CN1327501C - Selective laser back flow preparing method for flip-chip convex point - Google Patents
Selective laser back flow preparing method for flip-chip convex point Download PDFInfo
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- CN1327501C CN1327501C CNB2004100530409A CN200410053040A CN1327501C CN 1327501 C CN1327501 C CN 1327501C CN B2004100530409 A CNB2004100530409 A CN B2004100530409A CN 200410053040 A CN200410053040 A CN 200410053040A CN 1327501 C CN1327501 C CN 1327501C
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Abstract
The present invention relates to a selective laser back flow preparing method for flip chip convex points. A stenciling method and a selective laser back flow technology are combined to prepare the convex points of a flip chip. A metal matrix is arranged on a chip, soldering paste is filled in all holes arranged on the metal matrix, the laser is focalized in the holes of the metal matrix, and the soldering paste is back flown into the metal convex points under the action the laser. In the process of preparing all the convex points arranged on the flip chip point by point, the metal matrix maintains a contact state with the chip. The method of the present invention is suitable for preparing convex points by using various materials, and has the advantages of low cost, high speed of laser scanning, short single point forming time, high positioning accuracy of the convex point and free setting of salient point parameters. The present invention effectively avoids the phenomenon of device failure caused by overall heating, and is suitable for the encapsulation of some special devices, such as thermosensitive devices and optoelectronic devices.
Description
Technical field
That the present invention relates to is a kind of preparation method of flipchip-bumped, and particularly a kind of method that adopts the laser selective backflow to prepare flipchip-bumped belongs to the Electronic Packaging field that integrated circuit is made.
Background technology
The interior connection that flip chip technology (fct) allows area to arrange has advantages such as high I/O number, high density, high electrical property and high silicon chip utilance; And when the tin ball refluxed, the surface tension in the scolding tin was with the small misalignment of self-correcting chip, and this self-aligned characteristic is brought very high manufacturing assembling qualification rate.The stud bump making technology that adopts mainly contains at present: evaporation solder alloy, plating Bumping Technology, ailhead method, stencil methods, laser ball implanting etc.Galvanoplastic biggest advantage wherein is to accomplish smaller pitch (perhaps spacing), and its shortcoming is more time-consuming, and not every scolder all can be electroplated; The basic technology of stencil methods is: at first, wafer is placed on the pallet, is sent to screen printer by conveyer belt; Then, be coated to soldering paste on the web plate after, all reference points are just searched by the video system of printing machine, at whole web plate cleaning surfaces ground wiping soldering paste, are injected in all perforates; At last, pallet and wafer send out from printing machine.Stencil methods does not need required expensive device of evaporation and accurate metal form, do not need to electroplate thick film photolithography technology essential in the Bumping Technology yet, can realize the stud bump making of all exits on the wafer simultaneously, this method technology is simple, easy to operate, be applicable to various salient point scolders, is considered to a kind of low-cost stud bump making technology.But the preparation method compares with other salient point, and the spacing that stencil methods prepares salient point is restricted, and is difficult to prepare the thin space salient point that other method can realize, its common spacing is 200 μ m～400 μ m.
Summary of the invention
The objective of the invention is at the deficiencies in the prior art, a kind of selective laser backflow preparation method of flipchip-bumped be provided, have with low cost, the advantage that the salient point forming quality is high.
For realizing such purpose, the present invention combines stencil methods and prepares the salient point of flip-chip with the selective laser technique of backflow, metal form is placed on the chip, soldering paste is inserted all perforates on the metal form, on the soldering paste of laser focusing in the metal form perforate, soldering paste is refluxed into salient point.Prepare in the process of all salient points on the flip-chip in pointwise, metal form and chip keep in touch.
Method of the present invention specifically comprises the steps:
(1) metal form is placed on the chip of salient point to be prepared, and the position of regulating metal form makes it aim at chip, apply soldering paste with scraper then, soldering paste is inserted in all perforates on the metal form.After soldering paste is inserted perforate, still keep metal form to contact with chip.Perforate centre distance minimum on the metal form is about 130 μ m.
(2) adopt the lasing light emitter of laser generator as the salient point preparation.The laser that laser generator produced, focuses in the perforate of metal form the about 15 μ m of laser facula radius via eyeglass deflection, the reflection of scanner after restrainting through standard.Soldering paste in the perforate refluxes into metal salient point under laser action, and in the perforate not by laser scanning to soldering paste still keep original form, therefore, in the laser reflux course, can bump size as requested determine the laser recirculation zone area in the perforate on the metal form.If adopt vibration mirror scanning device (galvanometric scanner), higher preparation speed (about 0.1S/ point) and better salient point reflux mass, the about 50 μ m of salient point minimum diameter will be obtained with dynamic focusing function.
(3) behind all salient points on laser has refluxed metal form, salient point has been welded under the scolder of chip on the metal (UBM, Under Ball Metal) fully, and this moment breaks away from metal form and chip will no longer influence the salient point size.Can there be residual soldering paste on the inwall of perforate and the chip on the metal form,, therefore, be easy to remove residual soldering paste on the chip by cleaning, and obtains high-quality chip bump thus because stencil methods usually uses water-soluble soldering paste to prepare chip bump.
Method of the present invention is applicable to multiple material preparation salient point, has the unexistent cost advantage of other method; Adopt the pointwise reflow process, laser scanning speed is fast, and the single-point curring time is short; Because laser scanner has higher resolution, salient point positioning accuracy height; The salient point parameter can freely be set, even also can prepare the salient point of different sizes on same chip.The present invention can effectively avoid the component failure phenomenon of being heated and causing because of the overall situation, especially is fit to some particular device encapsulation, as temperature-sensitive device, photoelectric device.
Description of drawings
Fig. 1 is the selective laser backflow preparation method schematic diagram of flipchip-bumped of the present invention.
Among the figure, 1 is laser generator, and 2 is the X-axis motor and the deflection eyeglass of sweep mechanism, and 3 is the y-axis motor and the deflection eyeglass of sweep mechanism, and 4 is metal form, and 5 is chip, and 6 is soldering paste (before refluxing), and 7 is salient point (back of refluxing).
Embodiment
Below in conjunction with accompanying drawing technical scheme of the present invention is further described.
The selective laser backflow preparation method operation principle of flipchip-bumped of the present invention as shown in Figure 1.Related technical process is as follows:
A) metal form is aimed at and the soldering paste coating
B) selective laser refluxes
Adopt the lasing light emitter of neodymium-doped yttrium-aluminum garnet (Nd:YAG) laser as the salient point preparation.Laser that laser generator 1 is produced through accurate bundle after, respectively after the deflection of the Y-axis deflection eyeglass of scanner, X-axis deflection eyeglass, reflection, focus in the perforate of metal form 4 the about 15 μ m of laser facula radius again.Soldering paste 6 in the perforate refluxes into metal salient point 7 under laser action, and in the perforate not by laser scanning to soldering paste 6 still keep original form.Therefore, in the laser reflux course, can bump size as requested determine the laser recirculation zone area in the perforate on the metal form 4.Laser scanner comprises the y-axis motor and the deflection eyeglass 3 of the X-axis motor of sweep mechanism and deflection eyeglass 2, sweep mechanism.If adopt vibration mirror scanning device to prepare the salient point 7 of flip-chip, can further improve salient point backflow efficient (reaching about 0.1S/ point), and obtain better salient point 7 reflux mass, the about 50 μ m of salient point minimum diameter with dynamic focusing function;
C) clean chip
Behind all salient points 7 on laser has refluxed metal form 4, salient point 7 has been welded on the UBM of chip 5 fully, and break away from metal form 4 this moment will no longer influence salient point 7 sizes with chip 5.Can there be residual non-irrigated cream 6 on the perforate inwall of metal form 4 and the chip 5, because stencil methods uses water-soluble soldering paste to prepare chip bump usually, therefore, be easy to remove residual soldering paste on the chip 5 by cleaning, and obtain high-quality chip bump 7 thus.
Claims (1)
1, a kind of selective laser backflow preparation method of flipchip-bumped is characterized in that comprising the steps:
1) metal form (4) is placed on the chip (5) of salient point to be prepared, and the position of regulating metal form (4) is aimed at chip (5), then soldering paste (6) is inserted in all perforates on the metal form (4), keep metal form (4) to contact with chip (5), the perforate centre distance minimum on the metal form (4) is 130 μ m;
2) adopt the lasing light emitter of laser generator (1) as the salient point preparation, after the laser that laser generator (1) is produced is restrainted through standard, again through eyeglass deflection, the reflection of scanner, focus in the perforate of metal form (4), laser facula radius 15 μ m, soldering paste in the perforate refluxes into metal salient point (7) under laser action, and in the perforate not by laser scanning to soldering paste (6) still keep original form, in the laser reflux course, bump size decision metal form (4) is as requested gone up the laser recirculation zone area in the perforate;
3) behind all salient points (7) on laser has refluxed metal form (4), break away from metal form (4) and chip (5), remove the residual soldering paste (6) on the chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100530409A CN1327501C (en) | 2004-07-22 | 2004-07-22 | Selective laser back flow preparing method for flip-chip convex point |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100530409A CN1327501C (en) | 2004-07-22 | 2004-07-22 | Selective laser back flow preparing method for flip-chip convex point |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1588634A CN1588634A (en) | 2005-03-02 |
| CN1327501C true CN1327501C (en) | 2007-07-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB2004100530409A Expired - Fee Related CN1327501C (en) | 2004-07-22 | 2004-07-22 | Selective laser back flow preparing method for flip-chip convex point |
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Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101457106B1 (en) * | 2007-11-19 | 2014-10-31 | 삼성전자주식회사 | In-line package apparatus and method |
| KR101387492B1 (en) * | 2007-11-26 | 2014-04-22 | 삼성전자주식회사 | A heating unit, a reflow apparatus and a reflow method |
| CN102315139B (en) * | 2011-09-07 | 2013-08-07 | 中国航天科技集团公司第九研究院第七七一研究所 | Technology of drop-out printing for manufacturing micron-sized salient point on wafer |
| CN103151275A (en) * | 2011-12-06 | 2013-06-12 | 北京大学深圳研究生院 | Manufacturing method for flip chip gold bumps |
| CN103769710A (en) * | 2014-01-23 | 2014-05-07 | 无锡江南计算技术研究所 | Manual scaling powder distribution method |
| US11069671B2 (en) * | 2018-03-23 | 2021-07-20 | Taiwan Semiconductor Manufacturing Company, Ltd. | Semiconductor package and method |
| CN108987287A (en) * | 2018-06-29 | 2018-12-11 | 南京矽邦半导体有限公司 | A kind of packaging method by biting alloy generation ball grid array after Reflow Soldering on pdm substrate |
| US11646293B2 (en) | 2020-07-22 | 2023-05-09 | Taiwan Semiconductor Manufacturing Co., Ltd. | Semiconductor structure and method |
| CN114515903A (en) * | 2022-03-04 | 2022-05-20 | 中国电子科技集团公司第三十八研究所 | Laser column planting method for CCGA high-lead welded column |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4758533A (en) * | 1987-09-22 | 1988-07-19 | Xmr Inc. | Laser planarization of nonrefractory metal during integrated circuit fabrication |
| CN1159077A (en) * | 1994-08-08 | 1997-09-10 | 惠普公司 | Method of bulging substrate by holding soldering paste stacking |
| TW387830B (en) * | 1998-09-04 | 2000-04-21 | Advanced Systems Automation Pt | Method of producing solder bumps on substrate |
| US6053397A (en) * | 1996-11-12 | 2000-04-25 | Hewlett-Packard Company | Method for the manufacture of micro solder bumps on copper pads |
-
2004
- 2004-07-22 CN CNB2004100530409A patent/CN1327501C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4758533A (en) * | 1987-09-22 | 1988-07-19 | Xmr Inc. | Laser planarization of nonrefractory metal during integrated circuit fabrication |
| CN1159077A (en) * | 1994-08-08 | 1997-09-10 | 惠普公司 | Method of bulging substrate by holding soldering paste stacking |
| US6053397A (en) * | 1996-11-12 | 2000-04-25 | Hewlett-Packard Company | Method for the manufacture of micro solder bumps on copper pads |
| TW387830B (en) * | 1998-09-04 | 2000-04-21 | Advanced Systems Automation Pt | Method of producing solder bumps on substrate |
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| CN1588634A (en) | 2005-03-02 |
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