Package Structure and Communications Device

Abstract

Embodiments of this application disclose a package structure and a communications device to which the package structure is applied. The package structure includes a substrate, a die, and a bonding layer configured to bond the die to the substrate. Charged particles are disposed in the bonding layer. An electrode is disposed on a surface of the die away from the bonding layer. A potential of the electrode is opposite to that of the charged particle. The package structure further includes a first shielding structure. A potential of the substrate is zero. The first shielding structure is located on an outer surface of the die and is located between the bonding layer and the electrode, to prevent the charged particles from migrating to the electrode.

Claims

1.-20. (canceled)

21. A package structure, comprising: a substrate; a die; a first shielding structure; and a bonding layer bonding the die to the substrate, wherein charged particles are disposed in the bonding layer, a first electrode is disposed on a surface of the die that faces away from the bonding layer, a potential of the first electrode is opposite to a potential of the charged particle, a potential of the substrate is zero, the first shielding structure is located on an outer surface of the die and is disposed between the bonding layer and the first electrode.

22. The package structure according to claim 21, wherein the charged particles are positive ions, the potential of the first electrode is negative, and the first shielding structure is connected to a zero potential in the package structure.

23. The package structure according to claim 22, wherein a first die grounding element is disposed on the surface of the die that faces away from the bonding layer, the first shielding structure comprises a leading wire electrically connected to the first die grounding element, and the leading wire and the first die grounding element in combination form a barrier strip between the bonding layer and the first electrode.

24. The package structure according to claim 23, further comprising a second electrode and a second die grounding element, the first electrode is disposed between the first die grounding element and the second die grounding element, and the leading wire is electrically connected between the first die grounding element and the second die grounding element.

25. The package structure according to claim 23, further comprising a second electrode and a second die grounding element, wherein the first electrode, the second electrode, the first die grounding element, and the second die grounding element are arranged in a same row, the first die grounding element and the second die grounding element are respectively distributed at a row head and a row end, the leading wire is electrically connected between the first die grounding element and the second die grounding element, and the first die grounding element, the leading wire, and the second die grounding element in combination enclose peripheries of the first electrode and the second electrode.

26. The package structure according to claim 23, wherein the surface of the die that faces away from the bonding layer comprises a gate region, a drain region, and an active region, the active region is disposed between the gate region and the drain region, the first electrode and the first die grounding element are distributed in the gate region, the first electrode is a gate electrode in the gate region configured to be used to input a radio frequency signal, a drain electrode is disposed in the drain region, and the drain electrode is configured to be used to output a radio frequency signal amplified by the active region.

27. The package structure according to claim 21, wherein the charged particles are positive ions, the potential of the first electrode is negative, and the first shielding structure is connected to a positive potential in the package structure.

28. The package structure according to claim 21, wherein the charged particles are positive ions, the potential of the first electrode is negative, the first shielding structure is connected to a negative potential in the package structure, and a potential of the negative potential is lower than the potential of the first electrode.

29. The package structure according to claim 21, wherein the charged particles are negative ions, the potential of the first electrode is positive, and the first shielding structure is connected to a zero potential in the package structure.

30. The package structure according to claim 21, wherein the charged particles are negative ions, the potential of the first electrode is positive, the first shielding structure is connected to a positive potential in the package structure, and a potential of the first shielding structure is higher than the potential of the first electrode.

31. The package structure according to claim 21, wherein the charged particles are negative ions, the potential of the first electrode is positive, and the first shielding structure is connected to a negative potential in the package structure.

32. The package structure according to claim 31, further comprising: a second shielding structure; and wherein the substrate comprises an upper surface and a lower surface, the die is bonded to the upper surface using the bonding layer, a pin is disposed on the substrate, the pin extends from the upper surface to the lower surface, the pin is electrically connected to the first electrode, and the second shielding structure is disposed on the upper surface and is disposed between the bonding layer and the pin.

33. The package structure according to claim 32, wherein the charged particles are positive ions, a potential of the pin is negative, and the second shielding structure is connected to a zero potential in the package structure.

34. The package structure according to claim 32, wherein the charged particles are positive ions, a potential of the pin is negative, and the second shielding structure is connected to a positive potential in the package structure.

35. The package structure according to claim 32, wherein the charged particles are positive ions, a potential of the pin is negative, the second shielding structure is connected to a negative potential in the package structure, and a potential of the negative potential is lower than the potential of the first electrode.

36. The package structure according to claim 32, wherein the charged particles are negative ions, a potential of the pin is positive, and the second shielding structure is connected to a zero potential in the package structure.

37. The package structure according to claim 32, wherein the charged particles are negative ions, a potential of the pin is positive, the second shielding structure is connected to a positive potential in the package structure, and a potential of the positive potential is higher than the potential of the first electrode.

38. The package structure according to claim 32, wherein the charged particles are negative ions, a potential of the pin is positive, and the second shielding structure is connected to a negative potential in the package structure.

39. The package structure according to claim 21, further comprising a passivation layer, wherein the passivation layer covers the first shielding structure.

40. A communications device, comprising: a radio frequency passive device; a radio frequency small signal device; and a package structure connected between the radio frequency small signal device and the radio frequency passive device, wherein the package structure comprises: a substrate; a die; a first shielding structure; and a bonding layer bonding the die to the substrate, wherein charged particles are disposed in the bonding layer, a first electrode is disposed on a surface of the die that faces away from the bonding layer, a potential of the first electrode is opposite to a potential of the charged particle, a potential of the substrate is zero, the first shielding structure is located on an outer surface of the die and is disposed between the bonding layer and the first electrode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To describe the technical solutions in embodiments of the present invention or in the conventional technology more clearly, the following briefly describes the accompanying drawings for describing the embodiments. Clearly, the accompanying drawings in the following descriptions show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

[0030] FIG. 1 is a schematic architectural diagram of a communications device according to an implementation of the present invention;

[0031] FIG. 2 is a schematic structural diagram of a package structure in the conventional technology;

[0032] FIG. 3 is a diagram of distribution of electric fields of the package structure in the conventional technology;

[0033] FIG. 4 is a schematic structural diagram of a package structure in an implementation of the present invention;

[0034] FIG. 5 is a diagram of distribution of electric fields of a package structure in an implementation of the present invention;

[0035] FIG. 6 is a diagram of distribution of a first shielding structure in an implementation of the present invention;

[0036] FIG. 7 is another diagram of distribution of a first shielding structure in an implementation of the present invention;

[0037] FIG. 8 is a schematic structural diagram of a package structure in an implementation of the present invention;

[0038] FIG. 9 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0039] FIG. 10 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0040] FIG. 11 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0041] FIG. 12 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0042] FIG. 13 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0043] FIG. 14 is a schematic diagram of a package structure in another implementation of the present invention;

[0044] FIG. 15 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0045] FIG. 16 is a diagram of distribution of a second shielding structure in another implementation of the present invention;

[0046] FIG. 17 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0047] FIG. 18 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0048] FIG. 19 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention;

[0049] FIG. 20 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention; and

[0050] FIG. 21 is a diagram of distribution of electric fields of a package structure in another implementation of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0051] The following describes the technical solutions in embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Clearly, the described embodiments are merely some rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] As shown in FIG. 1, a package structure provided in an embodiment of the present invention may be applied to a communications device. The communications device is a radio remote unit in a wireless communications base station. The radio remote unit (RRU) is generally divided into four big modules: a digital intermediate frequency module, a transceiver module, a power amplification module, and a filtering module. The digital intermediate frequency module is used for modulation and demodulation, digital up-down frequency conversion, A/D conversion, and the like for optical transmission. The transceiver module completes conversion from an intermediate frequency signal to a radio frequency signal. Then, the radio frequency signal is transmitted out by using an antenna port through the power amplification module and the filtering module.

[0053] The embodiments of the present invention relate to a package structure and a communications device having the package structure. The communications device is a radio remote unit in a wireless communications base station. The package structure is a power amplifier. A power amplifier located between a radio frequency small signal device and a radio frequency passive device in FIG. 1 to amplify a radio frequency signal includes the package structure provided in the present invention. Specifically, the power amplifier may be divided into a head amplifier, a driver amplifier, and a final stage power amplifier. The package structure in the embodiments of the present invention is applicable to any amplifier in the power amplifier, to resolve a problem of ion migration in the power amplifier.

[0054] In practice, to satisfy heat dissipation of the power amplifier, a bonding material is usually a sintered silver material. However, because silver ions have high water solubility, the sintered silver material easily migrates toward a negative voltage direction in a high-temperature, high-humidity, and electric field environment. A negative voltage exists in an actually used package structure. In a high-temperature and high-humidity environment, silver ions migrate under an effect of an electric field force. As a result, a pad of the power amplifier is short-circuited, affecting safety of a communications circuit.

[0055] As shown in FIG. 2 and FIG. 3, a package structure 100 includes a substrate 20, a die 30, and a bonding layer 40 configured to bond the die 30 to the substrate 20. There are positively charged silver ions 44 in the bonding layer 40. An electrode 34 is disposed on a surface 32 of the die 30 away from the bonding layer. A potential of the electrode 34 is opposite to that of the charged particle 42. Because the potential of the electrode 34 is negative, and a potential of the substrate 20 is zero, an electric field pointing from the substrate 20 to the electrode 34 (a direction is shown as A) is generated. The silver ions 44 generate movement (a direction of the movement is shown as B) under an effect of the electric field. Finally, a large quantity of silver ions 44 accumulate near the electrode 34. Consequently, the electrode 34 is damaged, and a safety hazard such as a short circuit is brought.

[0056] To avoid a short-circuit danger caused by ion migration in a package structure, the present invention provides a package structure with a shielding structure. As shown in FIG. 4, in an implementation, a package structure 100 includes a substrate 20, a die 30, and a bonding layer 40 configured to bond the die 30 to the substrate 20. The substrate 30, the bonding layer 40, and the die 30 are stacked from bottom to top. Charged particles 42 are disposed in the bonding layer 40, an electrode 34 is disposed on a surface 32 of the die 30 away from the bonding layer, and a potential of the electrode 34 is opposite to that of the charged particle 42. The package structure 100 further includes a first shielding structure 50, a potential of the substrate 20 is zero, and the first shielding structure 50 is distributed on an outer surface of the die 30 and is located between the bonding layer 40 and the electrode 34, to prevent the charged particles 42 from migrating to the electrode 34. In a specific implementation, based on settings of the potentials of the electrode 34 and the charged particles 42, the first shielding structure 50 makes a targeted selection of a positive potential, a negative potential, or a zero potential, to damage an electric field causing the charged particles 42 to move, and prevent migration and movement of the charged particles 42, thereby protecting the electrode 34 on the die 30, and ensuring reliability of the die.

[0057] GaN is usually selected as a material of the die 30. As a wide bandgap semiconductor, the GaN has a quite high breakdown electric field. It can be ensured that an active region of the die can have a sufficiently high power density, and a quite high power output in a high-temperature and high-voltage condition can still be ensured. In addition, the present invention is applicable to reliability guarantee of any die material, including but not limited to the GaN material.

[0058] As shown in FIG. 4, in an implementation, the charged particles 42 in the bonding layer 40 are positive ions, the potential of the electrode 34 on the surface of the die 30 away from the bonding layer 40 is negative, and in this case, the first shielding structure 50 selects to be connected to a structure whose potential is zero in the package structure 100. In an implementation, the structure whose potential is zero is a die grounding element 36 (not marked in FIG. 4) disposed on the surface of the die 30 away from the bonding layer 40. The first shielding structure 40 is connected to the die grounding element 36 by using a leading wire 52, so that the first shielding structure 50 and the die grounding element 36 enclose the electrode 34, and a new electric field (as shown in FIG. 5) is generated. In this case, the potentials of the substrate 20 and the first shielding structure 50 are both zero. Therefore, a direction of the electric field between the substrate 20 and the first shielding structure 50 is shown as A in FIG. 5. Electric field lines are equipotential lines. Therefore, the charged particles 42 in the bonding layer 40 do not move from the bonding layer 40 to the first shielding structure 50 under an effect of the electric field. The first shielding structure 50 and the die grounding element 36 together enclose the electrode 34. Therefore, no charged particle 42 can bypass the first shielding structure 40 to migrate from the bonding layer 40 to the electrode 34.

[0059] In an implementation, as shown in FIG. 6, there are two or more electrodes 34, there are a plurality of die grounding elements 36, the electrodes 34 are disposed between adjacent die grounding elements 36 at intervals, and the leading wire 52 is connected between two adjacent die grounding elements 36. To be specific, each electrode 34 is enclosed by the first shielding structure 50 and the die grounding elements 36.

[0060] In an implementation, as shown in FIG. 7, there are a plurality of electrodes 34, there are at least two die grounding elements 36, the electrodes 34 and the die grounding elements 36 are arranged in a same row, the die grounding elements 36 include a first element 362 and a second element 364 respectively distributed at a row head and a row end, the first element 362 is electrically connected to the second element 364 by using the leading wire 52, to form the first shielding structure 50. The first shielding structure 50 enclosing peripheries of all the electrodes 34 will change distribution of electric fields near the package structure 100, thereby suppressing migration of the charged particles 42.

[0061] In an implementation, as shown in FIG. 8, the surface of the die 30 away from the bonding layer 40 includes a gate region 322, a drain region 324, and an active region 326, the active region 326 is disposed between the gate region 322 and the drain region 324, the electrodes 34 and the die grounding elements 36 are distributed in the gate region 322, the electrodes 34 are gate electrodes 342 in the gate region 322 for inputting a radio frequency signal, a drain electrode 344 is disposed in the drain region 324, and the drain electrode 344 is used for outputting a radio frequency signal amplified by the active region 326.

[0062] In an implementation, the charged particles 42 are positive ions, the potential of the electrode 34 is negative, and the first shielding structure 50 is connected to a positive potential in the package structure 100. In this case, due to intervention of the first shielding structure 50, distribution of electric fields around the package structure 100 is shown in FIG. 9. Because the first shielding structure 50 is connected to the positive potential, distribution of electric fields between the first shielding structure 50 and the substrate 20 is shown as A: A direction of the electric field is from the first shielding structure 50 to the substrate 20. Under an effect of the electric field, positively charged particles 42 do not move from the bonding layer 40 to the first shielding structure 50. Therefore, the charged particles 42 do not migrate toward the electrode 34.

[0063] In an implementation, the charged particles 42 are positive ions, the potential of the electrode 34 is negative, the first shielding structure 50 is connected to a negative potential in the package structure 100, and a potential of the negative potential is lower than the potential of the electrode 34. In this case, due to intervention of the first shielding structure 50, distribution of electric fields around the package structure 100 is shown in FIG. 10. Because the first shielding structure 50 is connected to the negative potential, and the potential of the negative potential is lower than the potential of the electrode 34, distribution of electric fields between the first shielding structure 50 and the electrode 34 is shown as C: Although the charged particles 42 move from the bonding layer 40 to the first shielding structure 50 under an effect of the electric field, the electric field between the electrode 34 and the first shielding structure 50 suppresses movement of the charged particles 42 from the first shielding structure 50 to the electrode 34.

[0064] In an implementation, the charged particles 42 are negative ions, the potential of the electrode 34 is positive, and the first shielding structure 50 is connected to a zero potential in the package structure 100. In this case, due to intervention of the first shielding structure 50, distribution of electric fields around the package structure 100 is shown in FIG. 11. Because the first shielding structure 50 is connected to the zero potential, potentials of the first shielding structure 50 and the substrate 20 are equal, and electric field lines between the first shielding structure 50 and the substrate 20 are equipotential lines A, the negatively charged particles 42 do not move from the bonding layer 40 to the first shielding structure 50. Therefore, the charged particles 42 do not migrate toward the electrode 34.

[0065] In an implementation, the charged particles 42 are negative ions, the potential of the electrode 34 is positive, the first shielding structure 50 is connected to a positive potential in the package structure 100, and a potential of the positive potential is higher than the potential of the electrode 34. In this case, due to intervention of the first shielding structure 50, distribution of electric fields around the package structure 100 is shown in FIG. 12. Because the first shielding structure 50 is connected to the positive potential, and the potential of the positive potential is higher than the potential of the electrode 34, distribution of electric fields between the first shielding structure 50 and the electrode 34 is shown as C. The charged particles 42 move from the bonding layer 40 to the first shielding structure 50 under an effect of the electric field. However, the electric field between the first shielding structure 50 and the electrode 34 suppresses movement of negatively charged particles 42 from the first shielding structure 50 to the electrode 34.

[0066] In an implementation, the charged particles 42 are negative ions, the potential of the electrode 34 is positive, and the first shielding structure 50 is connected to a negative potential in the package structure 100. In this case, due to intervention of the first shielding structure 50, distribution of electric fields around the package structure 100 is shown in FIG. 13. Because the first shielding structure 50 is connected to the negative potential, a direction of the electric field between the first shielding structure 50 and the substrate 20 is shown as A. Under an effect of the electric field, negatively charged particles 42 move only from the bonding layer 40 to the substrate 20, and do not move toward the first shielding structure 50. Therefore, the charged particles 42 do not migrate toward the electrode 34.

[0067] In an implementation, as shown in FIG. 14, the substrate 20 includes an upper surface 22 and a lower surface 24, the die 30 is bonded to the upper surface 22 by using the bonding layer 40, a pin 26 is further disposed on the substrate 20, the pin 26 extends from the upper surface to the lower surface 24, the pin 26 is electrically connected to the electrode 34, the package structure 100 further includes a second shielding structure 60, and the second shielding structure 60 is disposed on the upper surface 22 and is located between the bonding layer 40 and the pin 26, to prevent the charged particles 42 from migrating to the pin 26. Because the pin 26 is electrically connected to the electrode 34, a potential of the pin 26 is the same as that of the electrode 34, and is opposite to that of the charged particle 42 in the bonding layer 40. Distribution of electric fields between the pin 26 and the bonding layer 40 is destroyed by disposing the second shielding structure 60 on the substrate, to prevent migration of the charged particles 42 toward the pin 26.

[0068] In an implementation, the charged particles 42 in the bonding layer 40 are positive ions, a potential of the pin 26 is negative, and the second shielding structure 60 is connected to a zero potential in the package structure 100. In an implementation, a substrate grounding element 28 is distributed on the upper surface 22 of the substrate 20, and the second shielding structure 60 is connected to the substrate grounding element 28 by using a connecting line 62. In this case, distribution of electric fields of the package structure 100 is shown in FIG. 15. The second shielding structure 60 is connected to the substrate grounding element 28 by using the connecting line 62. A potential of the second shielding structure 60 is zero. Therefore, potentials of the second shielding structure 60 and the substrate 20 are equal. Electric field lines between the second shielding structure 60 and the substrate 20 are shown as A, and are equipotential lines. The charged particles 42 do not move under an effect of the electric field. Therefore, the charged particles 42 do not migrate from the bonding layer 40 to the pin 26.

[0069] In an implementation, as shown in FIG. 16, there are a plurality of pins 26 in the package structure 100, there are at least two substrate grounding elements 28, the pins 26 and the substrate grounding elements 28 are arranged in a same row, the substrate grounding elements 28 include a head element 282 and an end element 284 respectively distributed at a row head and a row end, the connecting line 62 is electrically connected between the head element 282 and the end element 284, and the head element 282, the connecting line 62, and the end element 284 together enclose peripheries of all the pins 26.

[0070] In an implementation, the charged particles 42 in the bonding layer 40 are positive ions, a potential of the pin 26 is negative, and the second shielding structure 60 is connected to a positive potential in the package structure 100. In this case, due to intervention of the second shielding structure 60, distribution of electric fields around the package structure 100 is shown in FIG. 17. Because the second shielding structure 50 is connected to the positive potential, distribution of electric fields between the second shielding structure 50 and the substrate 20 is shown as A: A direction of the electric field is from the second shielding structure 50 to the substrate 20. Under an effect of the electric field, positively charged particles 42 do not move from the bonding layer 40 to the second shielding structure 50. Therefore, the charged particles 42 do not migrate toward the electrode 34.

[0071] In an implementation, the charged particles 42 are positive ions, a potential of the pin 26 is negative, the second shielding structure 60 is connected to a negative potential in the package structure 100, and a potential of the negative potential is lower than the potential of the pin 26. In this case, due to intervention of the second shielding structure 60, distribution of electric fields around the package structure 100 is shown in FIG. 18. Because the second shielding structure 60 is connected to the negative potential, and the potential of the negative potential is lower than the potential of the pin 26, distribution of electric fields between the second shielding structure 60 and the pin 26 is shown as C. The charged particles 42 move from the bonding layer 40 to the second package structure 60 under an effect of the electric field. However, the electric field between the pin 26 and the second shielding structure 60 suppresses movement of positively charged particles 42 from the second shielding structure 60 to the pin 26.

[0072] In an implementation, the charged particles 42 are negative ions, a potential of the pin 26 is positive, and the second shielding structure 60 is connected to a zero potential in the package structure 100. In this case, due to intervention of the second shielding structure 60, distribution of electric fields around the package structure 100 is shown in FIG. 19. Because the second shielding structure 60 is connected to the zero potential, potentials of the second shielding structure 60 and the substrate 20 are equal, and electric field lines between the second shielding structure 60 and the substrate 20 are equipotential lines A, the negatively charged particles 42 do not move from the bonding layer 40 to the second shielding structure 60. Therefore, the charged particles 42 do not migrate toward the electrode 34.

[0073] In an implementation, the charged particles 42 are negative ions, a potential of the pin 26 is positive, the second shielding structure 60 is connected to a positive potential in the package structure 100, and a potential of the positive potential is higher than the potential of the pin 26. In this case, due to intervention of the second shielding structure 60, distribution of electric fields around the package structure 100 is shown in FIG. 20. Because the second shielding structure 60 is connected to the positive potential, and the potential of the positive potential is higher than the potential of the pin 26, distribution of electric fields between the second shielding structure 60 and the pin 26 is shown as C. Due to existence of the electric field, the charged particles 42 move from the bonding layer 40 to the second shielding structure 60. However, the electric field between the second shielding structure 60 and the pin 26 suppresses movement of negatively charged particles 42 from the second shielding structure 60 to the pin 26.

[0074] In an implementation, the charged particles 42 are negative ions, a potential of the pin 26 is positive, and the second shielding structure 60 is connected to a negative potential in the package structure 100. In this case, due to intervention of the second shielding structure 60, distribution of electric fields around the package structure 100 is shown in FIG. 21. Because the second shielding structure 60 is connected to the negative potential, a direction of the electric field between the first shielding structure 50 and the substrate 20 is shown as A. Under an effect of the electric field, negatively charged particles 42 move from the bonding layer 40 to the second shielding structure 60. Therefore, the charged particles 42 do not migrate toward the electrode 34.

[0075] In an embodiment, to enhance a shielding effect of the first shielding structure 50, passivation may be performed on a surface of the first shielding structure 50, to form a passivation layer on the surface of the first shielding structure 50. To be specific, the package structure of this application includes a passivation layer, where the passivation layer covers the first shielding structure. Stability of a material of the first shielding structure can be ensured by covering the passivation layer on the surface of the first shielding structure.

[0076] The foregoing descriptions are merely specific implementations of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.