solutions of PdCl2 (80mg/L) under the room temperature, was handled 60 seconds;

Electroplated electrode: adopt chemical nickel plating to power up silver plated method, the height of electroplated electrode is 9um, and width is 40um;

Annealing: form the nickel silicon alloy layer;

The battery performance result:

	Uoc(mV)	Jsc(A/cm2)	FF(％)	Eff.(％)
					No activating process	628	36.34	73.8	17.2
Activating process is arranged	630	37.02	78.9	18.1

Behind the activating process, 1. battery sheet nickel plating speed and homogeneity be improved significantly; 2. the contact resistance Rs of battery sheet has reduction, thereby has promoted battery efficiency; 3. the bonding strength of electroplated electrode promotes, and helps the lifting subassembly reliability again.By above 3 effect, the battery efficiency of electroplating solar cell is promoted, reach the target of high-efficiency low-cost solar battery.

Claims

1. solar cell electroplating pretreatment process, it is characterized in that: at first be ready to electroplated battery sheet, then the battery sheet carried out activation treatment, concrete steps are as follows:

A. activated solution is equipped with:

Wherein HF concentration is 50～200ml/L;

NH ₄F concentration is 10～100g/L;

PdCl ₂Concentration is 0.1～1g/L;

2. a kind of solar cell electroplating pretreatment process according to claim 1 is characterized in that: the described time of handling in activated solution is 60 seconds.

3. a kind of solar cell electroplating pretreatment process according to claim 1 is characterized in that:

Wherein HF concentration is 80～120ml/L;

NH ₄F concentration is 20～60g/L;

PdCl ₂Concentration is 0.5～1g/L.